Design And Research Of Line-start Permanent Magnet Synchronous Motors With Compound Cage Rotor

For energy shortage is becoming an increasingly serious problem in recent years, the research and development of energy-efficient motor has become a hot spot issue. Compared with traditional induction motors, permanent magnet synchronous motors (PMSM) have high efficiency and power factor, which leads to a more extensive application prospect. This paper has done researches on the line-start permanent magnet synchronous motor(LSPMSM) with compound cage rotor, whose rotor is composed of a solid rotor and a squirrel-cage. This kind of motor has outstanding advantages, such as high efficiency, high power factor and good starting performance. With regard to the analysis and design of LSPMSM with compound cage rotor, the following work has been done.Firstly, this paper introduces the structure and working principle of LSPMSM with compound cage rotor. Based on the design proposal and with the help of simulation software the2D mathematical model of the motor is built. After doing researches with finite element methods, the analysis result shows the design proposal is feasible.Secondly, the influence of the change of structural parameters on the working performance of the motor is discussed. The varying parameters include the length of the air gap, the degree of irregularity of the air gap, the permeability of the magnetic slot-wedges, etc. Combined with the calculation results of Ansoft Maxwell and the demands of actual production, the optimal parameters are obtained and the design of the motor is optimized.Thirdly, after doing researches on the cogging torque of the motor, several methods are proposed to reduce it, which are proved to be effective by the Ansoft Maxwell finite element analysis software.Then, this paper analyzes the demagnetization of the permanent motor(PM) in the motor’s starting process and put forward the method to protect the PM from demagnetization using copper slot-wedges in the rotor.Finally, the paper introduces the design proposal of the lOkV、400kW LSPMSM with compound cage rotor, according to which the prototype of the motor is made and the prototype is tested. The test result shows the motor has good performance and reaches the expected standards.