Centralized Sensor Fault Reconstruction of DC Microgrids Based on Sliding Mode Observer

As the centralized protection of DC microgrid systems depends closely on the accuracy of sensors, sensor fault diagnosis becomes an issue of great importance. This paper proposes a centralized fault diagnosis method for the DC microgrid switched system based on the sliding mode observer. First the switched system of the microgrid is established to describe its dynamic response. Moreover, different types of sensor faults are analyzed and quantitatively modeled. On this basis, the system is divided into two subsystems through coordinate transformation, and a sliding mode observer is designed without increasing the system dimension. Finally, sensor fault reconstruction can be achieved through the nonlinear feedback term of the sliding mode observer. Simulation verification shows that the method proposed can accurately reconstruct various types of single sensor faults, which lays the foundation for sensor fault-tolerant control of the system.