Mechanism of wireless power transfer system waveform distortion caused by nonideal gallium nitride transistor characteristics

Abstract

Gallium nitride (GaN) field-effect transistors have low ON resistance and switching losses in high-frequency (>MHz) resonant wireless power transfer systems. Nevertheless, their performance in the system is determined by their characteristics and operation mode. A particular operating mode in a 6.78-MHz magnetic resonant wireless transfer system that employs class-D GaN power amplifiers in the zero-voltage switching mode is studied. Two operation modes, the forward mode and the reverse mode, are investigated. The nonideal effect under the device-level dynamic resistance and thermal effect are also analyzed. The dynamic resistance under different operation modes is demonstrated to have different generation mechanisms. Finally, the device characteristics with system operating conditions are combined, and the effects of temperature and dynamic resistance under different operating conditions are evaluated.

Dynamic Ron Effect in GaN HEMT in a Zero-Voltage-Switching Circuit Due to Off-Resonance Operation

“…1(a) shows a schematic of the WPT system. Ref [10] explains the details of this circuit. Rload is the equivalent resistance mapped to the transmission side from the receiver load.…”