Characterization of Digital Power Amplifier-Based Active Magnetic Bearings

Active magnetic bearings (AMB’s) are used to support rotors using magnetic forces, without any solid to solid contact. The AMB system has four main components: power amplifier, electromagnetic actuator, sensor and controller. In this work, the characterization of power amplifier for the AMB system is undertaken. The gain and phase lag of the power amplifiers over the operating frequency is obtained experimentally. Equivalent circuit models are made for the power amplifier. These characteristics of the amplifiers are used in developing the control algorithm for the AMB. The experimental results of these characterizations will help in understanding the gain of the power amplifier and also the lag between the signal input and the output signal over the desired frequency range.