JPS645365A - Controlling circuit for preventing uneven magnetization of transformer - Google Patents

Abstract

PURPOSE:To prevent the uneven magnetization of a transformer by equivalently detecting the amount of uneven magnetization of said transformer through detecting the average value of an exciting current while an excitation voltage is applied to the transformer. CONSTITUTION:In the uneven magnetization preventing control circuit of a transformer, the primary side terminals c, d of said transformer 6 are connected with the AC output terminals a, b of an inverter main circuit 100 composed of semiconductor switches 2-5 and a DC power 1 and a load 7 is connected with the secondary side of the transformer 6. Current detectors 10, 11 are provided on the primary and secondary sides of said transformer 6 and the output of said detectors is introduced into an exciting current detection circuit 13. Said detection circuit 13 outputs the difference between both current detectors as an exciting current detection value, and said detection value and the output of a voltage detection circuit 12 connected with the AC output terminals a, b of said main circuit 100 are introduced into an uneven magnetization correction circuit 14, the output of which is introduced into an inverter control circuit 15 so as to be formed into a driving signal to respective semiconductor switches 2-5. Then, said correction circuit 14 receives the output of said detection circuit 12-13 to detect the average value of only an exciting current when an excitation voltage is applied to the transformer 6.