基于占空比调制的异步电机模型预测转矩控制技术

Technology of Model Predictive Torque Control for Asynchronous Motor Based on Duty Cycle Modulation

针对模型预测转矩控制中所使用的电压矢量幅值与相角固定导致异步电机稳态性能较差的问题,提出了一种占空比调制策略。该策略首先将6个非零开关电压矢量扩充为12个非零电压矢量,其次根据转矩的无差拍跟踪计算电压矢量的作用时间与对应的等效电压矢量,对满足转矩变化趋势的等效电压矢量进行定子磁链的预测,最终选取定子磁链幅值误差最小的作为最优电压矢量。仿真结果表明,所提策略能有效减少转矩、磁链脉动及定子电流THD。

For the problem of poor steady-state performance of asynchronous motor resulting from fixed amplitude and phase angle of the voltage vector in the model predictive torque control,a duty cycle modulation strategy was proposed.Firstly,the six non-zero switching voltage vectors were expanded into twelve non-zero voltage vectors.Secondly,according to the deadbeat tracking of the torque,the action time of each voltage vector and the corresponding equivalent voltage vector were calculated.Finally,the stator flux linkage was predicted for the equivalent voltage vector satisfying the change trend of torque,and the minimum stator flux linkage amplitude error was chosen as the optimal voltage vector.The simulation shows that the strategy can effectively reduce the torque and flux linkage ripple and THD of stator current.