Current Spike Suppression Techniques for Magnetic Bearing Amplifier

The levitation coils or electromagnets designed for active magnetic bearing application typically have relatively large parasitic capacitance due to their large number of turns. When these coils are driven by a switching amplifier, the parasitic capacitance can cause current spikes and ringing during the switching process. As a magnetic bearing typically consists of multiple sets of coils for axial and radial directional controls, these spikes may interfere with sensors in the magnetic bearing system or cause false trigger of other sets of coils. In this paper, two current spike suppression methods are presented, and the effectiveness of each method is verified through experiments.