A Design Method of High-Constrained and Anti-Disturbance Coil for Magnetic Shielding Rooms

Magnetic compensated coils are extensively used in magnetic shielding rooms (MSRs) to eliminate residual magnetic fields as well as low-frequency magnetic disturbances. Moreover, the target field method (TFM) is usually utilized for designing the coils within complicated and confined spaces, while the image method (IM) is often adopted to reduce the distortion generated from the interactions between the coils and magnetic material. However, the higher order components of the stream function in conventional TFM contribute to the inhomogeneity of the field, which can be constrained by the Taylor expansion method (TEM). Consequently, this study proposed IM&TFM&TEM to enhance the uniformity of the ideal field. Particle swarm optimization (PSO) algorithm and nonlinear programming solver (fmincon) were applied to solve the coefficients that determine the winding of the coils. Subsequently, two pairs of biplanar uniform field coils were designed for both residual field and low-frequency (less than 5 Hz) magnetic noise compensation, and their effectiveness was verified by simulation analysis and experimental validation. The results showed that the uniformity of the static field in the target region was improved and the dynamic irregular field was compensated by introducing the proportional-integral–derivative (PID) algorithm.