| 摘要 |
PURPOSE: To prevent the effect of magnetostatic field and quasi-magnetostatic field by detecting a first signal proportional to the flux in a converter and a second signal proportional to a supply current for magnetizing the converter by means of a phase sensor for detecting higher harmonics of even orders. CONSTITUTION: A voltage supply 1 produces an output 2 having a lowest frequency and an output 3 having a frequency two times as high as the lowest frequency. A signal from the output 2 is delivered through an amplifier 4 to the exciting winding 5 of a converter. A signal from the output 3 is delivered to a phase detector 8 for detecting higher harmonics of even orders. The converter delivers a first signal to an input 6 of the detector 8 and a second signal to the inputs 6, 7 of the detector 8. When the detector is magnetized by magnetostatic field and quasi-magnetostatic field, the B-H curve is distorted to produce higher harmonics of even orders. Consequently, a signal from the output 10 of the detector 8 is delivered to a regulator 11 and the content of higher harmonics of even numbers is reduced to zero by a magnetostatic field in the opposite direction. A signal from the output 12 of the regulator 11 is delivered through an amplifier 13 to a compensation winding 14 and a required opposite magnetostatic field is generated. |
