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 factor improvement is the essence of any power sector for realible operations. This report provides literature study of a fixed capacitor thyristor controlled reactor type of power factor compensator by matlab simulation and implementation in programmed microcontroller. To retaining power factor closed to unity under various load condition the arduino ATmega8 microcontroller is used which is programmed by keil software. The simulation is done using proteus software which display power factor according to the variation in load whenever a capacitive load is connected to the transmission line, a shunt reactor is connected which injects lagging reactive VARs to the power system. This report also includes the matlab simulation for three phase power factor improvement by using fixed capacitor thyristor controlled reactor. As a
result the power factor is improved. The results given in this report provides
suitable matlab simulation and proteus simulation based reactor power compensation and power factor improvement and techniques using a FCTCR.
Automatic generation control (AGC) is a system for adjusting the power output of multiple generators at different power plants, in response to changes in the load. Since a power grid requires that generation and load closely balance moment by moment, frequent adjustments to the output of generators are necessary. The balance can be judged by measuring the system frequency; if it is increasing, more power is being generated than used, which causes all the machines in the system to accelerate. If the system frequency is decreasing, more load is on the system than the instantaneous generation can provide, which causes all generators to slow down.
Power factor improvement is the essence of any power sector for realible operations. This report provides literature study of a fixed capacitor thyristor controlled reactor type of power factor compensator by matlab simulation and implementation in programmed microcontroller. To retaining power factor closed to unity under various load condition the arduino ATmega8 microcontroller is used which is programmed by keil software. The simulation is done using proteus software which display power factor according to the variation in load whenever a capacitive load is connected to the transmission line, a shunt reactor is connected which injects lagging reactive VARs to the power system. This report also includes the matlab simulation for three phase power factor improvement by using fixed capacitor thyristor controlled reactor. As a
result the power factor is improved. The results given in this report provides
suitable matlab simulation and proteus simulation based reactor power compensation and power factor improvement and techniques using a FCTCR.
Automatic generation control (AGC) is a system for adjusting the power output of multiple generators at different power plants, in response to changes in the load. Since a power grid requires that generation and load closely balance moment by moment, frequent adjustments to the output of generators are necessary. The balance can be judged by measuring the system frequency; if it is increasing, more power is being generated than used, which causes all the machines in the system to accelerate. If the system frequency is decreasing, more load is on the system than the instantaneous generation can provide, which causes all generators to slow down.
Introduction
Definition of FACTS system
Necessity of facts devices
Shunt connected controllers
Types of facts controllers
Shunt connected controllers
Benefits of FACTS
The concept of FACTS (Flexible AC Transmission System) refers to a family of power electronics based devices able to enhance AC system controllability and stability and to increase power transfer capability.
The design of the different schemes and configurations of FACTS devices is based on the combination of traditional power system components (such as transformers, reactors, switches, and capacitors) with power electronics elements (such as various types of transistors and thyristors).
Power Quality Improvement Using A DVR (Dynamic Voltage Restorer)
ABSTRACT
Power quality is one of major problems in the today’s scenario. It has become important with the introduction of complex devices, whose performance is very sensitive to the quality of power supply. Power quality problem is an occurrence developed as a nonstandard voltage, current or frequency that results in a failure of end use equipment. Some of the major problems dealt here is the power sag and swell. This paper describes the effectiveness of using dynamic voltage restorer (DVR) in order to mitigate voltage sags and swells in low voltage distribution systems. Dynamic Voltage Restorer can provide the most cost effective solution to mitigate voltage sags and swells that is required by customer. The Dynamic Voltage Restorer (DVR) is a rapid, flexible and resourceful solution to power quality problems.
As the fifth in a series of tutorials on the power system, Leonardo ENERGY introduces its minute lecture on voltage and frequency control, using the analogy of a metal/rubber plate to demonstrate the centralised nature of frequency control, whereas voltage control is more a local matter.
Inter Connected Power System(Turbine Speed Governing Mechanism)Raviraj solanki
Inter Connected Power SystemTOPIC : Turbine Speed Governing Mechanism
Introduction
Turbine Speed Governing Mechanism
Mathematical Modeling
Adjustment Of Governor Characteristics
The speed governing system consists of the following parts .
