A New isolated Auxiliary Current Pump Module for Load Transient Mitigation of Isolated/Nonisolated Step-Up/Step-Down DC-DC Converter

This paper presents a new isolated auxiliary current pump module (ACPM), to improve the dynamic response of dc-dc converters under load transients. The developed isolated ACPM can be used as a generic auxiliary module for both isolated and nonisolated step-up/step-down dc-dc converters. The isolated ACPM is a low-power bidirectional converter, designed with higher bandwidth and operates only during the load transients. The performance of the developed auxiliary power converter has been evaluated in conjunction with an interleaved boost converter as main converter, which suffers from poor dynamic performance due to inherent right half plane zero effect. A suitable control scheme is designed and implemented for interleaved boost converter operating in conjunction with proposed isolated ACPM. Load current injection circuit employed in the proposed control scheme eliminates the requirement of complex nonlinear control algorithms. The proposed control scheme in particular suits for current-mode controlled converters operating along with isolated ACPM. Experimental results for a 250-W 100-kHz interleaved boost converter prototype with ACPM are presented. The peak overshoot/undershoot and the transient recovery time are reduced significantly with the incorporation of developed isolated ACPM.