Contribution to the optimization of energy withdrawn from a PV panel using an Embedded System

Considering the high initial capital cost of photovoltaic (PV) panels and their low conversion efficiency, it is imperative to operate the PV system at the maximum power point (MPP). In this context, our goal in this thesis is to develop and improve the PV system, by contributing to the optimization of energy withdrawn from PV panel using an embedded system. For this purpose, in order to simulate and test MPPT algorithm, the model of the PV panel should be first studied in accordance with the real behavior of the PV panel. Therefore, the single diode model of the PV panel is introduced in Matlab/Simulink and PSIM. Moreover, for the first time, the PV panel model is developed in Proteus; an experimental test bench was built to validate the developed model. On the other hand, this work proposes a modified incremental conductance (INC) algorithm to improve the MPP tracker (MPPT) capability for PV system when the irradiation is suddenly modified. Three modifications are made in the INC algorithm, which are described as follows: (1) A check to identify the increase in irradiation and make a correct decision. (2) Eliminate the all-division computations in the INC algorithm and make the algorithm structure simpler allowing the algorithm to be easily implemented by a low-cost embedded system. (3) A modified variable step INC algorithm is used, which can reduce the steady-state oscillations and improve the tracking speed under sudden irradiance variation. The first modification is simulated using PSIM through “Software in the Loop” test and the results show that the modified algorithm provides an accurate response to a sudden variation of solar irradiation with an efficiency of 98.8 %. The second modification is simulated using the PV panel model proposed in Proteus. For verification, a hardware test bench is implemented by using Arduino Uno board in which the low-cost Atmega328 microcontroller is integrated. This has led to a low-cost PV system with an efficiency of 98.5 %. The third modification is developed following the techniques employed in the automotive and aeronautical embedded system. This is done by following the V-cycle development process, which means that our controller will be validated using “Model in the Loop/Software in the Loop/Processor in the Loop” tests. In this sense, integrating the MPPT embedded system in the automotive or the aeronautical area will be possible. It should be mentioned that Matlab/Simulink is used for MIL/SIL/PIL tests, thus STM32F4 board is used for PIL test. On the other side, if minimizing the cost of the PV system is not important than guarantying a very high level of robustness and efficiency, it is required to use a more powerful method. Therefore in this thesis, we design and implement MPPT based on Kalman Filter. The expected outcome of this proposal is an efficient MPPT method which presents a very high level of robustness, reliability and accuracy. The obtained results clearly highlight the superiority of the proposed method; it yields an efficiency of 99.38 %, which is almost 3 % higher than the conventional INC method. In a nutshell, this thesis proposed two solutions, the first one is for low-cost applications with a good performance using the modified INC, and the second is for higher performance and critical applications by using Kalman filter.