A new auxiliary current injection circuit for improved transient response of step-up/step-down DC-DC converters

In this paper, a new auxiliary current injection circuit (ACIC) is developed aiming at improvement in the dynamic response of DC-DC converters under load transients. The developed ACIC can be used as a generic auxiliary module for both step-up/step-down DC-DC converters. The auxiliary current injection circuit is a bidirectional power converter, designed for low power ratings with higher bandwidth, to operate only during load transients. The performance of the developed auxiliary power converter has been evaluated in conjunction with an interleaved boost converter as main converter, which has limitation on bandwidth due to its inherent right half plane zero. Experimental results for a 250 W, 100 kHz interleaved boost converter prototype with auxiliary current injection circuit are presented. The peak overshoot/undershoot and the transient recovery time are reduced significantly with the incorporation of developed ACIC.