Model-Based Dynamic Control of Two-Degree-of-Freedom Modulation for Dual Active Half-Bridge Converter

Abstract

This article proposes a model-based dynamic control for dual active half-bridge converters to satisfy both a loss-minimizing operation and a high-dynamic response. First, the loss-minimizing operation is analyzed based on a two-degree-of-freedom (2-DOF) modulation scheme, where control variables consist of a phase shift and a duty ratio. The modulation scheme is optimized to minimize the transformer root-mean-square current or to achieve a zero-voltage-switching condition under varying conditions. Moreover, the output voltage control should be designed to provide fast dynamic performance under source and load variations. Therefore, the voltage controller is unified with the modulation schemes, where a model-based control is adopted to improve the dynamics of 2-DOF modulation. A model-based calculation part reduces the burden of an error compensation part with a load current feedforward. Finally, the effectiveness of the proposed method is verified by the experimental results.