Dynamic limits of a power factor preregulator

Power factor correction has been one of the hottest topics during the last years and hence, many new circuits have appeared. In general, it is assumed that preregulators based on multiplier circuits have poor dynamics and then, a second stage is needed to improve the output voltage dynamic behaviour. The other option is the use of single stage topologies which have fast output voltage regulation although the input current waveform is not sinusoidal. This paper presents an analysis of the dynamic behaviour of a conventional power factor preregulator. The objective is to find the limits of the dynamic characteristics of these circuits when the priority is to improve the output voltage regulation and not the total harmonic distortion or the power factor. A large signal model is presented and the theoretical results are validated with a prototype.