Research Of Multipolar Line-Start Low Speed And High Torque PMSM

Line start Permanent Magnet Synehronous Motor(PMSM) is a very high effieieney synehronous motor designed to operate at fixed frequeney and voltage. It is different from Variable-Speed Permanent Magnet Synchronous Motor, as a squirrel eage is provided in the Line-start PMSM to accelerate the rotor from standstill when started across the line. Compared to the traditional three-Phase Induction Motors, the Line-start PMSM has typical advantages such as higher effieiency and powerfactor within a wide load range. It accords with the national guideline of "energyn saving and environment Proteeting" and has good future of industry application. In some machines, such as mining machinery and lifting machinery, the mechanical energy which is transferred from electric network is transmitted to the load to finish doing work by the middle part consisted of large body, multistage reduction gears mechanism and drive mechanism, which are made of many iron and steel materials in manufacture. Instead of mechanical reductors, low speed and high torque PMSM are used for driving directly. The various disadvantages will be overcome fundamentally. Therefore, the development of low speed and high torque PMSM for gearless drive system has become one of the currently significant tasks.Torque components of line start PMSM are studied deeply. The maximum value of the PM generated torque which is related to the motor's minimum torque and the motor's maximum torque related to the pull-out performance are deduced, and the influence of reluctance parameters and no-load energized electromotive on torque components is analyzed, then the design rules to incorporate all torque demands of line start PMSM are presented.The commercial electromagnetic analysis software package Ansoft Maxwell has been used for magnetic field analysis. The transient parameters of the motor under rated load can be calculated by FEM base on the field-circuit coupled method. The reasonable electromagnetism design scheme comes true by adjusting the design value continuously. The principal axis of motor were analysed based on FEM of UG software and energy method, ensured the Multipolar Line-start PMSM were safe in encountered condition.Experiment data approve that the prototype has high performance. Contrasting experiment data and design calculation results show that the method and program developed in this paper are correct and feasible convenient in use as well. The research work in this paper is very important to improve the design method of permanent magnet synchronous motor.