Open-Circuit Fault Detection and Isolation Method for Five-Level PUC Inverter Based on the Wavelet Packet Transform of the Radiated Magnetic Field

This article proposes a noninvasive open-switch fault detection 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 fault detection 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.