MPC-Based Startup Current Shaping Strategy With State-Space Model of DAB in DC Distribution System

Abstract

The popularity of renewable energy sources and load structure changes make the development of dual active bridge (DAB) dc–dc converters in the dc distribution system. However, due to the fast start and the large output capacitors, DAB converters suffer from inrush current. This article aims to design a current shaping scheme with a fast dynamic response to startup quickly and control the inrush current. First, the state-space average model of the startup process and its simplification are analyzed. It presents a theoretical basis for the widely used vary-frequency segmented startup scheme. Then, the model predictive control with the current shaping (MPC-CS) scheme that features fast dynamic response is presented. Also, single objective cost function, demarcation method between operating modes, and enhanced preprocessing modules are introduced to address the difficulties increased by the high switching frequency using wide bandgap devices. Finally, evaluations and comparisons among two typical schemes and MPC-CS scheme are carried out on simulations and a full-silicon-carbide-based DAB converter with the distributed heterogeneous controllers, which verify the practicality of the MPC-CS.