GaN-Based Multi-Active-Bridge Converter with Hot-Swapping Capability

MSc thesis of Shumeng Wang

This thesis addresses a novel configuration of hot-swappable Multi-Active-Bridge (MAB) DC/DC converter in renewable-energy-based systems. As an extension of the Dual-Active-Bridge (DAB) converter, the MAB converter provides a multiport DC/DC converter solution with bidirectional power flow, simple phase shift control and galvanic isolation, but leaves problems in coupling operation, low availability and control complexity. In this thesis, the MAB converter with hot-swapping capability is proposed and studied. With a dedicated transformer design and circuit re-configuration, the converter allows a single port rigidly determines the voltage on the magnetizing inductance of the transformer, while the power flow of all other ports are naturally decoupled. The decoupled ports of this proposed MAB converter shows high independence in control and operation, thus can be hot-swappable and decentralized controlled. The hot-swapping interface circuit consisting of Negative-Temperature-Coefficient (NTC) and Metal-Oxide-Varistor (MOV) is proposed, and the benchmark of components selection is elaborated. The control of hot-swappable ports is implemented with a decentralized voltage loop and a SYNC module for phase shift control synchronization. A 2.2kW, 200kHz, two 350V, two 48V, four-port GaN-based MAB converter is simulated and tested for evaluation of decoupled operation, hot-swapping and decentralized control. Finally the hardware is designed and to be implemented for further and extended evaluation of hot-swappable MAB converter.