主动电磁轴承飞轮转子系统自适应偏置控制

Adaptive Variable Bias Control for the Active Magnetic Bearing Flywheel Rotor System

主动电磁轴承具有无接触、无磨损、无需润滑、动态特性可调等特点,广泛应用于高速飞轮储能系统。差动控制是主动电磁轴承飞轮转子系统中常用的控制方法。在传统的差动控制方式中,一个自由度上两个对置的电磁铁具有相同的恒定偏置电流,偏置电流与控制电流进行差分运算后再分别驱动两电磁线圈。由于恒定偏置电流的存在,即使控制电流为零,电磁轴承也存在一定的电能损耗。针对此问题,本文提出了一种自适应偏置差分控制方法,偏置电流随控制电流的变化而变化,且偏置电流的大小为控制电流的绝对值,分析了自适应偏置差分控制方法的稳定性,并通过系统仿真研究了新算法的控制性能。结果表明,本文提出的自适应偏置差分控制方法能够减少电能损耗,使主动电磁轴承飞轮转子系统保持稳定,同时又具有与传统差动控制方式相近的控制性能。

Active magnetic bearing(AMB)is the best choice for the supporting structure of a high-speed flywheel energy storage system due to its no contact,no wear,no need of lubrication and dynamic adjustable.Differential control method is widely applied to the control system of an AMB flywheel rotor system.In this control method,the two opposing electromagnets on the same degree of freedom have the same constant bias current,and the sums of the bias current and control current are used to drive the two electromagnetic coils.With the existence of the constant bias current,even in no load conditions,there exists always power consumption.In response to this concern,an AMB control method,called adaptive variable bias control,is presented in this paper.In the new control method proposed,the bias current varies with the control current,and the magnitude of the bias current is equal to the absolute value of the control current.Then stability of the new control method is analyzed by control theory.Finally,the control performances of the new control method proposed are investigated by simulations.The results show that,the adaptive variable bias control method can reduce the power loss,be nominally stable,and provide the control performances similar to conventional differential control method.