磁悬浮系统的电流控制方法

为了提高磁悬浮系统的响应速度与响应精度,综合时间最优控制、变结构控制及系统辨识理论,设计了三步电流控制法,即采用时间最优控制来获得电流最快速响应.根据跟踪误差,采用变结构控制来精确地跟踪理想电流,最后在线辨识得到线圈参数并计算出维持理想电流的最终控制电压.同时,推导了电流响应速度与控制系统硬件的约束关系.磁悬浮小球电流跟踪、阶跃响应以及幅频特性的实验表明,该算法能使系统在最短时间内精确地响应输入电流,不仅增加了系统带宽,改善了系统性能,而且还可以应用到其他电流控制场合.

Current Control Method for Magnetic Suspension System

Based on time optimal control, variable structure control and online identification theory, a three-step current control algorithm is developed to improve the response speed and precision of the magnetic suspension actuator, i. e. , adopting time optimal control approach to track the current as quickly as possible. The ideal current can be obtained with the variable structure control strategy according to the tracking error, and the control voltage keeping the setting current can be determined on the basis of the coil parameters from online identification. The constraint relations of the system hardware and the current response are also derived. The current tracking, step response and amplitude frequency characteristics experiments of the magnetic suspension ball demonstrate that the magnetic suspension system enables to respond to the input current in the shortest time with the proposed algorithm, and the bandwidth is expanded to improve the system.