This article proposes a noninvasive open-switch faultdetection method based on the analysis of the high-frequency signals. The faulty power switch is detected by metering the emitted near-field above a new topology u...
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This article proposes a noninvasive open-switch faultdetection method based on the analysis of the high-frequency signals. The faulty power switch is detected by metering the emitted near-field above a new topology using the wavelet packet transform and considering a complex control algorithm. The proposed method is tested on a single-phase five-level packed U-cell (PUC5) inverter. The latter is controlled using the finite-control set model predictive control (FCS-MPC) technique that generates the gate signals with a variable switching frequency. Moreover, unlike the conventional pulsewidth modulation strategy, the switching pattern provided by the FCS-MPC technique is not known in advance. Despite these complexities, the proposed faultdetection method proves its high performance and effectiveness. Experimental studies are carried out on a single-phase PUC5 inverter using the real-time controller (OP4510) from OPAL-RT and prove the capability of this method to properly identify the faulty switch in this multilevel topology.
An open-circuit insulated-gate bipolar transistor faultdetection technique for cascaded H-bridge (CHB) multilevel converters is presented in this paper. This technique, designed to be implemented independently for ea...
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An open-circuit insulated-gate bipolar transistor faultdetection technique for cascaded H-bridge (CHB) multilevel converters is presented in this paper. This technique, designed to be implemented independently for each CHB leg, utilizes one current sensor and one voltage sensor to monitor a leg's current and output voltage. Measured voltages are compared to expected voltages, and deviations are used to determine open-circuitfault locations based on the deviation's magnitude and current flow direction. Once potential fault locations have been identified, the fault location is systematically isolated and then verified, reducing the possibility of unnecessary corrective actions due to fault misidentification, e.g., an intermittent gate-misfiring fault being classified as an open-circuitfault. The proposed technique can be implemented for any number of cells, is independent of the pulse width modulation strategy used, and can be applied to symmetric and asymmetric CHB converters regardless of the cell input dc-source magnitudes utilized, i.e., cell input voltages are not required to be equal or to exist in specific ratios. For a CHB leg with M cells, the proposed technique identifies and isolates open-circuit switch faults in less than 2M measurement (sampling) cycles, and verification is completed in less than one full fundamental cycle. Experimentally obtained data demonstrate the efficacy of the proposed faultdetection and isolation technique.
Reliability of power converters is of crucial importance in switched reluctance motor drives used for safety-critical applications. open-circuitfaults in power converters will cause the motor to run in unbalanced sta...
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Reliability of power converters is of crucial importance in switched reluctance motor drives used for safety-critical applications. open-circuitfaults in power converters will cause the motor to run in unbalanced states, and if left untreated, they will lead to damage to the motor and power modules, and even cause a catastrophic failure of the whole drive system. This study is focused on using a single current sensor to detect open-circuitfaults accurately. An asymmetrical half-bridge converter is considered in this study and the faults of single-phase open and two-phase open are analysed. Three different bus positions are defined. On the basis of a fast Fourier transform algorithm with Blackman window interpolation, the bus current spectrums before and after open-circuitfaults are analysed in details. Their fault characteristics are extracted accurately by the normalisations of the phase fundamental frequency component and double phase fundamental frequency component, and the fault characteristics of the three bus detection schemes are also compared. The open-circuitfaults can be located by finding the relationship between the bus current and rotor position. The effectiveness of the proposed diagnosis method is validated by the simulation results and experimental tests.
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