Field-enhanced Variable-leakage Permanent Magnet Motor Design And Multi-physics Coupling Analysi

Variable leakage-flux permanent magnet(PM)machine(VLPMM)is a new type of variable flux PM machine(VFPMM).VLPMM utilizes the q-axis component of the armature current to change the saturation state of the flux leakage loop,and thus indirectly control the flux leakage,so as to flexibly adjust the air gap magnetic field with negligible excitation loss.As a new concept of PM motor with novel modulated magnetic mode,VLPMM is of great theoretical significance and engineering application value to further study its topology structure,electromagnetic design,optimization,and variable flux characteristics.Based on the extensive review of the state-of-art of VLPMM,this paper successfully incorporated the intensifying flux effect into VLPMM to improve the existing topological structure and proposed a novel intensifying flux variable leakage-flux permanent magnet motor(IF-VLPMM).The proposed IF-VLPMM not only inherits the variable leakage-flux characteristics of VLPMM as well as the wide speed range with high efficiency but also can realize the IF effect to improve the output torque at low speed and enhance the ability to resist irreversible demagnetization risk.In this paper,studies are established comprehensively and deeply on the IF-VLPMM which is taken as the research object in terms of its topology structure,variable flux characteristics,operating principle,design method,optimization strategy,multiphysical field coupling analysis,and experimental testing.The main research work of this paper includes the following aspects:(1)The background and significance of the research are described.The characteristics and operation mechanism of various kinds of VFPMMs are clarified,and introduces a new type of VLPMM with a novel magnetic modulation mode,and points out the theoretical significance and engineering value of studying the new VLPMM.(2)The design and planning of IF-VLPMM are systematically introduced.The topology structure of IF-VLPMM is designed,the operating principle of IF-VLPMM is expounded,and the stator and rotor of the IF-VLPMM are designed in detail.(3)Multi-objective optimization is carried out based on the IF-VLPMM initial design.The optimization process,objective function,and design variables were clarified to obtain the topology design of optimal performance of IF-VLPMM,and the effectiveness of the optimization design was verified by comparing the motor performance before and after optimization.(4)The speed regulation characteristics of IF-VLPMM were studied.The limiting voltage and current circle trajectory and flux weakening control method of IF-VLPMM are introduced,and the summarized mechanism for the wide speed range is.Then the efficiency and loss operation rule,speed range,and anti-demagnetization risk ability of IF-VLPMM are analyzed by simulation.(5)A multi-physical field coupling analysis method of IF-VLPMM is proposed.The modal analysis of the structure is carried out,and the temperature rise characteristics,vibration,and noise characteristics under different working conditions are analyzed to verify the rationality of the electromagnetic design.(6)The prototype was manufactured and the platform for the dynamic and static tests was built.The back electromotive force and variable leakage-flux characteristics of the prototype were calculated and tested to verify the correctness of the theoretical analysis and the feasibility of the motor design scheme by experiments.This paper provides a theoretical reference and technical basis for further research and application of IF-VLPMM.