A Parameter-Based Design Methodology for Double-Loop Control of Dual Active Bridge Converters

Abstract

The dual active bridge (DAB) converter is widely used in bidirectional power conversion applications due to its high efficiency, power density, and galvanic isolation. Although there have been many studies on the modeling of DAB converters, research on the impact of parameters on control gain design is still limited. This paper presents a parameter-based design methodology for the double-loop control of DAB converters. Small-signal models for voltage and current control loops are derived using generalized average modeling, with transfer function coefficients expressed in terms of DAB parameters. Through dominant pole analysis and low-frequency approximation, the transfer functions are simplified to allow intuitive proportional-integral (PI) gain design. The proposed method enables systematic gain tuning based on parameters such as rated power, transformer characteristics, and control bandwidths, without complex numerical procedures. Bode plot analysis confirms that the simplified model accurately represents the system dynamics in the low-frequency region. To validate control performance, the designed gains are implemented on a hardware-in-the-loop simulation (HILS) environment. Steady-state and transient experiments under varying load conditions verify that the proposed method achieves stable regulation and adjustable dynamic response. The results demonstrate that the proposed method enables accurate and stable double-loop control based on parameter values, while significantly simplifying the gain design process for DAB converters.