Boost型PWM整流器并联环流机理分析及抑制策略

Generating Mechanism and Control Strategy for Circulating Currents in Parallel Three-phase Boost Rectifiers

对Boost型脉宽调制(PWM)整流器的并联环流产生机理进行了详细分析。通过在αβ0坐标系下建模,将环流划分为共模环流、差模环流、高频环流3类,揭示了各类环流的影响因素。在此基础上,基于比例谐振调节器,针对差模环流和共模环流分别设计了独立控制器。由于αβ0坐标系不需要电网相位信息,因此该控制策略能够省略锁相环节,简化计算量和控制结构。在600kVA对拖平台上进行了实验,验证了机理分析的正确性与控制策略的有效性。

The generating mechanism of circulating currents in parallel three-phase Boost rectifiers is analyzed.A model of the circulating current inαβ0 stationary coordinate system is established.Base on this,the circulating current is classified into three components：common-mode circulating current,differential-mode circulating current and high frequency circulating current. The affecting factors of three components are also revealed.With these understanding,controllers based on proportional and resonant regulators are designed separately for common-mode and differential-mode circulating current. Since rotating transformation and phase detection are eliminated inαβ0 coordinate system,a simple structure and small computational cost are achieved.Experiments are carried out on a 600 kVA mutual-driving test-bed.The results prove the validity of the analysis and the proposed control strategy.