Offline Health Diagnosis of Power Device Based on Nonintrusive Inductively Coupled Approach

Understanding the causes of a power device's defect plays a crucial role in failure and reliability analyses, and hence, the need of health diagnosis. Health diagnosis involves the measurement of predefined electrical parameters of a power device under its usual operating condition and the analyses of their deviations from their norms. Instead of the conventional direct measurements of voltage and current waveforms in time domain, this paper proposes a nonintrusive measurement method that measures the ON-state impedance of a power device in frequency domain. The proposed method eliminates direct electrical contact with the device-under-test, and it has the ability to detect the deviation of the ON-state impedance from its norm for health diagnosis purpose.