Method and apparatus for control of pulse width modulation (pwm)

Abstract

A control method for a PWM converter which is connected to an AC current source via a reactor, and performs the sending and receiving of power between the AC power source and a DC power source, includes a step of separating a supplied AC current into an effective current and a reactive current and performing PWM control and a step for control so that said reactive current is larger when there is conversion of DC power into AC power, than when there is conversion of an AC power into DC power. In addition, the control apparatus includes a detector element which detects at least two phases of a three-phase AC current as a current detection value, a phase detection element which detects a voltage phase of the three-phase current, a current separation element which uses the voltage phase to separate the detected current detection value into an effective current and a reactive current, an effective current control element which performs feedback control so that the separated effective current becomes a required value, a reactive current control element which performs feedback control so that the separated reactive current becomes a required value, and a reference calculation element which calculates a reference value so that an reference value of a reactive current becomes larger for when the effective current and power voltage are of opposite polarities, than for when they are of the same polarity.