互感式自检测磁悬浮轴承系统的检测原理研究

基于差动变压器原理，提出从控制电磁铁线圈的两端提取因偏置磁通随位移变化而互感的诱导电压（电流），作为反馈信号构成闭环控制的自检测磁悬浮轴承系统。偏置电磁铁采用脉宽调制（PWM）电压信号驱动。所要检测的互感电压（电流）信号的PWM的电流频率的成分是电磁铁互感系数的函数，互感系数又是转子气隙位移的函数。该信号经过全波整流得到与转子位移成比例的电压信号，将该位移信号由PID控制器转换为调整转子位移的控制信号。

The study on testing principle of self-sensing magnetic bearing system of mutual induction type

Based on principle of differential transformer, self-sensing magnetic bearing system of closed loop control are proposed, which are pick-up mutual induction voltage(current)produced because of biased magnet flux adapt to transformation of displacement by way of feedback signal from the port of steering electromagnet winding. The biased electromagnet is driven by a constant voltage pulse width modulated (PWM) signal. The PWM carrier frequency component of the measured mutual induction voltage (current) is the function of the magnetic mutual inductance, which is the function of the gap displacement of rotor. The measured mutual induction voltage(current)signal is transformed to voltage signal, which is proportional to the airgap displacement by full wave rectification circuit. This signal is put into a PID controller to produce the control signal of steering rotor displacement.