Dynamic modeling and control of TL power amplifier using controlled source

The accurate closed-loop system model of Three-Level (TL) power amplifier for magnetic bearing was presented. The TL power amplifier was a nonlinear system and uncertain math model would affect the stability analysis of power amplifier. Based on the controlled source method, the nonlinear devices were replaced by controlled voltage source or controlled current source. The models of left half bridge and right half bridge were deduced. The four modes with TL control strategy were analyzed and the closed-loop system model of TL power amplifier was obtained. Simulation and experimental results were basically the same and confirmed the validity of the proposed model. The results show that the deduced model can better reflect the actual control characteristics of TL power amplifier.