改进圆形边界限定的永磁同步电机预测控制

Predictive Control of PMSM Based on Improved Circular Boundary Limitation

基于边界限定的预测控制是一种有效的低开关频率电机控制方法,该文针对该方法应用在永磁同步电机时存在的无法正常启动的现象进行研究,并提出改进方法。首先,对无法启动现象产生的原因进行研究,提出常规方法存在启动扭矩电流极限这一猜想,即在启动转矩电流较大时,所有的电压矢量均无法使电流轨迹进入到边界内,因此电机无法顺利启动。随后,分析不同电压矢量作用下的启动电流轨迹,验证其启动扭矩电流存在极限这一猜想,进而求解出启动扭矩极限的一般形式,并通过仿真验证了该极限值的正确性。针对启动扭矩受限问题,提出一种改进的电压矢量寻优策略,在所有电压矢量均不符合需求时,切换到能够使电流误差最快减小的电压矢量,进而保证闭环调速顺利启动。仿真与实验结果证明了改进方法的有效性,通过对比实验,验证了该方法在低开关频率下的优越性。

Predictive control based on boundary limitation is an effective low switching frequency method for motor control.This paper studies the phenomenon that the PMSM cannot start normally when it adopts the bounded-form method,and puts forward an improved method.First,the causes of the phenomenon are studied,and the conjecture that the starting torque current limit exists in the conventional method is proposed.That is,when the starting torque current is too large,all voltage vectors cannot make the current trajectory enter the boundary,so the motor cannot start normally.Then,the starting current trajectories under all effective voltage vectors are analyzed,and the conjecture of the starting torque limit is verified.Then the general form of the starting torque limit is worked out,and the correctness of the limit value is verified by simulation.To solve the problem of limited starting torque,an improved voltage vector optimization strategy is proposed.When all voltage vectors do not meet the requirements,it is switched to the voltage vector that can reduce the current error maximumly,so as to ensure the normal start of closed-loop speed regulation.Simulation and experimental results show the effectiveness of the improved method,and comparative experiments demonstrate the superiority of the proposed method at low switching frequencies.