双级式柔性消弧变换器网侧电流控制策略

Grid-side Current Control Strategy of Two-stage Flexible Arc-suppression Converter

对于双级式柔性消弧变换器,前级三相整流器网侧电流存在3次谐波分量和负序分量,严重影响供电电源质量。结合柔性消弧变换器的拓扑结构,对单相逆变器输出侧低频脉动分量、三相整流器网侧电流3次谐波分量和负序分量产生机理进行分析。通过指定次正、负序旋转坐标变换,提取网侧电流对应谐波分量的直流量,利用比例积分(PI)控制器实现精确调节,生成的各调制指令在基波旋转坐标系中求和后参与最终调制。最后,通过400 kVA柔性消弧变换器的仿真和现场实验结果分析,验证所提控制策略的合理性和可靠性。

For the two-stage flexible arc-suppression converter,the third-order harmonic component and the negativesequence component exist in the grid-side current of the front-stage rectifier,which seriously affects the quality of the power supply.Based on the topology of the flexible arc-suppression converter,the generating mechanism of the lowfrequency pulsating component on the single-phase output side,the third harmonic component and the negative sequence component of the grid-side current are analyzed.By specifying the positive and negative sequence rotation coordinate transformation,the direct current of the harmonic component corresponding to the grid side current is extracted,and the proportional integral(PI)controller is used to achieve precise adjustment.The generated modulation commands are summed in the fundamental wave rotating coordinate system and participate in the final modulation.Finally,through the 400 kVA flexible arc-suppression converter simulation and field experiment results analysis,the rationality and reliability of the proposed control strategy are verified.