为了实现电磁轴承系统的无传感器运行,提出一种基于占空比补偿的转子位移提取方法,利用TMS320F28335芯片的捕获接口实时获取占空比信号并进行数字滤波和信号调理,以此来替代电压信号的硬件解调过程,从而将转子位移提取的硬件复杂度减少了一半,并且在四自由度径向电磁轴承刚性转子系统平台上进行实验测试和反馈运行.实验结果表明,使用该方法提取的转子位移线性度很好,误差不高于5%,直接使用该方法提取出来的位移量进行反馈控制,实现电磁轴承系统在1 500r/min时的无传感器运行,外力扰动测试证实了无传感器电磁轴承系统具有一定的稳定性和鲁棒性.
To achieve the self-sensing operation of active magnetic bearings(AMBs),a strategy for estimating rotor's displacements based on duty cycle compensation was proposed.Instead of hardware demodulation,the real-time duty cycle was obtained through the CAP port of TMS320F28335,so that,the hardware complexity was reduced to half.Experiments were carried out on the platform of 4 degree-of-freedom radial AMBs.Experimental results showed that,linearity of this rotor's displacements estimator is quite good,the error is less than 5%,and the AMBs system performed well when the rotor rotation speed reached 1 500 r/min using the estimated rotor's displacements for feedback.Force disturbance tests confirmed the stability and robustness of this self-sensing strategy.