Model Predictive Torque Control And Rotor Position Estimation For Permanent Magnet Synchronous Motor

With the advantages of high power density,reliable operation,good control performance and strong load carrying capacity,permanent magnet synchronous motors are widely used in aerospace,medical devices,electric vehicles and other fields.Model predictive control has the characteristics of easy modeling,strong anti-interference ability and good stability.Combining the idea of direct torque control with model predictive control algorithm,the problem of large torque pulsation and poor dynamic response is solved to a certain extent.In addition the traditional position estimation method is based on vector control for detection,for the rotor position estimation method combined with model predictive control needs further research.In this paper,the main research object is a table-mounted permanent magnet synchronous motor,and the three-vector model predictive torque control method and rotor position estimation strategy for permanent magnet synchronous motor based on torque hysteresis loop are studied,and the following main research work is carried out:Firstly,the model prediction control algorithm of permanent magnet synchronous motor is systematically analyzed,and the single-vector and double-vector model prediction torque control is studied in depth.The simulation and experiment show that the single-vector model predictive torque control has the disadvantages of large torque pulsation,small voltage vector selection range and high harmonic content,while the dual-vector model predictive torque control expands the voltage vector selection range and reduces the harmonic content to a certain extent,but still has the problems of large torque pulsation and large computational effort.It is necessary to conduct further research.Then,a three-vector model prediction torque control strategy for permanent magnet synchronous motor based on torque hysteresis loop is studied for the problems of single-vector and two-vector model prediction torque control.The method introduces the idea of direct torque control based on the traditional model prediction torque control method and adopts the mechanism of hysteresis loop control,which can realize the flexible switching between singlevector and three-vector model prediction torque control,so that the optimized voltage vector can be selected more effectively and quickly.Compared with the traditional model prediction torque control method,it can suppress torque pulsation,reduce current harmonic content and lower switching losses more effectively.Simulation results demonstrate the effectiveness of the method.Finally,a rotor position estimation strategy based on a sliding-mode variable-structure adaptive phase-locked loop is studied to address the problems of high-frequency jitter and large rotor position estimation errors of the conventional sliding-mode observer.The method combines the sliding mode observer with the adaptive phase-locked loop,uses an improved hyperbolic tangent function instead of the sign function to achieve the weakening of the jitter,and uses the adaptive phase-locked loop for more accurate rotor position estimation.The method is combined with vector control and model predictive torque control,respectively,and the feasibility of the method is verified by simulation and experimental results.