The third order LLCL filter is gaining more attractive in grid connected PV inverter in terms of material cost saving than LCL filter. Several active and passive damping techniques prevail in mitigating the resonance problem for maintaining the grid power quality standards. In this paper an improved passive damping is examined with reduction of power loss for the LLCL filter. Particularly, it reduces the switching ripple much better than LCL filter, with a decrease in volume of the inductance. The filter design is also developed for the operation of stiff grid. Mathematical operations and transfer function are derived with frequency response for the accuracy of the filter design. In addition, comparative analysis of passive and improved passive damping control is proposed. The control strategy is improved with feedback linearization in order to avoid the glitches in inverter control and is verified with prototype grid connected PV inverter.
Design and implementation of a series switching SPSI for PV cell to use in ca...journalBEEI
A carrier-based grid synchronous method is proposed to develop the system efficiency, phase and power quality of the inverter output waves. The operating principle of a single-phase phase synchronous inverter (SPSI) is introduced, with proper synchronous paid to the switching-frequency synchronizing voltage made by the interleaved process, as well as actual mitigation approaches. In the construction of the SPSI, input and output filters are electrically coupled with the two sides of an inverter. The inverter power electronic switches and other electrical components are operated by carrier-based grid synchronous controller (CBGSC) with PWM regulator. The SPSI is designed and implemented with the Toshiba 40WR21 IGBT, Digital Microcontroller pulse controller (DMPC) and 4N35 Optocoupler with a fundamental frequency of 50Hz. The other parameters are considered as load resistance, =11Ω, duty cycle, 85%, carrier frequency, 2.5kHz and input DC voltage, ± 340V. In addition, LCL lowpass grid filters are used to convert squire wave to sine wave with required phase and frequency. Finally, the simulated and experimental results obtained with a carrier-based grid synchronous SPSI experimental prototype are exposed for justification, showing the phase error of 55% improvement, reduced 11% of THD and the conversion efficiency of 97.02% highly predicted by the proposed design technique to improve the microgrid system.
This paper deals with controlling a grid-connected dual-active bridge multilevel inverter for renewable energy integration. The concept of direct power control is integrated with model predictive control algorithm, which is termed as predictive direct power control, to control the real and reactive power injected into the power grid. The proposed multilevel inverter allows more options of feasible voltage vectors for switching vector selections in order to generate multilevel outputs, and thereby obtaining high power quality in the power grid. By using the predictive direct power control, simulation results show that the proposed multilevel inverter produces lower power ripple and manage to achieve currents with low total harmonic distortion which are well within the IEEE standard. The modeling and simulation of the system are implemented and validated by MATLAB Simulink software.
Neuro-Fuzzy Five-level Cascaded Multilevel Inverter for Active Power FilterIDES Editor
This paper presents an investigation of five-Level
Cascaded H-bridge(CHB) inverter as Active Power Filter in
Power System (PS) for compensation of reactive power and
harmonics. The advantages of CHB inverter are low harmonic
distortion, reduced number of switches and suppression of
switching losses. The Active Power Filter helps to improve
the power factor and eliminate the Total Harmonics Distortion
(THD) drawn from a Non-Liner Diode Rectifier Load (NLDRL).
The D-Q reference frame theory is used to generate the
reference compensating currents for Active Power Filter
while Neuro-Fuzzy controller(NFC) is used for capacitor dc
voltage regulation. A CHB Inverter is considered for shunt
compensation of a 11 kV distribution system. Finally a level
shifted PWM (LSPWM) technique adopted to investigate the
performance of CHB Inverter. The results are obtained through
Mat lab / Simulink .
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Minimization of Overall Losses of a Distribution System under Contingency Con...paperpublications3
Abstract: In this paper, a methodology has been proposed to minimize the losses of distribution systems (technical and non-technical losses) that is an absolutely necessary objective in the sound management of any electrical utility. The transmission & distribution losses in Indian power system are high. Most of the efforts of power planners concentrate on augmenting supply by building new power plants. But saving is possible by improving operating conditions for the distribution network. Due to inadequate planning and methods adopted for load shifting, some networks are under loaded while others are overloaded. Thus there is some scope for improvement in operating strategies. Network reconfiguration in distribution system is realized by changing the status of the sectionalizing switches and is usually done for loss reduction and avoids overloading. In primary distribution system (11KV), the need for reconfiguration occurs in emergency condition following the fault to isolate faulted section and in normal condition to reduce system losses or to avoid overloading of network. The main objective of the paper is to outline a methodology for management of distribution system for loss reduction by network reconfiguration. The possible techniques used for power loss reduction, which are network reconfiguration and capacitor addition. Case studies were simulated on an interconnected ring main distribution network.
Design and implementation of a series switching SPSI for PV cell to use in ca...journalBEEI
A carrier-based grid synchronous method is proposed to develop the system efficiency, phase and power quality of the inverter output waves. The operating principle of a single-phase phase synchronous inverter (SPSI) is introduced, with proper synchronous paid to the switching-frequency synchronizing voltage made by the interleaved process, as well as actual mitigation approaches. In the construction of the SPSI, input and output filters are electrically coupled with the two sides of an inverter. The inverter power electronic switches and other electrical components are operated by carrier-based grid synchronous controller (CBGSC) with PWM regulator. The SPSI is designed and implemented with the Toshiba 40WR21 IGBT, Digital Microcontroller pulse controller (DMPC) and 4N35 Optocoupler with a fundamental frequency of 50Hz. The other parameters are considered as load resistance, =11Ω, duty cycle, 85%, carrier frequency, 2.5kHz and input DC voltage, ± 340V. In addition, LCL lowpass grid filters are used to convert squire wave to sine wave with required phase and frequency. Finally, the simulated and experimental results obtained with a carrier-based grid synchronous SPSI experimental prototype are exposed for justification, showing the phase error of 55% improvement, reduced 11% of THD and the conversion efficiency of 97.02% highly predicted by the proposed design technique to improve the microgrid system.
This paper deals with controlling a grid-connected dual-active bridge multilevel inverter for renewable energy integration. The concept of direct power control is integrated with model predictive control algorithm, which is termed as predictive direct power control, to control the real and reactive power injected into the power grid. The proposed multilevel inverter allows more options of feasible voltage vectors for switching vector selections in order to generate multilevel outputs, and thereby obtaining high power quality in the power grid. By using the predictive direct power control, simulation results show that the proposed multilevel inverter produces lower power ripple and manage to achieve currents with low total harmonic distortion which are well within the IEEE standard. The modeling and simulation of the system are implemented and validated by MATLAB Simulink software.
Neuro-Fuzzy Five-level Cascaded Multilevel Inverter for Active Power FilterIDES Editor
This paper presents an investigation of five-Level
Cascaded H-bridge(CHB) inverter as Active Power Filter in
Power System (PS) for compensation of reactive power and
harmonics. The advantages of CHB inverter are low harmonic
distortion, reduced number of switches and suppression of
switching losses. The Active Power Filter helps to improve
the power factor and eliminate the Total Harmonics Distortion
(THD) drawn from a Non-Liner Diode Rectifier Load (NLDRL).
The D-Q reference frame theory is used to generate the
reference compensating currents for Active Power Filter
while Neuro-Fuzzy controller(NFC) is used for capacitor dc
voltage regulation. A CHB Inverter is considered for shunt
compensation of a 11 kV distribution system. Finally a level
shifted PWM (LSPWM) technique adopted to investigate the
performance of CHB Inverter. The results are obtained through
Mat lab / Simulink .
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Minimization of Overall Losses of a Distribution System under Contingency Con...paperpublications3
Abstract: In this paper, a methodology has been proposed to minimize the losses of distribution systems (technical and non-technical losses) that is an absolutely necessary objective in the sound management of any electrical utility. The transmission & distribution losses in Indian power system are high. Most of the efforts of power planners concentrate on augmenting supply by building new power plants. But saving is possible by improving operating conditions for the distribution network. Due to inadequate planning and methods adopted for load shifting, some networks are under loaded while others are overloaded. Thus there is some scope for improvement in operating strategies. Network reconfiguration in distribution system is realized by changing the status of the sectionalizing switches and is usually done for loss reduction and avoids overloading. In primary distribution system (11KV), the need for reconfiguration occurs in emergency condition following the fault to isolate faulted section and in normal condition to reduce system losses or to avoid overloading of network. The main objective of the paper is to outline a methodology for management of distribution system for loss reduction by network reconfiguration. The possible techniques used for power loss reduction, which are network reconfiguration and capacitor addition. Case studies were simulated on an interconnected ring main distribution network.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
A 10 d bm 25 dbm, 0.363 mm2 two stage 130 nm rf cmos power amplifierVLSICS Design
This paper proposes a 2.4 GHz RF CMOS Power amplifi
er and variation in its main performance
parameters i.e, output power, S-parameters and powe
r added efficiency with respect to change in supply
voltage and size of the power stage transistor. The
supply voltage was varied form 1 V to 5 V and the
range
of output power at 1dB compression point was found
to be from 10.684 dBm to 25.08 dBm respectively.
The range of PAE is 16.65 % to 48.46 %. The width o
f the power stage transistor was varied from 150 μm
to 500 μm to achieve output power of range 15.47 dB
m to 20.338 dBm. The range of PAE obtained here is
29.085 % to 45.439 %. The total dimension of the la
yout comes out to be 0.714 * 0.508 mm
2
.
