Patent ID: 8710781

Claim:
A power conversion device comprising: a pulse width modulating unit configured to convert three-phase voltage commands to a PWM pulse by comparing the voltage commands with a triangular wave carrier signal; a power converter configured to convert between a DC voltage and a three-phase AC voltage by driving a switching element according to the PWM pulse; a current detecting unit configured to detect a pulsed current flowing through a DC bus conductor of a main circuit in the power converter; and a voltage command correcting unit configured to: correct voltage commands for a maximum phase and a minimum phase so that two line voltages between the maximum phase and an intermediate phase and between the intermediate phase and the minimum phase are each equal to or larger than a predetermined value, the maximum phase being a phase having the largest value when momentary values of the three-phase voltage commands are arranged in descending order, the intermediate phase being a phase having the second largest value, the minimum phase being a phase having the third largest value, and to correct the voltage command for the intermediate phase, under a predetermined condition, the predetermined condition being set so that when the voltage command value for the maximum phase or the minimum phase is corrected, one of the voltage command for the maximum phase after the correction and the voltage command for the minimum phase after the correction reaches an upper limit or a lower limit of voltage command values, and one of the two line voltages is smaller than the predetermined value, and that when the predetermined condition holds, the intermediate phase is corrected by an amount equal to a shortage in a necessary correction amount.