Speed governor
Linkage mechanism
Hydraulic amplifier
Speed changer
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.
International Refereed Journal of Engineering and Science (IRJES)irjes
International Refereed Journal of Engineering and Science (IRJES) is a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications.
Introduction
Definition of FACTS system
Necessity of facts devices
Shunt connected controllers
Types of facts controllers
Shunt connected controllers
Benefits of FACTS
The concept of FACTS (Flexible AC Transmission System) refers to a family of power electronics based devices able to enhance AC system controllability and stability and to increase power transfer capability.
The design of the different schemes and configurations of FACTS devices is based on the combination of traditional power system components (such as transformers, reactors, switches, and capacitors) with power electronics elements (such as various types of transistors and thyristors).
Power Quality Improvement Using A DVR (Dynamic Voltage Restorer)
ABSTRACT
Power quality is one of major problems in the today’s scenario. It has become important with the introduction of complex devices, whose performance is very sensitive to the quality of power supply. Power quality problem is an occurrence developed as a nonstandard voltage, current or frequency that results in a failure of end use equipment. Some of the major problems dealt here is the power sag and swell. This paper describes the effectiveness of using dynamic voltage restorer (DVR) in order to mitigate voltage sags and swells in low voltage distribution systems. Dynamic Voltage Restorer can provide the most cost effective solution to mitigate voltage sags and swells that is required by customer. The Dynamic Voltage Restorer (DVR) is a rapid, flexible and resourceful solution to power quality problems.
As the fifth in a series of tutorials on the power system, Leonardo ENERGY introduces its minute lecture on voltage and frequency control, using the analogy of a metal/rubber plate to demonstrate the centralised nature of frequency control, whereas voltage control is more a local matter.
Inter Connected Power System(Turbine Speed Governing Mechanism)Raviraj solanki
Inter Connected Power SystemTOPIC : Turbine Speed Governing Mechanism
Introduction
Turbine Speed Governing Mechanism
Mathematical Modeling
Adjustment Of Governor Characteristics
The speed governing system consists of the following parts .
Speed governor
Linkage mechanism
Hydraulic amplifier
Speed changer
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.
International Refereed Journal of Engineering and Science (IRJES)irjes
International Refereed Journal of Engineering and Science (IRJES) is a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications.
This work presents investigation of passive filter performance on three-phase inverter with 180° conduction mode. The simulation model of the inverter is developed by using MATLAB/Simulink. The power circuit used Insulated Gate Bipolar Transistor (IGBT) as switching device. The inverter is controlled by using bipolar Sinusoidal Pulse Width Modulation (SPWM) technique. The IGBT was set to 25 kHz for switching frequency (fs). Three types of passive filters which are LC, RC and PI filters are used to investigate the ability to remove the unwanted signal that occurred on the inverter. The result is analyzed based on the performances of output filter in term of Total Harmonic Distortion in voltage (THDv), current (THDi), shape of output voltage and current. The THD must be less than 5% at rated inverter output voltage or current by referring to IEC 61727 Standard. The passive filter is modeled in MATLAB/Simulink environment to study the characteristics and performance of the filters.
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.
Simulated Analysis of Resonant Frequency Converter Using Different Tank Circu...IJERD Editor
LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region [5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits. The supported simulation
is done through PSIM 6.0 software tool
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.
This project introduces a high gain single stage boosting inverter with trap cl filter for alternative energy generation. As compared to two stage and multi stage approach, single stage boosting inverter has a simpler topology and lower component count. Trap cl filter is used to eliminate the harmonics and it can reduce the size and weight. Single stage boosting inverter can realize high DC input voltage boosting, good inversion power decoupling, good quality of Alternating current output waveform and good efficiency.
Hardware Analysis of Resonant Frequency Converter Using Isolated Circuits And...IJERD Editor
-LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region[5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits.
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
COMPARISON ANALYSIS OF SHUNT ACTIVE FILTER AND TRANSFORMERLESS PARALLEL HYBRI...cscpconf
This research work presents the comparison analysis of Shunt Active Filter (SAF) with Parallel Hybrid Active Filter (PHAF). The performances of SAF and PHAF have been analyzed with PI controllers based on Synchronous Reference Frame theory. In each case, simulation is carried out for three phase unbalanced non liner load conditions. The advantages of the designed system and the proposed current reference calculation methods are verified by simulations using MATLAB Power system Toolbox.
