SVG的一种控制策略研究

A Kind of Control Strategy of SVG

论文分析了SVG传统控制方法的局限性,研究了闭环动态无功功率控制以及功率单元直流电压平衡控制的新策略。基于功率单元的数学模型和瞬时无功功率理论,论文将参考电流信号直接变换为电压参考信号,省去了传统双闭环控制中的电流-电压转换器。另外,利用在参考电压矢量中叠加一个与输出电流矢量平行的有功电压矢量用来控制功率单元的直流电压平衡。仿真模型参数为SN=±4MVar、UN=10kV,N=12,Y连接。仿真结果证明,论文的方法能在突加额定负载下实现SVG从感性无功功率变换到容性无功功率(或反之)的稳定输出,同时即使在过渡过程中也能保持所有功率单元直流电压平衡。

The limitations of traditional controller for SVG are analyzed ,and novel closed-loop dynamic var control strategy and DC voltage balancing method of individual power cell are focused on .The novel strategy based on the mathemat-ical model of power cell and the instantaneous reactive power theory changes the current reference signal to voltage reference one directly ,and so gets rid of the current-voltage translator in inner loop of traditional double loop control method .Besides , through adding an active power voltage vector paralleling with output current to the reference voltage vector ,DC voltages balance of power cell could be achieved .Simulation results verify that a SN = ± 4MVar、UN =10kV cascade H bridge PWM SVG with star configuration has the capability of inductive to capacitive （or capacitive to inductive） operation at the rated re-active power of ± 4MVar while keeping the twelve DC mean voltages controlled and balanced even during the transient state .