An Enhanced Active Disturbance Rejection Control Scheme for DC Voltage Regulation in Photovoltaic Grid-Connected Four-Leg Inverter Using a Sliding Mode Observer

This paper proposes an Enhanced Active Disturbance Rejection Control (EADRC) scheme using a Super-Twisting Sliding Mode Observer (STSMO) for DC voltage regulation in a photovoltaic (PV) grid-connected four-leg inverter system. The approach addresses the challenges posed by system uncertainties, parameter variations, and external disturbances like irradiance changes and grid voltage sags. By integrating the STSMO into the ADRC framework, the proposed method improves disturbance estimation and rejection, enhances dynamic response, reduces measurement noise sensitivity, and ensures robust DC-bus voltage regulation. Both simulation and real-time OPAL-RT experimental results validate the effectiveness of the proposed method compared to conventional PI and traditional ADRC controllers.

Keywords: Three-phase photovoltaic (PV) grid-connected four leg voltage source inverter (4LVSI), PI ,MPPT, enhanced active disturbance rejection control (EADRC) scheme, super twisting sliding mode observer (STSMO)