Multi-Objective Optimization Control Strategy for SiC/Si Hybrid Switches

This paper presents a multi-objective optimization control strategy for SiC/Si hybrid switch (HyS) based on its electro-thermal coupled loss model. The new control method aims to achieve the highest conversion efficiency under light to medium load condition and balanced junction temperatures under heavy load condition by dynamically adjusting the turn-off delay time between the MOSFET and IGBT. An analytical electro-thermal power loss model is developed for the hybrid switch. Experimental results on a 8kW, 20kHz DC/DC buck converter using SiC/Si hybrid switches demonstrate that the new control strategy achieves 18% higher maximum power handling capability and 30
^o
C lower maximum junction temperature (at 8kW output) than the fixed delay time control approach previously reported. In addition, the conversion efficiency increases by 0.3% under light load condition (at 4kW).