Open-Circuit Fault-Tolerant Control and Topology Switching Strategy of Active Magnetic Bearing Power Electronics Controller

Active magnetic bearing (AMB) technology has been widely used in high-speed electrical machines. Power electronics controller amplifier is an important segment in AMB system. Failure of power electronics device is a common threat to the reliability of AMB amplifier and can cause serious damage. In order to improve the robustness of the amplifier, this article proposes open-circuit fault-tolerant control strategies based on different topologies. For single-axis systems, a pair of windings with a single degree of freedom can work in four different working modes based on the three-phase full-bridge structure. It can detect and locate the open-circuit fault of a power electronics switch in operation. After promotion to multiaxis systems, a novel kind of topology for amplifier with fault tolerant strategy has been proposed that can also detect the open-circuit fault of power electronics switch and switch to fault tolerance mode for a multiaxis system. Fault tolerant experiments verify the feasibility and rapid response of different fault tolerance strategies with an AMB testbed in this article.