| 摘要 |
PURPOSE:To eliminate current unbalance of a converter, by correcting the phase difference component of an automatic phase shifter. CONSTITUTION:An electric valve such as thyristor is connected in bridge to from an AC/DC converter, and the two or more AC/DC converters are arranged in parallel to constitute a DC large-capacity power source. In a control circuit of the power source, in order to prevent current unbalance of each converter due to impedance difference including a transformer and a cable at secondary side, phase correction signal is applied to input signal section of automatic pulse phase shifters APPS1-n to determine phase of each converter. In this case, a thermo sensor and a frequency detector V/F are installed. Thereby the thermo sensor detects temperature at periphery of the control circuit, and the frequency detector V/F detects frequency of the AC power source. Receiving these detecting signals, the phase correction circuit outputs correction signal to correct phase difference in the automatic pulse phase shifters APPS1-n. As a result, output voltage of each converter becomes the same and the current unbalance is eliminated.
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