Open Circuit Voltage Technique Research Articles

Fuzzy Logic MPPT Techniques in Solar Photovoltaic System

Abstract: This paper presents the comparative analysis of most commonly used Maximum Power Point Tracking (MPPT) techniques viz Open Circuit Voltage (OCV), Perturb and Observe (PnO) and Incremental Conductance (INC) methods that are capable of extracting maximum power from the PV generation system. The OCV technique is an indirect MPPT method that tracks the Maximum Power Point (MPP) using empirical data or mathematical expressions with numerical corrections and approximations. To operate PV panels at that point (MPP) there are many MPPT method in literature, FLC MPPT method was preferred in this study because, its rapid response to changing environmental conditions and not affecting by change of circuit parameters. The accuracy of FLC MPPT method used in this system to find MPP changes, from 94.8% to 99.4%. To charge a battery there are two traditional methods which are constant current (CC), and constant voltage (CV) methods. For fast charging with low loss constant current and voltage source is a need. One of the methods providing constant is PI control which used in this study. Keywords: FLC (Fuzzy Logic Controller), CV, CC, Simulink, MPPT

Comparison of Maximum Power Point Tracking Techniques on Photovoltaic Panels

In this study, a simulation is performed in Matlab/Simulink to evaluate the energy production performance of the perturb & observe, incremental conductance, short circuit current and open circuit voltage techniques. In order to evaluate the performance of the techniques, they are tested under constant temperature and irradiation conditions, as well as variable temperature and irradiation conditions. In the study, 1Soltech 1STH-215-P model photovoltaic panel is used. The maximum power point tracking is applied with a DC-DC boost converter, and the energy is stored in the battery. Maximum power point tracking algorithms are applied with m-file code using Matlab Function block in Simulink. The m-file codes, the extracted power waveforms and the amount of produced energy are presented in the study. It is observed that the energy performance of the short circuit current and open circuit voltage techniques varies depending on the measurement period, especially in variable weather conditions, while the perturb & observe and the incremental conductance algorithms are the ones that produce the most energy. While the open circuit voltage technique produces more energy than the short circuit current at constant temperature and variable irradiation, the short circuit current algorithm at constant irradiation and variable temperature produces more energy. While two sensors are used for current and voltage measurement in perturb & observe and incremental conductance techniques, the use of a single sensor in short circuit current and open circuit voltage techniques and the simplicity of the algorithms are seen as the advantageous aspects of these techniques.

Optimization of both Perturb & Observe and Open Circuit Voltage MPPT Techniques for Resonant Piezoelectric Vibration Harvesters feeding bridge rectifiers

When the characteristics of the input vibrations change with time, also the optimal operating point of a Resonant Piezoelectric Vibration Energy Harvester (RPVEH) changes with time. Such an optimal operating point is characterized by the highest value of the extracted electrical power and is called Maximum Power Point (MPP). This paper is focused on MPP Tracking (MPPT) techniques for RPVEHs. In the most widespread RPVEH AC/DC architecture, which is based on the use of a diode bridge rectifier cascaded by a DC/DC converter, MPPT requires that the voltage V0 at the output of the bridge rectifier is properly regulated. The first issue that is addressed in this paper is the derivation of a simple closed form expression of the power extracted by a RPVEH as a function of the voltage V0 as well as of the optimal value of V0. Moreover, a complete set of general guidelines leading to the proper choice of the values of the parameters of the two most widely used MPPT techniques for RPVEHs applications (the Perturb & Observe technique and the Open Circuit Voltage technique) are provided and experimentally validated. It is experimentally shown that, if the above MPPT techniques are not properly and carefully customized to the particular RPVEH application of interest, they may lead to very poor performances of the system.

A Combined MPPT Algorithm for Photovoltaic Systems Based Arduino Microcontroller

Photovoltaic energy is a renewable source of clean and attractive energy compared to conventional energy sources. Photovoltaic panels (PV) have a non-linear I-V characteristic that depends on climatic conditions. In order to operate the photovoltaic modules at their maximum power point (PMM), MPPT algorithms are developing in order to extract the maximum energy. The Perturb and Observe (P & O) technique is widely used in photovoltaic systems because of its simplicity but remains vulnerable to sudden changes in weather conditions. In this paper, a new multi-objective MPPT algorithm combining three techniques: MPPT type (P & O), fractional short-circuits current (FSCC) and fractional open circuit voltage technique (FOCV) is proposed. This multi-objective algorithm improves the performance of conventional MPPT (P & O). A variable pitch perturbation and detection of sudden changes in illumination and / or temperature levels allows better stabilization of the duty cycle once the PPM is reaching. The proposed algorithm is testing by Matlab/Simulink and the results obtained are compared with experimental results using Arduino Uno microcontroller and appropriate sensors.

A Glowworm Swarm Optimization-Based Maximum Power Point Tracking for Photovoltaic/Thermal Systems under Non-Uniform Solar Irradiation and Temperature Distribution

The output power of a photovoltaic (PV) system depends on the external solar irradiation and its own temperature. In order to obtain more power from the PV system, the maximum power point tracking (MPPT) is necessary. However, when the PV is partially shaded, there will be multiple peaks in the power-current (P-I) curve. The conventional MPPT methods may be invalid due to falling into the local peak. In addition, in a photovoltaic-thermal (PV/T) system, the non-uniform temperature distribution on PV will also occur, which complicates the situation. This paper presents a MPPT method with glowworm swarm optimization (GSO) for PV in a PV/T system under non-uniform solar irradiation and temperature distribution. In order to study the performance of the proposed method, the conventional methods including the perturbation and observe algorithm (P and O), and the fractional open-circuit voltage technique (FOCVT) are compared with it in this paper. Simulation results show that the proposed method can rapidly track the real maximum power point (MPP) under different conditions, such as the gradient temperature distribution, the fast variable solar irradiation and the variable partial shading. The outcome indicates the proposed method has obvious advantages, especially the performance being superior to the conventional methods under the partial shading condition.