PURPOSE: To set a running power-factor to be 1.0, by controlling the absolute value of the output voltage of an inverter and the absolute value of system voltage via a systematic reactor, to come to a constant voltage difference.
CONSTITUTION: After the DC power of a DC power source 1 is converted to AC power by a main converting section 2, the power is waveform-shaped through filters 3∼4 and is fed to a distributing system 7 via a main transformer 5 and a systematic reactor 6. A PLL circuit is composed of a phase detector 16 and a frequency controlling circuit 19, and in the same phase as that of the system, an inverter is operated. For a constant voltage controlling system(AVR system), system voltage as the reference voltage of the constant voltage control of the inverter is adopted, and a bias circuit for the reference voltage is set so that a device may be operated with a constant difference between as inverter output voltage absolute-value and a system voltage absolute-value. As a result, when the output of a voltage regulator 23 is zero, then the difference voltage of converters 13, 14 is applied to the main converting section by an error amplifier 18, a constant voltage controlling circuit 22, and the like.
Ito, Naoto
Morinaga, Daisaku
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