Comparison analysis of shunt active filter and transformerless parallel hybri...csandit
This research work presents the comparison analysis of Shunt Active Filter (SAF) with Parallel
Hybrid Active Filter (PHAF). The performances of SAF and PHAF have been analyzed with PI
controllers based on Synchronous Reference Frame theory. In each case, simulation is carried
out for three phase unbalanced non liner load conditions. The advantages of the designed
system and the proposed current reference calculation methods are verified by simulations
using MATLAB Power system Toolbox.
Modified Bidirectional Converter with Current Fed InverterIJPEDS-IAES
A bidirectional dc-dc converter with multiple outputs are concatenated with a
high frequency current source parallel resonant push pull inverter is
presented in this paper. The two outputs are added together and it is taken as
the input source for the inverter. The current source parallel resonant push
pull inverter implemented here with high frequency applications like
induction heating, Fluorescent lighting, Digital signal processing sonar. This
paper proposes a simple photovoltaic power system consists of a
bidirectional converter and a current fed inverter for regulating the load
variations. Solar power is used as the input source for the system. Simulation
of the proposed system is carried out in PSIM software and experimentally
verified the results.
Performance of Six-Pulse Line-Commutated Converter in DC Motor Drive ApplicationZunAib Ali
This paper presents the speed control of DC motor using six pulse controlled rectifier. The
conventional Proportional Integral (PI) control is used for firing angle control. The armature current is fed
back and compared with reference current representing desired speed values. The proposed system is
simulated using SimPowerSystem and Control System Matlab toolbox. The time domain plot of reference
and actual armature current are shown in results section. The results are satisfactory with deleterious effect
on input current. The frequency plot of input current is provided to show the harmonic contents, generated
as a result of control operation.
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
A complete description of including circuit diagram, gain equation, features of Instrumentational amplifier , its working principle, applications, practical circuits, Proteus simulation and conclusion.
Uet, Peshawar Pakistan
Batch-06
Concept of energy transmission & distribution ZunAib Ali
Downlaod is NOW Allowed (08/06/2016)
for more help: email me at zunaib_91@yahoo.com
Purpose of Electrical Transmission System
Main Parts of Power System
One-Line Diagram of Generating Station
Main Parts of Generating Station
Components of a Transmission Line
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
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.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
RAT: Retrieval Augmented Thoughts Elicit Context-Aware Reasoning in Long-Hori...
Lcl filter design
1. 1
School of Engineering & Applied Sciences,
Frederick University Nicosia, Cyprus
August, 2015
2. 2
An LCL filter is often used to interconnect an inverter to the utility grid in order to
filter the harmonics produced by the inverter.
So far, there is lack of a state-space mathematical modeling approach that considers
practical cases of delta- and wye-connected capacitors
This paper describes a design methodology of an LCL filter for grid-
interconnected inverters along with a comprehensive study of how to mitigate
harmonics.
3. 3
Simple type of filter that can be used is a series inductor,
but its harmonic attenuation is not very pronounced
High voltage drop is produced, hence the size of inductor becomes bulky.
High Order LCL Filter is used as replacement of conventional L filter for
smoothing output current of VSC
Higher attenuation along with cost savings,
overall weight and size reduction of the components.
Good performance can be obtained using small values of inductors and
capacitors.
4. 4
Little information available describing the systematic design of LCL filters
In order to design an effective LCL filter, it is necessary to have an appropriate
mathematical model of the filter.
The objective of this paper is to conduct a comprehensive analysis and modeling
of the three-phase LCL filter for VSC converters, suitable for wind energy or
photovoltaic applications.
Two configurations of three-phase full-bridge dc/ac inverter are compared:
first, a set of wyeconnected filter capacitors with damping
second, a deltaconnected filter output connection.
