Parallel DC/DC converters system with a novel primary droop current sharing control

In this study, a primary droop current sharing controller with output current commitment capability for a stand-alone renewable energy source was proposed. The specially designed DC/DC converter for renewable energy source consists of feedforward, voltage and droop current sharing control loops; furthermore, the droop voltage compensated scheme is also designed to improve current sharing performance under variation of the input voltage. When the renewable energy is abundant, the DC/DC converter with respect to this energy source can provide more load current and also can save energy bill from utility. The output voltage magnitude of the maximum power point tracking (MPPT)-controlled converter is used to signal the status of the renewable energy for the output current commitment judgment, and then shifts the output voltage droop characteristics to adjust output current through an 8 bits microprocessor PIC16F876. Finally, the design and analysis of the proposed scheme are introduced in this paper and some simulation and experimental results are also provided.