| 摘要 |
PURPOSE:To prevent a DC filter from being operated against a pattern change by providing a detector detecting a difference between a DC voltage converted at a converter and a command voltage signal of a command circuit to the DC filter device. CONSTITUTION:Power from an AC power supply 1 is converted into a DC voltage by a converter 2 and detected by a voltage detector 31. Further, signals of a command circuit 6 and a current detector 5 are compared by a comparator 7, a voltage command signal is obtained via a constant current control circuit 8 to control a trigger phase of a gate rectifier element of the converter 2 via an automatic pulse phase shifter 9, a difference with an output signal from a voltage detector 31 is obtained and the difference is fed to a pulsating component detector 32. Then the pulsating component is amplified, superimposed on an output pulsation of the converter 2 at a transformer 33b in an opposite phase and a smoothed voltage is fed to a load 4. Thus, the voltage fluctuation component due to the pattern change does not appear at the output of the subtractor 10 and the DC filter 3 is not operated.
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