Analysis And Design Of Six-Phase Flux-Switching Permanent Magnet Machine

Compared with traditional three-phase machine system, multiphase machine system has small torque ripple, high reliability and meet the requirements of high power drive system. Therefore it is widely used in aviation, aerospace, ships, electrical vehicles and other occasions with the requirements of high power and high reliability. Flux-Switching Permanent Magnet (FSPM) machine is a novel brushless machine having magnets in the stator, offering not only high efficency and high power density, but also simple rotor structure, suitable for high-speed operation and easy for thermal dissipation, exhibiting a bright future by overcoming the shortages of the traditional brushless machines having magnets in the rotor. In this thesis, the keys of the theoretical and technical issues about six-phase FSPM machine are deeply and systematically studied, including the basic structure and operation principles, then design method and optimization, finite element analysis, static electromagnetic characteristics. Moreover, a fault-tolerant control strategy for open-circuited fault of FSPM machine is proposed. At last, two six-phase FSPM machines with different combinations of stator slots and rotor poles are introduced, and the 24/22-pole prototype is manufactured and tested to validate the theoretical and simulated results. Overall, the thesis lays a theoretical foundation for the further reseach and development of the FSPM machine drive.The fruits of this thesis are as follows:1. On the basis of three-phase FSPM machine, the structures of two kinds of six-phase FSPM machines with different combinations of stator slots and rotor poles are proposed. The winding distribution of the 24/20-pole FSPM machine is symmetric, while the 24/22-pole FSPM machine is dual Y shifted 30°. Then the operaton principle of six-phase FSPM machine is analyzed.2. The output power-size equation of the FSPM machine is setup. Thus the volum of the FSPM machine can be obtained according to performance indexes. Then the design process of initial design scheme of the 24/20-pole FSPM machine, for example, is demonstrated. In order to compare the electromagnetic performances of the two six-phase FSPM machines, the outer diameter of the stator and axial length of both machines are kept same. Based on that, the effects of the main dimensions of the FSPM machine on the performance are studied.3. The FE analysis models based on APDL of six-phase 24/20 and 24/22-pole FSPM machines are built, and the calaulations of the static characteristics of both machines, including radial flux density of airgap, PM flux linkage, back-EMF, self-inductance, mutual inductance, cogging torque and electromagnetic torque, are carried out. At last, the iron loss of six-phase FSPM machine is calculated based on time step finite element method.4. The fault-tolerant control for open-circuited of six-phase FSPM machine is investigated. In order to keep torque constant both normal and faulty conditions, a fault-tolerant current control strategy is proposed.5. Two prototyped six-phase FSPM machines are designed, and the 24/22-pole one is manufactured. Then the primary measurements validate the theoretical and simulated results.