Extremum seeking control techniques applied to photovoltaic systems with multimodal power curves

Waleed Nwesaty (1) , Antoneta Iuliana Bratcu (1) , Ahmad Hably (2)

1 GIPSA-SLR - GIPSA - Systèmes linéaires et robustesse
2 GIPSA-SYSCO - GIPSA - Systèmes non linéaires et complexité

This paper proposes a modified Perturb and Observe (P&O) Extremum Seeking Control (ESC) technique in presence of multiple maxima. ESC is applied to single-phased grid-connected photovoltaic (PV) arrays which have to provide maximum power irrespective of solar irradiance conditions. In particular, partially shadow conditions may lead to steady-state power curves exhibiting multiple maxima. The power harvested from the PV generator is injected in the single-phased power grid by using two power converter stages: step-up DC-DC converter and DC-AC inverter. When multiple power maxima exist, the amplitude of the perturbation signal plays an important role in successfully tracking the global maximum. Two amplitude modulation strategies are analyzed for the same case study: amplitude modulation by using a first-order-system-response signal and amplitude modulation by using small duty ratio square-wave signal, respectively. MATLAB®/Simulink® numerical simulations are presented in order to assess the two approaches comparatively.

Mots clés: perturb and observe; modulation; hill climbing; cascade control; optimal control; Extremum Seeking Control; Renewable energy systems

Domaines: Automatique / Robotique; Energie électrique

Waleed Nwesaty, Antoneta Iuliana Bratcu, Ahmad Hably. Extremum seeking control techniques applied to photovoltaic systems with multimodal power curves. ICRERA 2013 - International Conference on Renewable Energy Research and Applications (ICRERA 2013), Oct 2013, Madrid, Spain. pp.1-6. ⟨hal-00873027⟩