Study Of Configuration And Digital Control On Bearingless Motors

The bearingless motor, which combines function of motor and magnetic bearing, is a novel special type motor. The bearingless motors have compact structure, higher reliability and shorter shaft length. For this reason, they have good application prospects in high-speed drives. In recent years, for the unique suspension principle and structure, bearingless motors have been developed for biologic engineering, aeronautics and astronautics, high technology energy resources, semiconductor manufacturing industries, food processing industries, medicine and sanitation industries, and so on. Therefore, the bearingless motors will be used widely in the future and the research on bearingless motors has realistic and far-reaching signification.In the paper, the research emphasizes on the structure, hardware of digital control system and digital control algorithm for a bearingless motor.Firstly, configuration and working principle of axial hybrid magnetic bearing are introduced. The flux path is calculated by using an equivalent magnetic circuit. The digital control system based on TMS320LF2407 DSP, including A/D and D/A converters, is designed.Secondly, some structures and control strategies for bearingless motors are discussed. The principle of radial suspension forces in bearingless motors is introduced. The mathematics models of radial suspension forces and the rotation part of the motor are deduced. A control system based on mathematics models is designed.Finally, in order to achieve the real-time of control system for bearingless motor, a DSP-board is designed, using TMS320LF2407 as the controller's CPU. By analyzing the principle and control strategy of bearingless motor, based on the DSP-board, including interface module and power module, the hardware of digital control system for bearingless motors is designed and a experimental platform for control system is set up. The parameters of the prototype motor are given and the control system has been tested. Test results are in accordance with the simulation results and theory results.