Force-Enhanced Switch Short-Circuit Fault-Tolerant Strategy for Power Amplifier of Active Magnetic Bearing

In active magnetic bearing (AMB) system, switch failures are critical faults that significantly affect system stability. Previous studies have predominantly focused on switch open-circuit failures, while research on switch short-circuit failures remains relatively sparse, leaving significant room for optimization. Traditional short-circuit fault-tolerant method is designed based on the control freedom, which imposes substantial limitations on electromagnetic force output capability. Consequently, meeting the requirements for stable suspension becomes challenging. This paper proposes a force-enhanced switch short-circuit fault-tolerant strategy aimed at expanding the range of force output by fully utilizing the voltage drop in the circuit. The theoretical analysis presented in this paper demonstrates that the force-enhanced method significantly outperforms traditional approaches in terms of force capability under any conditions. Experimental results further confirm that, in certain situations, traditional method may lead to instability due to insufficient force output capability, whereas the force-enhanced approach can maintain stable suspension. The proposed strategy offers a robust solution to the challenges posed by switch short-circuit failures, ensuring enhanced bearing capacity and stability in AMB systems.