This paper relates the new topology and simulations of a fully differential CMOS active filter for mm wave band applications. The advantages of the differential topology over the single ended one are discussed and the quality factor is tuned to insure application requirements, including narrow bandwidth and high selectivity due to a differential negative resistance that reuses the filter’s current. Using this topology enables independent tuning of the quality factor and low power consumption while compensating the resistive loss of the filter. Very high filter performance was obtained with the simulated active inductor based active filter that was designed using CMOS 0.35 µm technology from AMS foundry and that resonates at 30 GHz with a high quality factor of Q > 500.
Application of PI controller based active filter for harmonic mitigation of g...journalBEEI
The recent trends show the interconnection of PV system with electric grid. With this configuration the issue of harmonics comes into existence. The mounting figure of power-electronic instruments has formed considerable impression on the power-quality of electric supply. Harmonics deformations have conventionally been handled amid the application of passive-LC filters. Active Filter has emerged as a good substitute for passive filters to reduce the harmonics to great extent as it has numerous benefits over the former filters. The active filter’s most vital part is the applied control strategies. Several researches are being under process to advance the functioning of the filter. One of the important control requirements of filter is the regulation of DC link up capacitor voltage. Here the voltage supervision of capacitor is being done using PI controller. The paper show current harmonics compensation of PV grid connected system using PI controller based active filter. Simulation outcomes have been shown which displays the harmonics are within the IEEE boundaries.
Hysteresis SVM for Coupled Inductor Z Source Diode Clamped 3-Level Inverter B...IAES-IJPEDS
Due to its advantages such as it can defeat problems such as leakage current
and insertion of DC in the grid and provides low stress on power devices,
Diode-clamped three-level inverter (DCTLI) is habitually used in
transformerless photovoltaic (PV) connected to grid network. But it still has
a problem of shoot-through which dwells in its legs, so its operation not
reliable. Z source network is employed to permit operation without shoot
through risk and improve its reliability. Coupled inductors are replaced the
line transformers in to attain lower cost, reduced size, and improved its
reliability and efficiency. Coupled inductor which avoids leakage current
problem and losses. It employs coupled inductor z source diode clamped
three level inverter (CI-Z-DC-TLI) to boost the voltage and further progress
the consistency of the proposed system by avoiding the shoot through the
problem. The proposed system assures that common-mode voltage
and shoot-through risk is avoided. Moreover, controlling DC-TLI with
Hysteresis SVM algorithm which improves output voltage and current
control. Simulation and experimental results of this proposed system were
analyzed using MATLAB environment and FPGA hardware.
Qualitative Analysis of Darlington Feedback Amplifier at 45nm TechnologyjournalBEEI
The transistors are the key element of present communication system having high data rate. Some applications need high gain by using very low frequency, and then transistors are used. Amplifier is the key element in many applications of present high data rate communication system such as low noise amplifier (LNA), broadband amplifier, distributed and power amplifier. The Darlington pair amplifier is analyzed for high frequency performance and related effect of bandwidth. Broadband feedback Darlington pair amplifier is designed with enhanced gain, bandwidth and slew rate. This paper presents the comparison of single stage and three stage feedback Darlington feedback amplifier with reference to gain, bandwidth and slew rate. This paper is simulated on cadence analog design environment at GPDK 45nm technology. This paper shows that increase in gain, bandwidth and slew rate of three stage Darlington feedback amplifier can show better stability over the single stage Darlington feedback amplifier.
Design of 10 to 12 GHz Low Noise Amplifier for Ultrawideband (UWB) SystemIJECEIAES
Balanced amplifier is the structure proposed in this article, it provides better performance. In fact, the single amplifier meets the specification for noise figure and gain but fails to meet the return loss specification due to the large mis-matches on the input & outputs. To overcome this problem one solution is to use balanced amplifier topography. In this paper, a wide-band and highgain microwave balanced amplifier constituted with branch line coupler circuit is proposed. The amplifier is unconditionally stable in the band [9-13] GHz where the gain is about 20dB. The input reflection (S11) and output return loss (S22) at 11 GHz are -33.4dB and -33.5dB respectively.
A CONTROL APPROACH FOR GRID INTERFACING INVERTER IN 3 PHASE 4 WIRE DISTRIBUT...IJMER
With the increase in load demand, the Renewable Energy Sources (RES) are
increasingly connected in the distribution systems which utilizes power electronic
Converters/Inverters. Nowadays, 3-phase 4-wire distribution power system has been widely used in
residential and office buildings, manufacturing facilities, schools etc This paper presents a novel
control strategy for achieving maximum benefits from the grid-interfacing inverters when installed in
3-phase 4-wire distribution systems. The inverter can thus be utilized as: 1) power converter to inject
power to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics and
load neutral current. All of these functions may be accomplished either individually or
simultaneously. This new control concept is demonstrated with extensive MATLAB/Simulink
simulation studies
Impact of Positive Sequence Admittance and Negative Sequence Conductance of D...ijtsrd
Voltage fluctuations resulting from variable output power of renewable energy sources are strictly challenging power quality in distributed-generation systems. This paper presents a control method for distributed static synchronous compensator (D-STATCOM) to alleviate variation of both positive- and negative-sequence voltages. The D-STATCOM simultaneously operates as fundamental positive-sequence admittance and fundamental negative-sequence conductance to restore the positive sequence voltage to the nominal value as well as reduce the negative-sequence voltage to an allowable level. Both admittance and conductance are dynamically tuned to improve voltage regulation performances in response to load changes and power variation of renewable sources. A proportional“resonant current regulator with selectively harmonic compensation is realized to control the fundamental current of the D-STATCOM as well as reduce the harmonic current, which could be an advantage in practical applications due to high voltage distortion in low-voltage micro grids. Voltage-regulation performances are discussed for different D-STATCOM locations as well as different D-STATCOM currents. Computer simulations and laboratory tests validate effectiveness. CH. Venkata Krishna | N. S. Kalyan Chakravarthi"Impact of Positive Sequence Admittance and Negative Sequence Conductance of D-Statcom to Compensate Variations in Voltage Levels in Distributed Generation Systems" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-1 , December 2017, URL: http://www.ijtsrd.com/papers/ijtsrd5919.pdf http://www.ijtsrd.com/engineering/electrical-engineering/5919/impact-of-positive-sequence-admittance-and-negative-sequence-conductance-of-d-statcom-to-compensate-variations-in-voltage-levels-in-distributed-generation-systems/ch-venkata-krishna
Power Quality Improvement of Grid Interconnection of renewable Energy Based D...IJERA Editor
This paper presents a grid interfacing inverter which compensates power quality problems and also interface Renewable Energy Sources with the help of electric grid. Renewable Energy Sources are being increasingly connected in distribution system utilizing power electronic converters. Grid interfacing inverter can be used: 1) To improve the transfer of active power harvested from RES; 2) To meet load reactive power demand support ; 3) To reduce current harmonics by incorporating the current harmonic compensator at point of common coupling(PCC) ; 4) current unbalance and neutral current compensation in case of 3-phase 4-wire system. The fuzzy logic can be used in many applications especially, when the process/models are complex to analyse by using classical methods. Mainly fuzzy logic controller is used to control DC capacitor voltage. Simulations are carried out using MATLAB/SIMULINK to verify the performance of the controller. The output shows the controller has fast dynamic response high accuracy of tracking DC voltage reference and robust to load parameters variations.
LCL Filter for Grid Connected VSC Converter
Comprehensive analysis and modeling of the three-phase LCL filter for VSC converters, suitable for wind energy or photovoltaic applications.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
A 10 d bm 25 dbm, 0.363 mm2 two stage 130 nm rf cmos power amplifierVLSICS Design
This paper proposes a 2.4 GHz RF CMOS Power amplifi
er and variation in its main performance
parameters i.e, output power, S-parameters and powe
r added efficiency with respect to change in supply
voltage and size of the power stage transistor. The
supply voltage was varied form 1 V to 5 V and the
range
of output power at 1dB compression point was found
to be from 10.684 dBm to 25.08 dBm respectively.
The range of PAE is 16.65 % to 48.46 %. The width o
f the power stage transistor was varied from 150 μm
to 500 μm to achieve output power of range 15.47 dB
m to 20.338 dBm. The range of PAE obtained here is
29.085 % to 45.439 %. The total dimension of the la
yout comes out to be 0.714 * 0.508 mm
2
.
This paper relates the new topology and simulations of a fully differential CMOS active filter for mm wave band applications. The advantages of the differential topology over the single ended one are discussed and the quality factor is tuned to insure application requirements, including narrow bandwidth and high selectivity due to a differential negative resistance that reuses the filter’s current. Using this topology enables independent tuning of the quality factor and low power consumption while compensating the resistive loss of the filter. Very high filter performance was obtained with the simulated active inductor based active filter that was designed using CMOS 0.35 µm technology from AMS foundry and that resonates at 30 GHz with a high quality factor of Q > 500.
Application of PI controller based active filter for harmonic mitigation of g...journalBEEI
The recent trends show the interconnection of PV system with electric grid. With this configuration the issue of harmonics comes into existence. The mounting figure of power-electronic instruments has formed considerable impression on the power-quality of electric supply. Harmonics deformations have conventionally been handled amid the application of passive-LC filters. Active Filter has emerged as a good substitute for passive filters to reduce the harmonics to great extent as it has numerous benefits over the former filters. The active filter’s most vital part is the applied control strategies. Several researches are being under process to advance the functioning of the filter. One of the important control requirements of filter is the regulation of DC link up capacitor voltage. Here the voltage supervision of capacitor is being done using PI controller. The paper show current harmonics compensation of PV grid connected system using PI controller based active filter. Simulation outcomes have been shown which displays the harmonics are within the IEEE boundaries.
