This paper presents a new soft-switched Non isolated bi-directional ZVS - PWM active clamped DC-DC converter. In addition, unified ZVS is achieved in either direction of power flow with neither a voltage-clamping circuit nor extra switching devices and resonant components. Bi-directional power flow is obtained by the same power components and provides a simple efficient and galvanically isolated converter. The proposed converter can operate with soft switching, a continuous inductor current, fixed switching frequency, and the switch stresses of a conventional pulse width modulation converter regardless of the direction of power flow. These features are due to a very simple and inexpensive auxiliary active clamp technique is used for Zero-voltage-switching of the main and auxiliary switches. The active clamp auxiliary circuit significantly improves converter efficiency regardless of the direction of power flow as it reduces the losses due to switching transitions.The proposed converter has distinct advantages like high power density, high efficiency and low cost application. The detailed design and operating principles are analyzed and described. The simulation results are verified with the experimental results.

Keywords: Bidirectional DC - DC converters, non-isolation, energy conversion, ZVS operation, auxiliary switch, active clamp technique, soft switching.