A DC-DC converter topology is presented
combining the soft switching effects of the Snubber Assisted Zero
Voltage and Zero Current Transition (SAZZ) topology and the
increased inductor frequency of the dual interleaved boost
converter with interphase transformer. The snubber capacitors
and output capacitances of the main devices are discharged prior
to turn on using a single auxiliary inductor, eliminating turn on
losses. Furthermore, the turn off losses are significantly reduced
since the energy stored in the device output capacitance at turn
off is recovered at turn on. The effectiveness of the topology is
demonstrated on a SiC prototype operating at 12.5 kW, 112 kHz,
reducing the switching losses by 50%.
A New Active Snubber Circuit for PFC ConverterIDES Editor
In this paper, a new active snubber circuit is
developed for PFC converter. This active snubber circuit
provides zero voltage transition (ZVT) turn on and zero current
transition (ZCT) turn off for the main switch without any
extra current or voltage stresses. Auxiliary switch turns on
and off with zero current switching (ZCS) without voltage
stress. Although there is a current stress on the auxiliary
switch, it is decreased by diverting it to the output side with
coupling inductance. The proposed PFC converter controls
output current and voltage in very wide line and load range.
This PFC converter has simple structure, low cost and ease of
control as well. In this study, a detailed steady state analysis
of the new converter is presented, and the theoretical analysis
is verified exactly by 100 kHz and 300 W prototype. This
prototype has 98% total efficiency and 0.99 power factor with
sinusoidal current shape.
This paper presents a phase shifted series resonant converter with step up high frequency transformer to achieve the functions of high output voltage, high power density and wide range of Zero Voltage Switching (ZVS). In this approach, the output voltage is controlled by varying the switching frequency. The controller has been designed to achieve a good stability under different load conditions. The converter will react to the load variation by varying its switching frequency to satisfy the output voltage requirements. Therefore in order to maintain constant output voltage, for light load (50% of the load), the switching frequency will be decreased to meet the desired output, while for the full load (100%) conditions, the switching frequency will be increased. Since the controlled switching frequency is limited by the range between the higher and lower resonant frequencies , the switches can be turned on under ZVS. In this study, a laboratory experiment has been conducted to verify the effectiveness of the system performance.
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.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A DC-DC converter topology is presented
combining the soft switching effects of the Snubber Assisted Zero
Voltage and Zero Current Transition (SAZZ) topology and the
increased inductor frequency of the dual interleaved boost
converter with interphase transformer. The snubber capacitors
and output capacitances of the main devices are discharged prior
to turn on using a single auxiliary inductor, eliminating turn on
losses. Furthermore, the turn off losses are significantly reduced
since the energy stored in the device output capacitance at turn
off is recovered at turn on. The effectiveness of the topology is
demonstrated on a SiC prototype operating at 12.5 kW, 112 kHz,
reducing the switching losses by 50%.
A New Active Snubber Circuit for PFC ConverterIDES Editor
In this paper, a new active snubber circuit is
developed for PFC converter. This active snubber circuit
provides zero voltage transition (ZVT) turn on and zero current
transition (ZCT) turn off for the main switch without any
extra current or voltage stresses. Auxiliary switch turns on
and off with zero current switching (ZCS) without voltage
stress. Although there is a current stress on the auxiliary
switch, it is decreased by diverting it to the output side with
coupling inductance. The proposed PFC converter controls
output current and voltage in very wide line and load range.
This PFC converter has simple structure, low cost and ease of
control as well. In this study, a detailed steady state analysis
of the new converter is presented, and the theoretical analysis
is verified exactly by 100 kHz and 300 W prototype. This
prototype has 98% total efficiency and 0.99 power factor with
sinusoidal current shape.
This paper presents a phase shifted series resonant converter with step up high frequency transformer to achieve the functions of high output voltage, high power density and wide range of Zero Voltage Switching (ZVS). In this approach, the output voltage is controlled by varying the switching frequency. The controller has been designed to achieve a good stability under different load conditions. The converter will react to the load variation by varying its switching frequency to satisfy the output voltage requirements. Therefore in order to maintain constant output voltage, for light load (50% of the load), the switching frequency will be decreased to meet the desired output, while for the full load (100%) conditions, the switching frequency will be increased. Since the controlled switching frequency is limited by the range between the higher and lower resonant frequencies , the switches can be turned on under ZVS. In this study, a laboratory experiment has been conducted to verify the effectiveness of the system performance.
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.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
SIMULATION ANALYSIS OF CLOSED LOOP DUAL INDUCTOR CURRENT-FED PUSH-PULL CONVER...Journal For Research
The current electronic devices require DC power source, which is taken from a battery or DC power supply. DC-DC converter is utilized to get regulated dc voltage from unregulated one. Switched mode power supply (SMPS) are commonly used in industrial applications, because of more advantages compared to linear power supply. In SMPS we have isolated and non-isolated converters, where isolated converters are frequently used, in order to get more voltage with multiple outputs. So among different isolated converters, push-pull converter is chosen for micro converter applications to obtain high voltage conversion ratio by using HF transformer, due to their better utilization of transformer. New methodology of control is implemented for making ZVS and ZCS at same time and to reduce the number of switches in the secondary side of dual inductor CFPP converter, which is a voltage doubler circuit. This becomes the solution for problem identification. Thus this converter with soft-switching reduces the switching losses.The current-fed push-pull converters are used in many applications like photo-voltaic (PV) power converters for boosting the output voltage. Push-pull converter is chosen for micro converter applications, to obtain high voltage conversion ratio by using high frequency (HF) transformer, due to their better utilization of transformer. This deals with the design of dual inductor CFPP converter, where zero voltage switching (ZVS) and zero current switching (ZCS) is achieved for the primary side of the converter by using secondary switches. Primary side switches are controlled by closed loop control topology. The secondary side is made with voltage doubler to obtain high voltage. Open loop and closed loop control of dual inductor current fed push pull converter simulation is finished by MATLAB/SIMULINK and their outcomes are analyzed.
Multilevel inverters (MLI) are becoming more popular over the years for medium and high power applications because of its significant merits over two level inverters. This paper presents an implementation of multicarrier based sinusoidal pulse width modulation technique for three phase seven level diode clamped multilevel inverter. This topology is operated under phase opposition disposition pulse width modulation technique. The performance of three phase seven level diode clamped inverter is analyzed for induction motor (IM) load. Simulation is performed using MATLAB/SIMULINK. Experimental results are presented to validate the effectiveness of the operation of the diode clamped multilevel inverter using field programmable gate array.
