A novel control strategy for grid connected vsc with lcl filters controlling the errors by using the vector controller 1ch. Let us compare the above designed lclfilter with an lfilter in which the total inductances in both passive filters are identical. An improved lcl filter design in order to ensure stability without. If youd calculate the voltage at the right end without the resistor, l2 doesnt do anything and its just an lc filter. The results of simulations of the inverter system connected to grid 220 v, 50 hz using matlab simulink are also shown. The attenuating resistance of the lclfilter is assumed to be r d 3. Lcl filter parameter design is another issue that effects on output power quality directly. However, resonance at high frequency caused by the filter can lead stability problem. Threephase lclfilter for gridconnected inverter using.
Design and research on the lcl filter in threephase pv gridconnected inverters. Indirect current control of lcl based shunt active power. Performance analysis of lcl filter for grid interconnected. In such case l2 may be unnecessary m 3 lcl filter mains impedance converter l1 l2 l3 c l4 fig. The lcl filter was designed following the procedure in teodorescu et al.
Chapter 4 begins with a short introduction about inductances and their characteristics, and then a model for a nonlinear inductor is developed. This paper proposed method pwm waveforms are generated by svpwm technique using matlab simulink and l and lcl filter is designed connected to grid. Lcl filter design for gridconnected inverters by analytical. Analysis and design of a passively damping lcl filter in. Lcl filter design and performance analysis for grid.
Emc components from tdk electronics include emc filters for shielded rooms, data and singnal line chokes, commonmode filters, power line chokes, line filters, lcl filters, power line emc filters, emc feedthrough capacitors, emc feedthrough filters, reactors for power electronics, output filters. Keywords lcl filter, doubly fed induction generator dfig, matrix converter mc, indirect spacevector modulation isvm. An efficient procedure to design passive lclfilters for. Matlabsimulink power system toolbox software is used to simulate the power. Passive damping filter design and application for threephase pv gridconnected inverter 51 fig. Optimal design of lcl harmonic filters for threephase pfc. The simplest filter type is the singletuned filter. Topological structure of threephase pv gridconnected inverters wit h lcl filter. Lcl filter design for gridconnected inverters by analytical estimation of pwm ripple voltage. The four types of filters that can be modeled with the threephase harmonic filter block are shown below.
Pdf analysis of grid inverter system using lcl filter based. Energies 2014 open access energies semantic scholar. A novel control strategy for grid connected vsc with lcl. One of the troubling constraints of lcl filter is the resonance. A lowpass passive lclfilter is usually used to interconnect a power. Oct 27, 2015 lcl filter design and performance analysis for grid interconnected system. Lcl passive filter with damping configuration one solution to overcome the resonance effect is by using. Design and control of grid interfaced voltage source inverter. This paper presents the mathematical deduction of models for lcl filters with and without the damping resistor, the criteria for designing lcl filter, a systematic procedure for designing lcl filter and experimental tests with an isolated load. Current control of a voltage source inverter connected to. The transferfunction of the i 2 to u pwm is given as 1 where, i 2 is the output current of lcl filter, u pwm is. Lcl filters, as the interface between the gridconnected inverters and the grid, overcome some of drawbacks of l or lc filters, especially have great performance used in medium and high power. The lcl filter is known as an effective topology in significantly attenuating harmonics with small filter components.
New controller design for pmsg based wind generator with. A comparison between the designed lcl filter and l filter based singlephase gridconnected pv inverter system is carried out. This is used in a systematic design procedure to design the lcl filter components for allowable grid current harmonics. Institute of electrical and electronics engineers inc. Pdf lcl filter design for grid connected threephase. Shunt active power filter sapf, harmonic compensation, indirect current control. The transfer function of the lcl filter in grid side is computed and the subsequent frequency domain.
I read that for gridtied inverters it is common to use a lcl filter like above, to turn the pwm output from the hbridge into a sine. Design and control of lcl filter interfaced grid connected. Topological structure of threephase pv gridconnected inverters with lcl filter. Pr control of gridconnected 3level inverter with lcl filter. Inverter and filter design matlab simulink inverter ve filtre tasar. A novel control strategy for grid connected vsc with lcl filters. By analysing the per phase equivalent model of lcl filter, the design equations of filter inductances and filter capacitance are given below. Could you, please, tell me how i can implement this in simulink. Hence, a damper element is needed to overcome the dominant negative impact of the resonance. The structure of lcl filters is as shown in the schematics below. Hysteresis current controlled single phase gridconnected. The shortage of electric power is the major problem nowadays.
Reading instructions the bibliography is on page 71. U dc is the voltage of dc bus, i dc is the current of dc bus, s1s6 sixswitch made up threephase inverter, l 1 c s l 2 made up thirdorder lcl filter1. Lcl filter design for grid connected threephase inverter. Simulations were performed on matlab simulink platform and a prototype. Index terms voltage source inverter vsi, front end rectifier fer, dcac converter, lc filter i. Inverter and filter design matlab simulink, thd analysis inverter filtre tasar. Abstractthe use of power converters is very important in maximizing the power transfer from renewable energy sources. Its inductor also plays a role in inhibiting the current impact, which not only has a good dynamic performance, but also reduces the system cost.
