Power Factor Analysis of High-Frequency Transformer Based DC-DC Bidirectional Dual Active Bridge

Abstract

This paper presents a power factor analysis of high-frequency transformer (HF) in the DC-DC bidirectional dual active bridge (BDAB). The power factor is analyzed based on three modulation techniques: conventional phase shift modulation (PSM), triangular current modulation (TriCM), and trapezoidal current modulation (TrpCM). The analysis shows that the HF transformer suffers from poor power factor under PSM operating condition compared to both TriCM and TrpCM techniques. Poor power factor is another meaning of low efficiency and high power loss. On the other side, the voltage operation range of the converter is limited under both TriCM and TrpCM switching control methods. To extend the operating voltage range and achieving high power factor condition, combining both triangular and trapezoidal modulation methods is considered and analyzed in this research. The power factor is significantly improved as both TriCM and TrpCM techniques are combined. A deep mathematical representation for the HF transformer power factor, current, and transferred power are presented for each modulation technique. Matlab simulation tools are used to analyze and verify the derived power factor equations.