Dead Time Adaptive Control for Efficiency Improvement of GaN Transistor Based SPWM Modulated Inverter

Application of GaN transistors into design of three phase inverter can increase the efficiency. Further increase in efficiency can be achieved if the dead time is optimized since GaN transistors have higher voltage drop in reverse conduction region. The paper proposes adaptive change of dead time value during the period of sinusoidal current since optimal dead time depends on load current. Based on LT Spice simulation model and experimental measurements optimal dead time values at different load currents have been determined and look up table for implementation into microcontroller has been created. GaN based inverter was tested with adaptive dead time control pulses. Thermal measurements and simulation results show improvement of the efficiency of the inverter. The temperature of the transistors was reduced by 2 degrees Celsius after implementation of adaptive dead time.