中文摘要：

在电磁悬浮系统中，由于模型的强非线性，很难实现动子在不同气隙下的稳定悬浮，需要解决系统严重的非线性问题。同时，传统的两电平斩波器驱动方式会带来较大的电流纹波，减小电流控制精度。因此针对单自由度双电磁铁磁浮平台，建立了系统的二阶电流型非线性数学模型，通过三电平控制方法，减小悬浮电流纹波，且升高母线电压后不影响电流精度。结合PID控制器，设计了精确反馈线性化的双电磁铁工作电流切换模式，提出了单自由度磁浮系统全行程悬浮的控制方法。仿真和实验结果表明，在不同悬浮气隙条件下，设计的非线性控制系统能够实现悬浮体的稳定悬浮。

英文摘要：

In the magnetic suspension system, due to the strong nonlinearity of model, it is difficult to a- chieve the stable suspension of the mover over the entire operating range, and the nonlinear problem of the system has a significant impact on performance. Meanwhile, the traditional two-level chopper can pro- duce a large current ripple, and decrease the current control precision. For single degree of freedom double-electromagnet system, the nonlinear mathematical model of a second-order current suspension was established ; In order to reduce the current ripple, the accuracy of the current was improved through three- level control method; Combined with PID controller, the current switching mode based on the feedback linearization of double-electromagnet system was designed, and nonlinear control strategy for single degree of freedom magnetic suspension system was proposed. Simulation and experimental results show that the proposed nonlinear controller can achieve the stable suspension of the mover under different suspension gap.