Compared with the traditional electric excitation motor, the permanent magnet motor, especially the rare earth permanent magnet motor, has the advantages of simple structure, reliable operation, small volume, light weight, low loss and high efficiency, and the shape and size of the motor can be flexible and diverse. . Therefore, the application range is extremely wide, covering almost all fields of aerospace, defense, industrial and agricultural production and daily life. The main features of several typical permanent magnet motors and their main applications are described below.
The rare earth permanent magnet generator permanent magnet synchronous generator does not require a collector ring and a brush device as compared with the conventional generator, and has a simple structure and reduces the failure rate. After using the rare earth permanent magnet, the air gap magnetic density can be increased, and the motor speed can be increased to the optimum value to improve the power quality ratio. Almost all of the current aerospace and aerospace generators use rare earth permanent magnet generators. Its typical products are 150 kVA 14 pole 12 000 r / min ~ 21 000 r / min and 100 kVA 60 000 r / min rare earth cobalt permanent magnet synchronous generator manufactured by General Electric Company of the United States. The first rare earth permanent magnet motor developed in China is a 3 kW 20 000 r/min permanent magnet generator.
The permanent magnet generator is also used as the auxiliary exciter of large steam turbine generators. In the 1980s, China successfully developed the world's largest 40 kVA ~ 160 kVA rare earth permanent magnet auxiliary exciter, equipped with 200 MW ~ 600 MW turbo generators. Greatly improve the reliability of power plant operation.
