Experimental and Finite Element Analysis of Epoxy-Based Composites for Packaging Materials to Reduce Electric Field and Power Loss Under AC and DC Conditions

This work focuses on the performance of epoxy microcomposites, nanocomposites, and micro–nano hybrid composites as the packaging material of the power modules. The experiments consist of thermal conductivity, differential scanning calorimetry (DSC), space charge, dc electrical conductivity, thermally stimulated depolarization current (TSDC), and dielectric spectroscopy measurements. Moreover, the ac stationary electric field simulation and the dc transient electric field simulation are performed to analyze the electrical performance of the epoxy composites as the packaging materials in the power module structure under ac voltage and dc voltage, respectively. The ac field simulation uses dielectric spectroscopy data to obtain the electric field and power loss of the epoxy composites at different temperatures and frequencies under the ac voltage. On the other side, the dc electrical conductivity and TSDC experiment data are used for the dc transient electric field simulation to obtain the electric field considering the space charge under the dc voltage. The results show that the optimal addition of the filler content (20 wt% micro-AlN and 5 wt% nano-AlN) in the epoxy micro–nano hybrid composites can reduce the power loss and electric field at 150 °C and 1 MHz, under the ac condition. Furthermore, considering the space charge under the dc voltage, the electric field can also be reduced in epoxy micro–nano hybrid composites compared to pure epoxy.