基于变偏置电流控制方式的磁悬浮轴承系统控制策略

建立了五自由度磁悬浮轴承试验系统，介绍了变偏置电流控制方式的工作原理，采用H_∞控制策略设计数字控制器，根据系统固有频率处转子的振幅选择加权函数，将转速信号引入数字控制器，研究了变偏置电流控制时系统的动态性能，并与恒定偏置电流控制时系统的动态性能进行比较.研究结果表明，变偏置电流控制不会恶化系统的动态性能，同时能减少磁悬浮轴承25%以上的总电流消耗. 

Control strategy of active magnetic bearing system based on variable bias current control

The experiment setup of five degree-of-freedom active magnetic bearing (AMB) system was built up. The working principle of variable bias current control was presented. H_∞ control strategy was adopted for the digital controller design. Weight functions were selected according to the vibration amplitudes of the rotor operating at the natural frequency of the system. The signal of the rotation speed was introduced into the digital controller. The dynamic performance of the system with variable bias current was investigated, and also compared with the result of the system with fixed bias current. The results show the variable bias current control will not deteriorate dynamic performance of the system and it reduces the total currents of AMBs more than 25%.