The present invention focuses on the development of a high-efficiency single-stage bidirectional converter with multi-input power sources. In the present invention, it takes a three-winding coupled inductor as the main component of energy transmission, and utilizes only two power semiconductor switches to accomplish the multi-input function. According to the designed switching conditions, this circuit could be operated at discharge, charge and standalone states to simplify conventional structure in which multiple converters are used in boosting voltage and then connected in parallel to supply power. Moreover, the coupled inductor as the principal part of this circuit has high-voltage gain property, and the present invention fully utilizes the winding voltage in the high-voltage side to further increase the corresponding voltage gain superior to that in the conventional coupled-inductor strategy. This property is helpful to solve the power conversion problem caused by clean energies with inherent low-voltage characteristics. In addition, all switches and diodes have favorable voltage-clamped effects so that the voltage spikes induced by the leakage-induction energy can be alleviated effectively, and there are no high reverse-recovery currents within diodes because the leakage induction can restrain instantaneous changes in the current. Furthermore, the present invention has a charging route of low-voltage conversion without adding additional components, avoiding the power losses induced by the multistage conversion in the traditional auxiliary power systems, and utilizes the synchronous rectification technique to decrease the conducting losses.