Modeling Methodology and Control Strategy for Differential Step-up dc-dc Converters

Differential converters are usually composed of two converters and their control-oriented models are usually described by high order transfer functions. To overcome this drawback, this paper proposes a simplified modeling methodology and a control strategy for differential dc-dc converters operating as step-up converters. The proposed modeling is based on the use of the transfer functions related to the basic converters to derive the transfer functions of the differential converter. A control strategy which employs two loops is proposed to regulate the partial and the total output voltages for the differential converter. The modeling approach herein proposed is validated in the time and frequency domains. Experimental results of the differential converters operating in closed-loop are evaluated considering both the basic converters are driven by duty cycles either equal or different and assuming their respective triangular carries are shifted by 0° or 180°.