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A novel centroid-based diagnostic method of the power switches in five-leg Voltage Source Inverter (VSI) is proposed in this paper. Using a vectorial multi-machine description, a five-phase drive presenting an opened switch or an opened phase faults has typical operating characteristics in comparison to classical three-phase drives. Based on such characteristics, this work aims to provide a simple and robust diagnostic process for switches fault regardless of the shape of the back-EMFs (harmonic components) and the transient states due to the load variation. Original theoretical developments are presented. Experimental results are shown to validate the proposed strategy.

Health monitoring and diagnosis of photovoltaic (PV) systems is becoming crucial to maximise the power production, increase the reliability and life service of PV power plants. Operating under faulty conditions, in particular under shading, PV plants have remarkable shape of current-voltage (I-V) characteristics in comparison to reference condition (healthy operation). Based on real electrical measurements (I-V), the present work aims to provide a very simple, robust and low cost Fault Detection and Classification (FDC) method for PV shading faults. At first, we extract the features for different experimental tests under healthy and shading conditions to build the database. The features are then analysed using Principal Component Analysis (PCA). The accuracy of the data classification into the PCA space is evaluated using the confusion matrix as a metric of class separability. The results using experimental data of a 250 Wp PV module are very promising with a successful classification rate higher than 97% with four different configurations. The method is also cost effective as it uses only electrical measurements that are already available. No additional sensors are required.

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This study deals with a mixed model-based and signal-based approach for sensorless speed-controlled induction motor drive (IM) and insulated-gate bipolar transistors open-switch fault diagnosis. In comparison to the classical sensored drive systems, this structure presents particular characteristics in post-fault operation mode which can be taken into account for fault detection and identification process designing. Firstly, the fault effects analysis is achieved in the abc frame of the IM. Based on such analysis, a diagnostic algorithm, using the measured and estimated currents, is used to define the fault indices, which allow the detection of single open-switch, multiple open-switch and open-phase faults. The sensorless control algorithm used for rotor speed estimation, as well as the fault diagnostic algorithm, are all based on a first-order sliding mode observer. In addition to the simplicity and the fast fault detection, there are no-additional sensors or extra-hardware used by the proposed method. Experimental results, based on a dSPACE DS1104 controller board and a 3-kW induction machine, are shown to validate the proposed strategy.

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This paper proposes a procedure that is suitable for experimental investigation of real-time open-switch and open-phase faults diagnosis of a five-leg Voltage Source Inverter (VSI) feeding a five-phase bi-harmonic Permanent Magnet Synchronous Machine (5-Φ B-PMSM). The algorithm is based on the specific characteristics of multiphase machines, which allows inverter fault detection with sufficient robustness of the algorithm in the presence of fundamental and third harmonic components. Firstly, the inverter fault effects analysis is achieved in the characteristic subspaces of the five-phase PMSM. Specificities that are interesting for the elaboration of a real-time Fault Detection and Identification (FDI) process are highlighted. Original and particular algorithms are used for an accurate two-dimensional normalized fault vector extraction in a defined fault reference frame. This frame is dedicated only for fault detection and identification. To ensure the high immunity of the FDI process against transient states, a particular normalization procedure is applied. The normalized diagnostic signals are formulated from the defined frame and others variables derived from the reference and measured currents. Simulation and experimental results of open-switch and open-phase faults are provided to validate the proposed algorithm. Index TermsSpace vector theory, multiphase systems, fault diagnosis, five-phase permanent magnet synchronous machine, inverter open-circuit fault.