THREE-LEVEL POWER CONVERSION DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a three-level power conversion device that ensures a conduction balance and suppresses a neutral potential fluctuation.SOLUTION: The three-level power conversion device includes a three-level power converter 3 and control means 7 for performing PWM control thereof. The control means 7 includes: means for generating basic voltage references; maximum value detection means 732 for detecting a maximum value of the basic voltage references; minimum value detection means 733 for detecting a minimum value of the basic voltage references; switching means 734 for switching between the maximum value and the minimum value at a predetermined period; correction means 735 for subtracting an output from each of the three-phase basic voltage references to produce three-phase voltage references; PWM control means 74 for generating gate pulses from the three-phase voltage references and positive and negative carriers; and carrier generation means for generating a triangular reference carrier for the PWM control means 74 and generating the negative carrier and the positive carrier in the same phase and in the opposite phase, respectively. The switching means 734 operates at the timing of a minimum value of the triangular reference carrier generated by the carrier generation means.