Ross Liederbach with advisers P. Krein and R. Pilawa-Podgurski
Wide bandgap device materials offer promising attributes for power conversion at high temperatures. Peak junction temperatures for power electronic devices are in the realm of ~250 °C. This project is looking to identify a complete converter system for high ambient temperature operating conditions. Gallium nitride (GaN) power transistors should theoretically be able to withstand these extremes, but transient operation of these devices across a temperature range has not yet been thoroughly investigated. Characterizing the transient changes in switching devices through a wide temperature range allows for better system design and controls implementation. However, due to the complexity of a high-temperature system, i.e., finding suitable high temperature solders or attachment materials, mismatched thermal expansion coefficients across circuit materials, and a lab setup that will tolerate these temperatures, little research and experimentation has been done.
Many material and device characteristics change with temperature, and this holds for circuits as well. Accounting for these changing characteristics across all components requires additional design consideration to ensure an operational system capable of wide temperature range power conversion. Currently, a basic half-bridge circuit, shown in Figure 18, has been designed and is operational at room temperature. Further experimentation includes verifying the fidelity of measurements using high-temperature wire before increasing environmental temperature and processed power. This project, supported by a National Science Foundation Graduate Research Fellowship and NASA, sets the stage for further circuit development across a wider temperature range, including cryogenic operation.