Hysteresis SVM for Coupled Inductor Z Source Diode Clamped 3-Level Inverter B...IAES-IJPEDS
Due to its advantages such as it can defeat problems such as leakage current
and insertion of DC in the grid and provides low stress on power devices,
Diode-clamped three-level inverter (DCTLI) is habitually used in
transformerless photovoltaic (PV) connected to grid network. But it still has
a problem of shoot-through which dwells in its legs, so its operation not
reliable. Z source network is employed to permit operation without shoot
through risk and improve its reliability. Coupled inductors are replaced the
line transformers in to attain lower cost, reduced size, and improved its
reliability and efficiency. Coupled inductor which avoids leakage current
problem and losses. It employs coupled inductor z source diode clamped
three level inverter (CI-Z-DC-TLI) to boost the voltage and further progress
the consistency of the proposed system by avoiding the shoot through the
problem. The proposed system assures that common-mode voltage
and shoot-through risk is avoided. Moreover, controlling DC-TLI with
Hysteresis SVM algorithm which improves output voltage and current
control. Simulation and experimental results of this proposed system were
analyzed using MATLAB environment and FPGA hardware.
Qualitative Analysis of Darlington Feedback Amplifier at 45nm TechnologyjournalBEEI
The transistors are the key element of present communication system having high data rate. Some applications need high gain by using very low frequency, and then transistors are used. Amplifier is the key element in many applications of present high data rate communication system such as low noise amplifier (LNA), broadband amplifier, distributed and power amplifier. The Darlington pair amplifier is analyzed for high frequency performance and related effect of bandwidth. Broadband feedback Darlington pair amplifier is designed with enhanced gain, bandwidth and slew rate. This paper presents the comparison of single stage and three stage feedback Darlington feedback amplifier with reference to gain, bandwidth and slew rate. This paper is simulated on cadence analog design environment at GPDK 45nm technology. This paper shows that increase in gain, bandwidth and slew rate of three stage Darlington feedback amplifier can show better stability over the single stage Darlington feedback amplifier.
Design of 10 to 12 GHz Low Noise Amplifier for Ultrawideband (UWB) SystemIJECEIAES
Balanced amplifier is the structure proposed in this article, it provides better performance. In fact, the single amplifier meets the specification for noise figure and gain but fails to meet the return loss specification due to the large mis-matches on the input & outputs. To overcome this problem one solution is to use balanced amplifier topography. In this paper, a wide-band and highgain microwave balanced amplifier constituted with branch line coupler circuit is proposed. The amplifier is unconditionally stable in the band [9-13] GHz where the gain is about 20dB. The input reflection (S11) and output return loss (S22) at 11 GHz are -33.4dB and -33.5dB respectively.
A CONTROL APPROACH FOR GRID INTERFACING INVERTER IN 3 PHASE 4 WIRE DISTRIBUT...IJMER
With the increase in load demand, the Renewable Energy Sources (RES) are
increasingly connected in the distribution systems which utilizes power electronic
Converters/Inverters. Nowadays, 3-phase 4-wire distribution power system has been widely used in
residential and office buildings, manufacturing facilities, schools etc This paper presents a novel
control strategy for achieving maximum benefits from the grid-interfacing inverters when installed in
3-phase 4-wire distribution systems. The inverter can thus be utilized as: 1) power converter to inject
power to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics and
load neutral current. All of these functions may be accomplished either individually or
simultaneously. This new control concept is demonstrated with extensive MATLAB/Simulink
simulation studies
Impact of Positive Sequence Admittance and Negative Sequence Conductance of D...ijtsrd
Voltage fluctuations resulting from variable output power of renewable energy sources are strictly challenging power quality in distributed-generation systems. This paper presents a control method for distributed static synchronous compensator (D-STATCOM) to alleviate variation of both positive- and negative-sequence voltages. The D-STATCOM simultaneously operates as fundamental positive-sequence admittance and fundamental negative-sequence conductance to restore the positive sequence voltage to the nominal value as well as reduce the negative-sequence voltage to an allowable level. Both admittance and conductance are dynamically tuned to improve voltage regulation performances in response to load changes and power variation of renewable sources. A proportional“resonant current regulator with selectively harmonic compensation is realized to control the fundamental current of the D-STATCOM as well as reduce the harmonic current, which could be an advantage in practical applications due to high voltage distortion in low-voltage micro grids. Voltage-regulation performances are discussed for different D-STATCOM locations as well as different D-STATCOM currents. Computer simulations and laboratory tests validate effectiveness. CH. Venkata Krishna | N. S. Kalyan Chakravarthi"Impact of Positive Sequence Admittance and Negative Sequence Conductance of D-Statcom to Compensate Variations in Voltage Levels in Distributed Generation Systems" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-1 , December 2017, URL: http://www.ijtsrd.com/papers/ijtsrd5919.pdf http://www.ijtsrd.com/engineering/electrical-engineering/5919/impact-of-positive-sequence-admittance-and-negative-sequence-conductance-of-d-statcom-to-compensate-variations-in-voltage-levels-in-distributed-generation-systems/ch-venkata-krishna
Power Quality Improvement of Grid Interconnection of renewable Energy Based D...IJERA Editor
This paper presents a grid interfacing inverter which compensates power quality problems and also interface Renewable Energy Sources with the help of electric grid. Renewable Energy Sources are being increasingly connected in distribution system utilizing power electronic converters. Grid interfacing inverter can be used: 1) To improve the transfer of active power harvested from RES; 2) To meet load reactive power demand support ; 3) To reduce current harmonics by incorporating the current harmonic compensator at point of common coupling(PCC) ; 4) current unbalance and neutral current compensation in case of 3-phase 4-wire system. The fuzzy logic can be used in many applications especially, when the process/models are complex to analyse by using classical methods. Mainly fuzzy logic controller is used to control DC capacitor voltage. Simulations are carried out using MATLAB/SIMULINK to verify the performance of the controller. The output shows the controller has fast dynamic response high accuracy of tracking DC voltage reference and robust to load parameters variations.
LCL Filter for Grid Connected VSC Converter
Comprehensive analysis and modeling of the three-phase LCL filter for VSC converters, suitable for wind energy or photovoltaic applications.
Power Quality Improvement using Passive shunt filters, TCR and TSC combinationIJERA Editor
In this thesis Power Quality Improvement is examined using Passive shunt filter, TCR and TSC combination. Today’s electric power systems are connected to many non-linear loads. The characteristics of these non-linear loads inevitably change the sinusoidal nature of the a.c. power current, resulting in the flow of harmonic current in the a.c. power system. Use of shunt passive filters in the reduction of harmonics offers the advantages of more simplicity, high reliability, high efficiency and low cost. The uncontrolled ac-dc converter suffers from operating problems of poor power factor, injection of harmonics into the ac mains, variations in dc link voltage of input ac supply, equipment overheating due to harmonic current absorption, voltage distortion due to the voltage drop caused by harmonic currents flowing through system impedances etc.The combinations of passive filters with TCR and TSC are designed and analyzed to improve the power quality at ac mains. This scheme has resulted in improved power quality with overall reduced rating of passive components used in front end ac-dc converters with R-L load.
This paper presents an h-infinity robust loop shaping control and LCL filter to mitigate the effects of harmonic currents in the photovoltaic system integrated with the grid. To eliminate the negative effects of the LCL filter, this work applied notch filter active damping. Existing methods for the elimination of harmonic currents were reviewed. Proportional integral control, fuzzy logic control, h-infinity control, and robust loop shaping control are presented. The grid current was analyzed in the system with all controllers applied to control the voltage source inverter of the system to eliminate harmonics in the grid current caused by the inverter and nonlinear loads for two cases, one being constant loading of the linear and nonlinear load and another is the switching of the nonlinear load during the simulation. The results obtained from the proposed method for the two tests conducted were compared with those from other methods to prove the robustness of the proposed technique. The method manages to reduce the total harmonic distortion of the grid current from 7.85% to 0.79% for case 1 and from 11.67% to 1.14% for case 2.
PV Cell Fed High Step-up DC-DC Converter for PMSM Drive ApplicationsIJMTST Journal
In this concept novel high step-up dc–dc converter with an active coupled-inductor network is presented for
a sustainable energy system. The proposed converter contains two coupled inductors which can be
integrated into one magnetic core and two switches. The primary sides of coupled inductors are charged in
parallel by the input source, and both the coupled inductors are discharged in series with the input source to
achieve the high step-up voltage gain with appropriate duty ratio, respectively. In addition, the passive
lossless clamped circuit not only recycles leakage energies of the coupled inductor to improve efficiency but
also alleviates large voltage spike to limit the voltage stresses of the main switches. The reverse-recovery
problem of the output diode is also alleviated by the leakage inductor and the lower part count is needed;
therefore, the power conversion efficiency can be further upgraded. The voltage conversion ratios, the effect of
the leakage inductance and the parasitic parameters on the voltage gain are discussed. The voltage stress
and current stress on the power devices are illustrated and the comparisons between the proposed converter
and other converters are given. The simulation results are presented by using Mat lab/Simulink software.
