In the field of electric aircraft, passing the RTCA DO-160G Section 24 “Icing test” is one of the specific requirements to realize electrification for aircraft power train with high reliability. "No Icing and Bedewing" inside the inverters were considered as a safe side criterion for the standard in this study. To achieve this criterion, we proposed "Sealed inverter filled with low humidity atmosphere", which is realized by the “two functional sealings with flexible and moisture proof material”. “Icing test” in DO-160G was performed with the prototype of high voltage inverter applied the proposed sealing structure. As a result, no icing and bedewing were proved for prototype inverter applied the proposed inverter package, which contributes to the environmental reliability of insulation properties.

Previously, the authors have proposed a contactless probe-type current sensor with low insertion impedance. In this paper, the insertion impedance of the proposed current sensor at high frequencies are clarified. Then, we measured the actual high-speed switching current flowing through a GaN device and compared the measured waveforms with those of a coaxial-type shunt resistor. Comparison of the measured waveforms showed that the coaxial shunt resistor exhibited ringing in the waveform due to the effect of insertion impedance, but the proposed current sensor exhibited less ringing, indicating that the measurement is minimally invasive to the circuit under test.