Abstract Power amplifier of magnetic bearing is a switching system. In order to design a circuit, it is necessary to accurately analyze the actual characteristics of switching power amplifier. Based on the three-level PWM operating principle of output load current, mathematical models of switching power amplifier are deduced and the equations of output load current are derived by using the Fourier series theory. The simulations of mathematical models and equations are implemented. Three kinds of results are basically the same by comparing the model simulation results with the Orcad circuit simulation results and experimental results. All of results show that the model is feasible and effective. The high speed magnetic suspension motor which uses these designed three-level power amplifiers runs successfully at 60 000r/min.
Wang Jun,Xu Longxiang. Equivalent Mathematical Models of Switching Power Amplifier for Magnetic Bearing[J]. Transactions of China Electrotechnical Society, 2010, 25(4): 53-58.