Control Strategy of Photovoltaic Generation Inverter Grid-Connected Operating and Harmonic Elimination Hybrid System

ABSTRACT:  

This paper proposes a three-phase three-wire photovoltaic generation inverter grid-connected operating and harmonic elimination hybrid system. The hybrid system mainly consists of photovoltaic array battery, photovoltaic output filter, three-phase voltage-type inverter, inverter output filter and passive filters. Based on working principle and working characteristics of the proposed hybrid system, the composite control strategy about active power, reactive power  and harmonic suppression is proposed. The composite control strategy mainly consists of a single closed-loop control slip of active power and reactive power, double closed-loop control slip of harmonics. Simulation results show the correctly of this paper’s contents, the hybrid system have an effective to improve power factor, supply active power for loads and suppress harmonics of micro-grid.

KEYWORDS:

1.      Micro grid

2.      Harmonic restraint

3.      Active power control

4.      Reactive power control

5.      Photovoltaic generation

SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

     

Figure 1. Structure of novel hybrid system.

 EXPECTED SIMULATION RESULTS:

(a) Current dynamic waveform of load and grid side

(b) Current spectrum waveform of load and grid side

(c) Voltage and current dynamic waveform of grid side

(d) Voltage waveform of the DC capacitor

Figure 2. Simulation results when photovoltaic generation is connected.

(a) Current dynamic waveform of load and grid side

(b) Current spectrum waveform of load and grid side

(c) Voltage and current dynamic waveform of grid side

(d) Voltage waveform of the DC capacitor

Figure 3. Simulation results when photovoltaic generation is not connected.

CONCLUSION:

Aiming at the shortages and problems of active power, reactive power and harmonic control technology in microgrid, a three-phase three-wire photovoltaic generation inverter grid-connected operating and harmonic elimination hybrid system is proposed in this paper. The principle and control strategy of the proposed hybrid system are studied. Through the research of this paper, the following conclusions can be drawn:

(1) The compensation of active, reactive power and the real-time dynamic control of harmonics can be realized through the proposed hybrid system.

(2) Based on the working principle of the proposed hybrid system at different time, the hybrid control method of active power, reactive power and harmonic suppression is proposed. The proposed control strategy is simple and easy to be implied in engineering.

(3) Simulation results show the correctly of this paper’s contents, at the same time, the proposed control method can also be applied to other similar systems in this paper.

REFERENCES:

[1] Ding Ming, Wang Min.Distributed generation technology. Electric Power Automation Equioment, vol. 24, no.7, pp. 31–36, July 2004.

[2] Liang Youwei , Hu Zhijian , Chen Yunping. A survey of distributed generation and it s application in power system. Power System Technology, vol. 27, no.12, pp. 71-75, December 2003.

[3] Wang Chengshan, Xiao Chaoxia, Wang Shouxiang. Synthetical Control and Analysis of Microgrid. Automation of Electric Power Systems, vol. 32, no.7, pp. 98-103, April 2008.

[4] Liu Yang-hua1,Wu Zheng-qiu,Lin Shun-jiang. Research on Unbalanced Three-phase Power Flow Calculation Method in Islanding Micro Grid. Journal of Hunan University(Natural Sciences) , vol. 36, no.7, pp. 36-40, July 2009.

[5] Xie Qing Hua, Simulation Study on Micro-grid Connection/Isolation Operation Containing Multi-Micro-sources. Shanxi Electric Power,vol. 37, no.8, pp. 10-13, August 2009.

Performance Investigation of Shunt Hybrid Active Power Filter With A Synchronous Reference Frame Based Controller

ABSTRACT:  

This paper presents a novel synchronous reference frame based (SRF) control strategy for shunt hybrid active power filter (SHAPF). The control strategy includes a direct current control (DCC) and an indirect current control (ICC) strategy. SHAPF can achieve harmonic compensation and dynamic reactive power compensation with the proposed controller. In this proposed method, as distinct from studies in literature, dynamic reactive power compensation and dc link voltage control is realized with ICC and harmonic current compensation is realized with DCC. Also, the proposed controller provides a variable SHAPF dc link voltage which is adjusted according to the reactive power compensation requirements in order to decrease the switching losses of converter and achieve power savings. The performance of proposed controller is verified with experimental results.

KEYWORDS:

1.      Active Power Filter (APF)

2.      Harmonics

3.      Reactive Power Compensation

4.      Direct Current Control

5.      Indirect Current Control

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. Power Circuit Diagram of SHAPF

 EXPECTED SIMULATION RESULTS:

(a)

(b)

Fig.2. Reactive Power Trend (a) and Current Harmonic Spec. (b) of Case I

(a)

(b)

Fig.3. Reactive Power Trend (a) and Current Harmonic Spec. (b) of Case II

CONCLUSION:

This paper presents a SRF based controller approach for SHAPF. In proposed control method, DCC strategy is preferred for harmonic compensation control to maintain superior dynamic and steady state performance on the compensation of low order harmonics. ICC strategy is used for the reactive power compensation controller and the dc link voltage controller to simplify the controller and provide a successful performance without being affected by dynamic changes in active and reactive current components. Additionally, the dc link voltage is determined with adaptive to the reactive power demand of load by the proposed control method. By the help of this ability, the switching losses of SHAPF is decreased by keeping only required voltage level on dc link. The proposed control method is applied on the laboratory prototype of SHAPF. The steady state and dynamic performance of controller is verified with the experimental results.

