Electromagnetic Bearing Control System Design And Research

An active magnetic bearing (AMB) is a typical mechtronical system which includes an electric sub-system (sensors, controller and power amplifier) and a mechanical sub-system (rotor, stator and coil). The performance of the AMB is mainly determined by the electric sub-system. This thesis is focused on the electric system, especially power amplifier and DSP based controller.First, the classifications and the principles of the magnetic bearings are introduced. Then the research status, the future trend and the industry application of the AMB are simply reviewed. The mathematic model of a single degree-of-freedom AMB is built and its performance is simulated through MATLAB/SIMULINK. By configuring the PID parameters, the influence the PID parameters to the AMB's step response performance is discussed.Then, the principles, circuit topologies and control methods of the switching power amplifiers for the AMB are presented. A three-level PWM switching power amplifier is proposed and is designed, and its performance is simulated and measured.The digital controller for the AMB is introduced. The PID arithmetic is decided to be the control method of the control system. The digit controller based on TMS320F240 DSP includes software part and hardware part is designed. An interactive way to regulate the control parameters through a visual interface on PC is provided, thus the adjustment of parameters can be deviated from the emulator and becomes more convenient.Finally, the integration of the control system is discussed. The whole AMB system is debugged, and the suspension of four degree-of-freedoms rotor is realized in the static and dynamic conditions. It is shown that the control system developed can meet the performance demands.