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Control of Grid Connected Photovoltaic Systems with Microinverters: New Theoretical Design and Numerical Evaluation
Author(s) -
Yahya Abdelhafid,
El Fadil Hassan,
Oulcaid Mustapha,
Ammeh Leila,
Giri Fouad,
Guerrero Josep M.
Publication year - 2018
Publication title -
asian journal of control
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.769
H-Index - 53
eISSN - 1934-6093
pISSN - 1561-8625
DOI - 10.1002/asjc.1704
Subject(s) - control theory (sociology) , maximum power point tracking , photovoltaic system , backstepping , inverter , engineering , controller (irrigation) , boost converter , grid connected photovoltaic power system , nonlinear system , computer science , voltage , adaptive control , electrical engineering , control (management) , artificial intelligence , agronomy , physics , quantum mechanics , biology
This paper addresses the problem of controlling grid connected photovoltaic (PV) systems that are driven with microinverters. The systems to be controlled consist of a solar panel, a boost dc–dc converter, a DC link capacitor, a single‐phase full‐bridge inverter, a filter inductor, and an isolation transformer. We seek controllers that are able to simultaneously achieve four control objectives, namely: (i) asymptotic stability of the closed loop control system; (ii) maximum power point tracking (MPPT) of the PV module; (iii) tight regulation of the DC bus voltage; and (iv) unity power factor (PF) in the grid. To achieve these objectives, a new multiloop nonlinear controller is designed using the backstepping design technique. A key feature of the control design is that it relies on an averaged nonlinear system model accounting, on the one hand, for the nonlinear dynamics of the underlying boost converter and inverter and, on the other, for the nonlinear characteristic of the PV panel. To achieve the MPPT objective, a power optimizer is designed that computes online the optimal PV panel voltage used as a reference signal by the PV voltage regulator. It is formally shown that the proposed controller meets all the objectives. This theoretical result is confirmed by numerical simulation tests.