Abstract: Electric power conversion device has first and second operation modes. First operation mode is of converting DC power from a first terminal into DC power having a desired voltage to be output to second terminal. Second operation mode is of converting DC power from the second terminal into DC power having a desired voltage to be output to first terminal. Switching section is configured to, in first operation mode, be turned on to cause short-circuiting between both ends of capacitor of rectifying circuit, and, in second operation mode, be turned off. First conversion part is configured to, in first operation mode, supply DC power-from first terminal, from first winding to second conversion part through a conversion circuit, and, in second operation mode, output to first terminal a voltage obtained by adding an output voltage of rectifying circuit to an output voltage of conversion circuit.

Abstract: A switching circuit is configured to switch on/off a current that flows through a resonance circuit constituted by a primary winding of a transformer, a capacitance element, and an inductor that are connected in series. Electric power that is induced in a secondary winding of the transformer is rectified by a rectifier circuit. A switch is connected in parallel with the capacitance element. A control unit is configured to control the switching circuit and the switch. The control unit is configured to select a first operation in which an operation frequency of the switching circuit is controlled by switching off the switch, and select a second operation in which a period during which a current flows from the switching circuit to the primary winding of the transformer is controlled by switching on the switch.

Abstract: Electric power conversion device has first and second operation modes. First operation mode is of converting DC power from a first terminal into DC power having a desired voltage to be output to second terminal. Second operation mode is of converting DC power from the second terminal into DC power having a desired voltage to be output to first terminal. Switching section is configured to, in first operation mode, be turned on to cause short-circuiting between both ends of capacitor of rectifying circuit, and, in second operation mode, be turned off. First conversion part is configured to, in first operation mode, supply DC power-from first terminal, from first winding to second conversion part through a conversion circuit, and, in second operation mode, output to first terminal a voltage obtained by adding an output voltage of rectifying circuit to an output voltage of conversion circuit.

Abstract: A switching circuit is configured to switch on/off a current that flows through a resonance circuit constituted by a primary winding of a transformer, a capacitance element, and an inductor that are connected in series. Electric power that is induced in a secondary winding of the transformer is rectified by a rectifier circuit. A switch is connected in parallel with the capacitance element. A control unit is configured to control the switching circuit and the switch. The control unit is configured to select a first operation in which an operation frequency of the switching circuit is controlled by switching off the switch, and select a second operation in which a period during which a current flows from the switching circuit to the primary winding of the transformer is controlled by switching on the switch.