Design Of Low Speed And High Torque Wound Rotor Ls-PMSM And Analysis Of Starting Performance

Crane has a wide range of application in engineering machinery and equipment. Nowadays, the asynchronous motors-gear reducer transmission mode is generally used in the crane. To overcome its shortcomings, this paper proposes a low speed and high torque wound rotor line-start permanent magnet synchronous motor(LS-PMSM). The rotor slots are uniformly distributed in the rotor core outer circumference, permanent magnets have embedded in the rotor core, and three-phase windings are placed in the rotor slots. The external connected rotor resistance can vary flexibility along with the starting process to solve the difficulties of starting, such as high current and instantaneous torque impact. It's also designed as multi-pole to cancel the reducer and to achieve direct-drive operation. This type of motor adopts the advantage of efficiency and power factor independent of load rate to improve the efficiency and power factor with a wide range.The electromagnetic design of low speed and high torque wound rotor line-start permanent magnet synchronous motor is analyzed combined with multi-pole permanent magnet motor design features. A 75kW,30 poles low speed high torque wound rotor line-start permanent magnet synchronous motor is designed. Two dimension static magnetic field finite element method is applied to calculate the synchronous reactance parameters of wound rotor line-start permanent magnet synchronous motor. For the structural characteristics of this motor, based on established mathematical model of starting process, the calculation of rotor external starting resistance is obtained. The starting performance of the motor is simulated by Ansoft software and compared with squirrel cage rotor line-start permanent magnet synchronous motor. The simulation results show the rotor external starting resistance can be adjusted steplessly to improve the starting performance of wound rotor line-start permanent magnet synchronous motor. This paper lays a theoretical foundation for further study of this novel motor, and opens up a new way for research and development of the lifting equipment.