A Novel MPPT based Solar Irradiance Estimator: Integration of a Hybrid Incremental Conductance Integral Backstepping Algorithm for PV systems with Experimental Validation

Solar irradiance is an indispensable parameter in diverse energy applications. In PV systems, it can help to monitor the evolution of system performance. Consequently, numerous solar irradiance estimators have been proposed in the literature, some depend on the PV model, that is not always fully available, while others introduce an alteration of the PV operating point to the short-circuit or open-circuit point. It is always desirable to operate the PV system at the maximum power point (MPP), hence periodically altering the operating point of the system can deteriorate the performance of the maximum power point tracking (MPPT) controller. Alternatively, the operation of the PV system at the MPP can be exploited to estimate solar irradiance. In spite of the fact that numerous MPPT algorithms have been proposed in existing literatures, very few have demonstrated their suitability for irradiance estimation. The state-of-the-art reveals that only the conventional MPPT algorithms have been successfully applied to irradiance estimation. However, these conventional schemes still present noticeable shortcomings under fast varying environmental conditions. To address these limitation, this paper put forward a high performance MPPT based irradiance estimator. The proposed estimator is constructed around a simple algebraic equation that relies on the measurement of PV current and voltage only, thus endorsing its high simplicity. Prior to the estimation of solar irradiance, the overall PV system is driven by a high-performance hybrid incremental conductance integral backstepping (H-INC-IBS) MPPT controller. The principal benefits of this controller are high robustness and fast stabilization of the operating point at the MPP, which are optimal requirements of the system. Several experiments have been performed under changing irradiance and temperature conditions as well as experimental conditions. By consistent evaluations and comparisons against the conventional MPPT solar irradiance estimator, this paper aim to emphasize the superiority of the proposed solar irradiance estimator in providing more accurate estimation of solar irradiance.