Design And Locked Rotor Characteristics Analysis Of Line-start Permanent Magnet Synchronous Motor With Compound Cage Rotor

Line-start permanent magnet synchronous motor (LSPMSM) with compound cage rotor has obvious advantages:compared with the ordinary line-start permanent magnet synchronous motor, it has outstanding start-up performance; compared with the common induction motor, it has better power density, higher power factor and efficiency. LSPMSM with compound cage rotor has a wide range of economic operation, which is very suitable for high start-up performance requirements, high efficiency and energy saving applications.Focusing on the main performance requirements, according to the basic principle of LSPMSM with compound cage rotor, and considering the influence of various factors on the performance of the motor, this paper designed a kind of 10kV/355KW LSPMSM with compound cage rotor, studied the locked rotor characteristics of the motor, manufactured the prototype and did the performance tests. The tests results show that the designed motor has high efficiency, high power factor, excellent start-up performance and broad economic operating range, which fully meets the requirements of the performance index。This paper first introduces the research background and research status of the LSPMSM with compound cage rotor, and compares the structural performance of each type of LSPMSM, then describes the structure characteristics and working principle of the LSPMSM with compound cage rotor.Secondly, in the light of the main factors affecting the performance of the motor, such as the length of the air gap, the degree of irregularity of the air gap, the permeability of the magnetic slot-wedges, the cogging torque, and the pull-in performance etc., the FEM simulation models of the motor are built, and the influences of the factors are discussed. Considering the calculation results, the effect laws of these influence factors are found. The conclusion can provide reference for the next step of the LSPMSM with compound cage rotor design and optimization.After that, according to the main performance index requirements, the working principle and the effect laws of the parameters on the performance of the motor, electromagnetic design is done. The finite element analysis software ANSYS Maxwell 16.0 is used to design and optimize the motor, and then, the final design of the LSPMSM with compound cage rotor is determined. Subsequently, performance analysis and loss calculation of the designed motor are done by FEM, which verify that the designed motor meets the design objectives and requirements.The LSPMSM with compound cage rotor has the following blocking characteristics:the locked rotor torque includes not only the constant torque, but also the fundamental frequency pulse torque and second harmonic pulse torque, and the permanent magnet, solid rotor, squirrel cage respectively generates different influences on the locked rotor torque. In this paper, the locked rotor characteristics are analyzed by FEM, and the laws of the change are concluded.Finally, according to the final design of the LSPMSM with compound cage rotor, prototype is manufactured, a series of tests are carried out, such as no-load EMF, locked rotor, no-load and rated load test, etc. The efficiency, power factor and starting performance of the prototype are calculated, and the working characteristic curve is drawn. Through a series of experiments and simulation results, it is proved that the designed motor has high efficiency, high power factor, excellent start-up performance and broad economic operating range, which meets the requirements of design objectives.The design and calculation method of the LSPMSM with compound cage rotor provides a reference for the design and optimization of this type of motor. The research on the locked rotor characteristic of the LSPMSM with compound cage rotor provides a reference for the locked rotor test and performance discussion of this type of motor.