Magnetic Bearing Control System

Active magnetic bearing is a new style bearing which suspends the rotor in the air by using magnetic to achieve non-contact levitation. The basic function of magnetic bearing is controlling the rotor with non-contact, non-lubrication, wear-free. In the future, magnetic bearing is the main direction of development in high-speed rotating mechanism bearing.A magnetic bearing consists of two electronic control systems and mechanical systems. Electronic control system is a key part of the magnetic bearing system, which mainly consists of sensors, controllers and power amplifiers. This paper main introduce the electronic control system.First, the basic principle of magnetic bearing systems is introduced. The eddy current sensor is a important part of the magnetic bearing system. This paper focuses on the eddy current coils and eddy current sensor circuit. By analyzing the principle of eddy current sensor, the authors study the effect of the probe coil structure of sensor performance and design of a number of experimental eddy current probes. According to the characteristics of magnetic bearings, the eddy current displacement detection circuit is designed. Then the paper introduced the research of the PID controller and the PWM power amplifier. Some insignificance in the control system has been solved. A special mechanical system and a DC power are designed for the installation and calibration of eddy current sensors for the four DOF magnetic bearing, the reasons which introduce errors and interferences are analyzed, the errors and interferences are reduced to the lowest level. Finally, by the experimental testing, the method of tuning PID controller parameters is introduced, through debugging to make magnetic bearing stability.