Tracking the maximum power point of solar panels through direct estimation of optimum voltage with temperature

Abstract

Abstract Electricity production from photovoltaic (PV) panels is maximized when the operating point is located at the maximum power point thanks to dedicated controllers. These controllers are driven to track the maximum power by using various algorithms within distributed or centralized architectures accounting for factors such as partial irradiation and temperature changes. The effect of irradiance on the optimal panel voltage is weak or even negligible, while it is strong and quasi-linear-dependent on temperature. Based on this observation, this article introduces a straightforward method for tracking the maximum power of a PV panel by using an optimizer, focusing solely on its temperature response as an input variable. The proposed approach hinges on linearizing the relationship between panel temperature and operating voltage. This relationship enables the estimation of the maximum power point through temperature measurement alone. Thus, after determination of the linear temperature coefficient of the voltage requiring only the knowledge of two optimal voltages at different temperatures, for example from the datasheet of the panel, the power tracking involves only one temperature sensor placed on the panel alongside a voltage sensor for regulation. The principle, modelling, and validation post-panel ageing of the method are detailed in this paper. Simulation, conducted using real experimental irradiation and temperature data, attests to the effectiveness of the control. Results indicate an average effectiveness of the method of >99.1% in tracking the maximum power, with the panel generating 2.33 kWh out of a possible 2.35 kWh. This performance is comparable to that of tracking devices employing more complex algorithms. The simplicity and efficiency of the method make it a promising option for maximizing the power production at low cost from PV systems in small or residential, on- or off-grid connected applications.