Control with Fault Detection of the DC Microgrids Using SDRE-Controller-Observer

In the present work, using the State-Dependent Riccati Equation approach, the optimal optimizer-controller is designed for a small DC network isolated from the network. The objectives are to control the output voltage of the solar cell, as well as output voltages of the battery, the capacitor bank and the DC busbar, and to detect possible faults in a timely manner. In the State-Dependent Riccati Equation observer–controller design process, a non-linear model is used for modeling the dynamic behavior of the microgrid in different operating conditions. The efficiency of the studied microgrid has been assessed in the presence of uncertainty in system parameters and measurement noise. The results of the simulations show the ability of the suggested approach to detect faults in a timely manner, not to recognize the disturbance as a fault, as well as the effective and resistant performance of the progressive controller even in the disturbance presence. Quantitatively, the proposed fault detection method was able to generate non-zero residual current in the presence of faults, allowing for fault detection by defining an appropriate threshold. The threshold used in the study was 50. Additionally, the fault detection system was able to avoid misdiagnosis of disturbances as faults.