A novel exponent I–V relation based maximum power point algorithm for photovoltaic panel

Abstract

• This paper introduces an explicit I–V relation formulated by three coefficients (known as an exponent model) to calculate accurate VMP using analytical expression with a single step. • A simple procedure for the determination of the exponent model coefficients in the standard test conditions (STC) and in the different environmental test conditions is described. Successively, the adjusted coefficients are used to calculate VMP . • The exponent model compares its accuracy with the universally adopted practical model (single-diode-model) in terms of the relative error in VMP and PMP tested in different environmental conditions. • The performance of the proposed model in different test conditions is simulated in detail using a PV system, and is also compared with, the P&O, the series-diode model based MPP (SDMPP) [24] and the Lambert W function based MPP (LWMPP). The efficiency comparison is conducted in the steady state and the dynamic conditions with proving the superiority of the proposed model. • The model has an additional feature of the estimation of the irradiance with an additional cost of PV temperature measurement. • The model successfully tracks the accurate MPP if 10% tolerance is considered in the output power of the PV modules manufactured by the same manufacturer. Moreover, the model performance is found marginally deviated in case of aging of a PV module. • In the laboratory, a prototype PV system with a boost converter, a resistive load and a controller (to regulate the boost converter voltage at the MPP) is designed and tested when the PV modules are placed in an open atmosphere under the clear sky. The experimental results are also compared with the P&O algorithm to establish the superiority of the proposed model. • The only limitation of the proposed model is a frequent adjustment of the coefficients with an additional cost of a PV temperature measurement in order to estimate accurate MPP. In this paper, a new model based MPP tracking algorithm in different environmental conditions is presented. A PV power converter driven by a maximum power point (MPP) controller adjusts the PV source voltage at the MPP ( V MP ) to harvest maximum power from the PV source. The proposed EXMPP algorithm calculates V MP using an analytical expression with a single step; derived from an explicit I–V relation. This algorithm overcomes voltage fluctuations in steady state condition which occurs in iterative based algorithms such as perturb-and-observe, incremental conductance and their improved versions. The algorithm also enhances the dynamic performance when it was compared to iterative and explicit model based algorithms. The algorithm is tested and validated in different climatic conditions using simulation study and experimental results. The proposed algorithm is also verified for a larger manufacturer tolerance and aging effect in the PV module. The proposed explicit I–V relation based EXMPP algorithm with module integrated converters provides an attractive performance in rapid environmental conditions changes.