Journal of the Korean Solar Energy Society ISSN:1598-6411(Print) 2508-3562(Online) 한국태양에너지학회 논문집

In 2021, the solar power generation capacity of South Korea was 14.6 GW, accounting for 71% of the total renewable energy generation capacity. The market for photovoltaic power conversion devices with high efficiency and power density is expanding rapidly in the country. Gallium Nitride (GaN), a compound semiconductor with a wide band gap, can be used under high voltage and current compared to silicon materials, resulting in its wide use in photovoltaic power conversion devices. Excellent heat dissipation performance of GaN-based devices should be achieved due to their significantly high power and efficiency. In this study, the heat dissipation characteristics of a PCB with FR4 (Flame Retardant 4) material composed of various heat dissipation structures for the effective heat dissipation of GaN-FETs for power conversion systems applicable to a 3 kW solar power generation system were investigated using thermal analysis. Part of the heat generated from the GaN-FET was directly dissipated on its surfaces to the external air, and the other part was transferred to the PCB through conduction and then discharged to the external air through convection on the surfaces of the PCB package. Via holes were considered to improve the heat transfer rate of the PCB in the thickness direction, and a heat sink was applied to expand the heat transfer area. In this study, the heat dissipation characteristics were investigated based on four types of heat dissipation structures of the PCB using the ANSYS transient thermal analysis program. The effect of via holes exposed to external air were analyzed using two types of heat dissipation structures. In addition, two other types of heat dissipation structures were analyzed to compare the top and top/bottom cooling of the PCB package. It was observed that the efficiencies of heat dissipation of the via holes that were unexposed to external air and in both the top and bottom cooling cases were more advantageous than that of the exposed holes and the top cooling case, respectively.