GaN-HEMT Power Module of Aluminum-Clad Printed Circuit Boards for Small Power Loop Inductance and High Cooling Performance

Gallium nitride high-electron-mobility transistors (GaN-HEMTs) are promising for high-speed switching capability and small
on
-resistance. However, large turn-
off
surge and limited cooling capability due to their small chip size are hindering their application to high power conversion. To solve these problems, this letter proposes a novel power module structure with small power loop inductance and small thermal resistance based on recently proposed power module structures. The proposed structure comprises two aluminum-clad printed circuit boards (PCBs) that sandwich the GaN-HEMT devices. These PCBs generate eddy current inside the aluminum base to reduce power loop inductance and provide an additional thermal path to improve the cooling performance. These features were tested by an experiment that compared 3-kW half-bridge prototype power modules of the proposed and conventional structures. As a result, the proposed structure revealed power loop inductance of 1.4 nH and thermal resistance of 0.72 K/W, which corresponded to a reduction by 53% and 20%, respectively, compared to the conventional structure.