Research On Torque Ripple Suppression Strategy Of Doubly Salient Permanent Magnet Motor

The Doubly Salient Permanent Magnet Motor(DSPM)has the advantages of simple structure,easy maintenance,wide speed range and high power density.It was widely used in industrial production,aerospace and automotive manufacturing.However,when the DSPM is in the low speed operation state,a torque ripple is generated,thereby restricting the running performance for the motor.On the one hand,since the DSPM belongs to the double salient pole structure,when the motor stator and rotor salient pole face enter the coincident region,the motor air gap length becomes short instantaneously,resulting in the edge magnetic field effect and the air gap magnetic field energy mutation.Thus the torque-angle characteristic of the motor produces a torque change in the process,which causes the synthetic torque output waveform fluctuating greatly.On the other hand,under the traditional control strategy,the DSPM is affected by nonlinear factors,which will inevitably lead to the motor of steady-state running has larger torque ripple.Especially,when the motor is commutating,the electromagnetic torque is no longer generated after the previous related disconnection,and the latter phase is not turned on immediately,causing the waveform to fluctuate up and down.In this paper,the following design proposals are proposed in this paper:(1)Aiming at the problem of motor torque ripple caused by the edge flux effect caused by the periodic coincidence of the stator and rotor salient pole structure of DSPM,the method of changing the rotor pole arc width and the stator air gap side tooth pole surface structure is proposed.The parameters and the distribution of the air gap magnetic flux of the motor stator and rotor reciprocating tooth edge are analyzed and the feasibility ofweakening the torque ripple scheme of the DSPM is clarified.(2)The method of wedge-shaped slots on both sides of the stator teeth is used to improve the distribution of the magnetic field lines of the motor,and the slot depth,width and the height of the tooth top are optimized respectively to obtain the optimal slot size and slot position.The simulation results show that the radial component of the air gap magnetic density at the edge of DSPM decreases and the tangential component increases obviously.Compared with the original DSPM,although the average torque is reduced,the motor torque ripple is weakened.(3)Based on the traditional PID can not effectively control the motor operation,This chapter designs the DSPM current sharing function control system based on Brain Emotional Learning(BEL)model,and the BEL model is similar to the adaptive PID controller,which can be automatically changed according to the change of target parameters.Adjusting the system control parameters to achieve better control effect,the DSPM current sharing function control system obtained by simulation analysis can not only achieve wonderful speed control performance,but also achieve significant torque ripple suppression.