The invention relates to a method for dynamically eliminating residual
magnetism of an iron core of a converter
transformer, and belongs to the field of
transformer demagnetization. According to the method, a
capacitance energy storage and release device is connected to the two ends of a
transformer winding,
capacitance energy storage causes RLC oscillation of the transformer, a
magnetic field is generated through current caused by the RLC oscillation, and magnetic domains of iron core ferromagnetic materials are rearranged through the changed
magnetic field, so that the demagnetization effect on residual
magnetism of the transformer is achieved. The method comprises the following steps: drawing a
hysteresis loop in the demagnetization process of a transformer by collecting
voltage and current data in the demagnetization process, translating an end point of the
hysteresis loop to an original point, and judging the residual
magnetism direction and size of initial demagnetization according to the area of each quadrant of the
hysteresis loop; and then transformer demagnetization is carried out again, the residual magnetism direction and size of the first demagnetization are evaluated according to the hysteresis loop of the second demagnetization, and whether the residual magnetism is smaller than a threshold value is judged. According to the method, the direction and size of residual magnetism in the demagnetization process can be evaluated in real time, the demagnetization energy is dynamically adjusted, and sufficient demagnetization of the converter transformer is ensured.