Sensor Fault Estimator and Fault Tolerant Controller for Boost Converter

DC-DC power converters play an important role in energy conversion systems. Due to the age or unexpected conditions, sensors are prone to faults. The faulty sensors may cause wrong commands from the controller such that the actual voltage and current depart from the desired values. Therefore, there is a strong motivation to develop a fault-tolerant control scheme for power converters to improve their reliability. In this study, a boost converter is concentrated. It is demonstrated the existing linear fault estimator can effectively estimate sensor faults under open-loop operation condition but fail to estimate sensor faults in a closed-loop control circuit. A novel nonlinear fault estimator is addressed which can ensure an accurate estimate of both system states and sensor faults. A fault-tolerant design scheme using sensor signal compensation and nonlinear controller is proposed which can guarantee the closed-loop boost converter can track the desired voltage reference under sensor faulty conditions. The passivity of the tolerant control circuit is proved mathematically, and the effectiveness of the proposed algorithms are demonstrated by simulation studies.