Analysis and design of three-phase AC-to-DC converters with high power factor and near-optimum feedforward

This paper presents a three-phase pulsewidth modulated AC-to-DC power converter with unity power factor and near-optimum dynamic regulation. A general mathematical model of the converter has been established to lead to a comprehensive analysis. The averaged small-signal technique is used to obtain the near-optimum feedforward compensator, thus resulting in the output impedance, and the audio susceptibility become zero, that is, the output voltage of the converter presented in this paper is independent of variations of the DC load current and the utility voltage. The proposed procedure of analysis is simple and effective, and it is also easy to implement. Finally, the theoretical formulations are verified both by simulated and experimental results in a 5 kW laboratory prototype system.