A Comprehensive Monitoring System for Online Fault Diagnosis and Aging Detection of Non-Isolated DC–DC Converters’ Components

TLDR

Online monitoring is essential for dc‑dc converters in industrial settings to achieve fault‑tolerant operation and prevent catastrophic failures. This work proposes a comprehensive monitoring system for non‑isolated dc‑dc converters. The system monitors switching devices, capacitors, and inductor inter‑turn faults using only two voltage sensors (across the diode and inductor) and two temperature sensors, and tracks capacitor ESR and switch on‑state voltage as aging precursors, with performance evaluated on a laboratory prototype. The system detects switch/diode open and short faults within one switching cycle, is simple, cost‑effective, and applicable to buck, boost, and buck‑boost converters, with experimental results confirming its effectiveness for fault diagnosis and aging monitoring.

Abstract

Online monitoring is an inevitable necessity for dc-dc converters in industrial applications to achieve a fault-tolerant structure, which ensures reliable operation and prevents catastrophic failures. In this paper, a comprehensive monitoring system is proposed for non-isolated dc-dc converters. The proposed approach is mainly focused on monitoring the most prone to failure components of these converters including switching devices and capacitor. Using the proposed monitoring system, switch/diode open circuit and short circuit faults are detected in less than one switching cycle. Furthermore, online monitoring of the capacitor equivalent series resistance and switch on-state voltage as effective precursors of aging is also carried out. Finally, an inter-turn fault detection technique is presented for the converter inductor. The mentioned monitoring tasks are accomplished using only two electrical sensors (for capturing voltages across the converter diode and inductor) and two temperature sensors. The presented monitoring approach is simple, cost-effective, easy to implement, and applicable for all non-isolated dc-dc converters including buck, boost, and buck-boost converters. Performance of the monitoring system is evaluated by considering different scenarios in the experiments carried out on a laboratory prototype. The results confirm the effectiveness of the proposed system for fault diagnosis and aging monitoring in non-isolated dc-dc converters.