Investigation of the output droop characteristics of parallel-connnected DC-DC converters

The analytical proof that output voltage droop characteristics of parallel-connected DC-DC power converters are only appropriate for very limited applications is presented. Because the converters are rarely made to be identical, near-uniform current-sharing without additional control can be achieved only when converters connected in parallel have similar characteristics of being very close to the ideal current sources. This can occur at a cost of poor voltage regulation. As an alternative, the current-sharing control technique, which requires no remote-sensing, is proposed. The technique ensures uniform or designated current distribution throughout the specified load range. A control circuit module is independently implemented without any preliminary knowledge or any circuit modification of the source converters