Abstract: A method for suppressing magnetizing inrush current of the transformer with flux linkage control includes connecting a small-capacity direct current/alternating current (DC/AC) converter with the secondary winding or auxiliary winding of transformer, detecting the primary side phase voltage before closing load, inducing the core flux linkage reference according to the relationship between the winding voltage and core flux linkage. The core flux linkage closed-loop PI control system is constructed to control the converter voltage in the synchronous coordinate, then the core flux linkage can track its reference with no static error, thus the sinusoidal flux linkage with 90-degree difference from the grid voltage can be pre-established in the core before no-load closing. By these methods, no matter when the main transformer closes, the core flux linkage is always in the steady state, and the magnetizing inrush current can be eliminated completely.

Abstract: A magnetic integrated hybrid distribution transformer includes a main transformer, a series isolation transformer and a converter, wherein: an iron core includes an iron beam unit, an iron yoke unit and a leakage magnetic core unit. The main transformer includes secondary windings, primary windings and control windings all of which are layer-windings and wound around main transformer iron beams. The series isolation transformer includes converter side windings and grid side windings all of which are pancake-windings and wound around isolation transformer iron beams. The converter side windings and the control windings are respectively connected with the converter by the star connection with neutral point. Leakage magnetic cores are respectively inserted between the primary windings and the control windings or between the converter side windings and the grid side windings, so as to achieve magnetic integration design of the transformer and output connection inductor of the converter.

Abstract: A method for suppressing magnetizing inrush current of the transformer with flux linkage control includes connecting a small-capacity direct current/alternating current (DC/AC) converter with the secondary winding or auxiliary winding of transformer, detecting the primary side phase voltage before closing load, inducing the core flux linkage reference according to the relationship between the winding voltage and core flux linkage. The core flux linkage closed-loop PI control system is constructed to control the converter voltage in the synchronous coordinate, then the core flux linkage can track its reference with no static error, thus the sinusoidal flux linkage with 90-degree difference from the grid voltage can be pre-established in the core before no-load closing. By these methods, no matter when the main transformer closes, the core flux linkage is always in the steady state, and the magnetizing inrush current can be eliminated completely.

Abstract: A magnetic integrated hybrid distribution transformer includes a main transformer, a series isolation transformer and a converter, wherein: an iron core includes an iron beam unit, an iron yoke unit and a leakage magnetic core unit. The main transformer includes secondary windings, primary windings and control windings all of which are layer-windings and wound around main transformer iron beams. The series isolation transformer includes converter side windings and grid side windings all of which are pancake-windings and wound around isolation transformer iron beams. The converter side windings and the control windings are respectively connected with the converter by the star connection with neutral point. Leakage magnetic cores are respectively inserted between the primary windings and the control windings or between the converter side windings and the grid side windings, so as to achieve magnetic integration design of the transformer and output connection inductor of the converter.