Performance Analysis of Shunt Active Power Filter Base On Active Reactive Power Theory

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1 Performance Analysis of Shunt Active Power Filter Base On Active Reactive Power Theory Brijesh Kumar Sen *1, Seema Agrawal 2, Mahendra Kumar 3, R. K. Somani 4 Department of Electrical Engineering 1,2,3 Rajasthan Technical University, Kota, 4 MIT, Kota, INDIA ABSTRACT This research work describes synchronous reference frame (SRF) based control algorithm for shunt active power filter (SAPF) to mitigate harmonics and improve power quality. System consists with a non-linear load, coupling inductor, a three phase three-leg current controlled voltage source inverter (CC-VSI) with a DC link capacitor. Increasing application of non-linear loads and large scale use of power electronics techniques causes power quality problem. The most severe problem is harmonics that pollutes entire power system and may damage system equipment. So it is important to build up system for taking care of these harmonic problem. SAPF is better configurations to improve power quality. In this paper desired reference current is determined for voltage source converter (VSC) of SAPF using SRF algorithm for mitigation of harmonic source current. The proposed system is simulated using MATLAB/Simulink and results show capability of proposed system. Keywords power quality, synchronous reference frame, shunt active power filter, voltage source converter I. INTRODUCTION The number of non-linear loads has been increasing for years and they now form a large part of electrical loads in power system, their harmonic effects become more and more destructive [1,2]. The dispersed nature of non-linear loads such as power electronic loads, static power converters, adjustable speed drives, battery charger, cyclo-converters, energy saving, etc. cause harmonics in electric power system. With distortion of current and voltage waveform due to presence of harmonic result in high THD components in form of nonsinusoidal current and voltage, and need to be compensated to improve power quality. A method used for elimination of harmonics is used of SAPF in which reference signals are generated to remove distortion from distorted current and voltage waveform [3,4]. SAPF constantly monitor harmonic components and reactive power flow in system and performance of filter depends on accuracy and time taken in compensating harmonic components from load current. Ordinarily passive filters, power line conditioners, phase advancers etc. were utilized for power system quality enhancement. These conventional techniques involve many drawbacks such as sluggish transient response, overcompensation of reactive power, generates resonance problem and fixed compensation. Various control methods with various control strategies like instantaneous reactive power theory, modified p-q theory, instantaneous id-iq theory are presented in development of three phase APFs [5-7]. With advent of fast self-commutating semiconductor switches that have changed APF innovation. In earlier thyristors, bipolar junction transistors (BJT) and power MOSFET were utilized for APF invention; later, static induction thyristors (SIT) and gate turn off thyristors (GTO) were utilized to manufacture APF. An installation of insulated gate bipolar transistors (IGBT s) for APF invention, it has been assumed an ideal switch for APF s. Now days, SAPF have showed up as an effectual technique to solve problem of harmonics, unbalanced load currents, with reactive power compensation. APFs are associated with AC lines in order to take out voltage variations and harmonic components. Shunt active power filter eliminates current harmonic components working as source with only harmonic components and power factor correction, so that only fundamental component is provided in AC lines [8-11]. The SAPF is associated in parallel with line through a coupling inductor. Its fundamental power circuit comprises of a three phase three-leg current controlled voltage source inverter with a DC link capacitor [12,13]. An APF operates by generating a compensating current with 180-degree phase opposition and infuses it back to line in order to remove current harmonics introduced by non-linear load. This results in smother harmonic content present in line and make current waveform sinusoidal. So procedure involves finding harmonic component present in source current, generating reference current, producing switching pulses for power circuit, generating a filtering current and infusing it back to line [14-16]. In this paper, a non-linear load supplied by a three phase voltage source is proposed. An APF is acquainted in parallel with this system for compensation of current harmonics caused by non-linear loads. Here SRF algorithm [3-5] is utilized for reference current extraction from distorted source current. The switching pulses for power circuit is produced through PI controller using Vdc reference and Cdc voltage. The proposed control system is simulated using MATLAB/Simulink. 107

2 II. SYSTEM CONFIGURATION The basic system comprises of three phase AC source which is connected through non-linear load and a SAPF is connected across them, as shown in Fig. 1. The whole system works on SRF based control algorithm. In proposed system PI controller used Vdc reference and Cdc voltage to generate pulses through control unit which feeds into current controlled voltage source inverter. A current controlled voltage source inverter consists of six IGBT diode switches, PI controlled generated gate pulses feed in it. Thus CC-VSI starts conducting at 0.1 step time, before that due to non-linear load harmonics are introduced in system. So that source voltage and current becomes distorted. To overcome from this problem, we are using SAPF-SRF based algorithm to filter out harmonic present in source side. Load current harmonics are compensated by infusing equal and opposite magnitude of current with help of SAPF using SRF algorithm [3-5, 11-14]. Fig. 1. Proposed system configuration block with SAPF III. SRF BASED CONTROL ALGORITHM Number of control methodologies being utilized for determination of reference current in SAPFs namely instantaneous reactive power theory (p-q theory), sliding mode control strategy, unity power factor technique, one cycle control etc. Here, SRF theory is utilized to assess three-phase reference currents (ica *, icb *, icc * ) by active power utilized filters by focusing on source currents (ica, icb, icc). Fig. 2 shows block diagram which clarifies three-phase SRF theory, utilized for harmonic component extraction [1-2]. Fig. 2. Block diagram of SRF algorithm. The d-q currents in this manner acquired comprises of AC and DC parts. The fixed DC part represents fundamental component of current and AC part represents harmonic component. This harmonic component can be effectively removed utilizing a high pass filter (HPF), as actualized in fig. 2. The d-axis current is a blend of active fundamental current (id dc) and load harmonic current (ih). A fundamental component of current pivots in synchronism with rotating frame and thus can be considered as dc. By filtering id, current is accessed, which represents fundamental component of load current in synchronous frame. In this manner, AC component idh can be acquired by subtracting id dc part from aggregate d-axis current (id), which abandons harmonic component present in load current. The sum of fundamental reactive load currents and part of load harmonic currents are represented by q- axis current (iq) in rotating frame. So q-axis current can be completely used to figure reference compensation currents.now inverse transformation is achieved to change currents from two-phase synchronous frame d-q into two-phase stationary frame α-β according to equation (3). cos sin dh i i sin cos i (3) i q Finally, current from two-phase stationary frame α-β-0 is changed again into three-phase stationary frame a-b-c according to equation (4) and compensation reference current ica *, icb * and icc * are acquired. 108