This paper deals with the design of filters and THD analysis of a low - frequency ac (20Hz) transmission system. The LFAC system is interfaced with the 50Hz main power grid with a cycloconverter. The wind power is collected in dc form,and is connected to the L FAC transmission line with a twelve pulse inverter. The waveforms at the sending end and receiving end of the transmission line are plotted.THD analysis of LFAC system is carried out. The circuit model of LFAC system is simulated in MATLAB/SIMULINK.
The negative impacts or side effects of a damper circuit insertion in an LCL passive filter utilized to filter DC/AC inverters output voltage is presented in this paper. For comparative study, this paper discusses two damping configurations, namely series and parallel damping, as well as the LCL filter without damping element. Four criteria are used to explore the impacts of the damper circuits, i.e. their total harmonic distortions (THDs), the output voltage amplitude, the output power and the power efficiency. Theoretically and emphirically shown by previous studies, the damper can indeed reduce the peak resonance frequency of the filter in its frequency response curve. However, in any circumstance, it can potentially reduce the inverters power and efficiency, voltage output amplitude, and cannot improve its THD reduction. The analysis results have shown that the side effects depends also on the load conditions, which are different for each damping circuit configuration.
Recently, LCL has become amongst the most attractive filter used for grid-connected flyback inverters. Nonetheless, the switching of power devices in the inverter configuration creates harmonics that affect the end application behavior and might shorten its lifetime. Furthermore, the resonance frequencies produced by the LCL network contribute to the system instability. This paper proposes a step-by-step guide to designing an LCL filter by considering several key aspects such as the resonance frequency and maximum current ripple. A single-phase grid-connected flyback microinverter with an LCL filter was designed then constructed in the MATLAB/Simulink environment. Several different parameter variations and damping solutions were used to analyze the performance of the circuit. The simulation result shows a promising total harmonic distortion (THD) value below 5% and harmonic suppression up to 14%.
Harmonic enhancement in microgrid with applications on sensitive loadsIJECEIAES
Power quality issues are an important and growing problem in microgrid. There are two reasons; the more active consumer is participating in the power sector, the use of renewable energy which having a great impact on voltage variation. This paper discusses power quality disturbance and especially harmonic distortion issues in microgrid, and suggests a solution to maintain the operation of the distribution system within power quality standard. To protect sensitive loads from harmonics produced by the grid and by renewable energy sources, passive harmonic filter has been proposed in this paper. The electrical system of a nuclear research reactor as sensitive loads is designed by using Electrical Transient Analyzer Program (ETAP) software. The results show these technical issues are presented with their influence on electrical voltage and harmonic specter.
Adiabatic describe the thermodynamic processes in which there is no energy exchange with the environment, and therefore very less dissipated energy loss. These circuits are low power circuits which use reversible logic to conserve energy. Adiabatic logic works with the concept of switching activities which reduces the power by giving stored energy back to the supply. The main design changes are focused on power clock which plays the vital role in the principle of operation. This has been used because many adiabaticcircuits use a combined power supply and clock, or a power clock (Four Phase).To achieve this, the power supply of adiabatic logic circuits have used time varying voltage charging signal, in contrast to traditional non-adiabatic systems that have generally used constant voltage charging from a fixed-voltage power supply. Thereby the circuit topology and operation of the circuit has been changed so that the source current of CMOS transistor change its direction and goes back to the supply(Recovery) when the power clock falls from VDD to zero. Power efficient blocks can be designed by using adiabatic logic which can be used in combinational and sequential circuits. The simulation of the designs is done using a backend tool called MENTOR GRAPHICS in 130nm technology
A miniature tunable quadrature shadow oscillator with orthogonal control IJECEIAES
This article presents a new design of a quadrature shadow oscillator. The oscillator is realized using one input and two outputs of a second-order filter cell together with external amplifiers in a feedback configuration. The oscillation characteristics are controlled via the external gain without disturbing the internal filter cell, following the concept of the shadow oscillator. The proposed circuit configuration is simple with a small component-count. It consists of, two voltage-different transconductance amplifiers (VDTAs) along with a couple of passive elements. The frequency of oscillation (FO) and the condition of oscillation (CO) are controlled orthogonally via the dc bias current and external gain. Moreover, with the addition of the external gain, the frequency range of oscillation can be further extended. The proposed work is verified by computer simulation with the use of 180 nm complementary metal–oxide–semiconductor (CMOS) model parameters. The simulation gives satisfactory results of two sinusoidal output signals in quadrature with some small total harmonic distortions (THD). In addition, a circuit experiment is performed using the commercial operational transconductance amplifiers LM13700 as the active components. The circuit experiment also demonstrates satisfactory outcome which confirms the validity of the proposed circuit.
Low frequency ac transmission for power systems by Aamir SaleemAamir Saleem
Voltage instability is one of the major issue in
HVAC power network operating at 50 Hz frequency due to
limited power transfer capability and distance limit. The stable
operation of power system must be kept within limits to
increase the efficiency of power transmission system. In this
research Low Frequency AC (LFAC) transmission system has
been proposed as a new power transmission technology to
reduce the losses of transmission network and controlling the
reactive power using Flexible AC transmission device. A
LFAC Transmission lines operates at 16.7Hz frequency for
transmission of power from source to load and use two
Frequency converters at source and load side. The normal
operation of power system depends on the reactive power
flowing through the power transmission lines, which can be
adjusted by a flexible AC transmission device; Static
synchronous compensator. LFAC transmission lines with
STATCOM controller improve the Power system voltage
stability under various disturbances and enhance the power
transmission capability as compare to HVAC transmission.
The simulations are done in Matlab Simulink 2017a .The
Output of Matlab Simulink model shows that voltage will
become Stable and reactive power is compensated for best
performance for power system.
Implementation Of Thyristor Controlled Series Capacitor (TCSC) In Transmissio...IJERA Editor
A grid of transmission lines operating at high or extra high voltages is required to transmit power from
generating stations to load. In addition to transmission lines that carry power from source to load, modern power
systems are highly interconnected for economic reasons. The large interconnected transmission networks are
prone to faults due to the lightning discharges and reduce insulation strength. Changing of loads and atmosphere
conditions are unpredictable factors. This may cause overloading of lines due to which voltage collapse takes
place. These problems can be eased by providing sufficient margin of working parameters and power transfer,
but it is not possible due to expansion of transmission network. Still the required margin is reduced by
introduction of fast dynamic control over reactive and active power by high power electronic controllers. This
paper describes about implementation of Thyristor Controlled Series Capacitor (TCSC) in transmission line
model in order to enhance power flow at the receiving end. The triggering pulses to the thyristor are given using
Arduino.
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Advanced Active Filter AAF with Reduced DC Link Voltageijtsrd
In recent years voltage and current harmonics are become serious problem in transmission and distribution system. To eliminate these voltage and current harmonics and to achieve clean grids, AAF are been used. The existing AAF technology requires a higher dc link voltage to achieve the THD requirement therefore this paper presents an Advanced Active Filter AAF for IGBT and LCL network in order to maintain voltage balance among dc link. This method is well capable of balancing charging and discharging of dc link voltage without increasing circuit complexity. This modulation technique is very effective in terms of voltage balancing as well as for maintaining voltage output THD at low level. The proposed system is implemented in Simulink platform of MATLAB software and performance shows its effectiveness over conventional IGBT used for inverter Tamil Selvan P | Vinothkumar K | Sugumar V ""Advanced Active Filter (AAF) with Reduced DC Link Voltage"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd21764.pdf
Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/21764/advanced-active-filter-aaf-with-reduced-dc-link-voltage/tamil-selvan-p
TCSC AND SVC OPTIMAL LOCATION TO IMPROVE THE PERFORMANCE OF POWER SYSTEM WITH...eeiej_journal
Wind generation connection to power system affects steady state and transient stability. Furthermore, this
effect increases with the increase of wind penetration in generation capacity. In this paper optimal location
of FACTS devices is carried out to solve the steady state problems of wind penetration. Two case studies
are carried out on modified IEEE39 bus system one with wind reduction to 20% and the second with wind
penetration increase by 50% in the two cases system suffer from outage of one generator with load at bus
39 decreases from 1104 MW to 900 MW.
Similar to Design of Optimal LLCL Filter with an Improved Control Strategy for Single Phase Grid Connected PV Inverter (20)
The aim of this research is the speed tracking of the permanent magnet synchronous motor (PMSM) using an intelligent Neural-Network based adapative backstepping control. First, the model of PMSM in the Park synchronous frame is derived. Then, the PMSM speed regulation is investigated using the classical method utilizing the field oriented control theory. Thereafter, a robust nonlinear controller employing an adaptive backstepping strategy is investigated in order to achieve a good performance tracking objective under motor parameters changing and external load torque application. In the final step, a neural network estimator is integrated with the adaptive controller to estimate the motor parameters values and the load disturbance value for enhancing the effectiveness of the adaptive backstepping controller. The robsutness of the presented control algorithm is demonstrated using simulation tests. The obtained results clearly demonstrate that the presented NN-adaptive control algorithm can provide good trackingperformances for the speed trackingin the presence of motor parameter variation and load application.
