一种新型的永磁同步电机直接转矩控制方法

永磁同步电机传统直接转矩控制方法采用磁链和转矩双闭环结构实现对电机转矩的直接控制.由于控制过程中要保持磁链幅值恒定,不仅限制了电机的动态性能,同时,为了实现恒定的定子磁链幅值,还需要额外的无功电流,降低了电机功率因数,增加了系统损耗.本文从转矩优化和无功电流优化控制的角度出发,提出了一种新型的直接转矩控制方法,控制过程中直接根据转矩控制要求选择电压矢量,不要求磁链幅值恒定,对转子位置要求不高,控制过程中能够实现磁链幅值的动态调整,电机在具有良好动态性能的同时具有较高的功率因数.仿真结果验证了理论分析的正确性和方法的可行性.

A Novel Direct Torque Control Method for Permanent Magnet Synchronous Motor

The double closed loop structure of stator flux linkage and torque is used to realize direct control of motor torque in traditional direct torque control of permanent magnet synchronous motor. Because flux amplitude is kept as constant,dynamic performance of the motor is not only restricted,but also reactive current is increased. When reactive current is increased,motor power factor is reduced and system loss is increased. From the points of perspective of optimal control of the torque and reactive current,a novel direct torque control method is presented in this paper. Voltage vectors are merely selected according to the requirement of the torque control in the period of control. In the control process,stator flux amplitude can be dynamically adjusted and rotor position is less demanded. So dynamic performance of the motor and power factor are significantly improved. The correctness and feasibility of the proposed method are verified by the simulation results.