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AssigneeHitachi, Ltd.
InventorsKeijirou Sakai, Toshiaki Okuyama, Kinya Nakatsu, Seiji Ishida, Hiroshi Fujii, Junji Kato, Masahiro Hiraga
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A single-phase PWM converter system in accordance with the present invention employs a sample-and-hold circuit which samples and holds a direct current in the state wherein one of two-phase gate signals of a positive or negative side arm is ON and the other phase is OFF, determines the sign of an output of the sample-and-hold circuit according to the two-phase gate condition, detects a phase current at the input side of the converter, and controls a voltage at the input side of the converter so that the detected current value agrees with a power supply current command. Further, a three-phase PWM converter system in accordance with the present invention detects the effective current and the ineffective current of the power supply current from the direct current, and based on the values, controls the PWM converter so that the sine wave power supply current whose power supply power factor is 1 is provided.
A PWM converter system having a PWM converter, an input side being connected to an AC power source via an AC reactor or a transformer and output side DC terminals being connected to a smoothing capacitor therebetween, for converting the alternating current to the direct current, and a controller therefor,
Dependencies are inferred from the claim text.