A Multi-Input Single-Control (MISC) battery charger for DC nanogrids

Renewable power and storage have made DC based domestic distribution an attractive alternative for future homes. Due to low power rating of the system, it is very important to reduce number of converter stages and use the generated energy efficiently. Therefore, instead of using different dedicated converters from various uni-directional renewable sources, this paper proposes a single stage boost converter with multiple inputs that can efficiently decimate generated energy to charge a battery. This philosophy of interfacing renewable sources will have commercial value when some of the additional sources are not large enough to mandate a dedicated converter. The converter is called Multi-Input-Single Control (MISC) converter. The converter varies the duty cycle based on optimum operation of the largest power source (e.g., MPP in case of solar panel), where as the other smaller unidirectional sources act as slave. As per the characteristic of the source, the proposed converter works under various operating modes which are discussed in this paper. The concept is validated using a laboratory prototype for different operating scenarios with a solar panel as a master source working under MPPT.