Active Magnetic Bearing Amplifier Design based on SiC Devices

Active Magnetic Bearing (AMB) levitate rotor by magnetic force without friction. The purpose of this paper is to design a SiC-based power amplifier for the AMB controller. Firstly, the structure and control principle of the magnetic bearing system are introduced. Secondly, the improvement of power amplifier performance of SiC device relative to traditional Si device is analyzed. Device selection and digital PI control circuit are also introduced. In addition, step response experiments at 20kHz and 40kHz switching frequencies are designed for the power amplifier of SiC devices. Then the AMB at two switching frequencies is evaluated from response speed. Finally, based on the experimental results under two different working conditions of AMBS, the corresponding conclusions are drawn.