Direct suspension displacement control for bearingless permanent magnet motors

In this paper a polar-coordinate mathematical model of suspension force of bearingless permanent magnet motor is derived based on traditional suspension force model. Combined with space vector pulse with modulation algorithm, the direct suspension displacement control is proposed depending on the polar-coordinate mathematical model and the suspension current closed-loop control is omitted using the proposed control strategy. So the suspension control is simplified. The simulation results show the proposed control strategy can enhance system dynamic performance and achieve stable suspension under rated work condition.