Minimizing the Duration of the Transient Processes in a Buck Converter with Pulse Width Modulation and Inert Output Filter

This work addresses the problem of identifying the feedback ratios in a buck converter with pulse width modulation and an inert output filter, with the ultimate goal of minimizing the duration of the transient processes. Feedback ratios in buck converters with pulse width modulation are conveniently adjustable using linear approximation for the neighborhood of the steady-state operating conditions. In the presence of an inert output filter or large input ripple, however, a pulse width modulator operates in saturation mode for a prolonged period of time (with a duty cycle of 0 or 1), which leads to losses in the estimated performance and to slowing down the transient processes. The solution we offer implies introducing a ‘fictional under-frequency’ of a pulse width modulator in order to calculate the feedback ratios separately for the transient process and, upon completion of the transient process, using the feedback ratios calculated for the base pulse width modulator frequency of conversion.