Analytical Power Loss Model for GaN transistors

An analytical switching losses model of the power semiconductor devices is a precise and simple way to evaluate and optimise the efficiency of power electronic converters; which are one of the most important parts of electrical vehicles (EVs) because they work as the interface between the elements in the electric power train and the energy storage systems. These models allow to predict and enhance the performance of the converter, by giving the ability to optimise the losses, thus increase the efficiency and the reliability of the converters and the EV system. Given their suitability for high-frequency power applications, Gallium Nitride (GaN) High Electron Mobility Transistors (HEMTs) are a widely used solution, yielding high power density levels at the full system. However, this also increases the impact of the effect of parasitic elements in the device on the turn-on and off transitions at the switching operation. In this paper, a simple analytical model for GaN transistors is provided. The switching waveforms are divided into multiple stages to simplify the analysis and to help in getting a more accurate model. Using the proposed model the switching losses can be calculated, and the switching transitions can be predicted precisely. The novelty of this work is the ability to calculate the current overshoot which makes it possible for a better switching losses estimation. The results will be compared with simulation results, which were done using LTspice software.