电磁轴承电磁铁单边工作控制方式的实现

Realization of single side working mode of active magnetic bearings

由于电磁力与位移及励磁电流的强非线性,使电磁轴承AMB(Active MagneticBearing)系统精确建模比较困难,较高的偏置电流增加了系统的功耗,系统的高刚度与大范围稳定又是一对矛盾体.为此,在建模型时,以电磁力为控制量,将电磁力计算公式、电磁铁及功率放大器集成为电磁力构件,避开了电磁力非线性的影响;在基础电流为0.2 A时,采用电磁轴承单边的工作方式,实现了系统的高刚度;以模糊控制方法解决了系统高刚度与大范围稳定的矛盾.仿真与试验表明:以电磁力构件的方式构造电磁轴承模型有较好的精度,采用单边的工作方式降低了系统的功率损耗,采用模糊控制方法实现了系统大范围稳定小范围内高刚度.

It is difficult to provide an accuracy model for an AMB（active magnetic bearing） system due to the strong nonlinearity among magnetic force, the currents flowing in the coils and the displacements between the rotor and the AMBs. The bias currents in the coils increase the system power loss. For AMBs, higher stiffness and system stability in a larger displacement range could not be achieved at the same time. Magnetic force was considered as a controlled object and a component named magnetic force component with magnets and power amplifiers included was built to avoid nonlinearity of the model for the AMB system. With a base current of 0.2 A in the coils, high bearing stiffness was obtained when single side working mode of AMBs was achieved. To achieve higher stiffness and stability in a larger range at the same time, a fuzzy control method was used. Simulations and experiments show that a more accurate AMB model can be obtained with magnetic force component used; System power loss is reduced when single side working mode of AMBs is achieved and higher stiffness and stability in a larger range are achieved at the same time with the fuzzy control method used.