Being the control unit of the boost

摘要

PROBLEM TO BE SOLVED: To provide a controller of a voltage boosting converter for quickly avoiding the generation of an overvoltage.;SOLUTION: The voltage boosting converter 12 boosts a DC voltage from a DC power supply B. An inverter 14 converts an output voltage from the voltage boosting converter into an AC voltage. An AC motor M1 is driven by an output voltage from the inverter 14. A controller 30 for controlling the voltage boosting converter 12 decreases an output voltage instruction value of the voltage boosting converter 12 if a rotational speed of the AC motor M1 decreases and an absolute value of a fluctuation rate of the rotational speed is a predetermined value or larger. The inverter 14 is controlled by a control mode selected from among a plurality of control modes including three modes of a sinusoidal PWM control mode, an over-modulation PWM control mode and a rectangular PWM control mode. The controller 30 of the voltage boosting converter decreases the output voltage instruction value of the voltage boosting converter 12 only when the control mode of the inverter 14 is the rectangular PWM control mode or the over-modulation PWM control mode.;COPYRIGHT: (C)2007,JPO&INPIT