Design And Performance Analysis Of A Novel Flux Axial Regulating Memory Motor

Nd-Fe-B permanent magnet is usually used in permanent magnet synchronous motor(PMSM).Because of its high coercivity,it is difficult to adjust the magnetic field of PMSM,and its constant power operation range is small,which greatly limits its application range.In order to make this kind of motor with excellent performance be used in more occasions,controlling the air gap magnetic field intensity of PMSM has become a research hotspot.In recent years,a kind of memory motor with high remanence and low coercivity permanent magnet materials has been widely studied.This kind of motor directly adjusts the magnetization level of permanent magnet by current pulse,which changes the air gap magnetic field of the motor and reduces copper loss and the risk of permanent magnet demagnetization.In this thesis,a new type of flux-axial regulated memory motor is proposed.The main research work includes the following aspects:1.The principle and design concept of flux-axial regulated memory motor are elaborated in detail.Firstly,according to the design concept,several different motor models are put forward,and the mathematical models of each structure are deduced by magnetic circuit method.Then,the magnitude of the magnetomotive force,the magnetoresistance of the weak magnetic structure and the magnetizing field required by the memory permanent magnet are compared and arranged.In addition to the structure that can not be effectively magnetized,two schemes of weak magnetic circuit formed by stator and weak magnetic circuit formed by magnet conductor are selected for further study.2.Quantitative design of the selected scheme is carried out according to the results of magnetic circuit selection.After establishing the target motor model,the type and brand of memory permanent magnet are determined firstly,and the thickness of the required memory permanent magnet is measured by using the limit condition.After that,two kinds of magnetic conductors are designed and simulated separately.The size of E0 and the distribution of air gap magnetic field are measured before and after weak magnetic field operation.It is proved that both structures can effectively regulate the air gap magnetic field of the motor,but the air gap magnetic field distribution through the stator weak magnetic structure is not uniform,which will give the follow-up magnetic field.Distribution optimization and NVHoptimization pose challenges.3.Detailed design of the magnetizing winding and circuit is carried out.First,the magnitude of the required magnetizing current is measured.Then,the problem of uneven distribution of magnetic field in the process of magnetizing is optimized.Finally,the magnetizing circuit is designed according to the magnitude of the magnetizing current and verified by finite element analysis.It is verified that both structures can be used for memory permanent magnets.However,due to the saturation of the magnetic circuit,the magnetizing current through the weak magnetic structure of the magnetizer is larger than that through the stator weak magnetic structure,and the heat dissipation capacity is lower than that of the former.