数字控制延时对电流环解耦有效性的影响

Research on the Impacts of Digital Control Delay on the Effectiveness of Current Loop Decoupling

分析数字控制延时对同步旋转坐标系下的两种电流解耦方法(电压前馈解耦和复系数PI控制器解耦)有效性的影响,揭示开关频率较低或控制频率较高情况下解耦失效的本质,进而提出通过延时补偿来有效抑制电流环的耦合,从电流环的解耦有效性、电流环的动态响应速度方面比较两种解耦方法的优劣。在相同的条件下,相比于电压前馈解耦方法,复系数PI控制器解耦方法的d、q轴电流耦合度大约是其50%,动态响应速度是其两倍。仿真和实验结果验证了理论分析的正确性。

This paper analyzes the effect of digital control delay on the effectiveness of current loop decoupling(feed-forward decoupling and complex vector PI decoupling)in the synchronous rotating frame,revealing the nature of the decoupling failure under the condition of low switching frequency or high control frequency.And the delay compensation method for suppressing the current loop coupling is proposed.The advantages and disadvantages of the two decoupling methods are then compared in term of the decoupling effectiveness and the dynamic response speed of the current loop.Compared to the feed-forward decoupling,the coupling between d axis and q axis of complex vector PI decoupling is reduced by 50%,and the dynamic response speed is about twice.Simulation and experimental results are carried out to verify the correctness of the theoretical analysis.