Development of T-type Dual Active Bridge DC-DC Converter with Switching Operation Mode Over Wide-Voltage-Operation Range

Abstract

This paper proposes a T-type dual active bridge (DAB) converter with switching operation mode to improve the converter efficiency over a wide range of load and voltage. The T-type DAB converter outputs two waveforms: a square wave and a square waveform with half of the input voltage. By applying the switching operation mode, the converter efficiency is improved. In addition, voltage control for the T-type DAB converter is also proposed. Owing to the proposed voltage control, the slow voltage response is avoided because the operation modes are seamlessly switched by matching the transferred power of each mode. In an experiment conducted using a 1.5-kW prototype, the validity of proposed method is confirmed. A maximum efficiency of 97.9% is achieved at the nominal voltage condition. At the half-output-voltage condition, the converter loss is reduced by up to 62.3%, when the switching mode is applied. Moreover, the output voltage control is effective, regardless of switching operation mode.