Asymmetrical PWM Scheme Balancing Voltages Dual-outputs Interleaved Four-switch Buck-Boost DC-DC Converter

Abstract

This paper proposed a dual-outputs interleaving buck-boost (DOBB) dc-dc converter and a proper PWM scheme for the converter. With the conventional PWM scheme, a DOBB converter inherits natural output voltage balancing, but only when D$\geq$0.5 (boost region). The proposed asymmetrical PWM scheme helps the DOBB converter eliminate the duty ratio limitation. As a result, the two output voltages are automatically balanced even with unbalanced load conditions without any dedicated controller and/or auxiliary circuits in a whole range of duty ratio. A 1.6-kW prototype converter is built and tested to verify the performance of the proposed converter.