| 摘要 |
PURPOSE:To make is possible to detect ever-changing power-factor angle at a continous signal level, by taking out the maximum output level of a phase difference memory circuit operating alternately every half cycle only during a period corresponing to the phase difference. CONSTITUTION:A phase voltage and a phase current of a circuit being measured by wave-shaping circuits 6a1 and 6a2, and then, these waves are put into zero-cross circuit 6b1, and 6b2, and only a portion in the positive direction is converted to a rectangular shape. Output of the circuits 6b1 and 6b2 are converted by logic circuits 6c1 and 6c2 to waves correspond ing to phase differences differed by 180 deg. in phase, and then, the waves are put into phase difference memory circuits 6d1 and 6d2 and integrated. Respective output of the phase difference memory circuits 6d1 and 6d2 are added to a adding circuit 6g through switching circuits 6e and 6f, and continous signals proportional to power-factor angle are obtained. It is possible, by doing so, to execute reciprocal switching between a load commercial power source and an inverter power source by taking a positive synchronism. |
