MOTOR DRIVE DEVICE AND ELECTRICALLY ASSISTED VEHICLE PROVIDED THEREWITH

摘要

Provided are a motor drive device capable of an operation of charging a battery even when the power generation voltage of a motor is higher than the voltage of the battery, and an electrically assisted vehicle using the same. A voltage conversion circuit (400) is provided between a secondary battery (101) and a three-phase bridge inverter circuit (500) for driving a motor (105), and on the basis of an instruction from a main control circuit (300), the voltage conversion circuit (400) increases the output voltage of the secondary battery (101) and supplies power with the resultant voltage that is higher than the output voltage to the three-phase bridge inverter circuit (500), and when the motor (105) performs a power generation operation and the output voltage of the motor (105) is higher than the supply voltage of the secondary battery (101), decreases the output voltage of the motor (105) and supplies the resultant voltage that is lower than the output voltage of the motor (105) to the secondary battery (101), thereby charging the secondary battery (101). Further, by performing on/off control on a bypass circuit connected between input/output terminals of the voltage conversion circuit (400), the assist operation or the regeneration operation corresponding to the situation becomes possible.