The Electromagnetic Design And Optimization Of A New Surface-interior Permanent Magnet Synchronous Motor

It is generally divided into two types-Surface Permanent Magnet Synchronous Motor and Interior Permanent Magnet Synchronous Motor in the conventional permanent magnet synchronous motor. The former has a smaller area of weak magnetic speed, lower power density, but faster dynamic response, smaller torque ripple characteristics and more suitable for servo drives than the later. Moreover, on the base of permanent magnet reluctance torque, interior permanent magnet synchronous motor also has a superimposed reluctance torque, which is not only beneficial to improve the magnitude of power density and overload capacity of the motor, but also easy to apply in the field-weakening control system. Nevertheless, interior permanent magnet synchronous motor still has some drawbacks, such as the big amplitude of torque ripple and leakage flux, the slightly less mechanical strength and it has to design the bridge across the magnetic. Combining the advantages of these two permanent magnet synchronous motors, a new hybrid rotor of permanent magnet synchronous motor is proposed in this paper.A novel Surface-Interior mixing rotor is proposed in this paper by combining structural characteristics of typical permanent magnet rotors. In order to determine the structural parameters, the structural sizes are designed preliminarily such as stator, rotor, air-gap and so on. Calculating the electromagnetic parameters of Surface-Interior PMSM, an equivalent magnetic circuit model is established. With designing and optimizing the ratio and shape of two parts of permanent magnets, the graphs of efficiency and power factor are obtained along with different parameters. The optimal results will be got through comparing torque ripple and power index under different parameters. In the case of equal amount of motor parameters and permanent magnet, the models of surface permanent magnet synchronous motor, interior permanent magnet synchronous motor and surface-interior permanent magnet synchronous motor are set up using the finite element method. The performance parameters, such as torque ripple and power index, are calculated through optimizing the shape and size of permanent magnet. Using finite element method to optimize the ratio and shape of permanent magnet, the reasonable of electrical parameters designed and optimized, and superiority of this structural motor performance, would be verified through contrasting and analyzing, and the results are calculated by magnetic circuit method and finite element method.