| 摘要 |
PURPOSE:To offset biased magnetization flux going to flow into a core by operating a switching element in response to load currents flowing through a secondary wiring and flowing currents in the direction opposite to the magnetization currents made to be contained in load currents through an excitation control winding. CONSTITUTION:An excitation control winding 8 sharing a core 7 for a transformer 3 is mounted to the transformer 3, the excitation control winding 8 and a secondary winding 4 are coupled magnetically, and a control impedance 9 and a switching element 10 are connected in series with the excitation control winding 8. The switching element 10 functions as a thyristor at that time, and operates so as to flow currents idc in the direction opposite to DC sections idL flowing in load currents iL flowing through the secondary winding 4 through the excitation control winding 8 in response to load currents iL. That is, the angle of lag of control alpha of the switching element consisting of the thyristor is selected so that currents ic flowing through the excitation control winding 8 satisfy DC components thereof idc to load currents iL. Accordingly, the quantity of biased magnetization in the core is offset by both components of the DC sections idL of load currents iL and the DC sections idc of excitation control winding currents ic, thus substantially removing biased magnetization. |
