Investigation of Effects of Rising and Falling Time, Ringing Phenomena and Dead Time in GaN Inverter on Iron Loss with Very High Sampling Rate

Abstract

Although general impacts of the ringing phenomena occurring at dozens of megahertz and the rapid rising time in several nanoseconds in voltage waveform of the gallium nitride-field effect transistor (GaN-FET) inverter on the iron loss in ring core tests were considered in some recent studies, those works only used oscilloscopes with a medium sampling rate (e.g. 100 MS/s), which may cause the analysis and evaluation to be not really sufficient and correct. Hence, our paper investigates the detailed relations and effects of the rising time, falling time, ringing phenomena and voltage spike at many pulses in voltage waveform on the iron loss in a ring core under the GaN-FET inverter excitation using a top-notch oscilloscope with a very high sampling rate of 10 GS/s for measurement. Furthermore, the unique characteristics of the input current in negative and positive ranges relating to the ringing phenomena are considered as another novelty and contribution of this research. Moreover, the relations between the total harmonic distortions of the magnetic flux density and input current with the iron loss are examined. The effect of large changes in the dead-time of GaN-FET devices on the iron loss of the ring core is also examined.