磁悬浮高速转子基于位移刚度力超前前馈补偿的高精度自动平衡方法

Autobalancing for Magnetically Suspended High-speed Rotors Based on Lead Feedforward Compensation for Displacement Stiffness Force

磁悬浮转子高速旋转时产生与转速同频的不平衡振动,向外界传递振动力,干扰外部动力学环境。为消除同频不平衡振动力(即自动平衡),可采用消除同频电流与补偿位移刚度力相结合的轴承力消除方法,但磁轴承功放环节的低通特性使位移刚度力补偿存在误差,并降低系统稳定性,且上述影响随转速升高而显著增大。为增强自动平衡效果,提出一种基于位移刚度力超前前馈补偿的高精度自动平衡方法,在消除同频电流的同时,采用不平衡量—电流前馈以补偿同频位移刚度力,并引入功放的简化逆模型对前馈量进行超前校正,消除功放低通特性的影响。对该方法进行仿真和试验验证,仿真结果同频轴承力减小到无超前校正时的20%,试验结果同频振动加速度减小到无超前校正时的28%,验证了该方法的有效性。

Synchronous periodic vibration forces are induced when a magnetically suspended rotor rotates at high speed. For the purpose of removing vibration forces, namely autobalancing, a method attenuating both synchronous current and displacement stiffness force is used in some applications. But the low-pass characteristic of power amplifier which increases with rotational speed causes error of thecompensation for position stiffness force and even reduces system stability. A method based on lead feedforward compensation is proposed to achieve high-precision autobalancing. A feedforward mechanism from synchronous component of position to current is set up to compensate displacement stiffness force, and the simplified inverse model of power amplifier is included in the feedforward channel to reject the low-pass characteristic. Simulations indicate it reduces synchronous force to 20% of that without lead correction. Experiments indicate it reduces synchronous vibration acceleration to 28% of that without lead correction.