Patent ID: 8085557
Filing Date: 2011-12-27
Classification: H02M,Y02B

Abstract:
1. A bidirectional DC-AC inverter that converts a direct current voltage input from a battery with a voltage higher than a voltage of a system power supply to an alternating voltage equal to the voltage of the system power supply, and converts an alternating voltage input from the system power supply to a direct current voltage with which the battery is charged, the inverter comprising: an H bridge circuit that coverts the direct current voltage input from the battery to the alternating voltage and converts the alternating voltage input from the system power supply to the direct current voltage, the H bridge circuit including four switching elements each having a first end and a second end, the four switching elements including two first switching elements the first ends of which are connected to each other, and two second switching elements the second ends of which are connected to each other; a connecting portion connected to the H bridge circuit; a smoothing filter connecting the connecting portion to the H bridge circuit, the smoothing filter having a capacitor and two coils connected to the capacitor; and a control section that controls the switching elements, wherein, when the alternating voltage input from the system power supply is converted to the direct current voltage with which the battery is charged, the control section controls the first switching elements in such a manner that the two coils function as booster coils; wherein the smoothing filter includes a voltage sensor that detects the value of an alternating voltage input to the smoothing filter and an electric current sensor that detects the value of an alternating current input to the smoothing filter, and; wherein the control section controls the first switching elements by a duty cycle calculated based on: an output voltage supplied from the H bridge circuit; the value of the voltage detected by the voltage sensor; a target value of an alternating current from the smoothing filter is necessary for outputting the direct current voltage with which the battery is charged from the H bridge circuit; and the value of the electric current detected by the electric current sensor.