Investigating the Analytical Model of GaN HEMT Device to Identify the High-Frequency Oscillation in Bridge-Leg Circuits

The potential of Gallium Nitride (GaN) wide band gap (WBG) power semiconductor devices has been extensively investigated in recent years. The superior figure-of-merits of GaN high electron mobility transistors (HEMT) over contemporary devices like Si MOSFET and Silicon Carbide (SiC) MOSFET gives an edge in power electronics-based industrial applications. However, the privilege of fast switching frequency and low conduction resistance are intimidated by the crosstalk oscillation issues that occur during the switching transients. Therefore, a comprehensive analytical model of the GaN HEMT device based on the Double Pulse Test (DPT) circuit is developed and analyzed thoroughly using the high-frequency equivalent circuit In this paper, the analytical model is developed considering the profound effect of different parasitic elements which includes the gate loop inductance and the stray power loop inductance. Model equations for the current and voltage are derived using the circuit conditions in the Laplace domain, and their nature of oscillation is observed. The simulation of the GaN devices using the DPT circuit is performed in LTSpice and derivation and analysis of model equations of current and voltage for the DPT is done in MATLAB.