Patent ID: 6804130
Filing Date: 2004-10-12
Classification: H02P

Abstract:
An inverter apparatus for obtaining a voltage command vector from a frequency command value and a voltage command value calculated by a V/f operation based on the frequency command value, and carrying out a PWM modulation based on the voltage command vector, thereby outputting a voltage, comprising:current detecting means for detecting a current vector having a magnitude of a current and a current phase, voltage limitation value calculating means for calculating a voltage limitation value which is proportional to an excess when the magnitude of the current exceeds a current limitation value, voltage limitation vector calculating means for calculating the voltage limitation value of a voltage limitation vector by setting, to zero, a component of a vector in a reverse direction to the current phase which is orthogonal to the voltage command vector direction, voltage correcting means for adding the voltage limitation vector to the voltage command vector, and acceleration command frequency based on the voltage limitation value and the current phase.