Open Loop and Closed Loop Performance of Switched Reluctance Motor with Vario...IAES-IJPEDS
Switched reluctance motor (SRM) is becoming popular because of its simple construction, robustness and low-maintenance. This motor is very useful for high speed applications because no windings are placed on rotor and can also be used for variable speed applications in industries. Converter is one of the important elements in SRM which plays a very crucial role. In this paper various converter topologies for 6/4 switched reluctance motor and Asymmetric bridge converter topology for 8/6 switched reluctance motor are discussed. Finally a closed loop for each converter topology is proposed. The converter topologies are simulated by using MATLAB/SIMULINK. Constant speed is achieved in closed loop control.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
ANALYSIS, DESIGN AND IMPLEMENTATION OF ZERO-CURRENT-SWITCHING RESONANT CONVER...hunypink
This paper presents a Buck type circuit structure, the designing of ZCS resonant Buck converter and analysis of the working principles involved. The designed buck converter uses ZCS technique and the function is realized so that the power form is converted from 12V DC to 5V DC (1A). A detailed analysis of zero current switching buck converters is performed and a mathematical analysis of the mode of operation is also presented. In order to reduce the switching losses in associated with conventional converters; resonant inductor and resonant capacitor (LC resonant circuit) is applied which helps to turn on-off the switch at zero current. The dc-dc buck converter receives the energy from the input source, when the switch is turned-on. If the switch is turned-off the LC resonant circuit pumps the energy by ensuring that the current does not come to zero. During the hardware implementation Ton, Toff, duty cycle & operating frequency values were determined and thoroughly tuned through the NE555 IC circuit. As a result of this various waveforms across capacitors,inductors and load resistor were observed. A simulation study was carried out and the effectiveness of the designed converter is verified by PSpice simulation results.
The power electronics device which converts DC power to AC power at required output voltage and frequency level is known as inverter. Multilevel inverter is to synthesize a near sinusoidal voltage from several levels of dc voltages. In order to maintain the different voltage levels at appropriate intervals, the conduction time intervals of MOSFETS have been maintained by controlling the pulse width of gating pulses. In this paper single phase to three phase power conversion using PWM technique. The simulation is carried out in MATLAB/Simulink environment which demonstrate the feasibility of proposed scheme.
This paper presents investigation and performance analysis of novel down sampling based clamping SV PWM technique for diode and cascaded Multi-level Invereter fed to Induction motor drive. A novel down sampling based clamping SVPWM has developed by adding triangular off set to sinusoidal fundamental waveform is modified by down sampling the reference wave by order of 10 so this technique is called clamping space vector pulse width modulation techniques such as PD, POD and APOD. so as to shift the lower order harmonics to higher order side. This novel carrier is compared with the offset injected space vector reference waveform to generate the required PWM pulses to the inverter. To analyze the performance of the proposed PWM technique it is implemented on seven level diode and cascaded Multi-level Inverter using Matlab/Simulink software tool for output line, phase voltage, currents, speed, torque and Total harmonic distortion analysis.
Design and Simulation of Low Pass Filter for Single phase full bridge Inverte...IJERA Editor
Sinusoidal pulse width modulation SPWM technique is widely preferred to other modulation techniques as the
Inverter output frequency obtained is equal to the required fundamental frequency. SPWM with unipolar voltage
switching is used as it results in cancellation of harmonic component at the switching frequencyin the output
voltage, also the sidebands of the switching frequency harmonics disappear and in addition to this, other
dominant harmonic at twice the switching frequency gets eliminated. Hence, due to these advantages unipolar
voltage switching with SPWMis used for Inverter switching. In this paper, an in-depth analysis of unipolar
voltage switching technique with SPWM as applied to a single-phase full bridge Inverter is described and
designing of an efficient, active low pass filter LPF is discussed for an particular cut-off frequency,푓푐 and
damping factor zeta, 휁 and the filter is placed at the output side of a single-phase full bridge Inverter and
therefore eliminating the harmonic component from the Inverter output voltage resulting in a pure sinusoidal ac
voltage waveform.
Sinusoidal PWM and Space Vector Modulation For Two Level Voltage Source Conve...ZunAib Ali
Complete detail of Sinusoidal PWM and Space Vector Modulation For Two Level Voltage Source Converter
Space Vector Modulation includes:
Switching states, space vector, space vector diagram, space vector and switching states relationship, Dwell time, switching sequence
To overcome the problem of mismatched voltage levels between parallel-connected low voltage photovoltaic (PV)
arrays and the higher grid voltage, a hybrid boost three level dc-dc converter is developed based on three level inverter with
the traditional single phase diode clamping. Only one inductor, two capacitors in series, and those power switches and diodes,
which are easy to be integrated, are used for establish the topology with transformerless high voltage gain. The operation
principle of the topology is analyzed, and then the pulse width modulation (PWM) control method is obtained according to
the switching functions about the output pulse voltages of both half-bridges. Therefore, the converter can not only operate
with high voltage gain, but also make the duty cycles of power switches closer to 0.5. A feedforward closed loop control
operation is proposed such that even in varying input the converter is capable of giving a constant output. Finally an
experimental is set up in the laboratory for open loop control operation. All experimental results verify the feasibility of the
circuit and validity of the PWM control method.
