Optimalno sledenje fotonapetostnega sistema soncu ob upoštevanju izgub pogonskega sklopa : doktorska disertacija

slovenian

doktorska dela

2011

Univerza v Mariboru, Fakulteta za elektrotehniko računalništvo in informatiko

Doctoral thesis deals with optimal sun-tracking of a photovoltaic system considering the electric drive losses. The Sun tracking PV system assures that the highest possible share of the available solar radiation reaches the surface of the PV modules. The electric drive which enables tracking is considered as the loss of the energy produced in the PV system. The maximum of the energy produced in the PV system is achieved by the continuous tracking of the PV system. Since the electric drives are determined by constant speed and time, and angle quantization the maximum of the energy produced can only approximate. The doctoral thesis presents a new method for determining such trajectories of the PV modules that change the position of the PV modules in such a way that the production of the electric energy in the given time interval of the observation reaches its maximum. The goal is to determine the maximum efficiency of the PV tracking system considering the tracking system energy consumption. To achieve this, exact values of the available solar energy are needed for a given moment. To do this, a new method for predicting direct and diffuse solar radiation on the Earthćs surface, in the form of the time dependent function, is developed. The method is confirmed by the comparison of the measured and the predicted solar radiation for clear days. The developed method for predicting the solar radiation in the form of the time dependent function and energy consumption of the tracking system, given as the functions of the azimuth and tilt angle change, are applied together to determine those trajectories of the PV module, where the PV system energy production, gives the maximum. To find a solution of the nonlinear and bounded optimization problem, a stochastic search algorithm called DifferentialEvolution is applied. The approach for determining the maximum of the energy produced in the PV system has not been researched yet. The explicitly defined objective function, which is minimized in the optimization procedure considering the optimization bounds, is used. Thus it is assured the maximum of the possible energy produced in the PV system, considering the applied model of the PV system, tracking system consumption, predicted solar radiation, and the properties of the applied optimization method. The use of the different and more advanced models of the PV system, the sun tracking system consumption or prediction of the solar radiation, can lead to the different optimal trajectories of the sun tracking system. However, this cannot reduce the importance of the proposed method. The proposed method gives the maximum of the possible energy produced in the discussed PV system, considering the applied models and data.

07.08.2023