An adaptive nonlinear controller for microgrid inverters

In this paper, we propose an adaptive nonlinear controller for Voltage Source Inverters (VSI) used in microgrids. We aim to enforce the output voltage to track a given reference even if the load resistance is unknown and time variable. After the system modeling, the controller is designed using the backstepping technique and it includes an estimation of the load resistance. Many simulations have been carried out under different conditions to validate the designed controller. The simulation results show that the elaborated controller allows a perfect tracking of the reference voltage and an asymptotic stability. It is worth mentioning that the designed controller can operate in both microgrid modes: grid connected mode and islanded mode.