An Optimized Hybrid Model-Based Unified-Phase-Shift Control Strategy for Single-Phase Dual Active Bridge DC-DC Converter

This paper proposes a Hybrid Model-Based Unified-Phase-Shift (HM-UPS) control method for the single-phase dual active bridge (DAB) DC-DC converter. The main advantages of the proposed HM-UPS strategy are fast dynamic response, output voltage and output current control, and increasing the high bandwidth of the control phase-shifted angle over the whole transmission power range. Furthermore, an optimization method reduces the leakage inductance peak current and increases the converter’s total efficiency. A comparison is made between the proposed control scheme and the single-phase-shift (SPS), extended-phase-shift (EPS), virtual direct power control (VDPC), and simple UPS strategy in terms of dynamic performance and efficiency. Finally, the effectiveness of the proposed control approach is validated by simulation results in MATLAB/Simulink environment.

I. Introduction

Power electronic converter topologies play a significant role in various applications [1]-[5]. A dual active bridge (DAB) DC-DC converter is one of these topologies introduced in the early 1990s [6]. This converter is the most popular isolated bi-directional topologies (see Fig. 1) due to its specific advantages such as high power density, galvanic isolation, inherent zero voltage switching (ZVS) capability, easy to control, symmetrical structure, and bi-directional energy flow capability [7], [8], [9]. Thus, this converter is suitable for many applications such as distributed generation systems, solid-state transformers (SST), electric vehicles, railway locomotive power traction systems, and photovoltaic (PV) systems.