三电平PWM整流器半实物研究

Research on Three-level PWM Rectifier of Semi-hardware-in-loop

本文基于三电平PWM整流器数学模型,采用状态反馈解耦后双闭环调节,辅以闭环观测器估计负载电流作前馈补偿的直接电流控制方案,同时通过辨识虚拟电网磁链,代替测量电网电压锁相作为控制中的定向矢量;针对三电平变换器中点电位平衡这一固有问题,采用准确解析计算使之平衡的零序电压分量,有效消除中点电位波动。最后搭建基于硬件在回路的半实物仿真实验装置,实现了低谐波双向能量传递,动静态性能良好,验证了控制策略的可行性和有效性。

In this paper, at first, a valid direct current control concept, which combines the current state feedback decoupling and the dual close loop control, is researched according to the mathematical model. Consequently, adding the feed forward control, the observer is proposed to estimate load current. And a virtual line-flux-linkage vector is observation, which may serve as the oriented vector in the vector control of the PWM rectifier instead of the line voltage vector. And then a control method is proposed to control the neutral-point voltage charge unbalance, which is an inherent problem of three-level converter. The zero sequence component is calculated accurately, so that the fluctuation of NPP can be availability eliminated. Finally, semi-hardware-in-loop experiment device is constructed, and semi-hardware-in-loop experiment is operated. As a result, the three-level rectifier has sinusoidal low harmonic input current, power dual transmitted and favorable dynamic and steady state performance, which proves that the control strategy is the validity.