| 摘要 |
PROBLEM TO BE SOLVED: To prevent output of an unintended torque from a motor, and to output more-stabilized motive power, if a changeover of the series and parallel connection of a plurality of capacitors is performed, when motive power is outputted from the motor using as a power source, a power unit whose voltage across terminals is adjustable by a changeover of the series and parallel connection of the capacitors. SOLUTION: A control unit 60 computes the time constant (charge and discharge characteristics) of a smoothing capacitor 38 from the electrostatic capacity of the smoothing capacitor 38 and the resultant resistance of a power unit 22 corresponding to command signals to switches SW1-SW3, estimates the voltage across the terminals of the smoothing capacitor 38 (a potential difference acting between the positive electrode bus-bar 32 and the negative electrode bus-bar 34 of an inverter circuit 30), on the basis of the time constant and the resultant voltage of the power unit 22 corresponding to the command signals to the switches SW1-SW3, generates a PWM signal using the estimated voltage so that a command torque is outputted from a motor 36, and outputs it to the inverter circuit 30. |