This paper presents a fast and accurate fault detection, classification and direction discrimination algorithm of transmission lines using one-dimensional convolutional neural networks (1D-CNNs) that have ingrained adaptive model to avoid the feature extraction difficulties and fault classification into one learning algorithm. A proposed algorithm is directly usable with raw data and this deletes the need of a discrete feature extraction method resulting in more effective protective system. The proposed approach based on the three-phase voltages and currents signals of one end at the relay location in the transmission line system are taken as input to the proposed 1D-CNN algorithm. A 132kV power transmission line is simulated by Matlab simulink to prepare the training and testing data for the proposed 1D- CNN algorithm. The testing accuracy of the proposed algorithm is compared with other two conventional methods which are neural network and fuzzy neural network. The results of test explain that the new proposed detection system is efficient and fast for classifying and direction discrimination of fault in transmission line with high accuracy as compared with other conventional methods under various conditions of faults.
Among the most widespread renewable energy sources is solar energy; Solar panels offer a green, clean, and environmentally friendly source of energy. In the presence of several advantages of the use of photovoltaic systems, the random operation of the photovoltaic generator presents a great challenge, in the presence of a critical load. Among the most used solutions to overcome this problem is the combination of solar panels with generators or with the public grid or both. In this paper, an energy management strategy is proposed with a safety aspect by using artificial neural networks (ANNs), in order to ensure a continuous supply of electricity to consumers with a maximum solicitation of renewable energy.
In this paper, the artificial neural network (ANN) has been utilized for rotating machinery faults detection and classification. First, experiments were performed to measure the lateral vibration signals of laboratory test rigs for rotor-disk-blade when the blades are defective. A rotor-disk-blade system with 6 regular blades and 5 blades with various defects was constructed. Second, the ANN was applied to classify the different x- and y-axis lateral vibrations due to different blade faults. The results based on training and testing with different data samples of the fault types indicate that the ANN is robust and can effectively identify and distinguish different blade faults caused by lateral vibrations in a rotor. As compared to the literature, the present paper presents a novel work of identifying and classifying various rotating blade faults commonly encountered in rotating machines using ANN. Experimental data of lateral vibrations of the rotor-disk-blade system in both x- and y-directions are used for the training and testing of the network.
This paper focuses on the artificial bee colony (ABC) algorithm, which is a nonlinear optimization problem. is proposed to find the optimal power flow (OPF). To solve this problem, we will apply the ABC algorithm to a power system incorporating wind power. The proposed approach is applied on a standard IEEE-30 system with wind farms located on different buses and with different penetration levels to show the impact of wind farms on the system in order to obtain the optimal settings of control variables of the OPF problem. Based on technical results obtained, the ABC algorithm is shown to achieve a lower cost and losses than the other methods applied, while incorporating wind power into the system, high performance would be gained.
The significance of the solar energy is to intensify the effectiveness of the Solar Panel with the use of a primordial solar tracking system. Here we propounded a solar positioning system with the use of the global positioning system (GPS) , artificial neural network (ANN) and image processing (IP) . The azimuth angle of the sun is evaluated using GPS which provide latitude, date, longitude and time. The image processing used to find sun image through which centroid of sun is calculated and finally by comparing the centroid of sun with GPS quadrate to achieve optimum tracking point. Weather conditions and situation observed through AI decision making with the help of IP algorithms. The presented advance adaptation is analyzed and established via experimental effects which might be made available on the memory of the cloud carrier for systematization. The proposed system improve power gain by 59.21% and 10.32% compare to stable system (SS) and two-axis solar following system (TASF) respectively. The reduced tracking error of IoT based Two-axis solar following system (IoT-TASF) reduces their azimuth angle error by 0.20 degree.
Kosovo has limited renewable energy resources and its power generation sector is based on fossil fuels. Such a situation emphasizes the importance of active research and efficient use of renewable energy potential. According to the analysis of meteorological data for Kosovo, it can be concluded that among the most attractive potential wind power sites are the locations known as Kitka (42° 29' 41" N and 21° 36' 45" E) and Koznica (42° 39′ 32″ N, 21° 22′30″E). The two terrains in which the analysis was carried out are mountain areas, with altitudes of 1142 m (Kitka) and 1230 m (Koznica). the same measuring height, about 84 m above the ground, is obtained for these average wind speeds: Kitka 6,667 m/s and Koznica 6,16 m/s. Since the difference in wind speed is quite large versus a difference in altitude that is not being very large, analyses are made regarding the terrain characteristics including the terrain relief features. In this paper it will be studied how much the roughness of the terrain influences the output energy. Also, that the assumption to be taken the same as to how much they will affect the annual energy produced.
Large-scale grid-tied photovoltaic (PV) station are increasing rapidly. However, this large penetration of PV system creates frequency fluctuation in the grid due to the intermittency of solar irradiance. Therefore, in this paper, a robust droop control mechanism of the battery energy storage system (BESS) is developed in order to damp the frequency fluctuation of the multi-machine grid system due to variable active power injected from the PV panel. The proposed droop control strategy incorporates frequency error signal and dead-band for effective minimization of frequency fluctuation. The BESS system is used to consume/inject an effective amount of active power based upon the frequency oscillation of the grid system. The simulation analysis is carried out using PSCAD/EMTDC software to prove the effectiveness of the proposed droop control-based BESS system. The simulation result implies that the proposed scheme can efficiently curtail the frequency oscillation.
This study investigates experimentally the performance of two-dimensional solar tracking systems with reflector using commercial silicon based photovoltaic module, with open and closed loop control systems. Different reflector materials were also investigated. The experiments were performed at the Hashemite University campus in Zarqa at a latitude of 32⁰, in February and March. Photovoltaic output power and performance were analyzed. It was found that the modified photovoltaic module with mirror reflector generated the highest value of power, while the temperature reached a maximum value of 53 ̊ C. The modified module suggested in this study produced 5% more PV power than the two-dimensional solar tracking systems without reflector and produced 12.5% more PV power than the fixed PV module with 26⁰ tilt angle.
This paper focuses on the modeling and control of a wind energy conversion chain using a permanent magnet synchronous machine. This system behaves a turbine, a generator, DC/DC and DC/AC power converters. These are connected on both sides to the DC bus, where the inverter is followed by a filter which is connected to the grid. In this paper, we have been used two types of controllers. For the stator side converter, we consider the Takagi-Sugeno approach where the parameters of controller have been computed by the theory of linear matrix inequalities. The stability synthesis has been checked using the Lyapunov theory. According to the grid side converter, the proportional integral controller is exploited to keep a constant voltage on the DC bus and control both types of powers. The simulation results demonstrate the robustness of the approach used.
The development of modeling wind speed plays a very important in helping to obtain the actual wind speed data for the benefit of the power plant planning in the future. The wind speed in this paper is obtained from a PCE-FWS 20 type measuring instrument with a duration of 30 minutes which is accumulated into monthly data for one year (2019). Despite the many wind speed modeling that has been done by researchers. Modeling wind speeds proposed in this study were obtained from the modified Rayleigh distribution. In this study, the Rayleigh scale factor (Cr) and modified Rayleigh scale factor (Cm) were calculated. The observed wind speed is compared with the predicted wind characteristics. The data fit test used correlation coefficient (R2), root means square error (RMSE), and mean absolute percentage error (MAPE). The results of the proposed modified Rayleigh model provide very good results for users.
This paper deals with an advanced design for a pump powered by solar energyto supply agricultural lands with water and also the maximum power point is used to extract the maximum value of the energy available inside the solar panels and comparing between techniques MPPT such as Incremental conductance, perturb & observe, fractional short current circuit, and fractional open voltage circuit to find the best technique among these. The solar system is designed with main parts: photovoltaic (PV) panel, direct current/direct current (DC/DC) converter, inverter, filter, and in addition, the battery is used to save energy in the event that there is an increased demand for energy and not to provide solar radiation, as well as saving energy in the case of generation more than demand. This work was done using the matrix laboratory (MATLAB) simulink program.
The objective of this paper is to provide an overview of the current state of renewable energy resources in Bangladesh, as well as to examine various forms of renewable energies in order to gain a comprehensive understanding of how to address Bangladesh's power crisis issues in a sustainable manner. Electricity is currently the most useful kind of energy in Bangladesh. It has a substantial influence on a country's socioeconomic standing and living standards. Maintaining a stable source of energy at a cost that is affordable to everyone has been a constant battle for decades. Bangladesh is blessed with a wealth of natural resources. Bangladesh has a huge opportunity to accelerate its economic development while increasing energy access, livelihoods, and health for millions of people in a sustainable way due to the renewable energy system.
When the irradiance distribution over the photovoltaic panels is uniform, the pursuit of the maximum power point is not reached, which has allowed several researchers to use traditional MPPT techniques to solve this problem Among these techniques a PSO algorithm is used to have the maximum global power point (GMPPT) under partial shading. On the other hand, this one is not reliable vis-à-vis the pursuit of the MPPT. Therefore, in this paper we have treated another technique based on a new modified PSO algorithm so that the power can reach its maximum point. The PSO algorithm is based on the heuristic method which guarantees not only the obtaining of MPPT but also the simplicity of control and less expensive of the system. The results are obtained using MATLAB show that the proposed modified PSO algorithm performs better than conventional PSO and is robust to different partial shading models.
