Application and Performance Analysis of Hollow Cores in Lightweight Design of Induction Coil Sensor

Conventional induction coil sensors are typically large and heavy, but the lightweight design of satellite-borne induction coil sensors is necessary and important due to the limitation of the satellite's volume and mass. Numerous finite element simulations, low-noise amplification circuit designs, and systematic tests are conducted in this study to effectively demonstrate the feasibility of replacing solid cores with hollow ones for achieving lightweight magnetic core designs. It is found that when the core hollow ratio is taken as 0.6 and 0.9, the magnetic flux can be achieved as 99% and 95% while the mass is reduced by 36% and 81%, respectively. Meanwhile, the sensitivity of the solid core increases instead when it is properly hollowed out, and further studies show that there is a negative correlation between the length-to-diameter ratio of the solid core and the optimal hollowing ratio corresponding to the maximum sensitivity. The distal attenuation of the magnetic permeability of hollow cores is better than that of solid cores, which is favorable for the winding of induction coils. Our experimental results are in good agreement with the simulated ones, which shows that proper hollowing can achieve almost the same or even better magnetic field concentration effect as that of solid cores of the same size while significantly decreasing the weight of the cores. Our results provide a potential solution for the lightweight design of induction coil sensors.