Input-series and output-series connected modular DC-DC converters with active input voltage and output voltage sharing

This paper proposes a new modular configuration, namely the input-series and output-series connection for DC-DC converters. A three-loop control scheme, including a dedicated input voltage controller is proposed to achieve equal sharing of the input as well output voltages by the series connected modules. The reference to the input voltage loop is chosen as the average of all converter input voltages. Such a reference minimizes the interaction among the various control loops. The proposed scheme is validated experimentally on a 400 W prototype system comprising of two forward converters.