  Power electronic equipment regulated by the International Thermonuclear
Experimental Reactor (ITER) organization must pass the relevant steady-state
magnetic field immunity test. The main body of magnetic field immunity test is
magnetic field generator coil. Through mathematical derivation in this paper,
the magnetic field calculation formulas of four-coil configuration under ideal
and actual models are obtained. The traditional method of magnetic field
performance calculation is compared with the general formula method under the
ideal model. A global parameter optimization method based on Lagrange
Multiplier by KKT conditions is proposed to obtain the coil parameters of
high-uniformity magnetic field. The magnetic field distribution in the uniform
zone is revealed by the finite element method. The model analysis is proved to
be correct and effective by experimental results. The research of this paper
provides a practical scheme for the coil design with high magnetic field and
high-quality uniformity.