This paper also proposes the lcl filter design to eliminate the harmonics. The obtained filter parameters were firstly tested using a matlabsimulink software tool. Demetriadis school of electrical and computer engineering national technical university of athens, greece abstractthe utilization of inverters for the interconnection of. Design and research on the lcl filter in threephase pv grid. Whereas the transfer function leading to the capacitor current, i c, is given by equation 9. The following figure gives the definition of the quality factor q and practical formulae for computing the. In order to achieve the lower current harmonic, an lcl filter is widely. Besides, enhanced dynamic execution, harmonic attenuation and decreased volume might be accomplished with the utilization of lcl filter. Design and analysis of dcac inverter using passive lcl.
Lcl filter design for threephase twolevel pfc using line impedance stabilization network. Lcl filters are mainly used for gridconnected inverters to meet the grid interconnection standards so lcl filter has come into wide use in the inverter fig 4. Power quality improvement by designing the lcl filters for. D s 3 s 5 s 4 s 6 s 2 ua l a1 c s l 1 l c 1 s 1 k 1 l a2 b 2 l c2 ub uc u d c i dc pv a i i c fig. The undamped control for pwm rectifier based on lcl filter.
So far, there is lack of a statespace mathematical modeling approach that considers practical cases of delta and wyeconnected capacitors. Current control of a voltage source inverter connected to the grid via lcl filter a. Im sending you a picture of a equivalent model of the output lc filter in the laplace domain. Simulink model of three phase gridconnected inverter with l filter 5. Designing of lcl filter and stability analysis of a three phase grid. You can control whether the block implements an iir or fir lowpass filter using the filter type parameter.
The total mvar rating of the filters set is then 600 mvar. Current control of a voltage source inverter connected to the. However, lcl filter can cause resonance in certain frequency that affects system performance, as well as the parameters of lcl filter are hard to design. In 14 and the recent work in 15 the parameter design of lcl filter design is thoroughly discussed considering grid standards for the quality of injected power. Lcl filter an alternative and attractive solution of first and second order filter problems is to use an lcl. Lcl fiter design for grid connected npc inveters in offshore wind turbins.
Design of lcl filter in front end converters suitable for. Design and research on the lcl filter in threephase pv grid ijcee. In the interim, the aggregate inductance of the received lcl filter is much more diminutive as contrasted with the l filter. A simulationaided lcl filter design for gridinteractive. Discrete filter mathworks makers of matlab and simulink. As the conventional energy sources are depleting at a faster rate, there is an urgent need to investigate the alternative energy sources which help to solve the problem. In some cases reactor l4, is already placed in front of the converter. The objectives of the project are divided in two parts. An example of lcl filter design is presented and discussed. Design and control of grid interfaced voltage source inverter with output lcl filter sajad sarajian 1 1department of electrical engineering, islamic azad university, ashtian branch, ashtian, iran june 8, 2014 abstract this paper presents design and analysis of an lcl based voltage source converter using. Lcl filter, pr controller and harmonic compensators design 3. It produces lots of harmonics which necessitates significant suppressions prior to be connected to the grid.
After that, they were tested through the development of an experimental setup. Chapter 4 begins with a short introduction about inductances and their characteristics, and. Figures are numbered continuously in their respective chapters. Lcl filter design and performance analysis for grid interconnected systems a. The internal resistances of inductance and capacitance are negligible.
Design of pr current control with selective harmonic. Single phase inverter with lcl filter by using matlab. Matlab simulink power system toolbox software is used to. Designing of lcl filter and stability analysis of a three.
This article discusses the mitigation of highfrequency harmonics through high voltage converters. Table i specification of the threephase pfc recitifier are given in sections v and vi, respectively. Different aspects of designing an lcl filter are discussed, and a design procedure is subsequently presented for passive lcl filters. Lcl filter design inlcuding the current control tuning. The design is validated by simulations in matlab simulink and experiments on a laboratory prototype. The controller parameters are selected as 30, 900 and. Modeling and control of a three phase voltage source inverter with. A lcl filter is often used to interconnect an inverter. Uso da interligacao do matlabsimulink e o psim atraves da ferramenta. Inverter and filter design matlab simulink inverter. An lcl filter draws much attention in gridconnected applications, but the design faces challenges. Inverters connected to the grid, filter is required as an interface between the inverter and the electric grid.
The discrete filter block independently filters each channel of the input signal with the specified digital iir filter. A voltage source inverter vsi is one which takes a. Introduction in modern electric power supply distribution systems, there is a sharp rise in the usage. The most effective filter for suppressing of the current harmonics occurring from the switching frequency injected into. You can specify the filter structure as direct form i, direct form i transposed, direct form ii, or direct form ii transposed. Chapter 3 begins with an overview of the threephase grid connected voltage source converter with lcl filter. The parameter of the system is listed as in table 1. Lcl filter is an attractive solution because of its many potential advantages such as higher harmonic attenuation and smaller inductances compared with l filter 7. Pdf lcl filter design for grid connected threephase inverter. Lcl filter is applied in pwm rectifier with the better filtering effect. Due to the effects of global warming from greenhouse gas released to the atmosphere by combustion of fossil fuels, high prices of fossil fuels and their unsteady supply, researchers are becoming more concerned in the renewable energy. Then, the whole system is simulated with simulink to verify the discussed procedure. Index terms lcl filter, total harmonic distortion, switching loss, renewable.
