Patent ID: 7436144
Filing Date: 2008-10-14
Classification: H02M,H02P

Abstract:
1. An inverter device comprising: a calculating unit configured to calculate at least one output-voltage command value based on a frequency command value for driving a motor and a state quantity of the motor, in each calculation period; a signal output unit configured to output a pulse-width-modulation signal according to the output-voltage command value; and a switching unit configured to switch a direct voltage according to the pulse-width-modulation signal to supply an alternating voltage having a predetermined frequency to the motor, wherein the calculating unit is configured to calculate a plurality of output-voltage command values when a phase change amount is higher than a threshold, and to calculate a single output-voltage command value when the phase change amount is equal to or less than the threshold, wherein the calculating unit is configured to calculate more number of output-voltage command values when the frequency command value is higher than a threshold than when the frequency command value is lower than the threshold.