REFERENCES:

[1] H. Fujita and H. Akagi, “A practical approach to harmonic compensation in power systems-series connection of passive and active filters,” IEEE Trans. Ind. Appl., vol. 27, no. 6, pp. 1020–1025, 1991.

[2] H. Akagi, “Active and hybrid filters for power conditioning,” ISIE’2000. Proc. 2000 IEEE Int. Symp. Ind. Electron. (Cat. No.00TH8543), vol. 1, 2000.

[3] H. Fujita, T. Yamasaki, and H. Akagi, “A hybrid active filter for damping of harmonic resonance in industrial power systems,” IEEE Trans. Power Electron., vol. 15, no. 2, pp. 215–222, Mar. 2000.

[4] S. Srianthumrong and H. Akagi, “Medium-voltage transformerless ac/dc power conversion system consisting of a diode rectifier and a shunt hybrid filter,” IEEE Trans. Ind. Appl., vol. 39, no. 3, pp. 874–882, May 2003.

[5] R. Inzunza and H. Akagi, “A 6.6-kV Transformerless Shunt Hybrid Active Filter for Installation on a Power Distribution System,” IEEE Trans. Power Electron., vol. 20, no. 4, pp. 893–900, Jul. 2005.

Hybrid Shunt Active Filter Offering Unity Power Factor and Low THD at Line Side with Reduced Power Rating

ABSTRACT:  

This paper present analysis of hybrid active power filter with synchronous reference frame control algorithm. The proposed topology consist of active power filter and passive power filter are connected in shunt with the mains feeding a nonlinear load. The shunt passive power filter is tuned to eliminate most dominate 5th order load current harmonic. The shunt active power filter is used compensate all other higher order load current harmonics. This approach help toreduce the overall rating of shunt active power filter, and maintain unity power factor at line side with low THD, which makes system more economical for industrial usage. Detail design steps for 5th order tuned filter is also discussed and results are presented. The proposed shunt active power filter is also tested for dynamic loading condition. Hardware results for the verification of proposed control algorithm is also presented and discussed.

KEYWORDS:

1.      Hybrid Active Filter

2.      Passive Filter

3.      Total Harmonic Distortion

4.      Synchronous Reference Frame

5.      Unity Power Factor

SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig. 1: Main Power Circuit Diagram of HAPF

EXPECTED SIMULATION RESULTS:

Fig. 2: Simulation Result ofSPPF (a) Phase-A Output Load Current

without Compensation (b) Phase-A Source Current with Compensation

(c) Phase-A 5th Order Harmonic Current

(d) Phase-A Source Voltage and Source Current

Fig. 3: FFT Curve ofSPPF (a) FFT of Output Load Current without

Compensation (b) FFT o f Source Current with Compensation

Fig. 4: Simulation Result of SAPF Under Fixed Load (a) Phase-A Output

Load Current without Compensation (b) Phase-A Source Current after

Compensation (c) D C Bus Voltage Across Capacitor (d) Phase-A Actual

Compensating Current (e) Phase-A Source Voltage and Source Current

Fig. 5: Simulation Result ofSAPF under Dynamic Load (a) Phase-A

Output Load Current without Compensation (b) Phase-A Source Current

after Compensation (c) Phase-A Actual Compensating Current (d) DC

Bus Voltage Across Capacitor

Fig. 6: Hysteresis Controller Results (a) Reference and Actual

Compensating Currents of Phase-A (b) Line-Line Voltage oflnverter

Fig.7: FFT Curve of Source Current after Compensation by using SAPF

(a)     under Fixed Load (b) under Dynamic Load

Fig. 8: Simulation Result ofHAPF(a) Phase-A Load Current without

Compensation,(b) Phase-A Source Current with Compensation,

(c) Phase-A Phase Voltage and Current, (d) DC Link Voltage oflnverter,

(e) Phase-A Actual Compensating Current

Fig. 9: Simulation Result ofHAPF (a) Three Phase Output Load

Current, (b) Three Phase Load Current, (c) Three Phase Source Current,

(d) FFT Curve of Source Current with Compensation

CONCLUSION:

This paper analyze the performance and simulation of hybrid active power filter (HAPF). Through the simulation analysis, this paper verified the mitigation of harmonic, to achieve unity power factor with reduced rating of SAPF. Proposed control technique is able to give fast dynamic response during variable load condition, which demonstrate the robustness of controllers. The proposed topology is an effort to provide cost effective solution for harmonic elimination in various industrial application

REFERENCES:

[I] B. Singh, V. Verma, A. Chandra and K. AI-Haddad " Hybrid filter for power quality improvement" IEEE proc. Gener. Transm. Distrib. , Volume:152, No.3 , May 2005.

[2] J. Arrillaga and N. R. Watson, Power System Harmonics, 2nd ed. Hoboken, NJ: Wiley, 2003

[3] B. Singh, K. AI-Haddad, and A. Chandra, " A reviewof active filter for power quality improvement," IEEE Trans. Ind. Electron. , Vol. 46, nO.5 pp. 960-971 , Oct.l999.

[4] H. Akagi, " Active harmonic filters" Proc. IEEE, vol. 93, no. 12, pp.2128-2141 , Dec. 2005.

[5] K. K. Shyu, M. Yang, Y.M. Chen, and Y.F.Lin, "Model reference Adaptive control design for a shunt active po we filter systems," TEEE Trans. Tnd. Electron., vol. 55, no. 1, pp. 97-106, Jan. 2008.