Patent ID: 6924618
Filing Date: 2005-08-02
Classification: B60H,H02M,H02P,Y02T

Abstract:
1. An inverter controller for driving a motor comprising: a rectifier connected to an AC power source, said rectifier including an inverter which converts a DC power received from said rectifier into an AC power to supply the AC power to the motor; a capacitor which has a predetermined capacitance, said capacitor being connected between DC buses of said inverter; a generator which generates a voltage command value for each phase of the motor on the basis of a motor speed command value received from outside of said inverter controller; a detector which detects a DC voltage between the DC buses of said inverter; a first corrector which calculates a voltage correction coefficient by comparing the DC voltage received from said detector with a predetermined DC reference voltage; a second corrector which corrects the voltage command value for each phase of the motor by multiplying the voltage command value and the voltage correction coefficient; a selector which selects either two-phase modulation or three-phase modulation as a modulation type used in pulse width modulation control of said inverter; a computer that computes a carrier frequency used in the pulse width modulation control of said inverter; and a pulse width modulation controller that controls a pulse width modulation so that a value of a voltage to be applied to the motor equals the voltage command value corrected by said second corrector, by using the modulation type selected by said selector and the carrier frequency computed by said computer.