矩阵变换器负载不平衡时网侧电流控制

The Current Balanced Control of Power Grid of Matrix Converter With Unbalanced Load

矩阵变换器输出与输入通过器件直接连接,输入电流直接由输出电流合成,当负载电流不平衡时,传统的空间矢量调制方法下输入电流畸变和不对称严重。为实现负载电流不平衡时输入电流仍能对称正弦,从占空比和调制比两个方面,深入分析了造成输入电流不平衡的原因,并在此基础上提出了一种抑制策略:对传统的调制比计算方法进行改进,提出采用给定输入电流与输出电流计算占空比的方法,使输入电流逼近给定电流,从而达到控制输入电流平衡的目的。仿真结果表明,无论负载电流平衡与否,采用所提调制比计算方法,输入电流均能平衡正弦,实验结果证明了该方法的正确性与可行性。

Input side and output side of matrix converter are connected to each other by transistors, input current is directly synthesized by output current, the distortion and unbalance of input current is very high and serious by using traditional space vector modulation when load is unbalanced.To achieve the balance of input current under output current unbalanced, the reason is analyzed deeply from duty ratio and modulation ratio, and based on this a method is put forward.The traditional modulation ratio of space vector is improved,which is calculated by using input current and output current, making input current close to given current and then achieveing the aim of input current balan- ced.Emulated results indicate that whatever the load is balanced or unbalanced,the input current can be balanced and sinusoidal by using proposed method.Experimental results validate that the proposed method is right and feasible.