High-frequency wireless charging system study based on normally-off GaN HEMTs

The Gallium nitride high electron mobility transistor (GaN HEMT) has become popular in the power electronics industry as it offers the possibility to reach lower switching loss and higher switching frequency compared to Si devices. This paper adopts a normally-off GaN HEMT in the wireless power transfer (WPT) system to charge a 48V battery pack on the E scooter. 178W power was delivered to the battery pack with 813 kHz switching. A simulation model of GaN HEMT is also built in LTspice to itemize the system loss. At the end some thoughts of improving the system efficiency were proposed.