Multifunctional Magnetic Nanocomposite Encapsulant for Electromagnetic Interference Shielding in Power Electronics

As power densities and switching frequencies dramatically increase in wide bandgap power electronics, EMI increasingly impacts power conversion efficiency and reliability, which requires mitigation for effective operation. Herein, we propose a nanocomposite encapsulant created by directly incorporating magnetic iron oxide nanoparticles into a silicone matrix for the purpose EMI shielding. The addition of small amounts of particles to the silicone resulted in a 1.7 dBµV drop in EMI intensity; however, the addition of the iron oxide reduced the dielectric breakdown strength of the silicone matrix by 83% with respect to concentration. Further efforts to optimize the dielectric properties of the nanocomposites with respect to the nanoparticle loading is necessary to directly apply this technology; yet the results indicate magnetic nanocomposites could be a potential avenue towards mitigating EMI in power devices.