LPPT control of a photovoltaic system against sudden drop of irradiance

The objective of this paper is to deal with the problem of false convergence in the occasion of sudden drop of irradiance during limited power point tracking (LPPT) control of a photovoltaic (PV) system. In the case of LPPT control, the power output of a PV array is operating at a specified reference power level that is below the maximum power point (MPP). Because of sudden drop of irradiance, the power output of PV system may suddenly become zero and, subsequently, get stuck there unless the irradiance level is significantly raised again. The particular problem happens because of MPPT convergence detector that is used in existing LPPT controller in the case of power scarcity. Here, the new MPPT convergence detector is developed to avoid the false convergence problem. The proposed algorithm is compared with a conventional LPPT algorithm and tested through MATLAB simulation.