Levels of PAHs and Potentially Toxic Metals in Three Species of Fresh and Smo...IOSR Journals
Three samples of fish, Scomber japonica (titus), Sardinellaeba (sardine) and Merlucciuspolli (fresh stock fish) were collected from Ojo main market in Lagos. Two low molecular weight polycyclic aromatic hydrocarbons (naphthalene and anthracene) were determined using high performance liquid chromatography, (HPLC), after extraction with n-hexane by ultrasonication and clean up using SPE cartridges. Heavy metals were determined in the samples using atomic absorption spectrometer, (Perkin Elmer, Analyst 200) after digestion with aqua regia. The fat content was determined gravimetrically. The unsmoked samples had naphthalene range from 0.0788±0.0078 μg/g in Merlucciuspolli to 0.3845±0.0199 μg/g in Scomber japonica. Anthracene levels ranged from 0.4798± 0.0072 μg/g in unsmoked samples of Merlucciuspolli to 1.2254±0.0071 μg/g in Scomber japonica. The low fat containing specie (Merlucciuspolli) accumulated PAHs over the smoking periods, while a decrease was observed in the high fat containing species (Scomber japonica and Sardinellaeba). The highest concentration of Pb (8.65 μg/g), Cu (9.53 μg/g), Fe (201.80 μg/g) and Zn (122.15 μg/g) in the unsmoked fishes were found in unsmoked Scomber japonica while the highest concentration of Cr (13.68 μg/g) and Ni (5.88 μg/g) in the fishes were found in the unsmoked Merlucciuspolli. Cadmium was not detected in all the samples. The low fat containing specie showed increase in heavy metals over the smoking periods, while the high fat containing species also accumulated these heavy metals at 1 hour smoking period, but a decrease was noted over the 2 hours and 3 hours smoking periods. Smoking has effect on the level of these toxicants, as PAHs and heavy metals tend to accumulate on smoking. Smoking appeared to influence toxicants levels the fishes. Levels of the PAHs were higher than the regulatory permissible limits of the World Health Organization. Levels of the toxic metals were within the WHO set permissible limits except for Pb (in unsmoked Scomber japonica), Fe (in Sardinellaeba smoked for 1 and 2 hours, and in Merlucciuspolli smoked for 2 and 3 hours) and Cr (in all the samples).
SIMULATION ANALYSIS OF CLOSED LOOP DUAL INDUCTOR CURRENT-FED PUSH-PULL CONVER...Journal For Research
The current electronic devices require DC power source, which is taken from a battery or DC power supply. DC-DC converter is utilized to get regulated dc voltage from unregulated one. Switched mode power supply (SMPS) are commonly used in industrial applications, because of more advantages compared to linear power supply. In SMPS we have isolated and non-isolated converters, where isolated converters are frequently used, in order to get more voltage with multiple outputs. So among different isolated converters, push-pull converter is chosen for micro converter applications to obtain high voltage conversion ratio by using HF transformer, due to their better utilization of transformer. New methodology of control is implemented for making ZVS and ZCS at same time and to reduce the number of switches in the secondary side of dual inductor CFPP converter, which is a voltage doubler circuit. This becomes the solution for problem identification. Thus this converter with soft-switching reduces the switching losses.The current-fed push-pull converters are used in many applications like photo-voltaic (PV) power converters for boosting the output voltage. Push-pull converter is chosen for micro converter applications, to obtain high voltage conversion ratio by using high frequency (HF) transformer, due to their better utilization of transformer. This deals with the design of dual inductor CFPP converter, where zero voltage switching (ZVS) and zero current switching (ZCS) is achieved for the primary side of the converter by using secondary switches. Primary side switches are controlled by closed loop control topology. The secondary side is made with voltage doubler to obtain high voltage. Open loop and closed loop control of dual inductor current fed push pull converter simulation is finished by MATLAB/SIMULINK and their outcomes are analyzed.
Multilevel inverters (MLI) are becoming more popular over the years for medium and high power applications because of its significant merits over two level inverters. This paper presents an implementation of multicarrier based sinusoidal pulse width modulation technique for three phase seven level diode clamped multilevel inverter. This topology is operated under phase opposition disposition pulse width modulation technique. The performance of three phase seven level diode clamped inverter is analyzed for induction motor (IM) load. Simulation is performed using MATLAB/SIMULINK. Experimental results are presented to validate the effectiveness of the operation of the diode clamped multilevel inverter using field programmable gate array.
Open Loop and Closed Loop Performance of Switched Reluctance Motor with Vario...IAES-IJPEDS
Switched reluctance motor (SRM) is becoming popular because of its simple construction, robustness and low-maintenance. This motor is very useful for high speed applications because no windings are placed on rotor and can also be used for variable speed applications in industries. Converter is one of the important elements in SRM which plays a very crucial role. In this paper various converter topologies for 6/4 switched reluctance motor and Asymmetric bridge converter topology for 8/6 switched reluctance motor are discussed. Finally a closed loop for each converter topology is proposed. The converter topologies are simulated by using MATLAB/SIMULINK. Constant speed is achieved in closed loop control.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
ANALYSIS, DESIGN AND IMPLEMENTATION OF ZERO-CURRENT-SWITCHING RESONANT CONVER...hunypink
This paper presents a Buck type circuit structure, the designing of ZCS resonant Buck converter and analysis of the working principles involved. The designed buck converter uses ZCS technique and the function is realized so that the power form is converted from 12V DC to 5V DC (1A). A detailed analysis of zero current switching buck converters is performed and a mathematical analysis of the mode of operation is also presented. In order to reduce the switching losses in associated with conventional converters; resonant inductor and resonant capacitor (LC resonant circuit) is applied which helps to turn on-off the switch at zero current. The dc-dc buck converter receives the energy from the input source, when the switch is turned-on. If the switch is turned-off the LC resonant circuit pumps the energy by ensuring that the current does not come to zero. During the hardware implementation Ton, Toff, duty cycle & operating frequency values were determined and thoroughly tuned through the NE555 IC circuit. As a result of this various waveforms across capacitors,inductors and load resistor were observed. A simulation study was carried out and the effectiveness of the designed converter is verified by PSpice simulation results.
The power electronics device which converts DC power to AC power at required output voltage and frequency level is known as inverter. Multilevel inverter is to synthesize a near sinusoidal voltage from several levels of dc voltages. In order to maintain the different voltage levels at appropriate intervals, the conduction time intervals of MOSFETS have been maintained by controlling the pulse width of gating pulses. In this paper single phase to three phase power conversion using PWM technique. The simulation is carried out in MATLAB/Simulink environment which demonstrate the feasibility of proposed scheme.
This paper presents investigation and performance analysis of novel down sampling based clamping SV PWM technique for diode and cascaded Multi-level Invereter fed to Induction motor drive. A novel down sampling based clamping SVPWM has developed by adding triangular off set to sinusoidal fundamental waveform is modified by down sampling the reference wave by order of 10 so this technique is called clamping space vector pulse width modulation techniques such as PD, POD and APOD. so as to shift the lower order harmonics to higher order side. This novel carrier is compared with the offset injected space vector reference waveform to generate the required PWM pulses to the inverter. To analyze the performance of the proposed PWM technique it is implemented on seven level diode and cascaded Multi-level Inverter using Matlab/Simulink software tool for output line, phase voltage, currents, speed, torque and Total harmonic distortion analysis.
