Development of PWM power amplifier for active magnetic bearings

Abstract

Power amplifier is an important element in active magnetic bearings (AMB), which generally require an efficient transconductance power amplifier having fairly broad bandwidth and high power capacity. The paper presents a practical design scheme for switching power amplifier for AMB. Based on mechatronics coupling theory, the influence of voltage and current of power amplifier on a rotor's rotating speed and control accuracy is investigated. Considerations in the design are given. A PWM power amplifier based on IGBT power modules is developed and applied in an actual AMB system. Experimental results show the current switching capability of the power amplifier to be higher than 10 A, 48 V at 20 kHz.