Switching Transition Modeling of eGaN HEMT in Power Converters

Selection of power switch driver resistance is crucial for power converter design, and an improper resistance value can lead to reduced efficiency and undesired operational behavior such as over-voltage and false turn-on. To select appropriate resistance, this letter proposes an accurate switching transition modeling method for switches in DC-DC converters, which can help guide engineers design switch drivers. For a converter with multiple components, i.e., a high-order converter system, the traditional analytical methods become very complex due to a large number of operating modes. To alleviate this problem, in the proposed modeling method, all nonlinear switches are modeled as linear systems, and various operating modes are combined into one mode in the proposed model. With the simplified mode, the driver parameters can be easily obtained. To verify the proposed model, we take the enhanced gallium nitride high electron mobility transistor (eGaN HEMT) high-order DC-DC converter as an example for experimentation. The eGaN HEMT is highly sensitive to parasitic parameters and switching frequency, and thus the high-order converter can demonstrate the ease of design with the proposed modeling method. Experiments on a Z-source converter and a quadratic-boost converter validate the feasibility of the proposed modeling method.