异步电机DTC系统的负载转矩观测与滑模控制

Induction Motor DTC System Based on Sliding Mode Control and Load Torque Observer

为改善常规直接转矩控制中磁链和转矩脉动大的问题,本文提出了带负载转矩观测器的异步电动机DTC系统的滑模控制方法。内环根据异步电动机在dq坐标系下的数学模型和滑模控制理论,设计了一种基于转矩和磁链误差的滑模控制器;外环选取比例-积分滑模控制器取代PI控制器,利用获得的参考电压矢量,通过SVM技术得到逆变器开关控制信号。利用电压重构获取逆变器输出电压,可以减少系统的硬件成本。为验证所设计的控制系统的性能,使用Matlab/Simulink进行仿真验证。仿真结果表明,基于滑模控制的直接转矩控制策略系统响应更迅速,设计的控制方案鲁棒性强,且明显减弱了转矩和磁链脉动,抗干扰能力更强。该研究在异步电机调速系统中具有很好的控制效果和应用前景。

To reduce flux and torque ripple associated with traditional direct torque control of induction motor,a direct torque control with load torque observer based on sliding mode control strategy is put forward in this paper.According to the mathematical models of induction motor in synchronous rotation coordinates and the theory of sliding mode control,hysteresis comparators are substituted by sliding mode controllers based on torque and flux errors for the inner loop.A proportional-integral sliding mode controlleris considered to replace PI controller for the outer speed loop.The space vector modulation technology is used in order to maintain a fixed switching frequency of inverter.The voltage reconstruction is adopted to obtain the output voltage of the inverter in order to reduce the number of sensors and the cost of the system.In order to verify the performance of the control system,simulation is carried out based on Matlab/Simulink.The simulation results show that the DTC based on sliding mode control has better dynamic response than traditional DTC.Moreover,the proposed control scheme can not only significantly reduce torque and flux ripple,but also have good robustness and strong anti-interference.The study has a good application prospect and a great control performance for the system of induction motor speed control.