Four Switch Buck/Boost Converter to Handle Bidirectional Power Flow in DC Subgrids

A non-isolated DC-DC converter is used for connecting different devices with a supply voltage of up to 60 V. Stand-alone operation is possible as well as using the communication interfaceof the converter to work in single orparallel configuration and to handle the bidirectional power flow in DC subgrids. Therefore, different voltage droop control characteristics are used. Constant current and constant voltage operation is implemented over the full voltage rangefor battery systems. A maximum power point tracking (MPPT) algorithm enables the connection of different photovoltaic panels. Experimental results based on a prototype with a maximum power of 300W and a peak efficiency of 97% verify the validity.