Fault diagnostic algorithm for three-level neutral point clamped AC motor drives, based on the average current Park's vector

• Published in: IET power electronics Vol. 7; no. 5; pp. 1127 - 1137
• Main Authors: Mendes, Andre M. Santos, Abadi, Mohsen Bandar, Cruz, Sérgio Manuel A
• Format: Journal Article
• Language: English
• Published: Stevenage The Institution of Engineering and Technology 01.05.2014; The Institution of Engineering & Technology
• Subjects: AC motor drives; Clamping; current sensor; Diagnostic systems; electric current measurement; Fault diagnosis; IGBT; insulated gate bipolar transistor; insulated gate bipolar transistors; inverter output current period; Inverters; Mathematical analysis; motor line current measurement; motor supply current waveform; Motors; neutral‐point clamped inverter; normalised average current Park vector approach; power convertors; semiconductor open‐circuit fault diagnostic technique; Semiconductors; three‐level neutral point clamped AC motor drive; vectors; Vectors (mathematics); voltage sensor; fault diagnosis; power convertors; voltage sensor; insulated gate bipolar transistors; motor supply current waveform; neutral-point clamped inverter; current sensor; insulated gate bipolar transistor; vectors; IGBT; inverter output current period; semiconductor open-circuit fault diagnostic technique; normalised average current Park vector approach; electric current measurement; motor line current measurement; three-level neutral point clamped AC motor drive; AC motor drives
• ISSN: 1755-4535; 1755-4543
• DOI: 10.1049/iet-pel.2013.0416

This study presents a new fault diagnostic technique for a semiconductor open-circuit fault in a neutral-point clamped inverter, based on the average current Park's vector approach. This method relies on the measurement of two motor line currents and is able to perform a complete diagnosis in less than half of the inverter output current period. The implementation of this diagnostic technique requires no additional current or voltage sensors besides the ones already used by the control algorithm of the converter. The diagnostic method uses the modulus and angle of the normalised average current Park's vector to detect the fault and identify the faulty insulated gate bipolar transistor (IGBT) pair, respectively. Simultaneously, the normalised average values corresponding to the positive and negative parts of the motor supply currents waveforms are used to identify the inner faulty IGBTs with even and odd numbers, respectively. The diagnostic method is also robust to transient conditions imposed by load and speed variations. The performance and effectiveness of the proposed diagnostic technique are validated both by the simulation and experimental results.