摘要: Insulation performance of high voltage IGBT modulesis one of the key attributes in power system applications.However, the existing standards of IGBT devices and research onthe evaluation of insulation performance of high voltage IGBTmodules are insufficient; for example, partial discharge resistanceunder DC voltage blocking condition is not considered. In thispaper, a new test was proposed to allow the measurement ofpartial discharges in all the components of IGBT modules underDC voltage. The topology of the measuring circuit is arrangedin the polarity discrimination way to exclude the interference,and the voltage and discharge current waveforms during thepartial discharge process are measured by the wideband timedomain measurement technique. According to the proposed test,the discharge phenomenon of the IGBT modules below the ratingvoltage were detected. A comprehensive waveform analysis on thevoltage and discharge current was performed, and the influenceof the applied voltage on the waveform parameters was obtained.The waveform parameters are influenced by the applied voltageand insulation structure, which enables the discrimination of thecauses of the observed partial discharge in the IGBT moduleunder DC voltage by the waveform analysis technique. Basedon the waveform analysis technique, the types and causes of theobserved partial discharges were discussed and inferred, and thecorrectness of the inference was further verified by observation.The proposed test and waveform analysis technique provide thepossibility to evaluate and distinguish partial discharges in thehigh voltage IGBT module under DC voltage, which may behelpful to insulation performance evaluation and insulation defectdiagnosis in high voltage IGBT module.