An improved state-space averaged model of a dual active bridge converter for use in acausal system modeling

Abstract

The dual active bridge (DAB) is an attractive device for high-power DC to DC bidirectional power conversion. In order to develop a closed-loop controller for a DAB, an accurate dynamic model must be developed. A continuous model is preferred because it provides more insight into the principle dynamics and is suitable for use in an acuasal simulation. Acausal notation for simulation defines relationships in their natural form, as a system of differential equations, and leaves the method of solving the equations up to the simulation engine. This paper develops a continuous state-space averaged model for a DAB that is shown to be accurate when numerical solutions are compared to a more detailed numerical model that includes switching dynamics. The improved model is suitable for many types of power and control simulations.