A Dual-Active-Bridge Based Four-Port Bidirectional DC-DC Converter for Renewable Energy Integration

In this article, a four-port bidirectional DC-DC converter is proposed for the integration of various renewable energy sources with a battery energy storage. The nominal voltage of the battery is kept at a higher value than the source voltage level, which demonstrates a unique feature of the proposed converter. The mathematical modelling and power transfer equations considering various operating condition is derived for the converter. Also, a controller with a decoupling feature is designed to control the battery current as well as maintain the DC link voltage constant during the entire operation. Moreover, the developed controllers enable the converter to track the maximum power point (MPPT) of solar energy. The performance of the converter is substantiated by carrying out simulation studies considering various possible modes of operation.