Effective Calculation Method Suggested for Large-caliber Magnetic Field Immunity Testing System of ITER

The results were revealed in IEEE Transactions on Industrial Electronics.

The research group was led by Prof. GAO Ge and JIANG Li. They studied the effect of coil offset on the performance of the large-caliber magnetic field immunity testing system for ITER (International Thermonuclear Experimental Reactor).

The magnetic field around the Tokamak device plays an important role in the safe operation of magnetic sensitive equipment. Different intensities will affect the normal operation of devices and equipment. As one of the effective ways to solve the strong magnetic compatibility test, the large- caliber magnetic field immunity testing system has attracted much research attention. The test device is a magnetic field generation system composed of multiple coils. The coil offset during design and installation will change the magnetic field performance of the internal test area.

"We built an experimental platform," said Huang Ya, first author of the paper.

To study the relationship between coil offset and magnetic field performance, the group conducted in-depth research on the 18 degree of freedom offset of three groups of coils.

After studying the influence of single and multiple variables, they improved the calculation method from the law of magnetic field distribution data, and completed the fast calculation of the maximum allowable offset under multiple parameters.

The experimental results verified the correctness of the theoretical analysis.

The factors they studied in this research included the large diameter magnetic field withstand test device, and the error caused by coil offset to the magnetic field uniformity.

In the paper, scientists described the calculation method of magnetic field caused by coil offset through coordinate transformation, and discussed the magnetic field performance distribution of single coil and two coils with different positions and angle offsets.

On the premise of more deviation variables, they proposed a reasonable method to determine the allowable deviation of equipment coil.

Aside from that, they summarized a set of novel formulas. These formulas provided a theoretical basis for the actual installation, and with the formulas, and the allowable offset of the required error could be easily calculated.

This work was supported by project funded by China Postdoctoral Science Foundation, and Natural Science Foundation of Anhui Province.

 Magnetic field distribution around tokamak (Image by HUANG Ya)