Control And Analysis Of Pole-changing Doubly Salient Permanent Magnet Motor

Permanent magnet synchronous motor(PMSM)has been widely used in the field of electric vehicles for advantages of high efficiency and power density.However,the excitation field of traditional PMSM is directly generated by permanent magnet(PM),and it is difficult to be regulated,which limits the regulation ability of speed.Polechanging PMSM(PC-PMSM)combines the characteristics of traditional PMSM and pole-changing(PC)motor,and the mechanical characteristics of PC-PMSM can be changed by switching the connection of windings.On the basis of retaining the advantages of traditional PMSM,PC-PMSM expends the efficient operating range observably,which is one of the effective means to improve the operational performance of electric vehicles.This thesis takes the pole-changing doubly salient permanent magnet(PC-DSPM)motor as the study object,and conducts research on the control of PC-DSPM motor.The electronic PC principle and electromagnetic characteristics of PC-DSPM motor were analyzed in this paper.Based on these,the mathematical model of motor was created,and the corresponding simulation model was built in Matlab/Simulink.Then,combining with dual three-phase control theory,flux-weakening control strategy,active disturbance rejection control(ADRC),tracking differentiator(TD),finite-time extended state observer(FTESO)and so on,TD electronic PC strategy based on the novel ADRC was proposed for the PC-DSPM motor.Simulation and experimental results showed that the PC strategy by adopting TD prolonged the transition process,but the comparison of speed,torque and current in dq-axis showed that the adoption of TD significantly reduced the fluctuation of torque and current,and realized the smooth PC operation of PC-DSPM motor.In addition,an improved ADRC based on FTESO was proposed under the same operation condition,which further reduced the speed and torque ripple in the PC process.The main contents of this paper include:1.The development trend and significance of electric vehicles were introduced briefly.The development status of various electric vehicle driving motors and PC motor were reviewed.The analysis and research of PC methods and processes were summarized.2.The electronic PC principle and electromagnetic characteristics of PC-DSPM motor were analyzed.The mathematical model of motor was created,and the corresponding simulink model was built in Matlab/Simulink,which lays the foundation for the research of PC control system of PC-DSPM motor.3.Two sets of windings of the PC-DSPM motor were controlled by a six-leg inverter and dual three-phase control theory,and the electronic PC strategy by changing current angles was proposed.According to the mechanical characteristic curves under different modes,two PC points of the PC-DSPM motor in constant power region were selected.TD was proposed to arrange the change process of current angles to realize the smooth PC operation,and TD electronic PC strategy of PC-DSPM motor was simulated and analyzed in Matlab/Simulink.4.The core ideas and components of ADRC are introduced in detail.The mathematical models of ADRC in speed loop and current loop of PC-DSPM motor are deduced,and simulation models of ADRC are established in Matlab/Simulink.A novel ADRC based on FTESO is proposed to improve the performance of traditional ADRC.The fluctuates of speed and torque based on two kinds of ADRC during the PC process of PC-DSPM motor are compared to verify the superiority of the novel ADRC.5.The PC experimental platform for the PC-DSPM motor with RTU-box 204 as the core part is built,and electronic PC experiments are carried out at two PC points in constant power region.The feasibility of the proposed strategy is verified by comparing the current change process,speed and torque fluctuates during the PC process.