GaN Quad-Active-Bridge Converter for Hybrid PV-Battery Systems

A quad-active-bridge (QAB) multiport converter will be developed based on an innovative circuit topology, a high-frequency planar magnetic transformer, and the latest generation of wide bandgap (WBG) transistors. The WBG-based QAB converter will provide a high-efficiency and ultra-compact interface capable of connecting with an array of photovoltaic (PV) panels, battery packs, electric vehicles (EV) for charging/discharging, and distribution grids. The proposed WBG QAB converter is anticipated to outperform the existing discrete power electronics solutions in the market, promoting wider penetration of renewable energies and electric vehicles into the utility grid. This proposed WBG QAB converter has the following features: (1) Bi-directional autonomous power flow management between any two of the four ports, (2) High power efficiency by utilizing WBG transistors and an innovative soft switching strategy, (3) High power density, benefiting from switching WBG transistors at 100 kHz PWM frequency, and (4) High-reliability by utilizing an ultra-compact planar phase shifting transformer enables galvanic isolation between the four ports of the converter. The current state-of-the-art technologies cannot achieve higher power density, efficiency, better modularity, and lower cost than the proposed technology. Furthermore, such an integrated and modular power converter solution will dramatically reduce the installation area and cost. The team’s expertise in power converter controls, prototyping, and testing GaN and SiC-based converters will be beneficial for the successful execution of the proposed project. In Phase I of this project, targeting a 50 kW WBG QAB converter, the multi-physics modeling, simulation, and design optimization of the proposed converter concept will be completed, which lays a foundation for the hardware prototyping in Phase II. The four features of a 240Vac, 50 kW WBG QAB converter will be thoroughly quantified and evaluated to confirm that this concept meets the existing standards with distributed systems and exhibit high commercial potential and substantial application prospects.