Effect of Different Coating Materials on Partial Discharge Characteristics and Electrical Tree of Printed Circuit Board

Printed Circuit Boards (PCBs) are commonly used in power devices. With the development of power electronic technology, the performance of PCBs cannot meet the demand for high switching rates and high-power devices. Some cases of PCB insulation failure are often discovered in power devices. Among them, deterioration in the PCB layer is a very common problem. However, the process of deterioration cannot be observed because of the opacity of PCB. Based on the double-layer PCB, different insulation materials are used to study how the surface insulation material affects PCB degradation. In this paper, the electric tree growth and partial discharge characteristics of different epoxide materials combined with copper-clad laminate were compared and analyzed, and the difference in insulation characteristics was analyzed by pulse sequence analysis (PSA) and phase-resolved partial discharge (PRPD) pattern. It is found that the discharge characteristics of different materials can be qualitatively judged by the shape of the dV (voltage differences) plot and the distribution of dV. The changes of partial discharge inception voltage can correspond to apparent charge, thus reflecting the insulation properties of materials.