Reliability of Magnetic Sensors under Transient Electromagnetic Interference and High Temperature

In smart grids, the magnetic sensors encounter reliability issues due to transient electromagnetic interference (EMI) and elevated temperature. In this work, we employed the finite-element method to simulate the reliability of current sensors used in gas-insulated substations under strong EMI and high temperature. By utilizing a damped oscillatory wave as the excitation source, the effect of the copper shielding layer on the induced electromagnetic field in the sensor chip was analyzed through simulation. We found that the induced electromagnetic field responses at the chip and bonding wires exhibit damped oscillatory waves as the excitation source. Interestingly, the intensity of induced electromagnetic field is substantially reduced by introducing the copper shielding layer, indicating effective anti-EMI. The thermal stress–strain simulation shows that the severe stress concentration (310.31 MPa) occurred at the bonding interfaces due to mismatch of the coefficients of thermal expansion. We design a cavity-integrated packaging structure that can reduce the stress by 74.6% and the wire deformation by 32.4%. To diminish both the EMI and the thermal stress/strain, a novel packaging structure consisting of a 3D-printed resin framework filled with electromagnetic shielding materials is proposed. This work provides useful guidance for the packaging design to improve the reliability of magnetic sensors in smart grids.