Известия Томского политехнического университета: Инжиниринг георесурсов (Apr 2018)
Construction of adaptive algorithm of power extreme control in solar energy system
Abstract
The relevance of the discussed issue is caused by the need to improve energy efficiency of DC-DC power converting devices for needs of alternative power engineering. One of the problems of converting solar energy into electrical one is a low level of energy efficiency of this process. Due to variable value of illumination of solar panels during the day, the parameters of energy received are variable, hence, the settings of secondary electrical energy converters must be adaptive. Improving the quality of functioning of alternative power sources is possible due to the use of methods of extreme regulation. The paper considers some famous algorithms for a control system of boosting voltage converter which implement the search for operating parameters of the converter of the maximum power point. The problem of choosing optimal algorithm from the adaptive (with the choice of step) and non-adaptive algorithms of disturbance and observation is relevant as well. In addition, the algorithm of increasing conductivity was investigated. Comparison and construction of these algorithms and a new combined algorithm of extreme regulation on their basis were carried out. The main aim of the study is to compare the maximum power point search algorithms; develop a new algorithm for a voltage converter control system and physical model of the final device and estimate its efficiency. The methods: reviewing of technical publications concerning maximum power point tracking algorithms; simulation modeling using Matlab/Simulink and certain experiments with a prototype of two-phase DC-DC boost converter. The experiments and modeling include: setup of PI-regulator, imitation of various levels of blackout of a solar battery, assessment of the converter efficiency. The results. The authors developed the simulation models for adaptive and non-adaptive perturbation and observation and incremental conductance method and studied their application for different levels of illumination. The software for a microprocessor control system was designed. The authors carried out the experiments in simulation of different levels of illumination of the solar battery to estimate the efficiency of the device. The research demonstrates high value of maximum power point tracking efficiency (99 %) for option with adaptive algorithm of a step change. At the experiment the similar indicators of accuracy (95-96 %) were obtained, at quantization time of 10 ms (for not adaptive algorithm of perturbation and observation).
