Patent ID: 8848408

Claim:
A discharge control device for an electric power conversion system, the electric power conversion system comprising an electric power conversion circuit, a capacitor and an electrical switching device, the electric power conversion circuit being equipped with a series connection unit, the series connection unit comprising a switching element at a high voltage side and a switching element at a low voltage side connected in series, the electric power conversion circuit converting a direct current power of a direct current power source to a predetermined electric power, the capacitor being placed between input terminals of the electric power conversion circuit and the direct current power source in order to smooth the voltage between the input terminals of the electric power conversion circuit, the electrical switching device opens and closes electrical connections between the electric power conversion circuit, the capacitor and the direct current power source, the discharge control device comprising a discharge controller, a first power source and a second power source, wherein the discharge controller adjusts a charged voltage of the capacitor to a voltage of not more than a predetermined voltage by operating the switching elements at a high voltage side and the switching elements at a low voltage side when the electrical switching device is turned off, the first power source receiving the voltage of the capacitor when the capacitor is discharged, and generating a first supplying voltage by decreasing the voltage of the capacitor during the discharge of the capacitor, the first supplying voltage being supplied to a first driving circuit for controlling the switching element at a high voltage side, and the second power source receiving the first supplying voltage of the first power source and generating a second supplying voltage based on the first supplying voltage, which is higher than the first supplying voltage, the second supplying voltage being supplied to a second driving circuit for controlling the switching element at a low voltage side.