| Recently,the environmental pollution and energy shortage become more and more serious.To build a clean and efficient energy system,it has become an irresistible trend for electric vehicles(EVs)to replace traditional fuel cars.However,the traditional permanent magnet synchronous motors still have limitations in the multiple operating conditions,which cannot meet the high-performance requirements of the new generation of EVs.Therefore,a variable leakage flux permanent magnet synchronous motor(VLF-PMSM)is studied in this thesis.Based on the new concept of “variable leakage flux”,the saturation degree of leakage flux bridge can be controlled through the special rotor design.VLF-PMSM has good flux-weakening characteristic and strong load capacity,which can meet the requirements of multiple operating conditions for permanent magnet motors used in electric vehicles.However,when EVs face complex and variable operating conditions,the mechanical position sensors are prone to failure.Thus,the VLF-PMSM sensorless control system is studied in this thesis.By exploring the basic characteristics of VLF-PMSM,the influence of its characteristics on the sensorless control system is analyzed,and the corresponding optimization scheme is proposed.The research contents of this thesis include:(1)The basic structure and operation principle of the VLF-PMSM motor are analyzed,and the inductance characteristics of the motor are studied by finite element simulation.Then,the VLF-PMSM vector control model is established,and the performance of VLF-PMSM prototype is verified based on d SPACE1003 experimental platforms.(2)The sensorless control of VLF-PMSM based on high-frequency signal injection is analyzed theoretically.The corresponding simulation model is established,and the simulation results are analyzed.Then,according to the basic characteristics of VLF-PMSM and the comparison of high-frequency signal injection methods,the highfrequency pulsating voltage signals injection that is more suitable for VLF-PMSM is studied deeply.In addition,a fault detection strategy of position sensor based on model observation of VLF-PMSM is proposed and analyzed based on simulation.(3)According to the influence of the motor parameter variation characteristics on the VLF-PMSM sensorless driving system,a parameter-sensitive adaptive control strategy is proposed.Based on the detailed analysis of the influence mechanism of the salient ratio variation on the VLF-PMSM sensorless driving system,an adaptive detection filter is proposed to improve the estimated accuracy of rotor position.Also,a parameter adaptive sliding mode controller is introduced to improve the dynamic and steady-state performance of the VLF-PMSM driving system based on parametersensitive adaptive strategy.Finally,the feasibility and effectiveness of the proposed strategy is verified by experiment results.This study provides a certain reference value for the exploration of VLF-PMSM sensorless drive system. |
