基于空间矢量调制的无刷双馈电机直接转矩控制

Direct Torque Control of Brushless Doubly-fed Machine Based on Space Vector Modulation

针对传统直接转矩控制中采用滞环比较器对转矩和磁链进行控制,存在着转矩和磁链脉动大、开关频率不固定等问题,提出了一种基于空间矢量调制的无刷双馈电机直接转矩控制方法。采用转矩、磁链PI控制器代替传统直接转矩中的滞环比较器,以转矩和磁链误差作为控制量,采用空间矢量调制代替电压矢量开关表合成电压矢量,对转矩误差和磁链误差进行补偿。仿真结果表明,与传统直接转矩控制相比,基于空间矢量调制的无刷双馈电机直接转矩控制系统磁链轨迹更趋近于圆形,降低了转矩脉动,系统具有良好的动静态性能。

The traditional direct torque control system employs two hysteresis comparators to regulate the stator flux and torque respectively, which has existed large torque fluctuation and inconstant switch frequency, etc. A control strategy direct torque control based on space vector modulation is proposed in this paper.The strategy with the torque error and flux error as control quantity and uses toeque and flux PI controller replace the conventional hysteresis comparators of traditional direct torque control system, and adopts space vector modulation instead of voltage vector switch to synthesize voltage vector to compensate the torque error and flux error. The simulation results show that the flux trajectory closer to a circle,torque fluctuation largely decrease and the static and dynamic performance of the system was improved with the strategy based on space vector modulation compared to the traditional DTC.