PV single-phase grid-connected converter : dc-link voltage sensorless prospective

Zakzouk, Nahla E. and Abdelsalam, Ahmed K. and Helal, Ahmed A. and Williams, Barry W. (2017) PV single-phase grid-connected converter : dc-link voltage sensorless prospective. IEEE Journal of Emerging and Selected Topics in Power Electronics, 5 (1). pp. 526-546. ISSN 2168-6777

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    In this paper, a dc-link voltage sensorless control technique is proposed for single-phase two-stage grid-coupled photovoltaic (PV) converters. Matching conventional control techniques, the proposed scheme assigns the function of PV maximum power point tracking to the chopper stage. However, in the inverter stage, conventional techniques employ two control loops: outer dc-link voltage and inner grid current control loops. Diversely, the proposed technique employs only current control loop and mitigates the voltage control loop, thus eliminating the dc-link high-voltage sensor. Hence, system cost and footprint are reduced, and control complexity is minimized. Furthermore, the removal of the dc-link voltage loop proportional-integral controller enhances system stability and improves its dynamic response during sudden environmental changes. The system simulation is carried out, and an experimental rig is implemented to validate the proposed technique effectiveness. In addition, the proposed technique is compared with the conventional one under varying irradiance conditions at different dc-link voltage levels, illustrating the enhanced capabilities of the proposed technique.