Bamboo-inspired metamaterials design: Microstructure dielectrophoretic orientation for enhancing insulation performance of advanced power modules

The application of nonlinear conductivity coatings in high-voltage power module is a promising strategy for significantly improving electrical insulation performance. The core of the improvement principle is that the nonlinear conductivity realizes a dynamic optimization of the discharge risk inside the material. The realization of this nonlinear conductivity requires sufficient microscopic arrangement of fillers that align with the macroscopic insulation structure. However, conventional methods fail at precise arrangement control so that typically require high filler concentration, which markedly increases dielectric loss and leakage current. Drawing inspiration from the bamboo structure, metamaterials offer an efficient tuning of nonlinear characteristics with lower filler concentrations through thoughtful design. In this context, we introduce a novel approach to fabricate SiC whisker / silicon elastomer metamaterial coatings leveraging the dielectrophoretic effect. Comprehensive testing of the physical and chemical properties of the composites confirmed the successful preparation of the material. And the metamaterial exhibits excellent nonlinear conductivity and low dielectric loss across various temperatures. Notably, after applying the metamaterial coating, the maximum electric field stress within the power module was reduced by nearly ten times, and the partial discharge inception voltage (PDIV) increased by 58.9 %, 74.7 %, and 32.8 % at 30 °C, 60 °C, and 90 °C, respectively. From solid physical mechanism to exquisite material design and practical device-level implementation, this study offers valuable insights into enhancing the insulation performance of power module and demonstrates substantial potential for further industrial applications.