基于扩充虚拟矢量的永磁同步电动机模型预测直接转矩控制

Model predictive instantaneous torque control of permanent magnet synchronous motor based on finite voltage vector set optimization

针对传统模型预测直接转矩控制策略存在的计算效率低、电压跳变过高、稳态特性较差等问题,提出一种改进模型预测直接转矩控制策略。为提升电动机的稳态特性,基于最近三矢量原则构建36个虚拟电压矢量,并结合无差拍原理调节虚拟电压矢量中冗余矢量的作用时间;为防止逆变器输出线电压跳变过高以对电动机产生不良影响,仅选取电压跳变不超过Udc/2的电压矢量作为备选电压矢量。同时,结合模型通过无差拍原理预测出参考电压矢量,选取与参考电压矢量位于同一扇区的电压矢量作为最终备选矢量集。实验结果证明了在额定工况下改进控制策略较传统控制策略的电磁转矩、定子磁链幅值误差和电流谐波畸变率分别减少了37.42%、32.00%和44.52%,程序执行时间减少了约11.52%。

To address the problems of traditional model predictive direct torque control strategy,such as low computational efficiency,high voltage jump and poor steady-state characteristics,an improved model predictive direct torque control strategy is proposed.To improve the steady-state characteristics of the motor,36 virtual voltage vectors are constructed based on the principle of the nearest three vectors.The action time of redundant vectors in the virtual voltage vector is adjusted by combining the principle of no beat.To prevent excessive voltage jump in the output line of the inverter from causing adverse effects on the motor,only voltage vectors with voltage jump not exceeding U_(dc)/2 are selected as alternative voltage vectors.Meanwhile,the reference voltage vector is predicted by combining the model with the deadbeat principle,and the voltage vector located in the same sector as the reference voltage vector is selected as the final candidate vector set.Compared with traditional control strategies under rated operating conditions,the experimental results show that the improved control strategy reduces the electromagnetic torque,stator flux amplitude error,and current harmonic distortion rate by 37.42%,32.00%,and 44.52%,respectively.The program execution time is reduced by approximately 11.52%.