Analysis On Steady Characteirstic About Doubly Salient Permanent Magnet Wheel-hub Motor Used For Electric Vehicle Driving System

This paper introduces the design of doubly salient permanent magnet wheel-hub motor used for electric vehicle driving system, the size of this motor was estimated. Based on this size, the mathematical model of this motor was build. The pole numbers of the rotor and the stator are8and12respectively, the phase number is3. The steady characteristics of this motor are carried out based on2-D finite element analysis (FEA) method written in Visual C++. On the base of existing conclusions about Doubly Salient Permanent Motor, the steady characteristics and correlative factors of the motor system are investigated thoroughly in this text by the methods of both theory analysis and simulation experiment test.The doubly salient permanent magnet motor is chosen as the wheel hub motor combined with the standard of the electric car’s drive system. The rotor structure and the motor’s size are given according to the standard of wheel hub. And then the size of the stator and the perman-ent magnet are devised based on the relevant formula.2-D Delaunay triangulation based on Visual C++is used in the FEA, afterwards, the data is imported to the procedure of FEA, by which the Magnetic field distribution, air-gap flux density, torque-angle characteristics and mechanical characteristics are investigated. As a driven motor, it can be used as a generator when the electric car convert potential energy to kinetic energy, therefore, the generator’s output characteristics is studied through FEA.The operation principle and the cogging structure of this motor cause the huge torque ripple inevitably. The huge torque ripple will arouse vibration and noise, which will seriously affect the performance of the electric vehicle. Due to reduce it, the structure with equal stator-rotor pole arc is discussed from the view of improving the structure of this motor, which can minimize the torque ripper effectively. Meanwhile, some control strategies are put forward such as the method of controlling winding thyristor according to the conditions of flux linkage. Eventually, The arc of rotor polar has adjusted, then all the corresponding torque-angle characteristics and torque ripple ratio were analysed, find the best stator-rotor arc combination...