Design And Analysis Of Novel Reduced Rare Earth Hybrid Magnets Partitioned Stator Flux Switching Machine

With the constantly increasing development of the rare earth permanent magnet motor, the dramatic increase in usage of rare earth magnet brings about serious price-up of rare earth materials in China. Hence, the cost of permanent magnet motor is significantly increased. Therefore, the continuous research and development of reduced rare earth permanent magnet machines should be very important. Then, by employing the concept of partitioned stator into the flux switching machine, and combing the idea of reduced rare earth magnets, a novel hybrid excitation partitioned stator flux switching machine is proposed in this thesis. By adopting the new partitioned stator structure, the separation of permanent magnets and armature windings is achieved, which is an effective solution to the constraints of the motor torque density and other properties due to the conflict of the amount of magnets and armature windings in stator-permanent machines. Besides, the permanent magnets all located in the outer partitioned stator are conducive to cooling, and the auxiliary anti-demagnetization coils are adopted. Hence, the permanent magnets’ irreversible demagnetization issue due to the high temperature is avoided, the reliable operation of the motor is ensured.Firstly, the general situation of rare earth materials and the industry situation are fully overviewed. The necessity of researching the reduced rare earth magnets machines is also analyzed. The shortcomings of the current stator permanent magnet motor are summarized. Then, the principle of the partitioned stator structure is introduced, and the difference between the principle of partitioned stator structure and double stator structure is explained. Based on the introduction, the structure and operation principle of the proposed machine are introduced and analyzed. And the flux formation principle of the motor is presented in detail. In addition, the consistency and compensation of the three phase armature windings of the proposed machine is verified. The mathematical equations of the hybrid excitation partitioned stator flux switching machine are also presented in this thesis.Secondly, the two permanent magnets’ size relation is determined by using magnetic circuit analysis. The main parameters of the proposed motor are calculated. The initial dimensions of the proposed machine, rated parameters and winding arrangement are presented. Besides two optimization methods are adopted in this thesis, namely the optimization design method of single parameter and multi-objective sensitivity, and the results of the two methods are basically the same. Based on the finite element method, the electromagnetic performances, including the permanent magnet field distribution, air gap flux density, flux linkage, no-load back EMF, cogging torque, and the electromagnetic torque characteristics are analyzed. To avoid the demagnetization of the permanent magnet by the over-load armature excitation field, the auxiliary anti-demagnetization coils are adopted. Besides, the anti-demagnetization ability is discussed, and the influences of the auxiliary coils current density on the performance of the motor, including the field distribution, the no-load flux linkage, the torque characteristics and the inductance characteristics are all analyzed in details. Moreover, the thermal analysis of RRE-HMPSFS motor is simulated by 3D FEM.Finally, considering the motor performance, processing technic, and the manufacturing cost, the processing scheme of the proposed motor is discussed and the prototype is in the process of manufacturing.