Novel Bidirectional Four-Port DC-DC Converter Suitable for Bipolar DC Solar Household Integration

The growing focus on increasing renewable energy generation has expanded distributed generation schemes and localized DC grids worldwide. Therefore, DC households are becoming a more prevalent and efficient alternative to their ac counterpart. Even though the bipolar DC grid is more reliable and efficient than the unipolar counterpart, very few works are reported, and there exists scope for improvement. A novel four-port converter suitable for integrating renewable energy sources (e.g., solar PV), energy storage elements (e.g., lead-acid battery), and a bipolar port capable of bidirectional power flow (DC household), is proposed in this article. This scheme is named Bipolar Boost Four-Port Converter (BBFPC) and has inductively interfaced ports capable of handling bidirectional power flow. BBFPCis capable of performing the following functions: maximum power point tracking for solar PV, overcharge and overdischarge protections for the lead-acid battery, and either voltage regulation of the bipolar port in standalone mode or power distribution control of the bipolar port in grid-connected mode. The performance of the BBFPC PV-based bipolar DC system in various operating conditions is analyzed and validated using a 400 Wprototype.