基于滑模变结构的船用永磁同步电机直接转矩控制

Direct torque control of permanent magnet synchronous motor for ship based on sliding mode variable structure

电力推进在船舶动力系统中应用得越来越多,本文对船用永磁同步电机直接转矩控制进行仿真研究。针对传统永磁同步电机直接转矩控制中存在的磁链和转矩脉动较大,逆变器开关频率不稳定等问题,将滑模变结构控制策略引入。设计转矩和磁链2个滑模控制器,取代传统直接转矩控制中的2个滞环比较器,再运用空间矢量脉宽调制方法,控制电机运行。仿真结果表明这种控制策略能有效减小传统直接转矩控制存在的磁链和转矩脉动,实现逆变器开关频率恒定,并且对系统参数变化及外界扰动具有鲁棒性强的优点。

The electric propulsion is used more and more in the ship power system. The simulation of direct torque con- trol of permanent magnet synchronous motor is studied in this paper. The sliding mode variable structure control （SMC） strategy is introduced to solve the problems of large flux and torque ripple in direct torque control of permanent magnet syn- chronous motor （PMSM）. Design two sliding mode controllers of torque and flux linkage to replace the two hysteresis com- parators in the conventional direct torque control, and then use the space vector pulse width modulation （SVPWM） to con- trol motor operation. The simulation results show that this control strategy can effectively reduce the existing flux and torque ripple in the conventional direct torque control and keep the inverter switching frequency be constant, and it is strongly ro- bust to system parameter variations and external disturbance.