Robust Sensor Fault Reconstruction for Modular Multilevel Converter Based on Sliding Mode Observer

This paper presents a robust sensor fault reconstruction method for modular multilevel converter (MMC) based on sliding mode observer (SMO). An uncertain system with sensor failure is firstly established by resorting the MMC state space model. The main idea of sensor fault reconstruction is to introduce an appropriate filter and convert the sensor fault into a fictitious actuator fault form by constructing an augmentation system. Robust sliding mode observer is designed with convex optimization theory and linear matrix inequality (LMI) techniques. The sliding mode motion is maintained via equivalent output control method and the fault information is obtained directly to realize the fault information of the sensor. Finally, taking the parameters of the MMC system model as an example, the effectiveness and reliability of the proposed approach are verified by simulation.