Electromagnetic Field Analysis of Low Speed Disk Permanent Magnet Synchronous Motor

　　Electromagnetic Field Analysis of Low Speed Disk Permanent Magnet Synchronous Motor
　　As a new type high performance motor, eliminating the need for gear reduction, low speed disk permanent magnet synchronous motor (DPMSM) can simplify the structure of the entire transmission system and improve the system’s reliability. And there are still many characteristics of low mass, compact structure, low noise, small moment of inertia, steady running status in low speed and small electromechanical time constant in this kind of motor, so it has broad prospects for application.Low speed DPMSM is a kind of multi-polar low speed PMSM, the neodymium prices structure of this motor has two notable features. One is the technique of pole-slot match which is applied to the motor, it can decrease the number of stator’s slot and it can effectively inhibit cogging torque. The other is the structure of in-rotor which is applied to disk motor. This structure can reduce motor’s volume and raise motor’s power density.
　　Due to the structure of low speed DPMSM is different from traditional motor, common calculation and analysis methods can’t be applied to it. In this paper, the performance of this kind of motor is researched on the basis of magnetic field theory.In motor magnetic field calculation, the shape of magnet is optimized by finite element method (FEM). The influence http://www.999magnet.com/products/142-neodymium-prices on air gap flux distribution, leakage coefficient, EMF waveform and cogging torque which is produced by the variation in motor’s parameter is studied. After using the EMF waveform Fourier analysis, the rule of harmonic torque’s variation can be got. On the basis of considering both torque variation, the main electrical parameter can be optimized and the low speed motor running smoothness can be improved.Based on the electromagnet field calculation, low speed DPMSM is simulated according to the requirement of vector control method. The results of simulation indicate that the motor’s starting performance is well and it has steady running status in low speed. The results of simulation can also provide the favorable theory foundation of the hardware parameter for control system.