Design and Simulation of Low Pass Filter for Single phase full bridge Inverte...IJERA Editor
Sinusoidal pulse width modulation SPWM technique is widely preferred to other modulation techniques as the
Inverter output frequency obtained is equal to the required fundamental frequency. SPWM with unipolar voltage
switching is used as it results in cancellation of harmonic component at the switching frequencyin the output
voltage, also the sidebands of the switching frequency harmonics disappear and in addition to this, other
dominant harmonic at twice the switching frequency gets eliminated. Hence, due to these advantages unipolar
voltage switching with SPWMis used for Inverter switching. In this paper, an in-depth analysis of unipolar
voltage switching technique with SPWM as applied to a single-phase full bridge Inverter is described and
designing of an efficient, active low pass filter LPF is discussed for an particular cut-off frequency,푓푐 and
damping factor zeta, 휁 and the filter is placed at the output side of a single-phase full bridge Inverter and
therefore eliminating the harmonic component from the Inverter output voltage resulting in a pure sinusoidal ac
voltage waveform.
Sinusoidal PWM and Space Vector Modulation For Two Level Voltage Source Conve...ZunAib Ali
Complete detail of Sinusoidal PWM and Space Vector Modulation For Two Level Voltage Source Converter
Space Vector Modulation includes:
Switching states, space vector, space vector diagram, space vector and switching states relationship, Dwell time, switching sequence
To overcome the problem of mismatched voltage levels between parallel-connected low voltage photovoltaic (PV)
arrays and the higher grid voltage, a hybrid boost three level dc-dc converter is developed based on three level inverter with
the traditional single phase diode clamping. Only one inductor, two capacitors in series, and those power switches and diodes,
which are easy to be integrated, are used for establish the topology with transformerless high voltage gain. The operation
principle of the topology is analyzed, and then the pulse width modulation (PWM) control method is obtained according to
the switching functions about the output pulse voltages of both half-bridges. Therefore, the converter can not only operate
with high voltage gain, but also make the duty cycles of power switches closer to 0.5. A feedforward closed loop control
operation is proposed such that even in varying input the converter is capable of giving a constant output. Finally an
experimental is set up in the laboratory for open loop control operation. All experimental results verify the feasibility of the
circuit and validity of the PWM control method.
Levels of PAHs and Potentially Toxic Metals in Three Species of Fresh and Smo...IOSR Journals
Three samples of fish, Scomber japonica (titus), Sardinellaeba (sardine) and Merlucciuspolli (fresh stock fish) were collected from Ojo main market in Lagos. Two low molecular weight polycyclic aromatic hydrocarbons (naphthalene and anthracene) were determined using high performance liquid chromatography, (HPLC), after extraction with n-hexane by ultrasonication and clean up using SPE cartridges. Heavy metals were determined in the samples using atomic absorption spectrometer, (Perkin Elmer, Analyst 200) after digestion with aqua regia. The fat content was determined gravimetrically. The unsmoked samples had naphthalene range from 0.0788±0.0078 μg/g in Merlucciuspolli to 0.3845±0.0199 μg/g in Scomber japonica. Anthracene levels ranged from 0.4798± 0.0072 μg/g in unsmoked samples of Merlucciuspolli to 1.2254±0.0071 μg/g in Scomber japonica. The low fat containing specie (Merlucciuspolli) accumulated PAHs over the smoking periods, while a decrease was observed in the high fat containing species (Scomber japonica and Sardinellaeba). The highest concentration of Pb (8.65 μg/g), Cu (9.53 μg/g), Fe (201.80 μg/g) and Zn (122.15 μg/g) in the unsmoked fishes were found in unsmoked Scomber japonica while the highest concentration of Cr (13.68 μg/g) and Ni (5.88 μg/g) in the fishes were found in the unsmoked Merlucciuspolli. Cadmium was not detected in all the samples. The low fat containing specie showed increase in heavy metals over the smoking periods, while the high fat containing species also accumulated these heavy metals at 1 hour smoking period, but a decrease was noted over the 2 hours and 3 hours smoking periods. Smoking has effect on the level of these toxicants, as PAHs and heavy metals tend to accumulate on smoking. Smoking appeared to influence toxicants levels the fishes. Levels of the PAHs were higher than the regulatory permissible limits of the World Health Organization. Levels of the toxic metals were within the WHO set permissible limits except for Pb (in unsmoked Scomber japonica), Fe (in Sardinellaeba smoked for 1 and 2 hours, and in Merlucciuspolli smoked for 2 and 3 hours) and Cr (in all the samples).
Exact Analytical Expression for Outgoing Intensity from the Top of the Atmosp...IOSR Journals
This research is a part of the work devoted on the application of analytical Discrete Ordinate (ADO) method to the polarized monochromatic radiative transfer equation undergoing anisotropic scattering with source function matrix in a finite coupled Atmosphere –Ocean media having flat interface boundary conditions involving specular reflection and transmission matrix. Discontinuities in the derivatives of the Stokes vector with respect to the cosine of the polar angle at smooth interface between the two media with different refractive indices (air and water) is tackled by using a suitable quadrature scheme devised earlier. Atmosphere and ocean are assumed to be homogeneous. No stratification is adopted in the two media. Exact expression for the
emergent radiation intensity vector from the top of the atmosphere is derived. Exact expressions for the emergent polarized radiation intensity vector from the air-water interface as well as from any point of the two medium in any direction can also be derived in terms of eigenvectors and eigenvalues.
Influence of chimney effect on the radon effective dose of the lung simulated...IOSR Journals
One of the well-known radon prone areas of the world is Ramsar in Iran, which is surrounded by the
Alborz Mountain in its southern part and Caspian Sea on the north. The annual effective dose in the district of
Talesh-Mahalleh is higher than the annual dose limits for radiation workers. In this study, the indoor radon
level and effective dose of the lung were estimated using a Prassi portable radon gas survey meter in a model
house containing top soil samples from different parts of Ramsar. For the extremely hot samples, the effective
dose of the lung in winter season was 27.75±2.55mSv, when the windows and exhaust part of chimney were
closed. However, when the chimney was turned on and the exhaust part of chimney was open, the effective dose
of the lung was reduced to 1.27±0.23mSv. Also the seasonal radon effective doses of the lung with other samples
were reduced to low values. The results suggest by using chimney effect and chimney heaters a significant
lessening of the radon seasonal effective dose in dwellings of Ramsar can be achieved.
