Robust current control for grid-connected VSC: nonlinear adaptive control with perturbation estimation

This paper introduces a robust control strategy for grid-connected voltage source converters using Nonlinear Adaptive Control (NAC) enhanced by a perturbation observer (PO). This approach precisely regulates grid current and adapts to unknown dynamics, time-varying parameters, and disturbances impacting the system. By estimating and compensating for these perturbations, the strategy achieves adaptive feedback linearization, effectively managing the system's inherent nonlinearity without requiring an exact model or extensive measurements. The NAC offers substantial improvements over traditional vector control and feedback linearization, particularly under conditions where grid voltage significantly deviates from normal levels. Simulation results confirm the superior performance of the proposed method.