A Theoretical Concept of Decoupled Current Control Scheme for Grid-Connected Inverter with L-C-L Filter

This paper proposes a nonlinear decoupled current control scheme for grid-connected inverter with LCL filter. Decoupling the active and reactive channels is one of main demands in inverters. For inverters an L filter, decoupling can be achieved by proper feed-forward grid voltages. However, coupling complex issue converters filters. The resonance mode filter may cause instability, which adds more complexity to analysis. In this paper, state equations system are provided, highlight between currents injected into grid. Accordingly, non-linear proposed effectively decouples dampens resonant modes stability method verified Lyapunov criterion. Independency grid-impedance another feature approach. Moreover, only grid-side needed implementation scheme, avoiding need additional sensors output capacitor inductor. accurate modelling inverter, computation PWM sampling delays included controller design. Finally, various case studies provided that verify performance approach system.