A stable operation of wind turbines connected to the grid is an essential requirement to ensure the reliability and stability of the power system. To achieve such operational objective, installing static synchronous compensator static synchronous compensator (STATCOM) as a main compensation device guarantees the voltage stability enhancement of the wind farm connected to distribution network at different operating scenarios. STATCOM either supplies or absorbs reactive power in order to ensure the voltage profile within the standard-margins and to avoid turbine tripping, accordingly. This paper present new study that investigates the most suitable-location to install STATCOM in a distribution system connected wind farm to maintain the voltage-levels within the stability margins. For a large-scale squirrel cage induction generator squirrel-cage induction generator (SCIG-based) wind turbine system, the impact of STATCOM installation was tested in different places and voltage-levels in the distribution system. The proposed method effectiveness in enhancing the voltage profile and balancing the reactive power is validated, the results were repeated for different scenarios of expected contingencies. The voltage profile, power flow, and reactive power balance of the distribution system are observed using MATLAB/Simulink software.
The electrical and environmental parameters of polymer solar cells (PSC) provide important information on their performance. In the present article we study the influence of temperature on the voltage-current (I-V) characteristic at different temperatures from 10 °C to 90 °C, and important parameters like bandgap energy Eg, and the energy conversion efficiency η. The one-diode electrical model, normally used for semiconductor cells, has been tested and validated for the polemeral junction. The PSC used in our study are formed by the poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM). Our technique is based on the combination of two steps; the first use the Least Mean Squares (LMS) method while the second use the Newton-Raphson algorithm. The found results are compared to other recently published works, they show that the developed approach is very accurate. This precision is proved by the minimal values of statistical errors (RMSE) and the good agreement between both the experimental data and the I-V simulated curves. The obtained results show a clear and a monotonic dependence of the cell efficiency on the studied parameters.
The inverter is the principal part of the photovoltaic (PV) systems that assures the direct current/alternating current (DC/AC) conversion (PV array is connected directly to an inverter that converts the DC energy produced by the PV array into AC energy that is directly connected to the electric utility). In this paper, we present a simple method for detecting faults that occurred during the operation of the inverter. These types of faults or faults affect the efficiency and cost-effectiveness of the photovoltaic system, especially the inverter, which is the main component responsible for the conversion. Hence, we have shown first the faults obtained in the case of the short circuit. Second, the open circuit failure is studied. The results demonstrate the efficacy of the proposed method. Good monitoring and detection of faults in the inverter can increase the system's reliability and decrease the undesirable faults that appeared in the PV system. The system behavior is tested under variable parameters and conditions using MATLAB/Simulink.
The electrical distribution network is undergoing tremendous modifications with the introduction of distributed generation technologies which have led to an increase in fault current levels in the distribution network. Fault current limiters have been developed as a promising technology to limit fault current levels in power systems. Though, quite a number of fault current limiters have been developed; the most common are the superconducting fault current limiters, solid-state fault current limiters, and saturated core fault current limiters. These fault current limiters present potential fault current limiting solutions in power systems. Nevertheless, they encounter various challenges hindering their deployment and commercialization. This research aimed at designing a bridge-type nonsuperconducting fault current limiter with a novel topology for distribution network applications. The proposed bridge-type nonsuperconducting fault current limiter was designed and simulated using PSCAD/EMTDC. Simulation results showed the effectiveness of the proposed design in fault current limiting, voltage sag compensation during fault conditions, and its ability not to affect the load voltage and current during normal conditions as well as in suppressing the source powers during fault conditions. Simulation results also showed very minimal power loss by the fault current limiter during normal conditions.
This paper provides a new approach to reducing high-order harmonics in 400 Hz inverter using a three-level neutral-point clamped (NPC) converter. A voltage control loop using the harmonic compensation combined with NPC clamping diode control technology. The capacitor voltage imbalance also causes harmonics in the output voltage. For 400 Hz inverter, maintain a balanced voltage between the two input (direct current) (DC) capacitors is difficult because the pulse width modulation (PWM) modulation frequency ratio is low compared to the frequency of the output voltage. A method of determining the current flowing into the capacitor to control the voltage on the two balanced capacitors to ensure fast response reversal is also given in this paper. The combination of a high-harmonic resonator controller and a neutral-point voltage controller working together on the 400 Hz NPC inverter structure is given in this paper.
Direct current (DC) electronic load is a useful equipment for testing the electrical system. It can emulate various load at a high rating. The electronic load requires a power converter to operate and a linear regulator is a common option. Nonetheless, it is hard to control due to the temperature variation. This paper proposed a DC electronic load using the boost converter. The proposed electronic load operates in the continuous current mode and control using the integral controller. The electronic load using the boost converter is compared with the electronic load using the linear regulator. The results show that the boost converter able to operate as an electronic load with an error lower than 0.5% and response time lower than 13 ms.
More from International Journal of Power Electronics and Drive Systems (20)
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
NUMERICAL SIMULATIONS OF HEAT AND MASS TRANSFER IN CONDENSING HEAT EXCHANGERS...ssuser7dcef0
Power plants release a large amount of water vapor into the
atmosphere through the stack. The flue gas can be a potential
source for obtaining much needed cooling water for a power
plant. If a power plant could recover and reuse a portion of this
moisture, it could reduce its total cooling water intake
requirement. One of the most practical way to recover water
from flue gas is to use a condensing heat exchanger. The power
plant could also recover latent heat due to condensation as well
as sensible heat due to lowering the flue gas exit temperature.
Additionally, harmful acids released from the stack can be
reduced in a condensing heat exchanger by acid condensation. reduced in a condensing heat exchanger by acid condensation.
Condensation of vapors in flue gas is a complicated
phenomenon since heat and mass transfer of water vapor and
various acids simultaneously occur in the presence of noncondensable
gases such as nitrogen and oxygen. Design of a
condenser depends on the knowledge and understanding of the
heat and mass transfer processes. A computer program for
numerical simulations of water (H2O) and sulfuric acid (H2SO4)
condensation in a flue gas condensing heat exchanger was
developed using MATLAB. Governing equations based on
mass and energy balances for the system were derived to
predict variables such as flue gas exit temperature, cooling
water outlet temperature, mole fraction and condensation rates
of water and sulfuric acid vapors. The equations were solved
using an iterative solution technique with calculations of heat
and mass transfer coefficients and physical properties.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Water billing management system project report.pdfKamal Acharya
Our project entitled “Water Billing Management System” aims is to generate Water bill with all the charges and penalty. Manual system that is employed is extremely laborious and quite inadequate. It only makes the process more difficult and hard.
The aim of our project is to develop a system that is meant to partially computerize the work performed in the Water Board like generating monthly Water bill, record of consuming unit of water, store record of the customer and previous unpaid record.
We used HTML/PHP as front end and MYSQL as back end for developing our project. HTML is primarily a visual design environment. We can create a android application by designing the form and that make up the user interface. Adding android application code to the form and the objects such as buttons and text boxes on them and adding any required support code in additional modular.
MySQL is free open source database that facilitates the effective management of the databases by connecting them to the software. It is a stable ,reliable and the powerful solution with the advanced features and advantages which are as follows: Data Security.MySQL is free open source database that facilitates the effective management of the databases by connecting them to the software.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
2. Int J Power Electron & Dri Syst ISSN: 2088-8694
Design of Optimal LLCL Filter with an Improved Control Strategy for Single Phase Grid… (K. Arulkumar)
115
The power from the photovoltaic (PV) is injected into the grid through the voltage source inverter
(VSI). Among many topologies [2]-[4], transformerless inverters have attracted due to its physical size with
less space requirements and feasible cost constraints. The pulse width modulation (PWM) control is achieved
by closed loop current control with the current harmonics less than 5% [5]. The switching frequencies
between 2-15 kHz causes higher order harmonic disturbances in grid and losses. Higher order harmonics into
the grid due to switching frequencies, leakage current and the electromagnetic interference (EMI) [6] noise
are the significant issues in designing of filter circuit in the PV inverter.
Ripples and harmonics in the grid current can be reduced by filters connected at the output of the
inverter [7]. The first order filter consists of one inductor connected in series known as L-filter which is most
commonly used [8]. It does not have a resonance problem as compared to higher order filters. The inductor
achieves reasonable attenuation of the current harmonics. The attenuation of 20 dB/decade is achieved for
high frequency PWM converters. Higher order filters, LC & LCL have the combinations of inductors and
capacitors, can give better attenuation of the harmonics with the disadvantages of complex design, cost and
bulky [9]. The LC filter has better damping characteristics, but suffers from problem of infinite gain at
resonance. In grid connected system, the resonance frequency of the filter varies with the inductance value of
the grid [10]. The control of LCL filter is difficult compared to L filter, due to the presence of two more poles
and zeros. Care must be taken to design a controller for additional poles and zeros that can make the system
unstable if proper damping is not introduced. Damping of the LCL filter resonance can be either active using
the converter, or passive using elements like resistors, capacitors and inductors. Several methods of passive
damping [11]-[12] have been proposed for stiff grid operation.On the other hand, the active damping method
is used with costly sensors and power electronics for weak grid and dynamic grid variations.
This paper mainly focuses on control structure of single phase grid connected PV inverter with filter
design analysis. Section II illustrates the constraints of the LCL filter design and importance of Q-factor with
sensitivity analysis. An improved LLCL filter is introduced, in order to reduce the total inductance of the
conventional filter. The modified LLCL filter is designed without any change in the frequency response
characteristic of LCL filter. More advantage in suppressing the resonance peak with improved stability and
dynamic response. Three cases of parameter design have been differentiated and analyzed with simulated
results in section III. Improved current control structure is seen in section IV by implementing feedback
linearization for fast DC voltage control applied to PWM inverter. And it is verified by modeling a single
phase grid connected PV inverter with simulated and experimental results.
