Simulation Analysis of Magnetic - Sensitive Sensors under Transient Strong Electromagnetic Interference and High Temperature and Optimization of Packaging Structures

In smart grids, magnetic-sensitive sensors encounter reliability issues due to transient electromagnetic interference (EMI) and elevated temperatures. This study employs the finite-element method, focusing on current-testing sensors used in gas-insulated substations. By utilizing a damping oscillation wave as the excitation source, a simulation analysis compares the epoxy-molding compound's performance both with and without a copper shielding layer. Findings reveal that, in the absence of a shielding layer, the electric field, magnetic field, and current density responses at the detection points of the chip and bonding wires exhibit damping oscillations correlating with the excitation source. However, introducing the copper shielding layer substantially diminishes these metrics, suggesting its effective role in obstructing interference. Furthermore, a temporal correlation exists between the sensor's electromagnetic field and current density and the excitation source's waveform. When simulating in a high-temperature environment, the sensor's internal stress distribution becomes notably uneven, with pronounced stress concentrations at the gold wire-chip bonding points and solder joints. Notably, deformation is primarily observed in the center of the epoxy-molding compound and at the bonding wires. To mitigate these challenges, a novel packaging structure is introduced. Its shielding body, crafted from 3D-printed resin and filled with electromagnetic shielding materials, offers both electromagnetic shielding and a reduction in thermal expansion-induced stress and strain. Concurrently, a multi-layered shielding design is suggested to amplify the shielding efficacy, serving as a benchmark for sensor optimization.