| 摘要 |
A three-phase rectification circuit rectifies output voltage of a three-phase AC power supply, a step-up converter circuit steps up the output voltage, and a smoothing device smoothes the stepped-up output voltage. A voltage detection circuit detects output voltage VoL of the smoothing device, and an AC current component detection circuit extracts AC component included in output current of the three-phase rectification circuit and outputs a detection signal ViL corresponding to the AC component. A control circuit calculates a deviation DeltaVdc1 (=Vs-VoL-ViL) among an output voltage instruction Vs for output voltage of the step-up converter circuit and detection signals VoL and ViL obtained by the detection circuits, and generates a pulse signal for suppressing the deviation DeltaVdc1 to zero, thereby performing PWM control for a switching device of the step-up converter circuit.
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