Temperature Measurement of Pulsed Inductive Coil Continuous Discharge Based on FBG

Pulse inductor coils can generate pulsed strong magnetic fields, which can be used in electromagnetic emission, electromagnetic molding, pulse power supply, and many other fields. Coils usually work in extreme physical environments with strong magnetic fields, high temperature rises, and large impact forces. When the temperature exceeds the glass transition temperature of the insulating material, it will accelerate the aging of the insulating material and shorten the service life of the coil, so the coil temperature needs to be accurately measured. The wire inside the coil is a heat source, and the surface temperature of the wire needs to be measured directly. However, the interface is difficult to access and requires any sensor to tolerate electromagnetic interference, extreme temperatures, and high currents. The development of fiber Bragg gratings (FBGs) offers a potential solution to this requirement. Since FBG is sensitive to temperature and stress, in order to eliminate the influence of electromagnetic force, a steady-state temperature test platform is first built, and the change law of optical fiber wavelength change with temperature is obtained. Then, a 2-D coupled heat transfer model of a pulsed inductor coil is established, and the temperature change of the coil under continuous discharge conditions is calculated and compared with the measurement results. The results show that the error between the simulation data and the test data under different discharge times is small, which proves the feasibility of the proposed method, and the sensor can be used for coil continuous discharge test.