Flexible high efficiency battery-ready PV inverter for rooftop systems

Integration of energy storage with a grid-tied photovoltaic (PV) generation system in conventional residential and commercial applications uses legacy PV power electronics topologies. This paper presents a novel solar PV power electronics system which allows a seamless integration of energy storage with partial power processing technique. In the proposed topology, a dual active bridge DC-DC converter is applied to configure partially-rated power electronics system with bi-directional power flow, galvanic isolation, a high voltage boosting gain, and results in high conversion efficiency. The proposed topology is explained in detail and analyzed with the quantitative approach to verify the improvement of system efficiency and power density in the DC-DC power conversion unit: 99.5% efficiency and 3.3kW rated power for 7.5kW PV and 2.5kW battery system. Also, the steady-state operation of the proposed universal optimizer is verified through the controller hardware-in-the-loop test.