Current control in electric multiple unit (EMU) pulsewidth-modulated (PWM) rectifiers is crucial for the system’s stable operation and fast transient response. It should not only regulate the sinusoidal current under very low switching frequency but also eliminate dc current avoiding transformer core saturation. Therefore, proportional integral (PI) plus vector proportional integral with phase compensation (VPIc) controller is chosen for the current control in such single-phase rectifiers. However, the gains of PI and VPIc are coupled and determine the system performance together, invalidating the traditional gain tuning method. Therefore, a gain tuning method for PI + VPIc based on Nichols chart is proposed in this article, which decouples the two gains and simplifies the gain tuning into the tuning of gain margin and phase crossover frequency, while settling time and overshoot are considered for the optimal gain tuning. The designed system has good transient responses, stability, and robustness. The experimental results validate the theoretical analysis of the tuning method on a laboratory prototype and the effectiveness of the current control on the EMU PWM rectifiers.

中文翻译：

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多电机组PWM整流器消直流谐振电流控制器的整定方法

电动多路单元 (EMU) 脉宽调制 (PWM) 整流器中的电流控制对于系统的稳定运行和快速瞬态响应至关重要。它不仅要在非常低的开关频率下调节正弦电流，还要消除直流电流，避免变压器铁芯饱和。因此，在这种单相整流器中，选择比例积分 (PI) 加带有相位补偿 (VPIc) 控制器的矢量比例积分控制器进行电流控制。然而，PI 和 VPIc 的增益是耦合在一起的，共同决定了系统性能，使传统的增益调整方法无效。因此，本文提出了一种基于Nichols图的P​​I+VPIc增益调谐方法，将两种增益解耦，将增益调谐简化为增益裕度和相位交叉频率的调谐，同时考虑稳定时间和过冲以进行最佳增益调整。设计的系统具有良好的瞬态响应、稳定性和鲁棒性。实验结果验证了实验室样机上调谐方法的理论分析和动车组 PWM 整流器电流控制的有效性。