On performance evaluation of high-power, high-bandwidth current measurement technologies for SiC switching devices

Silicon carbide (SiC) power metal-oxide-semiconductor field-effect transistors (MOSFETs) switch at an unprecedented speed, even at high currents. For accurate dynamic characterization, current sensors must measure high currents at a high bandwidth. Moreover, at high switching speeds, parasitic impedances in the commutation loop become critical. To ensure high-accuracy measurements, the current sensor insertion impedance must be minimal. Here, a two-step current sensor evaluation method is proposed. This method serves the characterization and suitability assessment of high-power, high-bandwidth current sensors for fast-switching applications using SiC power MOSFETs. Conducting a small- and a large-signal transmission behaviour analysis separately results in holistic information about the current sensor behaviour in both time and frequency domain. The proposed method is validated using four commercially available current sensors that are widely used for SiC power MOSFET characterization. The work concludes transferring the knowledge derived in the conducted experiments to a practical, application-oriented sensor selection guide. This work proposes an evaluation method for high-power high-bandwidth current sensors. This method enables the suitability assessment of current sensors for accurately measuring device currents of fast-switching silicon carbide power metal-oxide-semiconductor field-effect transistors. The proposed method employs an established frequency-domain analysis at small-signal excitation levels, but extends this to a time- and frequency-domain analysis at high switched currents at a fast switching speed to more comprehensively determine the current sensor transmission behaviour. image