3. Development trend
Permanent magnet synchronous motors are widely used in industrial production and daily life due to their high efficiency, large specific power, simple structure and remarkable energy saving effect. Especially in recent years, the successful development of high heat resistance and high magnetic properties NdFeB permanent magnets and the further development and improvement of power electronic components, the research and development of rare earth permanent magnet synchronous motors have entered a new era at home and abroad. In the theoretical research and application fields, there will be a qualitative leap. At present, it is developing in the direction of ultra-high speed, high torque, high power, miniaturization and high functionality.
3.1 super high speed motor
The permanent magnet synchronous motor does not need the excitation winding, the structure is relatively simple, the magnetic field part has no heat source, no cooling device is needed, the coercive force of the material is high, and the air gap length can take a larger value, so that it is possible to greatly increase the rotation speed. At present, (2~3) X10r/rain motors have been made, such as the 150kW, 23000r/min radial air gap rotor structure for the use of rare earth permanent magnet generators developed by General Electric Company of the United States, and the outer rotor type for electric vehicles. 7.2kW, 27000r/rain motor. A motor of hundreds of thousands of revolutions per minute is currently being developed.
