Performance Evaluation of Bidirectional SEPIC-ZETA DC-DC Converter with Different Ambient Temperature

Bidirectional DC-DC converters allow power to be transferred in any direction between two electrical sources. These converters are increasingly employed in a variety of applications, including battery chargers and dischargers, energy storage devices, electrical vehicle motor drives, aircraft power systems, telecom power supplies, and others, due to their ability to reverse the direction of power flow. One of these basic types of bidirectional DC-DC converters is the SEPIC-ZETA converter. In this paper, the structure of this converter has been studied when MOSFET power switches are employed. Also, an electrical thermal analysis, which is based on the ambient temperature (between 25 °C and 40 °C), has been employed by using two MOSFET models (UJ3C065080K3S and SCT50N120). The study shows the effects of utilizing different MOSFET models on power losses and thermal analysis. According to the simulation results, the junction temperature of the MOSFET was 151.38 °C in the forwarding mode and for the first model (UJ3C065080K3S) at T = 40 °C, while the MOSFET junction temperature was 158.5 °C in the backward mode. In the second model (SCT50N120) and at the same T = 40°C, the MOSFET junction temperature exceeds 130.6°C in the forwarding mode. When the converter was operating in backward mode, its junction temperature was 128.7 °C. The bidirectional SEPIC-ZETA converter performs better in the second model of the MOSFET (SCT50N120).