Naturally Clamped Soft-Switching Current-Fed Three-Phase Bidirectional DC/DC Converter
A novel bidirectional Snubberless naturally clamped soft-switching three-phase current-fed dc/dc converter is proposed. A proposed secondary modulation technique naturally clamps the voltage across the primary-side devices with zero-current commutation, eliminating the necessity for active-clamping circuits or passive snubber and solving the traditional problem of device turn-off voltage spike. Switching losses are reduced significantly, owing to zero-current switching of primary-side devices and zero-voltage switching (ZVS) of secondary-side devices. Soft switching and natural voltage clamping are inherent and load independent. The proposed bidirectional converter achieves high efficiency, high density, high reliability, small volume, light weight, and low cost compared to the active-clamped ZVS counterpart.
Current fed converters employ residual-current device (RCD) snubber, active clamping, or other passive snubbers to absorb device turn-off voltage spike. The RCD snubber leads to low efficiency due to clamping energy dissipated in the snubber resistor. Active clamping results in high efficiency and simultaneously achieves zero-voltage switching (ZVS) of switches. However, it needs floating device(s) and high value of HF clamp capacitor for accurate and effective clamping. In addition, it suffers from demerits of high current stress (peak), higher circulating current at light load, dutycycle- dependent device voltage, and reduced boost capacity.
The proposed modulation technique eliminates activeclamping circuits or passive snubbers. With less number of components, the whole system is simplified, and cost can be reduced further. Switching losses are reduced significantly, owing to soft switching of devices, i.e., ZCS of primary switches and ZVS of secondary switches.Moreover, the losses resulting from the use of auxiliary active-clamping circuits or passive snubbers are completely avoided by this novel design.
TOOLS AND SOFTWARE USED:
- MP LAB
Pan Xuewei, Student Member, IEEE, and Akshay K. Rathore, Senior Member, IEEE, “Naturally Clamped Soft-Switching Current-Fed Three-Phase Bidirectional DC/DC Converter”, IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 62, NO. 5, MAY 2015.