Active Disturbance Rejection Control of Photovoltaic Three-Phase Grid Following Inverters Under Uncertainty and Grid Voltage Variations

A PV three-phase grid following inverter (GFI) with LCL filters can reduce current harmonics and deliver active power to the grid. Controlling such higher-order systems is challenging due system uncertainties, voltage variations, filter resonance. Active disturbance rejection control (ADRC) provides resilience these uncertainties a prompt response disturbances. linear extended state observer phase-locked loop are integrated into ADRC structure optimize tracking performance. The proposed controller uses structured inner outer closed-loop that takes account process delays dynamics. GFI operate under variable frequencies or even deviations in frequency caused by failure, able meet challenges as part of design synchronization approach. Both simulation experimental results given validate dual ADRC-based methods for an 8 kW laboratory prototype PV-GFI system.