Dynamic Modeling and Control of Dual-Active- Bridge DC-DC Converter With Triple-Phase-Shift Modulation

Dual-Active-Bridge (DAB) has emerged as one of the important isolated dc-dc converters due to its bidirectional power flow capability, simple architecture, and ability to achieve ZVS over a wide operating range. Extensive research in the past decade solved the problem of high circulating current and conduction loss through advanced switching techniques known as optimal Triple-Phase-Shift (TPS) modulation. As the power processing technique in DAB differs from the conventional PWM converters, the dynamic modelling of this converter, through the usual averaging of the converter state variables, is not directly applicable. Significant research has been carried out to develop a dynamic model of the DAB. Finally, a simple first-order large signal dynamic model of the DAB that can accommodate the advanced TPS modulation has emerged. The objective of this article is: 1) exposition of this model along with a brief review of other significant modelling approaches from the current literature; 2) supplement it with a sound theoretical foundation that is missing in the existing literature; 3) a simple feedback controller design based on this model that is modulation agnostic and useful for practising engineer; 4) sample PI controller design procedure with for a 1kW prototype with a TPS modulation strategy; and 5) evaluation of controller performance under circuit parameter variation.