Encephalization – An Evolutionary Predisposition to Diabetes: A “Large Brain ...IOSR Journals
Primates have proportionately three times larger brain as compared to that of other mammals of comparable size and humans, in turn, have three times larger brain as compared to that of all other primates of similar size. So we need to meet higher energy demands because brain is energetically expensive. This has a significant impact on our dietary patterns in addition to shaping of our body composition. Here we propose that our dietary patterns to meet our higher energy demands have been ultimately set by the instinct of higher energy intake and our larger brains have a stress effect on our metabolic organs (organs involved in energy metabolism like gut, liver, pancreas etc.). We discuss these two points from evolutionary (Evolutionary instinct) and physiological (Metabolic stress) point of view and argue that these two points explain the manifestation of diabetes primarily as a human disease and enhance our understanding of its mechanism.
“Impact of Demographics and Personality traits on Confidence level: Determina...IOSR Journals
The purpose of this study is to explore the relationship among demographics, personality traits and level of confidence. The impact of this paper is twofold, one is to measure the determinants of overconfidence in employees and other is in students. This paper adopts the primary data approach, collected from employees and students through questionnaires .Two diverse populations have been selected and various statistical technique (Pearson correlation, Pearson regression, Chi-square, and Kolmogorov-Smirnov tests) are used for analysis purpose using SPSS software on a 100 sample size. Research findings shows that in employees when Openness to experience increase , overconfidence level decrease, however all remaining personality traits(conscientiousness, agreeableness, emotional stability and openness to experience) is correlated with overconfidence. In students there is no correlation between overconfidence and any of the personality traits. The regression analysis findings show that no linear relationship exists between independent and dependent variable in employees for individual personality traits except of emotional stability. Only emotional stability has a significant predictor of overconfidence among all five personality traits. However the overall personality is the significant predictor of overconfidence in employees. For students, neither individual personality traits nor overall personality has linear relationship with overconfidence.
Monitoring Of Macronutrients Uptake by Soil and Potato Plants – A Comparative...IOSR Journals
Soil test1, 2 is necessary to identify optimal concentrations of essential elements required for plant growth. The fertility of soil is affected by the presence of some essential elements as Macronutrients like N, P& K. This study including the status of Macronutrients in the soil and potato plans. The percentage of nitrogen (N) in soil of potato plant was obtained 5.6% and 1.89% where as nitrogen percentage in plant ash was 17.45% and 16.4% respectively. But the phosphorus and potassium are present in adequate amount in soil. As it was found that the concentration of phosphorus (P) and potassium (K) in part per million in soil of potato was 62ppm and 148.3ppm and in potato plant ash the concentration was 64.23ppm and 103.3ppm respectively.
Antibacterial Application of Novel Mixed-Ligand Dithiocarbamate Complexes of ...IOSR Journals
Nine stable mixed ligand dithiocarbamate complexes of Nickel (II) ion were prepared. The complexes were characterized with electronic spectroscopy, infrared spectroscopy, conductance measurement, melting point and percentage metal analysis. Resulting analytical data gave credence to the assignment of a tentative square planar geometry to all the complexes. The complexes were proposed to have a general formulae of [Ni(Sal)(Rdtc)], where Sal = salicylaldehyde; R = dibenzylamine(Bz2NH), methylphenylamine(MePhNH),pyrrolidineamine(pyrrolNH),piperidineamine(piperNH),morpholineamine(MorpNH), anilineamine(AnilNH), para-chloroanilineamine(p-ClAnilNH), toludineamine(TolNH) and anisidineamine(AnisNH); and dtc = dithiocarbamate anion. The metal complexes were screened against six different bacteria strain using Agar diffusion method. The antibacterial studies reveal that the metal complexes exhibit broad spectrum antibacterial activity against Escherichia coli, Staphylococcus aureus, Klebsiella oxytoca and Pseudomonas aureginosa with inhibitory range of 10.5.—20.0mm.
I- Function and H -Function Associated With Double IntegralIOSR Journals
The object of this paper is to discuss certain integral properties of a I -function and H -function,
proposed by Inayat-Hussain which contain a certain class of Feynman integrals, the exact partition of a Gaussian
model in Statistical Mechanics and several other functions as its particular cases. During the course of finding,
we establish certain new double integral relation pertaining to a product involving I function and H function.
These double integral relations are unified in nature and act as a key formulae from which we can obtain as their
special case, double integral relations concerning a large number of simple special functions. For the sake of
illustration, we record here some special cases of our main results which are also new and of interest by
themselves. All the result which are established in this paper are basic in nature and are likely to find useful
applications in several fields notably electrical network, probability theory and statistical mechanics.
Nuclear Magnetic Resonance (NMR) Analysis of D - (+) - Glucose: A Guide to Sp...IOSR Journals
NMR spectroscopy has a wide range of applications including exchange phenomena, the
identification and structural studies of complex biomolecules. 1D 1H-NMR without water suppression, 1D
Carbon, 1D 13C-DEPT135, 2D Cosy, 2D HSQC, 2D TOCSY, 2D HMQC, and 2D HMBC techniques were used
to completely elucidate the structure of glucose with spectral induced at 400MHz.. The spectral were analysed
using spinworks 3. The results obtained from the spectral data were systematically combined to elucidate the
structure of the D-glucose. Full characterisation of D-glucose was achieved by assigning 1H and 13C signals,
starting from the known to unknown signals.
Study of Optical Property of Gel Grown Mercuric Iodate CrystalsIOSR Journals
Mercuric Iodate Crystals were grown by a simple gel technique using diffusion method. The optimum growth conditions were established for the growth of these crystals by changing various parameters such as pH of the gel solution, gel concentration, gel setting time, concentrations of reactants etc. The grown Mercuric Iodate crystals were spherical in shape. These crystals were opaque. The crystals were characterized using UV-VIS Specrophotometrry.
