“High-Accuracy Fault Detection and Compensation in Boost Converters: An Observer-Based Approach With 3-Sigma Threshold”

Abstract

The main benefit of fault detection in static converters is to increase operational safety, reliability, and system lifespan while reducing downtime, costs, and material or human risks. The general problem is to ensure the safe, continuous, and efficient operation of static converters despite the presence of faults by detecting them in time and compensating for them without excessively degrading the system. This paper presents a fault detection and active sensor fault-tolerant control (FTC) strategy for a DC–DC Boost converter integrated in DC power conversion applications. The Boost converter is modeled using its average state-space representation. A sensor fault is injected as a sudden 50% gain increase between 80 and 120 ms. A Luenberger observer is designed to estimate the inductor current and generate a residual signal for fault detection. A fixed threshold based on the 3-sigma method is used to trigger the fault flag. Once the fault is detected, an FTC mechanism replaces the faulty measurement with the observer’s estimate to ensure system stability. Simulation results in MATLAB validate the proposed approach. The statistical threshold ensures instantaneous fault detection (0.00 ms delay), while the active sensor FTC reconfiguration is completed within 2.0 ms. The strategy successfully limits transient switching overshoots to minimal values (0.0511 A for current, 0.1044 V for voltage). During the postfault period, the system maintains stable operation with a negligible steady-state voltage deviation of 0.298 V. It is clarified that the inherent steady-state errors (1.20% for voltage, 4.41% for current) originate from the numerical integration of the nominal model (yielding a simulation baseline of 2.00 A versus the 1.92 A theoretical value), rather than the FTC mechanism itself. The proposed method is simple, effective, and shows strong potential for DC microgrid applications., subject to practical hardware validation.