Patent attributes
A drive unit controls the operation of a corresponding power switching element such as IGBT which forms an inverter and a converter. The drive unit controls the operation of the corresponding power switching element to supply an operation current to a motor generator. First and second switching elements in the drive unit are simultaneously turned on when an operation signal transferred from a control device is switched to a turning-on instruction operation signal. The voltage at the gate terminal of the power switching element is shifted to a divided voltage obtained by dividing a voltage of the power source by first and second resistances connected in series in the drive unit. When a mirror time period of the power switching element is elapsed, the second switching element only is turned off in order to shift the gate voltage of the power switching element to the voltage of the power source.