Design & Implementation of Zero Voltage Switching Buck ConverterIJERA Editor
Zero voltage switching (ZVS) buck converter is more preferable over hard switched buck converter for low power, high frequency DC-DC conversion applications. In Zero voltage switching converter, turn on & turn off of a switch occurs at zero voltage that results in lower switching losses. In this converter soft switching is achieved by using resonant components. The optimal values of resonant components are determined by using electric functions derived from circuit configuration. This type of soft switched resonant converter offers very low electromagnetic interference (EMI).This study presents the circuit configuration with least components to realize highly efficient zero voltage switching resonant converter. It’s feasibility is confirmed with the developed proto type model and experimental results are verified.
A Single-Stage High-Frequency Isolated Secondary- Side Controlled AC-DC Conve...IDES Editor
This paper presents a new single-stage highfrequency
isolated ac-dc converter that uses a simple control
circuit. It is well suitable for wide input variation power
sources. The circuit configuration combines a diode rectifier,
boost converter and half-bridge dc-dc resonant converter. A
high power factor is achieved by discontinuous current mode
(DCM) operation of the front-end integrated power factor
correction circuit. The output voltage is regulated by fixedfrequency,
secondary-side phase-shift active rectifier. Softswitching
operation is achieved for all the switches. This
converter operates in three modes, which is classified
according to conduction of different switches and diodes. The
intervals of operation and steady-state analysis are presented
in detail. Design example of a 100 W proposed converter is
given together with its simulation and experiment results for
wide variation in input voltage.
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
Abstract: AC-DC soft-switching resonant converter with interleaved boost power factor corrector (PFC) is presented. In this converter, an interleaved boost PFC circuit is integrated with a soft-switching resonant converter. High power factor is achieved by the interleaved boost PFC circuit. The input current can be shared among the inductors so that high reliability, power factor and efficiency in power system can be obtained and ripples are also reduced. Another advantage of interleaved technique is reduction of THD. Thus the converter performance can be improved. The voltage across the main switches is confined to the dc-link voltage. Soft-switching operation of main switches and output diodes is achieved. Hence the switching losses are reduced significantly. Therefore, the overall efficiency is improved. Circuit is simulated with 110V AC input voltage and 45V DC output voltage is verified. Performance parameters such as voltage stress and output ripple are also analyzed. The simulation is done in PSIM. Power factor of 0.96 is achieved with this converter. For the hardware, dsPIC30F2010 is used for generating PWM pulse with switching frequency 90 kHz.
Keywords: Power factor correction (PFC), Soft switching, Resonant converter, Interleaved Boost converter.
Title: Resonant AC-DC Converter with Interleaved Boost PFC
Author: Aqulin Ouseph, Prof. Kiran Boby, Prof. Neena Mani
ISSN 2349-7815
International Journal of Recent Research in Electrical and Electronics Engineering (IJRREEE)
Paper Publications
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Phase-Shifted Full-Bridge Zero Voltage Switching DC-DC Converter Design with ...IJECEIAES
Design of phase-shifted full bridge zero voltage switching DC-DC converter has been very challenging due to circuit parasitic effect on the system dynamics. This paper presents steady-state analysis and iterative approach for the systemic design of phase-shifted full bridge DC-DC converter with improved dynamic performance and satisfactory operational requirement in terms of zero-voltage switching range, operating switching frequency and switching resonance. A 3 kW DC-DC converter is designed using the iterative design approach and the system dynamics performance was investigated in the MATLAB/Simulink environment. The converter zerovoltage switching simulation results were satisfactory with 90% efficiency under full load condition.
Review of Step down Converter with Efficient ZVS OperationIJRST Journal
This paper presents the review of step down converter with efficient ZVS operation. The designed buck converter uses ZCS technique and the function is realized so that the power form is converted from 12V DC 5V DC (1A). A detailed analysis of zero current switching buck converters is performed and a mathematical analysis of the mode of operation is also presented. In order to reduce the switching losses in associated with conventional converters; resonant inductor and resonant capacitor (LC resonant circuit) is applied which helps to turn on-off the switch at zero current. The dc-dc buck converter receives the energy from the input source, when the switch is turned-on. The buck–buck converters have characteristics that warrant a more detailed study. The buck converters under discontinuous conduction mode /continuous conduction mode boundary.
This project envisages a Buck dc – dc
converter mathematical analysis and simulation. This power
regulator is made up of some vital circuit elements such as
inductor, freewheeling diode, filter capacitor and electronics
power switch. The circuit is analysed based on two modes of
operation namely: continuous current conduction mode and
discontinuous current mode. Ansoft Simplorer software is
used to carry out the circuit simulation under the two modes
of operation which aided in verifying the calculated results.
Both calculated and simulated waveforms are displayed. The
results obtained are very similar.
A High Step Up Hybrid Switch Converter Connected With PV Array For High Volt...ijitjournal
T
his paper
presents
a
ste
p up DC
-
to
-
DC converter with
hybrid switch capacitor technique having
high
voltage conversion ratio with small
switch voltage stress
. The converter is suitable for the applications
where high voltage conversion is required. The proposed
DC
-
DC converter
has low voltage ratted
MOSFET switch and is connected to PV array to get high output voltage at small duty ratios.
Hence it has
high efficiency.
The principles of operations and the theoretical analysis are presented in this paper.
All the
simulations are
done in MATLAB
-
SIMULINK Environment and
results were obtained with voltage
conversion ratio of 4.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf91mobiles
91mobiles recently conducted a Smart TV Buyer Insights Survey in which we asked over 3,000 respondents about the TV they own, aspects they look at on a new TV, and their TV buying preferences.
Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
1. IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE)
e-ISSN: 2278-1676,p-ISSN: 2320-3331, Volume 11, Issue 3 Ver. II (May. – Jun. 2016), PP 28-32
www.iosrjournals.org
DOI: 10.9790/1676-1103022832 www.iosrjournals.org 28 | Page
Design Consideration for High Power Zero Voltage Zero Current
Switching Full Bridge Converter with Transformer Isolation and
Current Doubler Rectifier
Noor Ahmad1
, Awadhesh Kumar2
1
PG Scholar Department of Electrical Engineering Madan Mohan Malaviya University of Technology
Gorakhpur
2
Assistant Professor Department of Electrical Engineering Madan Mohan Malaviya University of Technology
Gorakhpur
Abstract: This paper presents the design and analysis and of the proposed zero voltage zero current switching
(ZVZCS) full bridge dc-dc converter with transformer isolation and current doubler rectifier for high power and
high performance by introducing ZVS for lagging leg and ZCS for leading leg operation It has a simple and
robust structure with asymmetrical shifted pulse width modulation technique. The ZVS operation is achieved
with the help of transformer leakage inductance and output capacitance of the switches for passive leg and to
obtain ZCS operation auxiliary transformer and two diodes are used for leading leg. Validation of the designed
parameters are verified by simulation of the proposed converter with a load of 3kW and converter operating
frequency is at 20kHz with a feature of current doubler rectifier.
I. Introduction
The use of conventional dc-dc converter with hard switching condition gives considerable switching
losses for various applications. With the use of soft switching technique in the conventional converters greatly
reduce the switching losses as switching losses are proportional to the switching frequency used generally
required wide range of frequency control. Quasi-Resonant converter and multi-resonant converter reduces the
frequency range [1,2 ] but high component stress make them impractical for high power applications. The
constant frequency converter are introduced [3,4 ] can provide ZVS and ZCS but component stress is large and
also EMI for high switching frequency. This makes the considerable detrition in the the overall converter
efficiency. There are many number of switching techniques are used to reduce the switching losses in the
converter topology [5]-[6]. These topologies uses high frequency to reduce the system size and weight. The
proposed ZVZCS full bridge dc-dc converter with transformer isolation and current doubler rectifier are used to
reduce the switching losses considerably by using parasitic capacitances of the switches to achieve the ZVS
operation of the lagging leg and ZCS operation of the leading leg with the use of the auxiliary transformer for
the shifted phase PWM converter. The operation of the converter allows the MOSFET switch capacitances to
make resonance with transformer leakage inductance to achieve the ZVS operation and auxiliary transformer
with diodes to reset the input current to achieve the ZCS operation of leading leg in ZVZCS full bridge dc-dc
converter with transformer isolation and current doubler rectifier.
Figure1.The proposed ZVZCS Converter
II. Circuit Configuration And Principle Of Operation
The proposed ZVZCS full bridge dc-dc converter with transformer isolation and current doubler
rectifier is shown in fig (1). In this converter the auxiliary circuit contain an auxiliary transformer and two
diodes for achieving ZCS condition for the leading leg transition of the switch. The primary winding of the
transformer is connected in series with the primary winding of the auxiliary transformer and the secondary
2. Design Consideration for High Power Zero Voltage Zero Current Switching Full Bridge Converter...
DOI: 10.9790/1676-1103022832 www.iosrjournals.org 29 | Page
winding of the auxiliary transformer is connected between the lagging leg and leading leg of the converter. To
obtain the appropriate phase delay for ZVZCS operation shifted phase PWM is used to control the output of the
controller. The ZVS condition is obtained on lagging leg with components CM2, CM4, Llk, Lf1 and Lf2 of the circuit
while the leading leg ZCS condition is operated by primary current. Llk is the leakage inductance of the both
main transformer and auxiliary transformer. The capacitances CM2, CM4 of the switch M2 and M4 provides ZVS
off of the switch M2 and M4 when turned off. Llk, Lf1 and Lf2 provide ZVS on by changing the voltage of C2 and
C4 in opposite and causing primary current flow through DM2 and DM4 prior to turn off the switch M2 and M4.
The leading leg operates in ZCS condition with the help of auxiliary circuit by introducing resetting voltage and
absorbs the trapped leakage inductor reactive energy and also provide resetting to the primary current prior to
switch transition. The key waveforms and operating modes are shown in the fig (2) and fig (3).
Figure2. Key waveforms of the converter
III. Modes Of Operation
The proposed converter operation is divided in five modes during complete cycle of the switching
frequency. For simplicity and ease of calculation the magnetising inductance of the primary and secondary
transformer is neglected.
MODE 1( t1 – t2 ) : The switch S1 and S2 are in conduction and power to the output is delivered through main
transformer, Df2, Lf1 and Lf2. The secondary winding of the auxiliary transformer is shorted by DA3 and S4. The
diode current at the output side is iDf2 =0 and the load current is given by iLo1 + iLo2 = Io. The switch current of S4
is the primary current of the circuit.
MODE 2( t2 – t3 ) : This mode initiated with the turning off of the switch S4. Resonance is created with the help
of C2, C4, Llk, Lf1 and Lf2 and the frequency of resonance is given by
2
lk f1 f2 eq1/ (L n (L L ))Co (1)
And equivalent capacitance is given as
2
eqC 2 ( / 1)C n n (2)
The voltage across S4 increases through zero results in ZVS turn off of the switch S4.
MODE 3( t3 – t4 ) : The switch S4 voltage reaches to maximum value, primary current flows through D2 diode of
the switch S2. The leakage inductor reactive energy is recovered to the dc side and the primary current decreases
to zero by the auxiliary transformer as
Vaux = ( Vdc / n) (3)
The D2 diode in conduction and switch S2 can be turned on through ZVS.
MODE 4 ( t4 – t5 ) : This mode shows the primary current becomes zero and the load current freewheels through
Df1 and Df2 diodes of the secondary. The switch S1 can be turned off with ZCS condition and the load current is
given by
iDf1 + iDf2 = Io (4)
3. Design Consideration for High Power Zero Voltage Zero Current Switching Full Bridge Converter...
DOI: 10.9790/1676-1103022832 www.iosrjournals.org 30 | Page
MODE 5 ( t5 – t6 ) : The switch S3 is turned on with ZCS condition and primary current flows through S2 and S3.
The secondary auxiliary transformer is shorted by diode DA1 and S2 switch. The load current is transferred from
the secondary diode Df2 to Df1.
This completes the one cycle of the converter operation in which ZVS and ZCS conditions are obtained
for the switches. From this mode 1 is initiated with switch S2 and S3 are in conduction mode.
