基于闭环电流预测的永磁同步电机电流环延时补偿策略研究

Research on Delay Compensation Strategy of Permanent Magnet Synchronous Motor Based on Closed-loop Current Prediction

永磁同步电机采用传统复矢量电流调节器在开关频率与电机频率比值较高时具有良好的参数鲁棒性与动态性能,但在低开关频率下,环路延时与参数摄动易使电流动态响应振荡甚至失稳。采用复矢量表示法对电流环延时环节进行精确建模,基于Smith预估器结构对传统电流预测延时补偿策略进行复矢量建模与频域分析。传统电流预测策略的开环结构在模型或者参数误差下会产生电流跟踪误差,针对该缺陷提出一种基于误差补偿器的闭环电流预测延时补偿算法。该算法采用改进Euler法对电流方程进行离散化,并通过将预测电流偏差积分反馈至预测方程形成闭环预测结构,可实现电流无静差跟踪,在抑制环路延时影响同时大大提升系统鲁棒性。实验结果验证理论分析的正确性和所提算法的有效性。

Conventional complex vector current regulator could attain good parameter robustness and dynamic performance at high control frequency.Nevertheless,the current’s dynamic response incurs inevitable oscillation or even instability when control frequency is low.The complex vector representation was applied to model the time delay of current loop accurately.The mathematical model of conventional current prediction strategy for time delay compensation was built based on the Smith predictor structure,and analyzed in frequency domain.The current tracking error will exist if the model’s structure or parameter is inaccurate.A closed-loop current prediction strategy was proposed based on error compensator for time delay compensation.The proposed strategy introduced the prediction error into the prediction equation and formed into the closed-loop structure,and applied the improved Euler method to the discretization of the current control equation.It can eliminate the deviation between the predictive current and actual current.The proposed method can depress the effect of time delay and strengthen the robustness of system.Experimental results verify the validity of the theoretical and the feasibility of the method.