This paper describes high efficiency non-isolated bidirectional converter which can be applied as the interface circuit between ultracapacitors or batteries with DC bus. All semiconductor devices in the proposed converter are almost soft switched while the control circuit remains PWM. So, the energy conversion through the converter is highly efficient. The proposed converter acts as a ZVT Buck to charge ultracapacitor or battery. On the other hand, it acts as a ZVT Boost to discharge ultracapacitor or battery. Performance of the proposed converter was simulated with PSPICE software. The results confirm aforementioned advantages and features of the proposed converter.