| 摘要 |
PURPOSE:To eliminate a transformer by detecting a DC component contained in the output voltage of an inverter by means of a saturable reactor, feeding it back to supplement the DC component. CONSTITUTION:A voltage type inverter is composed of an inverter with a DC power source 1 and N-P-N transistors 3a-3d, and its controller is composed of a voltage detector 7, an oscillator 8, a sine wave generator 10, an adder 11, an error amplifier 12, a triangular wave oscillator 13, a comparator 14, and a transistor driver 15. In this case, there are provided as a DC component corrector a saturable reactor 20, a resistor 21, photocouplers 22-23, an operational amplifier 28, and a feedback capacitor 20, etc. Thus, the reactor 20 is not magnetically saturated by the normally applied AC voltage, to allow a current to scarcely flow, but when a DC voltage is superposed and applied, it is magnetically saturated at the positive pole side of the DC component to supply a current, thereby correcting the DC component.
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