Patent ID: 7598689

Claim:
A motor drive apparatus comprising: a first drive circuit driving a first motor; a voltage converter performing a voltage conversion between a power supply and said first drive circuit; and a capacitor provided between said voltage converter and said first drive circuit; and a control device for controlling said first drive circuit and said voltage converter, wherein said voltage converter performs a voltage step-up operation of stepping up a power supply voltage to an arbitrary level and outputs the stepped-up voltage, and said first drive circuit starts an electric power conversion for driving said first motor in powering mode after said voltage step-up operation is completed, and said control device includes: a target voltage determination unit for determining a target voltage of said stepped-up voltage based on the number of revolutions of said first motor; a voltage conversion control unit receiving the target voltage determined by said target voltage determination unit for controlling said voltage converter such that said stepped-up voltage is equal to said target voltage; a determination unit for determining whether or not said stepped-up voltage reaches said target voltage and, when said determination unit determines that said stepped-up voltage reaches said target voltage, generating a signal indicating completion of the voltage step-up operation; and an electric power conversion control unit for causing said first drive circuit to start an electric power conversion for converting said stepped-up voltage into a drive voltage for said first motor, when said electric power conversion control unit receives said generated signal from said determination unit.