Permanent Magnet Synchronous Machine Modeling And Rotor Eddy Current Loss Analysis Based On Magnetic Network

In recent years, high-speed rail is developing dramatically in China, the operating mileage of the high-speed rail just ranked first in the world, while maintaining a high mileage under construction. In order to increase efficiency and save energy, the need of developing more efficient train motor traction system is more and more urgent. Compared to the current commonly used asynchronous motors, permanent magnet synchronous motors have the advantage of compact structure, high power density, high power factor. Meanwhile, the rotor rotate at the same speed with the magnetic field produced by stator current, so in an ideal steady state, there is no eddy current losses in the rotor.Compared to the finite element method, the magnetic network method can greatly increase the computing speed in guarantee of accuracy. This method can be used as a tool in the preliminary design and optimization of a electrical machine. In this paper, a 600kW permanent magnet synchronous motor is analyzed. The magnetic network model of the motor is established, the moving boundary between the stator and the rotor and the iterative process for solving the equations of motion of the motor is analyzed. Besides, a program framework of magnetic network analysis is built.The no-load and load characteristics of the motor are analyzed using the magnetic network method. The result is compared with the finite element analysis under the same conditions, to verify the model. Then, the rotor eddy current loss is calculated using harmonic analysis and discrete accumulation. Harmonic flux density sources and influencing factors in different parts of the inner rotor are analyzed based on simulation results. The simulation results are compared with the one using finite element method. The feasibility of using magnetic network method to calculate the different components of the rotor eddy current loss is investigated. In addition, the paper also analyzes the influence of stator slots number on the rotor eddy current.Finally, the research work of this paper is summarized, the problems emerging in the research process are presented, and further research in the magnetic network method in the analysis of permanent magnet motor is expected.