A Coordinate Transformation Based Power Decoupling and Restriction Control Strategy for Microgrid

YAN Xiang-wu, WANG Yue-ru, WANG Xing-hai

Abstract

 In low voltage microgrid, traditional power droop control will cause active and reactive power coupling problem. Virtual power droop control based on coordinate transformation was adopted and its decoupling characteristics, power sharing and restriction problems were studied. Relative gain analysis method was used to analyze the power coupling degree after adopting coordinate transformation. It is theoretically proved that the virtual power droop control can realize total power decoupling characteristics when the coordinate transformation matrix and line impedance have the same resistance and inductance ratio. Aiming at the problem that line impedance difference can cause uneven power sharing, a strategy was proposed, which aimed to improve power sharing accuracy by adding virtual negative impedance. In the light of the limitation of the existing power restriction range of virtual power droop control which is not equal to the actual power restriction range of the inverter, a new power restriction control strategy was proposed. Eight sections were divided for the operation points, in which the power exceeds the limits. The section number was determined according to the inverter output power and the corresponding adjustment measures were taken. Simulation results have verified the correctness and effectiveness of the proposed control strategy.

 

 

Keywords: microgrid,  power control,  coordinate transformation,  virtual power,  decoupling,  virtual impedance,  power restriction


Full Text:

PDF


References


WANG Cheng-shan. XIAO Zhao-xia, WANG Shou-xiang. Synthetical control and analysis of microgrid [J]. Automation of Electric Power Systems,2008, 32(7) ;98— 103. (In Chinese)

LV Zhi-peng, LUO An. Robust power control of paralleled micro-source inverters with different power ratings[J]. Proceedings of the CSEE, 2012,32( 12) ;35 — 42. (In Chinese)

LI Peng, YANG Shi-wang, WANG Yang,et al. Objective function diagonalization decoupling control of microgrid power based on relative gain analysis [J]. Proceedings of the CSEE, 2014,34(13): 2039-2046. (In Chinese)

WANG Cheng-shan, XIAO Zhao-xia, WANG Shou-xiang. Multiple feedback loop control scheme for inverters of the micro source in microgrids [J]. Transactions of China Electrotechnical Society, 2009, 24(2); 100—107. (In Chinese)

DE BRABANDERE К.BOLSENS B, VAN DEN KEYBUS J, et al. A voltage and frequency droop control method for parallel inverters [J]. IEEE Transactions on Power Electronics, 2007,22(4): 1107— 1115.

LI Yan. LI Yun-wei. Decoupled power control for an inverter based low voltage microgrid in autonomous operation [C]// Proceedings of the Power Electronics and Motion Control Conference. Wuhan:IEEE,2009; 2490 — 2496.

LI Yan,LI Yun-wei. Virtual frequency-voltage frame control of inverter based low voltage microgrid [C]//Proceedings of the IEEE Electrical Power &- Energy Conference. Montreal: IEEE, 2009:1-6.

ZHOU Xian-zheng. RONG Fei.LV Zhi-peng,et al. A coordinate rotational transformation based virtual power V/f droop control method for low voltage microgrid [J]. Automation of Electric Power Systems.2012.36(2): 47 — 51. (In Chinese)

LI Yun-wei.KAO Ching-nan. An accurate power control strategy for power-electronics-interfaced distributed generation units operating in a low-voltege multibus microgrid [J]. IEEE Transactions on Power Electronics.2009.24 (12) :2977 — 2988.

LI Peng. YANG Shi-wang. YIN Zi-heng. Voltage stabilization and decoupling droop control method for microgrid based on RGA [J]. Proceedings of the CSEE.2015.35(5): 1041 — 1050. (In Chinese)

MOU Xiao-chun.BI Da-qiang. REN Xian-wen. Study on control strategies of a low voltage microgrid [J]. Automation of Electric Power Systems.2010.34( 19) :91 — 96. (In Chinese)

KAN Jia-rong. XIE Shao-jun.WU Yun-ya. Research on decoupling droop characteristic for parallel inverters without control interconnection [J]. Proceedings of the CSEE,2008,28(21) : 40 — 45. (In Chinese)


Refbacks

  • There are currently no refbacks.