2. SYSTEM DESCRIPTION AND CHARACTERISTICS
2.1. Classical Methods and Constraints on LCL Filter Design
In grid power converters, switching frequencies at intervals 3-20 kHz causes greater harmonics and
disturbs the electric grid. It is therefore essential to attenuate the switching frequency harmonics and reduce
the current ripples to fulfill the standards of the IEEE 1547.2. High frequency component currents would lead
to electromagnetic interference noise mainly due to the parasitic capacitance disturbing the behavior of high
frequencies. The method of designing LCL filters depends on rating of power converters, fundamental and
switching frequency as inputs with an integrated control design of filters as explained in [13] . From the
Figure 2 (a). the inverter output inductor L1, the filter capacitor Cf, and the grid-side inductor L2 constitute
the LCL filter of the inverter. Compared to L filter, LCL filter is proved to have a better harmonic attenuation
for the reduction of filter inductance volume [14] which bypass the high frequency harmonics through the
capacitance branch. The scope is to lower the higher order harmonics on the grid side and to reduce the
oscillation effects. Therefore, in LCL filter design, inductors should be properly designed in observing the
current ripple, filter capacitance and damping of resonance in filters. The resonant frequency should be in the
range 10ω0 ≤ ωres ≤
ωsw
2
[15]. Figure 2 (b), (c) depicts the passive damped topology of LCL filter.
Frequency response analysis of passive damped LCL filters with damping resistors in series to attenuate the
resonance with the transfer function as in (1) and improved methods with passive elements as in (2) are
shown in Figure 3.
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Figure 2. a). LCL filter, b) passive damped LCL filter with Rd, c)passive damped LCL filter with Rd-Cd
Transfer function of LCL filter:
Gvi→ ig
(s) =
ig(s)
vi(s)
=
1
L2
(S2
+RdCfZ2
LCS+Z2
LC)
(S2+RdCfωres
2 S+ωres
2 )
(1)
If Rd is zero then,
Gvi→ ig
(s) =
ig(s)
vi(s)
=
1
L2
(S2+Z2
LC)
(S2+ωres
2 )
Where,
Z2
LC = [L1Cf]−1
ω2
res =
L2ZLC
2
L
For improved passive damping,
Gvi→ ig
(s) =
ig(s)
vi(s)
=
(RdCdS+1)
S(L1L2RdCdCfS3+L1L2(Cd+Cf)S2+RdCd(L1+L2)S+L1L2)
(2)
From Figure 3 it is clear that the magnitude of LCL filter is high with a resonant peak gain of 250
dB at 4.6 kHz. However, in passive damping and improved passive damping, the attenuation is reduced to 10
dB or less than that at 2.5 kHz with some power loss due to the resistor.
Figure 3. Frequency response of LCL filter
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2.2. Selection ofFilter Capacitance (Cf )
The selection of capacitor [16] is determined between reactive power in Cf and L1. If the
capacitance is high, the reactive power flowing into it is more which leads to current demands in L1. In the
design consideration large inductance (L1) and smaller capacitance (Cf) lead to the voltage drop across the
inductor L1. So, reactive power is chosen 15% of rated power as in (3) and from that the capacitance value
can be chosen as:
C = 15%
Prated
3∗2πflineVrated
2 (3)
Where, Prated is rated power and Vrated is grid RMS voltage.
2.3. Significance of Q-factor Analysis
The importance of damping is to lower the Q-factor at the resonant frequency without affecting the
frequency response at other frequencies. In Figure 3 frequency response analysis of higher order filter with
and without damping is analyzed. The series LC circuit gives a minimum impedance at resonance while
parallel LC circuit gives a maximum impedance at the resonant frequency. The value of Q-factor reduces in
passive damping at a dominant resonant frequency [17]. The quality factor of Lf-Cf can be expressed as,
Q =
1
Rf
√
Lf
Cf
(4)
For reducing the peak resonant, damping resistor is designed with an optimal Q-factor for the stiff
grid condition. Increase of grid inductance can reduce the passive damping effect and cannot achieve the
optimal Q-factor. Concurrently, the total power dissipation in the damping circuit is also an important
parameter.
3. DESIGN OF MODIFIED LLCL FILTER
Based on the traditional LCL filter, a small inductor is inserted in the branch loop of the capacitor,
composing a series resonant circuit at the switching frequency. It can, particularly, attenuate the switching-
frequency current ripple components much better than the LCL filter, saves the total inductance and thereby
leads to size reduction. The most convenient passive method is by adding physical resistors connected either
in series or in parallel with inductor or capacitor of the filter. It aims at reducing Q-factor at dominant
resonant frequency. Recently to reduce the inductor size a novel higher order LLCL filter [18] is proposed as
shown in Figure 4 with transfer function as in (5)
Figure 4. Schematic diagram of LLCL filter
Transfer function of
ig(s)
vi(s)
LLCL filter is given as
Gvi→ ig
(s) =
ig(s)
vi(s)
=
LfCfS2
+1
(L1 L2 Cf+(L1+L2 )Lf
CfS3+(L1+L2)S
(5)
For LLCL, ωres =
1
√(
L1L2
L1+L2
+Lf)cf
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3.1. Passive Damped Scheme of LLCL Filter
Modified LLCL filter topology [19] is used to reduce the damping power loss and high frequency
harmonic attenuation as shown in Figure 5 (a), (b). Because of a series resonant circuit Lf-Cf is at switching
frequency, the value of the inductor is much smaller than that of L1 & L2. From the Figure 5 (b) passive
damped LLCL2 & Figure 2 (c) improved passive damped LCL, the value of damping parameters Rd and Cd is
same. Most significantly, the total capacitance of (Cd+Cf) is encouraged to be less than 5% of apparent
reactive power at rated load. From (6) and (7) it is to be noted that the addition of poles and zeros in a system
gives rise to stability issues and care should be taken in designing the filters.
Figure 5. Various passive damped LLCL filters with Rd and Cda). LLCL1 b). LLCL2
Bode plot of the transfer function of(1) & (5) is depicted as in Figure 6 a) and it is clear that an
LLCL filter based grid connected VSI has almost same frequency response characteristic of LCL filter. In
Figure 6 b) the peak magnitude lies within 20 kHz, the first resonant peak occurs at 7.6 kHz within half of the
switching frequency and the next peak occurs at 20 kHz. The damping technique minimizes the resonant
peak within the range. And it is worth mentioned that compared to LCL filter, the additional inductor Lf does
not bring anycontrol difficulties, an additional grid inductance L2 is added to widen the bandwidth.
Transfer function ofimproved passive damping LLCL1
Gvi→ ig
(s) =
ig(s)
vi(s)
=
s3
A+s2
B+sC+1
s5a+s4b+s3c+s2d+se
(6)
a=L1L2LfCfCd ;
b=((L1L2+(L1+L2)Lf)RdCdCf) ;
c=((L1L2(Cd+Cf)+Lf Cf(L1+L2)) ;
d=RdCd(L1+L2) ;
e=(L1 + L2);
A=LfCf CdRd ;
B=LfCf ;
C=RdCd ;
Transfer function ofimproved passive damping LLCL2:
𝐺𝑣𝑖→ 𝑖𝑔
(𝑠) =
𝑖𝑔(𝑠)
𝑣𝑖(𝑠)
=
𝑠3
𝐴′+𝑠2
𝐵′+𝑠𝐶′+1
𝑠4𝑏′+𝑠3𝑐′+𝑠2𝑑′+𝑠𝑒′
(7)
b′
=((L1L2+(L1+L2)Lf)RdCdCf) ;
c′=((L1L2(Cd+Cf)+Lf(Cf+Cd)(L1+L2)) ;
d′=RdCd(L1+L2) ;
e′=(L1+L2);
A′=LfCf CdRd ;
B′=LfCf ;
C′=RdCd ;
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(a) (b)
Figure 6. a).Frequency response analysis of LCL and LLCL, b). Frequency response analysis ofdamping
techniques of LCL and LLCL
Figure 7. Sensitivity analysis ofparameter variation
of Lf (±20%)
Figure 8. Frequency response analysis of passive
damped LLCL
The bode plot of LCL and LLCL filter parameters, as given in Table 1is plotted in Figure 7with the
sensitivity analysis on parameter variation of±20%. The enlarge view of magnitude of LLCL filter is also
shown.Moreover, case I & case III as in Table 1 attenuate the resonance by -40 dB/decade,but in case II it is -
60 dB/decade as in Figure 8. The designed LLCL filter attenuates resonant harmonics around the switching
frequency and well suited for the single phase system.
Table 1. Filter Parameters in Design
Parameters
Case-I
Rd
damped
LCL
Case-II
Rd - Cd
damped LCL
Case-III
Rd - Cd damped
LLCL
L1 1.2mH 1.2mH 1.2mH
R1 0.1Ω 0.1Ω 0.1Ω
L2 1.2mH 1.2mH 0.22mH
R2 0.04Ω 0.04Ω 0.01Ω
Lf - - 32μH
Rf - - 0.2 Ω
Cf - 2μF 2μF
Rd 4Ω 30Ω 16.5Ω
Cd 4μF 2μF 2μF
4. SYSTEM MODELING AND CONTROL STRUCTURE
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4.1. Proposed Inverter Current Control Strategy
The current injected into the grid by a power converter should keep a certain relationship with
voltage at a point of connection. In order to avoid the glitches in the control of inverter it should be made
more robust with the accurate parameter analysis. The block diagram in Figure 9 shows conventional current
control loop structure [19] with grid side current feedback control. Where, Gp(s) expressed as process gain &
GC(s) denotes proportional resonant (PR) and harmonic compensator (HC) controller gain, H(s) implies
feedback gain of grid injected current, Ginv(s) indicates gain of inverter and Gvi→ig
(s) denotes a transfer
function of LLCL filter, given by(5).
