US Patent 10008969 Power supply system for electrically powered vehicle

When a voltage (auxiliary power supply voltage) on an auxiliary power supply line is instantaneously decreased to be smaller than a resetting voltage, a resetting operation is automatically started in each of the MG-ECU and the HV-ECU to perform an initialization process. After the resetting operation of the MG-ECU and/or the HV-ECU, the MG-ECU causes a converter to start a forced discharging operation when a DC voltage of a first smoothing capacitor is higher than a first reference voltage, and/or when a DC voltage of a second smoothing capacitor is higher than a second reference voltage.