基于电流边界限制条件的异步电动机弱磁控制

A flux weakening control for asynchronous motor based on current boundary limit condition

在空间矢量脉宽调制(SVPWM)控制策略下,通过分析异步电动机电流限制圆与电压限制圆的特性,结合电动机调速的实际应用情况,提出了一种基于电流边界限制条件的弱磁控制策略。该方法在调节励磁电流后能够使输出转矩电流逼近转矩电流限制条件,进而使定子电流矢量逼近电流限制圆。相对于电压闭环弱磁控制,该法可以将最大励磁电流作为励磁电流初始值,提高恒转矩区转矩的输出能力。在弱磁区不需要考虑电压裕量的问题,可以充分利用电压的输出能力,提高弱磁区转矩的输出能力。鉴于励磁电流调节过程的非线性,同时引入了模糊PI控制器,使得调节过程更加精确,具有更好的动、静态特性。

Under the space vector pulse width modulation( SVPWM) control strategy,by analyzing the characteristics of the current limiting circle and the voltage limiting circle,combined with the practical application conditions of variable frequency driving of motor,a flux weakening control strategy based on current boundary limit condition is proposed in this paper. After adjusting exciting current,this method can make the output torque current close to the torque current constraints condition,and then,the stator current vector close to the current limiting circle. Compared with the voltage closed-loop flux weakening control method,this method can make the biggest exciting current as the exciting current initial value,and improve the output capability of torque in the constant torque region. In the flux weakening region,it is not necessary to consider the problem of voltage margin,which can make full use of the output capability of voltage and improve the output capability of torque in the flux weakening region. In view of the non-linearity of the exciting current regulation process,the fuzzy PI controller was introduced,which makes the regulation process more precise and has better dynamic and static characteristics.