Converter for energy storage integration in photovoltaic plants

A highly efficient bi-directional DC/DC converter topology is proposed which is based on the Cuk principle. The photovoltaic systems, modular and not modular are described and the possible circuit topologies are compared: full bridge converter and Cuk converter. The proposed converter can be used for the integration of an energy storage system into a photovoltaic plant, which converts the variable output voltage of the storage components (60-90 VDC) into a constant DC voltage up to 650 V. An essential problem is the voltage peaks at the IGBT during the switching-off instants, which considerably exceed the maximum blocking voltage of the power semiconductor devices. This problem is solved by a special snubber circuit.