A Multitime-Scale Analytical Model of ZVS Buck Converter

This article presents a modeling method to build a complete and accurate multitime-scale analytical model for low-voltage eGaN HEMTs-based zero-voltage switching buck converter with consideration of parasitic inductors, nonlinear junction capacitors, and nonlinear transconductance. The switching steady-state modes and switching transient modes are discussed in detail based on their corresponding equivalent circuits. The state equations of each mode are solved by MATLAB software to obtain the key operating waveforms throughout one switching cycle. Moreover, the established switching steady-state model and switching transient model are numerically merged together through continuous state variables, and then the multitime-scale model for stable operation is formed based on the iterative method. The waveforms and switching energy losses predicted by the model within one switching cycle are compared with the experimental results, respectively, to verify the accuracy of the model. In the end, the dead time is optimized based on the proposed model, and the optimization result is verified to be effective in reducing the switching energy loss through the experiment.