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提出了一种适用于低压配电系统的新型动态无功补偿电路拓扑。主电路采用三相四桥臂逆变器结构,可以对负荷不平衡进行有效补偿。逆变器控制采用正弦脉宽调制(sinusoidal pulse width modulation,SPWM)控制,保证电压电流失真度低,并通过调节逆变器的输出电压从而动态调节静态无功补偿器(static var compensator,SVC)补偿无功功率,最终实现系统无功补偿为零的目的。通过与固定补偿电容器相结合,它能以较小的逆变器容量来补偿动态无功,提高系统的功率因数和电压稳定性。利用PSCAD/EMTDC平台对该系统进行了仿真研究。仿真结果验证了控制策略的可行性和有效性。
A new dynamic reactive power compensation circuit topology suitable for low voltage distribution system is proposed. The main circuit using three-phase four-leg inverter structure, load imbalance can be effectively compensated. Inverter control uses sinusoidal pulse width modulation (SPWM) control to ensure low voltage and current distortion and to dynamically adjust the static var compensator (SVC) by regulating the inverter output voltage. Reactive power compensation, the ultimate goal of zero reactive power compensation system. Combined with a fixed compensation capacitor, it compensates for dynamic reactive power with a small inverter capacity, improving system power factor and voltage stability. The system was simulated by using PSCAD / EMTDC platform. Simulation results verify the feasibility and effectiveness of the control strategy.