| The permanent magnet brushless DC motor had good speed regulating characteristic, good mechanical properties and high efficiency, and it was suitable for electric vehicle. But it had weak magnetic difficulties and torque ripple. A kind of special structure rotor was put forward based on the characteristics of the surface permanent magnet motor in the paper, in order to expand the range of speed, increase the power density, and keep costs down.The46/51pole-slot match was determined, together fractional slot concentrated winding table with cogging torque formula of the special rotor deduced in energy and Fourier transforms method. The three-phase symmetric fractional slot double winding was designed based on reducing electromagnetism loss. The installation positions of hall sensors were determined by the relationship of magnetic potential axis with back electromotive force30degree phase angle. According to the required rating data of the motor, the stator and rotor were designed.The planar simulation model was established in ANSYS, the magnetic field was calculated. The research showed that the magnetic circuit is rational, and the stator had assembled magnetic effect. The magnetic circuit of the permanent magnet and hidden was optimized. The results showed that optimizated motor had uniform magnetic field, high material use ratio.The simulation model was built by using the powerful simulation function-modules of the MATLAB/SIMULINK, based on the analysis of the mathematical model. The results indicated the simulation waveforms of current and back electromotive force were in keeping with the theory. The controller using TMS320LF2407A as the digital processor was designed, which could smoothly operate the motor, and provided theoretical basis for prototype machine. |
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