Study Of Vector Control And Torque Ripple Suppression In Dual-stator Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor has many advantages,such as small size,light weight,high torque density,and high efficiency,which are widely used in various fields.Reasonably design of permanent magnet synchronous motor control system can improve the performance of permanent magnet synchronous motor.Supported by the project “Study of design and fault tolerant control of unaligned dual-stator spoke-type permanent magnet synchronous motor for electric vehicle(Project No.: 20180550037)”of Liaoning Provincial Department of science and technology,this thesis studies a 36-slot,38-pole unaligned dual-stator spoke-type permanent magnet synchronous motor with low cost and high torque density.The main study contents of this thesis are shown as follows:Firstly,an unaligned dual-stator spoke-type permanent magnet synchronous motor structure is proposed,in which the outer and inner stator teeth are 90° electrical angle different from each other,the permanent magnets are arranged by spoke-type,and the phase concentrated windings are used.It can effectively reduce the cogging torque of unaligned dual-stator spoke-type permanent magnet synchronous motor,and then restrain the torque ripple of unaligned dual-stator spoke-type permanent magnet synchronous motor.Secondly,the structure and parameters of unaligned dual-stator spoke-type permanent magnet synchronous motor are analyzed,and a mathematical model of unaligned dual-stator spoke-type permanent magnet synchronous motor in a synchronous rotating coordinate system is established.The voltage equation,the magnetic flux equation,the torque equation,and the mechanical motion equation are given.Laying the foundation for the research of the control system of unaligned dual-stator spoke-type permanent magnet synchronous motor.At the same time,based on the finite element simulation software named ANSYS Electronics Desktop,the finite element analysis of no-load and load conditions of the proposed unaligned dual-stator spoke-type permanent magnet synchronous motor is carried out.No-load back EMF,cogging torque,electromagnetic torque and other waveforms are given.In ANSYS Twin Builder software,the double closed-loop vector control system of speed and current of unaligned dual-stator spoke-type permanent magnet synchronous motor is designed.The control system and the finite element model of unaligned dual-stator spoke-type permanent magnet synchronous motor are jointly simulated in different conditions.Thirdly,in order to reduce the cost of the control system and improve the stability of the control system,the control system based on three-phase four-switch inverter is designed.The SVPWM algorithm of three-phase four-switch inverter is derived in detail,and three-phase four-switch inverter is used as a fault-tolerant structure of three-phase six-switch inverter.The simulation results show that after the failure of the original three-phase six-switch inverter,unaligned dual-stator spoke-type permanent magnet synchronous motor can still output stable electromagnetic torque under the driving of three-phase four-switch inverter,which proves the feasibility of three-phase four-switch inverter as a fault-tolerant topology structure of three-phase six-switch inverter.Finally,the experimental platform of the control system of unaligned dual-stator spoke-type permanent magnet synchronous motor is built.The design process of the hardware of each part is given,and the experimental research is carried out to verify the correctness of the proposed scheme.