Design and analysis of power semiconductor test circuits

As the demand for electricity grows rapidly nowadays, power semiconductor devices managing ascending power consumption have become indispensable. The requirement of high power density increases, hence power electronics converters possessing the capability of large current and high switching frequency are now leading the developing trend. Therefore, obtaining accurate data of in-use devices and circuits should be greatly concerned. For the purpose of characterising the emerging power semiconductor, two test circuits have been implemented which possess one of two mainstream current sensing devices respectively. With the significantly high bandwidth, the coaxial shunt resistor is applied in current mensuration for accuracy in the first version of power semiconductor test circuit. However, to address the high current measurement, current transformers are introduced to the second version which provide the necessary galvanic isolation and relatively low disturbance while measuring large current. In this paper, a characterization of high speed switching series IGBT (IKW20N60H3) has been done on both versions under a conventional 400V/20A rated condition. Both the switching characteristics of high speed 600V-IGBT and the reverse behavior of its parallel diode have been observed and recorded with the experimental waveform tested by two current sensing devices respectively. The comparison concludes that the coaxial shunt resistor is a excellent candidate for measuring low current while the current transformer is more suitable for high current identification.