5. 5
LCL Filter Modeling
Fig. 1 LCL Filter Per Phase Model
𝐿1= Inverter Side Inductor
𝐿2= Grid Side Inductor
𝑅1= Inverter Side Resistor
𝑅2= Grid Side Resistor
𝑣1= Input (inverter) voltage
𝐿2= output system voltage
Fig. 2 General schematic for grid-interconnected dc power source
10. 10
LCL frequency response
Fig. 4 Bode Diagram
𝐻𝐿𝐶𝐿 =
𝑖 𝑔
𝑣 𝑖 important transfer function
The insertion of a series resistance
with the capacitor eliminates the
gain spike, smoothing the overall
response and rolling-off to −180◦
for high frequency, instead
of −270◦.
11. 11
Filter Design procedure
Several characteristics must be considered in designing an LCL filter,
such as current ripple, filter size, and switching ripple attenuation.
The reactive power requirements may cause a resonance of the capacitor
interacting with the grid.
Therefore, passive or active damping must be added by including a resistor
in series with the capacitor.
The following parameters are needed for the filter design:
VLL, line-to-line RMS voltage (inverter output);
Vph, phase voltage (inverter output);
Pn, rated active power;
VDC, dc-link voltage;
fg, grid frequency;
fsw, switching frequency; and
fres, resonance frequency.
12. 12
Filter Design procedure
Input parameters
Calculate Base Values
Calculate 𝐶𝑓 and 𝐿1
Provide desired 𝑘 𝑎
Calculate 𝐿2
Check 𝑓𝑟𝑒𝑠
Provide 𝑅𝑓
Output 𝐶𝑓 and 𝑅𝑓
13. 13
Filter Design procedure
𝑍 𝑏 =
𝐸 𝑛
2
𝑃𝑛
Base Impedance
𝐶 𝑏 =
1
𝜔 𝑔 𝑍 𝑏
Base Capacitance
For the design of the filter capacitance, it is considered that the maximum power
factor variation seen by the grid is 5%, indicating that the base impedance of the
system is adjusted as follows:
𝐶𝑓 = 0.05𝐶 𝑏
The maximum current ripple at the output of dc/ac inverter is given by
It can be observed that the maximum peak-to-peak current ripple happens at m = 0.5, then
𝐿1= Inverter Side Inductor
𝑉𝐷𝐶= DC Link Voltage
𝐸 𝑛= Line-Line Grid Voltage
14. 14
Filter Design procedure
The LCL filter should reduce the expected current ripple to 20%, resulting in a ripple value of
2% of the output current.
A 10% ripple of the rated current (𝐼 𝑚𝑎𝑥) for the design parameters is given by
∆𝐼𝐿𝑚𝑎𝑥 = 0.1𝐼 𝑚𝑎𝑥
Where,
𝐼 𝑚𝑎𝑥 =
𝑃𝑛 2
3𝑉𝑝ℎ
Hence, 𝐿1 becomes
𝐿1 = 𝑉𝐷𝐶 (6𝑓𝑠𝑤∆𝐼𝐿𝑚𝑎𝑥)
15. 15
Filter Design procedure
Now harmonic mitigation, the harmonic current generated by inverter to that of current
injected in the grid is given by:
where 𝑘𝑎 is the desired attenuation. 𝐶𝑓 = 0.01 ÷ 0.05 𝐶 𝑏
A resistor in series (Rf ) with the capacitor attenuates part of the ripple on the switching
frequency in order to avoid the resonance.
The value of this resistor should be one third of the impedance of the filter capacitor at the
resonant frequency
The constant r is the ratio between the inductance at the inverter side and the one at the grid side
16. 16
Lcl FILTERDESIGNEXAMPLE
The specifications are
𝐸 𝑛 = 120 3, line-to-line RMS voltage;
Ps = Pn = 5 kW, rated active power;
VDC = 400 V, dc-link voltage;
ωg = 2π60, grid angular frequency;
fsw = 15 kHz, switching frequency;
x = 0.05, maximum power factor variation seen by the grid;
ka = 0.2 (20%), attenuation factor.
𝑍 𝑏 =
𝐸 𝑛
2
𝑃𝑛
=
(120 3)2
5000
= 8.64ΩBase Impedance
𝐶 𝑏 =
1
𝜔 𝑔 𝑍 𝑏
= 307.16μFBase Capacitance
19. GSC Converter Control
Various tests have been conducted stand-alone mode for a load with different power
factors; in all cases, the filter output voltage has THD less than 2%.