基于多重三电平桥结构的静止无功发生器

针对一般电压源逆变器拓扑在静止无功发生器(SVG)逆变电路中输出电压质量的不足,提出了一种多重三电平桥结构.采用瞬时无功功率理论,分析了基于该拓扑结构的静止无功发生器实现无功功率控制的等效电路及工作原理.并设计了一种基于电流直接控制的控制方法,采用双闭环反馈控制策略.通过三角波比较方式的脉冲宽度调制技术对电流波形的瞬时值进行控制.经过对系统主电路进行仿真分析.获得了较高的逆变器输出电压质量和准确的三相无功指令电流,同时得到了补偿后网侧电压和电流的波形,电压和电流基本同相位,实现了对无功功率的有效补偿.

Static var generator based on multiple three-level bridge configuration

To improve the inverter output voltage quality of SVG(Static Var Generator),a multiple three - level bridge configuration is proposed, which employs a three - phase voltage source inverter to control reactive power. Its equivalent circuit and working principle is analyzed based on the instantaneous reactive power theory. The direct current control and double close - loop feedback control strategy are designed,which uses PWM by triangular wave comparison to control the instantaneous current. The main circuitry is analyzed with simulation and the inverter output voltage with higher quality and the accurate three - phase reactive directive current are obtained. The voltage and current waveforms of network side after compensation are of same phase,which proves the effective reactive power compensation.