IV. Circuit Description
ZVS for lagging leg is achieved by the resonance criteria with the help of main transformer leakage
reactance and ZCS is achieved with the help of auxiliary transformer by suppressing the primary current of the
main transformer. For ZVS operation of the lagging switches the parasitic capacitance voltage must real to the
positive maximum and the energy in the leakage inductor must be higher to make the resonance condition at the
primary side of the main transformer. The energy is given as
E = (1/2)IlkIP
2
> (4/3)CMOS + (1/2)CtrVdc
2
(5)
The time for ZVS operation of the lagging switch is given as
TZVS = t3 –t2 = CeqVdc / I1 (6)
And the ZCS time can be calculated as
TZCS = t4 – t3 = LlkI1 / Vaux (7)
The TZCS can be minimum and maximum according to the primary current as minimum and maximum. The
condition for safe ZCS operation is given as
TZCS max < (1 - Dmax) (8)
Dead Time Between Pulses:
The lagging leg dead time is between t2 and t3 as shown in the figure (2), denoted by Td2-4. The left term
defined as TZVS and the right term is as TZVS + TZCS denoted below
TZVSmax < Td2-4 < TZVSmax + TZCSmin (9)
For leading leg dead time is denoted by Tdl-3 between t4 and t5 as the dead time for safe limit of the switching is
given as
Tdl-3 < ( 1 - Dmax )Ts - TZCSmax (10)
Main Ttransformer:
The main transformer is used with a high frequency of 20 kHz and the leakage inductance is 1.5 µH. The
converter is operated with low duty ratio of 0.45 as open circuit voltage is considerable for many applications.
Auxiliary Transformer:
ZCS operation is achieved by auxiliary transformer to reduce the losses due to switching but there is
additional conduction loss due to flow of current in the auxiliary transformer and depend upon turn ratio and
duty cycle of the auxiliary transformer. In welding purpose duty ratio is low as there is high open circuit is
required therefore low conduction losses. The power delivered by auxiliary transformer to the source is given by
Paux = 0.5 LlkI1
2
2fs (11)
The power rating of the auxiliary transformer is low enough as 7% and the current rating of secondary
side of main transformer is low due to current doubler rectifier giving not much conduction loss in the converter.
V. Design Description
The design of the proposed converter is described as the input voltage of the converter is Vdc = 600
volts; output voltage is taken as Vo = 70 volts with the output current as Io = 29 ampere as a dc with a high
switching frequency of 20 kHz, the other parameters of the simulation model with result are given as
4. Design Consideration for High Power Zero Voltage Zero Current Switching Full Bridge Converter...
DOI: 10.9790/1676-1103022832 www.iosrjournals.org 31 | Page
Transformer main: n = N1/N2 =600/400, Llk = 1.5µH; Auxiliary Transformer: n1 = N1/N2 = 400/500; Parasitic
capacitance of switch: C = 6 nf;
Output inductor: Lo1 = 320 µH, Lo2 = 345 µH;
Output capacitor: Co = 150.5 µf;
The ripple current from the magnetising inductance of the main transformer is found to be
Δim = nVoTs / Lm (12)
Here we consider that the ripple current through each filter inductor is about 30% of the maximum load current,
therefore α = 0.3 and the output filter inductor is found as the formula
Lo1 = 2VoDmaxTs / αDmax Io max (13)
Lo2 = 2VoDmaxTs / α(1 – Dmax ) Io max (14)
The proposed converter having the value of Δim = 4.6 ampere and Lo1 = 320 µH and Lo2 = 345 µH.
VI. Simulation Analysis
A 2kW model is developed and constructed on mat lab Simulink software. The input of 600 volt dc is
applied and the output is taken as 70 volt with a high current of 29 ampere as a dc with a high switching
frequency of 20 kHz Figure 4. signifies the ZVS-Off condition of the lagging leg switch S4. Waveform of drain
to source voltage of switch S4 and gate signal is shown. Figure 5. signifies the ZVS-On condition of the
lagging leg switch S2. Waveforms of drain to source voltage of switch S2 and gate pulse is shown. Figure 6.
signifies the ZCS-Off condition of the leading leg switch S1. Waveforms of the input primary current and gating
signal is shown. Figure 7. signifies the ZCS-On condition of the leading leg switch S3. Waveform of the input
primary current and gating signal is shown.
Figure4. PWM gate signal and VDS (Volts) of switch S4.
Figure5. PWM gate signal and VDS (Volts) of switch S3.
Figure 6. PWM gate signal and input primary current (Ampere) of S1.
5. Design Consideration for High Power Zero Voltage Zero Current Switching Full Bridge Converter...
DOI: 10.9790/1676-1103022832 www.iosrjournals.org 32 | Page
Figure 7. PWM gate signal and input primary current (Ampere) of S2.
VII. Conclusion
A modified ZVZCS full bridge converter is proposed using auxiliary transformer and current doubler
rectifier. The converter operates with ZVS for lagging leg and ZCS for leading leg switches. The current doubler
rectifier is used at the secondary side to decrease the secondary winding current rating of the main transformer
with the increase in the efficiency of the converter. Various simulation results are shown in support of the
proposed converter.
References
[1]. Seong-Jeub Jeon and Gyu-Hyeong Cho., “ A Zero-Voltage and Zero-Current Switching Full Bridge DC-DC Converter With
Transformer Isolation ”, IEEE Transactions on Power Electronics, vol.16, no.5, pp. 573-580, 2001.
[2]. Bor-Ren Lin, Chun-Chi Chen, Chien-Lan Huang and Chao-Hsien Tseng“ Implementation of a ZVS Half-Bridge Converter
with Current Doubler Rectifier ”, Proc. Communications, Circuits and systems Proceedings, International
Conference,2006,p.2732-2736.
[3]. C.Cuadros et.al., “Design Procedure and Modelling of High Power, High Performance, Zero-Voltage Zero-Current Switched, Full
Bridge PWM Converter,” Proc.IEEE APEC, pp. 790-798, 1997.
[4]. J.A.Sabate et.al., “Design Consideration of High Power, High Voltage, Full Bridge Zero-Voltage Switched PWM Converter,”
Proc.IEEE APEC, pp. 275-284, 1990.
[5]. E. Morad, P.D. Ziogas, G. Joos, “High Frequency High Power DC-DC Full Bridge Converter with Zero-Current Zero-Voltage
Commutation,” Proc IEEE APECE, pp. 71-77, 1991.
[6]. P. Sudhrasana Rao, C. Nagakotrareddy, “ An Enhanced ZVS & ZCS Full Bridge Converter With Resonance Circuit In The
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