基于Super-twisting控制器的永磁同步电动机无传感器直接转矩控制

Sensorless Direct Torque Control of Permanent Magnet Synchronous Motor Using a Super-twisting Controller

永磁同步电动机(PMSM)参数易受无规律、非线性噪声扰动的影响;在直接转矩控制中定子磁链的计算多因采用纯积分环节而使观测精度不高,从而产生较大的转矩脉动和磁链脉动等。针对上述问题,利用扩展卡尔曼滤波(EKF)观测器实现对PMSM转速、位置、磁链的准确观测;同时,由于PI控制器对电动机参数变化较为敏感,设计一种Super-twisting控制器代替转矩PI控制器和参考电压矢量估算模块,并将准滑动模态中的sigmoid(s)函数代替符号函数sgn(s),进一步增强了系统鲁棒性,且减少了系统的复杂性。仿真研究表明,EKF观测器可以准确地对电动机转速、位置、磁链进行观测,同时Super-twisting控制器也进一步降低控制系统的转矩脉动,提高转速的观测精度。

Parameters of permanent magnet synchronous motor（PMSM）are susceptible to random and nonlinear noise disturbances.In direct torque control,observation accuracy is poor because pure integral is generally used in the calculation of stator flux,leading to torque ripple and flux pulses.To solve the problem,an extended Kalman filter（EKF）observer is used to make accurate observation of speed,position and flux of the PMSM.Meanwhile,as the PI controller is sensitive to changes in the motor parameters,a super-twisting controller is designed instead of a torque PI controller and a reference voltage vector estimation module.The function sigmoid（s）in a quasisliding mode is used to replace the symbol function sgn（s）,improving robustness and reducing complexity of the system.Simulation results show that the EKF observer can accurately observe the speed,position and flux of the motor.The super-twisting controller can reduce torque ripples in the control system,and improve observation accuracy of the speed.