Figure 9. Inverter power control loop
Figure 10. Proposed inverter current control structure
Table 2. Comparison on Different Cases
Parameters
CASE I
LCL
(Rd damped)
CASE II
LCL
(Rd- Cd damped)
CASE
III
LLCL
THD
Simulation 2.48 % 3.5 % 2.4 %
Experimental 3.82 % 4.04 % 3.5 %
DampingLosses (W)
Calculated 2.51 0.89 0.45
Measured 2.57 0.91 0.52
By considering the LLCL filter as shown in Figure 4i1 is the inverter current and the current flows
through the capacitor ic is being negligible compared to i1. The inverter current control structure as in Figure
10 exhibits the calculation of inverter current i1 from the duty ratio (D) needs grid voltage (Vg) that is related
to i1 by the undetermined grid impedance (Zgrid). To avoid this problem, a nonlinear control technique from
modern control theory named feedback linearization scheme [20], [21] is proposed. To exhibit the
undetermined grid impedance, Vg is treated as a DC parameter. Compared to inverter current i1 that is, the
current loop crossover frequency is much higher than grid frequency. The Figure 10 also shows duty cycle
(D) calculation from Vi using Vg and VDC as defined in (8). With the proposed control the respective
parameter makes the linear system with reduction in capacitor ripple current [22] and therefore reducing the
size of thecapacitor. The instantaneous current reference is used by the current compensator with the
feedback current to provide a duty ratio to the inverter. The DC bus voltage is fixed at the desired set point
and controlled current is injected into the grid. Here Vi controls the main inductor current IL. The inverter
current fed into the grid is given by (9). Where Ks represents the current feedback gain. Hence, the loop gain
transfer function is expressed as,
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𝐺𝑙𝑜𝑜𝑝(𝑠) = 𝐺𝑐(𝑠)𝐾𝑠𝐺𝑝
For the synchronization purpose, second order generalised integrator phase locked loop (SOGI-PLL)
technique [23,24] is used to synchronize inverter voltage to the grid voltage and frequency.
𝐷 =
(𝑖𝑔
∗ −𝑖𝑔)∗𝐺𝑐(𝑆)+𝑉𝑔
𝑉𝐷𝐶
(8)
𝑖𝑔 =
(𝑉𝐷𝐶∗𝐷)−𝑉𝑔
𝑍𝐿𝐿𝐶𝐿
(9)
4.2. Experimental and Simulation Results
In order to verify the proposed dampingtechnique andcontrol structure, simulation is carried out
using MATLAB/Simulink software. The parameters are the same as the designed in Table I. In order to
verify the theoretical analysis, a 250 W experimental prototype as in Figure 11 based on a DSP
(TMS320F28035) controller is constructed. A programmable DC power supply (chroma 62012P-80-60) is
used to emulate the renewable energy sources. The grid current is sensed by current sensor ACS712ELCTR-
20A, the type of IGBTs is IRFB4227PBF with switching frequency (Fs) as 20 kHz. A DC link capacitor of
united chemi-con KXG series 450 V, 100 μF is used. Total harmonic distortion (THD) is measured by the
Fluke-434-Power quality analyzer and the waveform is obtained with agilent (MSO). Grid voltage and
frequency are normally 230 V, 50 Hz.
With the feedback linearization control, Figure 12 shows the steady state experimental voltage
response of dc- link voltage of388 V as input to the inverter. The grid voltage and inverter output voltage
synchronization in Figure 13 a) shows this as a promising current control structure with grid voltage and
inverter voltage synchronized each other. The waveforms of inverter output voltage 388 V before filtering is
shown in Figure 13 b). With the conventional LCL filter parameters the waveform of voltage and current is
shown in Figure 14 with harmonics and spikes. To validate the proposed control structure and filter design,
experimental results of both LCL and LLCL filter output waveform is compared in Figure 15.a), b). It shows
that the proposed design of LLCL filter has less distortion in the waveform compared to LCL filter as the
THD is 3.5 % with the proposed LLCL filter and 3.82 % with the conventional LCL filter as mentioned in
Table 2. The results of the proposed grid connected system is shown in experimental results as in Figure 16
peak to peak voltage of 164.3 V and grid injected current of 2.2 A. The total harmonic distortion of the grid
current in the laboratary is THD=3.5% as shown in Figure 17 that meets the IEEE 519 standard by measuring
with the power quality analyzer FLUKE-434.
4.3. Result Analysis and Discussion
From the results it is to be that, increasing grid inductance can reduce the passive damping effect
and increases the losses in the circuit in case I & II in Table I. However, in case III resonant peak occurs
within the switching frequency with limited magnitude attenuation and current harmonic around it satisfy
IEEE 519-1992. The current harmonic (>=35th
) is less than 0.3% of fundamental current by the parameter
drift of Lf in range ±20% both in switching frequency and double of switching frequency. The proposed
improved control strategy enhances the performances by introducing feedback linearization making linear
structure in adding integrators to get fast and zero tracking errors and reducing the capacitor value as 100 μF.
The total harmonic distortions of the grid side current in the three cases are measured using
simulation and experiments and are listed in Table II. In case III, LLCL filter (L1=1.2 mH, L2=0.22 mH,
Lf=0.032 mH) are used, of which the control performance of the grid inverter is shown in Figure 17 and THD
is calculated as 2.4% in simulation and 3.5% in experimental. The damping loss calculation as in [8]. The
power losses in the filter are mainly caused by inverter-side inductor current ripples of both LCL and LLCL
filter. The damping power loss is mainly caused by volume of L2, Lf and Rd with the calculated and measured
value of LLCL filter as 0.45 W and 0.52 W less than LCL filter.
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Figure 11. Laboratory setup of grid connected PV
system
Figure 12. Experimental steady state DC bus voltage
(a) (b)
Figure 13. (a) Synchronization of inverter voltage and grid voltage (b) Simulated inverter output voltage
Figure 14. Experimental waveform ofvoltage and injected current into grid: a) with LCL filter
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(a) (b)
Figure 15. Experimental waveform ofvoltage and injected current into grid: a) with LCL filter as in case I
and b) with LLCL filter as in case III
Figure 16. Experimental results of the proposed grid connected system
Figure 17. Snapshot of THD measurement
5. CONCLUSIONS
For reducing the resonance in the filter circuit, damping resistors are added with an additional
inductance in LCL filter with improved control strategy is proposed in this paper. Comparative damping
analysis of LCL and LLCL filter is designed with case parameters defined. Addition of passive elements and
variation in filter parameters does not lose the stability. A Feedback linearization is used to control the duty
ratio of inverter control for fast dynamic process, by adding integral control to eliminate steady state error
that enhances the performance and shows satisfactory behaviour. The voltage transient is improved to
decrease of current ripple and the size of the capacitor is reduced. The robustness of the system are verified
using simulated and experimental results. The waveform of output current without any distortion shows that
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the inverter with proposed control structure can convert solar power to a high quality power into the utility
grid.
ACKNOWLEDGEMENTS
This work has been supported by power system research laboratory (TT-344), School of Electrical
Engineering, VIT University, Vellore.
NOMENCLATURE
Vi inverter voltage (V) i1 inverter current (A)
Vg grid voltage (V) ig grid current (A)
Prated rated power (W) Vrated rated voltage (V)
Fgrid grid frequency (Hz) VDC dc bus voltage (V)
Cf filter capacitance Rd damping resistor
Cd damping capacitance ωresresonant frequency
ω0 fundamental frequency Zgrid grid impedance
D duty ratio
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BIOGRAPHIES OF AUTHORS
K. Arulkumar was born in 1986. He received the B.E. degree in Electrical & Electronics from
Anna University, Chennai, in april 2008 and M.Tech (Power Electronics) degree from VelTech
Dr.RR & Dr.SR Technical University, Chennai in may 2011. He did in Ph.D in VIT University,
Vellore, India. His research interest include Grid connected Inverter control & solar PV system
integration.
D. Vijayakumar received his Bachelor Degree in Electrical and Electronics Engineering and
Master Degree in Power Systems in the year 2002 and 2005 respectively. He received his
Doctorate in April 2010 at Electrical Department in Maulana Azad National Institute of
Technology (MANIT), Bhopal, India. Presently, He is an Associate Professor & Program Chair
of EEE and Division Chair of Power Systems in the School of Electrical Engineering,VIT
University, Vellore, India. His research interest include power system protection, and Renewable
energy sources.
K.Palanisamy received his Bachelor degree from University of Madras, Chennai, India, and the
M.E. degrees from Anna University, Chennai,India, Ph.D from VIT University Vellore, India in
2000, 2004 and 2013, respectively. In 2004, he joined the Department of Electrical & Electronics
Engineering in Kongu Engineering College, Erode, as a Lecturer. Presently, he is an Associate
Professor with the School of Electrical Engineering, Vellore Institute of Technology, Vellore,
India. He is a certi-_ed Energy Auditor by Bureau of Energy Ef_ciency, Government of India.
His research interests are in power quality, energy conservation and renewable energy
integration.