Switch Failure Detection and Identification Using Diode Current for Single-Switch DC–DC Converters

Single-switch-based DC-DC converters are a foremost requirement in many applications, and so is their reliable operation. This article is concerned with switch fault diagnosis (FD) using a signal-based approach. Compared to many other methods such as model-based or knowledge-based diagnosis, the proposed signal-based approach is the simplest one. This approach presents merits like fast diagnosis speed, general applicability, cost-effectiveness, and robustness. The scheme is tested for switch open-circuit fault (OCF), and short-circuit fault (SCF) under both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) of operation. The robustness of the scheme is tested by considering variations in the duty cycle, passive component value, threshold value, and switching frequency. The scheme works fine under dynamic conditions for sudden changes in load current. The suggested diagnosis method uses the information of diode current and it avoids the use of additional sensors. The FD algorithm is capable of detecting and determining the type of fault in less than one switching time period. Validation of its effectiveness is carried out by simulation and experimental studies.