3 Where, 109

4 110

5 desired level. It is demostrated in Fig. 5. SAPF current is indicated in fig. 6 this current compensate harmonic current which is supplied by non linear load. The Self supported Dc bus volage is shown in Fig. 7. Harmonic spectrum before compensation is defined in Fig. 8. A spectral analysis after application of shunt active power filter is represented in Fig. 9. V. CONCLUSION SRF based SAPF explained in this paper to compansate line current harmonics generated due to non-linear loads in system. The switching pulses generated through PI controller using Vdc reference and Cdc voltage for power circuit was found to be effective and its validity is proved based on simulation results. Thus proposed system has been proved to be effective to minimize harmonic content in power lines within permissible limit as IEEE standards. References [1] C. Rejil and A. K. R, Design and Simulation of Three Phase Shunt Active Power Filter Using SRF Theory, Adv. Electron. Electr. Eng., vol. 3, no. 6, pp , [2] Bhasha Shaik Mohammad and B. Lalitha, Comparison of Control Algorithms for Shunt Active Filter for Harmonic Mitigation, Int. J. Eng. Comput. Sci., vol. 3, no. 10, pp. 1 6, [3] S. M. Shembekar and K. L. Deshmukh, Analysis of Reference Current Generation for Shunt Active Power Filter Using SRF Algorithm to Compensate Harmonic Current, International Journal of Science, Spirituality,Business and Technology (IJSSBT), vol. 3, no. 2, pp , [4] C. Sciences, M. R. Amer, O. A. Mahgoub, and S. A. Zaid, A Simple Algorithm for SRF Theory with Three Phase Shunt Active Power Filter, Journal of Engineering and Computer Sciences, vol. 6, no. 1, pp , [5] C. J. Msigwa, B. J. Kundy, and B. M. M. Mwinyiwiwa, Control Algorithm for Shunt Active Power Filter using Synchronous ReferenceFrame Theory, International Journal of Electrical, Computer, Energetic, Electronic and Communication Engineering, vol. 3, no. 10, pp , [6] T. Trivedi, C. Gupta, R. Jadeja, P. Bhatt, and M. Chaudhari, Energy Procedia Implementation of Synchronous Reference Frame Theory based Shunt Active Power Filter using DSP Controller, Energy Procedia, pp. 1 7, [7] B. R. Patel, P. Sarswat, N. S. Prof, and M. B. Jhala, Review Paper on Harmonic Mitigation using Shunt Active Filter Government Engineering College-Bhuj, India, International Journal for Scientific Research & Development, vol. 4, no. 9, pp , [8] K. L. Deshmukh and S. M. Shembekar, Design and Control of Shunt Active Power Filter, IORD Journal of Science & Technology, vol. 2, no. 3, pp , [9] S. U. Bhople and S. K. Rayarao, Comparison of Various ReferenceCurrent Generation Techniques for Performance Analysis of ShuntActive Power Filter using MATLAB Simulation, International Journal of Current Engineering and Technology, vol. 6, no. 2, pp , [10] Seemant Chourasiya, Seema Agrawal, A REVIEW: ControlTechniques for Shunt Active Power Filter for Power Quality Improvement from Non-Linear Loads, International Journal Electrical Engineering, 2015, Vol. 6, No.10, pp [11] Seema Agrawal, Seemant Chourasiya, D.K palwalia, A ComparativeAnalysis of Simulations and Results of Different Controllers Acting on Shunt Active Power Filters International Conference on Recent Trends in Engineering and Materials Science, 2016 [12] Shobhit Jain, Seema Agrawal, Amrita jain, D.K. Palwalia, Applied Precise Multivariable Control Theory on Shunt Dynamic Power Filter using Sliding Mode Controller, IEEE First International Conference on Power Electronics, Intelligent Control and Energy Systems,2016. Seema Agrawal, Prakash Kumar, D.K palwalia, Artificial Neural Network based Three Phase Shunt Active Power Filter, IEEE 7 th Power India International Conference,25-27 Nov.2016 [13] Seema Agrawal, D.K palwalia, Analysis of Standalone Hybrid PV-SOFC-Battery Generation System Based on Shunt Hybrid Active Power Filter for Harmonics Mitigation, IEEE 7th Power India International Conference, Nov [14] A. Gligor, Design and Simulation of a Shunt Active Filter in Application for Control of Harmonic Levels, Electrical and Mechanical Engineering, vol. 1, pp , [15] G. Ravindra, M. G. S. Prasad, and M. S. Kalavathi, Power Quality Improvement in Deregulated Power System by Using Active Filters, International Journal of Scientific & Engineering Research, vol. 3, no. 6, pp. 1 8,

Analysis of Reference Current Generation for Shunt Active Power Filter Using SRF Algorithm to Compensate Harmonic Current

BUSINESS AND TECHNOLOGY (IJSSBT), Vol., No., June 05 ISSN (Print) 77 76 Analysis of Reference Current Generation for Shunt Active Power Filter Using SRF Algorithm to Compensate Harmonic Current Mr. S.