A Model-based MPPT with Improved Tracking Accuracy

Model-based maximum power point tracking (MPPT) techniques have been developed to improve the tracking transients for PV systems operating under rapidly changing irradiance. Instead of searching heuristically for the maximum power point (MPP), these methods utilize a PV mathematical model to pre-determine the MPP analytically. The irradiance value, required for solving the model, is calculated indirectly using a PV model inverse, as well as the measured current and voltage. Unfortunately, the existing PV model inverse cannot be obtained in a closed form, and thus few simplifications were needed, that affect the accuracy of the irradiance estimation and lead to inaccurate tracking. This paper employs an introduced shunt PV model, distinguished by its ability to provide a closed form inverse, for developing an improved model-based MPPT. The improved accuracy of the irradiance estimation results in an enhanced tracking accuracy and more energy extraction in comparison with the available model based trackers. The effectiveness of the proposed model based MPPT is verified and its effectiveness is evaluated with respect to various existing MPPTs.