In this model, the lcl filter parameters are designed using a matlab script. Our study shows that a welldesigned inverter with an lcl filter interacts with other gridconnected inverters through the nonideal grid. The following figure gives the definition of the quality factor q and practical formulae for computing the reactive power q c and losses active power p. The obtained filter parameters were firstly tested using a matlab simulink software tool.
The lcl and controller parameters are interdependent and interrestricted as the grid current. To verify effectiveness of the pr controller for gridconnected 3level 3phase inverter with lcl filter, a matlab simulink model has been created. Lcl filter design and performance analysis for grid interconnected systems. To carry out the tests using the pr control and the harmonic compensation, a 3 kw gridconnected inverter was designed and constructed. Active damping of lclfilter resonance based on virtual.
Pdf analysis of grid inverter system using lcl filter. The calculated lcl parameters have been used in the simulink model to check the performance of the lcl filter and thd content of the voltages and currents. In the simulink model, the voltage at the load bus is regulated with the help of pi controller. Apec 2014 29th annual ieee applied power electronics conference and exposition. In this study, lcl filter design was performed by simulating and theoretical analysis detail of a gridconnected system in matlab simulink environment. Simulations were performed on matlabsimulink platform and a prototype. The use of lcl filter remains peak resonance effect that can potentially reduce inverter stability. Lcl filter design for threephase twolevel pfc using line. The design of lcl filter is having one of the important roles in the entire system and plays vital role for stability of the system. Threephase harmonic filter makers of matlab and simulink. Active damping of resonance oscillations in lclfilters based. Active damping of resonance oscillations in lcl filters based on virtual flux and virtual resistor gullvik william.
In this paper, we propose a simulationaided design for the lcl filter to be employed in gridinteractive pv inverters. Twostage singlephase gridconnected pv system with lcl filter typical topology. A neutralpointclamped npc threelevel inverter is used more and more in the gridconnected power generation system. Pdf modeling, analysis and design procedure of lcl. Design of lcl filter in front end converters suitable for grid connected wind electric generators. Electrical power quality improvement for renewable energy systems using lcl filter noah k. Such permission of the ieee does not in any way imply ieee endorsement of any of. Modeling and observer design of a nonlinear lcl filter for. But also combinations with capacitors like lc or lcl can. Next, a mathematical model for each part of the system is described. Lcl filter design inlcuding the current control tuning file. Jun 29, 2017 in this paper, the design consideration for passive damping of lcl filters in threephase voltage source inverters is discussed under the assumption of a nonideal distributed power grid. This is to certify that the thesis report entitled optimal lcl filter design for gridinterfaced distributed power generation system, submitted by ms deepika kumari bearing roll no.
Performance analysis of lcl filter for grid interconnected system with active damping m. But im having trouble designing something like this. A passive damping resistor is designed ensuring minimum power loss. The simplest variant is filter inductor connected to the inverters output. An analysis and design procedure of output lcl filter for singlephase gridconnected photovoltaic pv inverter system is presented in this paper. Equivalent circuit of gridconnected with lcl filter fig 5. Pdf pr control of gridconnected 3level inverter with lcl. The corresponding inverter output is shown in figure. The lowpass filter block independently filters each channel of the input signal over time using the filter design specified by the block parameters.
Simulation is done in matlab simulink environment for feasibility of the study. The sixth chapter contains the simulation results that have been obtained using. The procedure for designing an lcl filter is proposed and verified by simulations. This paper contributes a comprehensive analysis of designing a passive lcl filter for the shunt active filter that is modulated by using variable switching frequency techniques. The results are simulated by matlab simulink software. The block implements static filters with fixed coefficients. Secondly, the design of the output lcl filter is proposed in this paper.
First we present a generalized model of the passively cushioned lcl filter and then, the optimization process is implemented, which results in the low consumption of active and reactive energy of the capacitor resistance branch. Active damping of lclfilter resonance based on virtual resistor for pwm rectifiers stability analysis with different filter parameters christian wessels, jorg dannehl, student member, ieee and friedrich w. Optimal design of lcl harmonic filters for threephase pfc rectifiers j. Keywords lcl filter, doubly fed induction generator dfig. Index termslcl filter, series damping resistors sdr, parallel damping. Abstractthe use of power converters is very important in. It also gives the dynamic model of filter with simulation using simulink matlab. By taking care of cost problems, the lcl filter design is used in a way that using lower value of inductance which is expensive and bulky too, higher value of. Introduction inverters are used in a large number of power applications. Design and research on the lcl filter in threephase pv.