Time- and Frequency-Domain Characterization of Switching Losses in GaN FETs Power Converters

Abstract

This paper presents a methodology for the timefrequency characterization of switching losses in Gallium Nitride Field Effect Transistors used in power electronics applications, particularly in DC-DC converters. Typically, switching losses are measured in the time-domain through the integration of the instantaneous power, that is, the product of the voltage multiplied by the current, during the turn-on and turn-off transients. Nonetheless, as novel power transistors allow for switching times in the nanosecond range, the accuracy of such measurements is compromised by the limitations of the probe-oscilloscope systems in terms of bandwidth and dynamic range. Here, we analyze the time-domain switching loss measurement method, and then, through a complementary setup we demonstrate how to validate the results in the frequency domain. A DC-DC half-bridge buck converter circuit based on the EPC2001C was used as a representative test sample. Less than 1% of difference in critical parameters such as rise-time, pulse width, state-levels and, switching frequency, is encountered between the time and frequency domain approaches. Moreover, the measurement uncertainty was analyzed and estimated to be between ±1% and ±8%. This work allows for highly confident switching loss measurements, a better understanding of the switching phenomena and of the measurement system performance.

A novel algorithm for open switch fault detection and fault tolerant control of interleaved DC‐DC boost converters

“…On the other hand, note that the switching losses are proportional to the peak amplitude of the switches currents and their frequencies [20]. When a double OCF occurs and the phase and frequency of the PWM signals are changed according to the proposed algorithm, both the peak current and the frequency of the remaining healthy phases are doubled, and hence, the switching losses are quadrupled.…”

GaN and SiC Device Characterization by a Dedicated Embedded Measurement System

“…The development of a switching power converter board based on wide band-gap (WBG) semiconductors brings numerous performance advantages while also opening up many issues [1]; the most important ones are related to modelling [2,3], losses in both switching [4,5] and conduction operation [6], and EMI (ElectroMagnetic Interference) effects [7]. In fact, such devices, particularly those based on GaN which allow higher switching frequency compared to traditional silicon devices, require a more detailed knowledge of the device and layout parasitics and can generate conducted and radiated emissions.…”

“…In fact, such devices, particularly those based on GaN which allow higher switching frequency compared to traditional silicon devices, require a more detailed knowledge of the device and layout parasitics and can generate conducted and radiated emissions. With reference to switching losses, in [4,5], the lack of suitable models for estimating such losses is highlighted; in addition, measurements have to consider the probe-oscilloscope system to guarantee the fidelity in measuring the voltage-current waveforms. Measures are necessary to supply the lack of complete models; on the other hand, it is fundamental not to forget that the rise time is in the nanosecond range.…”

“…Measures are necessary to supply the lack of complete models; on the other hand, it is fundamental not to forget that the rise time is in the nanosecond range. As a consequence, the waveforms contain spectral component up to about 1 GHz [4], resulting particularly challenging for the current sensor bandwidth [8] and the related converter design [9]. With reference to conduction losses, the attention is focused on the conduction resistance R DS,on of the devices.…”