高速磁悬浮涡轮分子泵因其高能量密度、微振动、无需润滑等优点被广泛应用于工业领域, 但外部电源失效时, 高速转子跌落后与保护轴承产生剧烈撞击和摩擦, 将给系统带来致命损害。针对以上问题, 提出一种基于平均功率平衡法的电力失效补偿控制方法。首先, 设计电机能量回馈电路; 其次, 对Buck-Boost变换器进行数学建模, 设计一种双环非线性控制器, 其中电流内环使用滑模控制, 电压外环使用平均功率平衡控制, 并利用Lyapunov函数推导出系统的稳定性条件; 最后, 通过搭建磁悬浮分子泵PFCC实验平台, 对所提出的方法进行实验验证。结果表明: 本文所提出的方法具有快速响应和输出鲁棒性, 磁悬浮转子由额定转速21 000 r/min降至3 900 r/min时跌落, 电机的能量转化效率为96.6%, 提高了磁轴承系统的安全性。

High-speed magnetically suspended Turbo Molecular Pumps (TMPs) have been widely used in industrial applications for their high energy density, micro-vibration, and no lubrication requirements. However, the Active Magnetic Bearing (AMB) system will lose magnetic force once the main power fails, which may cause severe damage to the rotor and stator systems. In this study, an improved Power Failure Compensation Control (PFCC) method based on Average Power Balance Control (APBC) was proposed. First, a motor energy feedback circuit was designed. Then, a nonlinear controller consisting of double control loops was proposed, of which the fast inner current loop used Sliding Mode Control (SMC) and the outer voltage loop used APBC. The Lyapunov function was structured and analyzed to ensure system stability. Finally, a platform based on the high-speed magnetically suspended TMP was built. Several experimental results verify that the proposed PFCC method has fast response and robustness; meanwhile, the touchdown speed of the rotor is reduced to 3 900 r/min from the rated speed of 21 000 r/min with a higher energy conversion efficiency of up to 96.6%, which greatly improves the safety of the AMB system.