A method to quantitatively regulate the magnetization state of magnetic shielding device for reducing the static residual field

Magnetic shielding devices isolate the geomagnetic field with high-permeability soft magnetic material. Researchers adopt external compensation method to further reduce the static residual field. The common method is to apply continuous DC compensation magnetic field outside the shielding layers to offset the geomagnetic field. It aims to create a weak magnetic field environment by active approach. The prolonged intervention of the DC compensation system raises the energy consumption and increases the instability factors of the residual field. In this study, a method to quantitatively regulate the magnetization state of magnetic shielding device is proposed, which is achieved with a short-duration regulation magnetic field generated by external compensation coils. It enhances the ability of the magnetic shielding device to resist the geomagnetic field. The waveform of regulation magnetic field is designed based on the source analysis and variation model of the residual field. It is verified by a single-layer cubic magnetic shielding device. The results show that the static residual field at the center point and within the test region decreased by 86% and 57.7% comparing with the initial value, the energy consumption and the stability of residual field are improved comparing to the DC compensation method.