Photovoltaic (PV) energy is one of the most important energy sources since it is clean and inexhaustible. It is important to operate PV energy conversion systems in the maximum power point (MPP) to maximize the output energy of PV arrays. An MPPT control is necessary to extract maximum power from the PV arrays. In recent years, a large number of techniques have been proposed for tracking the maximum power point. This paper presents a comparison of different MPPT methods and proposes one which used a power estimator and also analyses their suitability for systems which experience a wide range of operating conditions. The classic analysed methods, the incremental conductance (IncCond), perturbation and observation (P&O), ripple correlation (RC) algorithms, are suitable and practical. Simulation results of a single phase NPC grid connected PV system operating with the aforementioned methods are presented to confirm effectiveness of the scheme and algorithms. Simulation results verify the correct operation of the different MPPT and the proposed algorithm.
This paper presents a single-stage three-level Neutral Point Clamped (NPC) inverter for connection to the electrical power grid, with integrated Maximum Power Point Tracking (MPPT) algorithm to extract the maximum power available from solar photovoltaic (PV) panels. This single-stage topology is more compact than the traditional topology, it was chosen because with the proper control strategy. It is suitable to connect the PV panels to the power grid. The paper describes the design of a 5 kW NPC inverter for the interface of PV panels with the power grid, presenting the circuit parameters and the description of the control algorithms. A phase locked loop control is used to connect the inverter into the grid. Then, a proposed DC Link voltage control to regulate the input voltage of the inverter. Although an MPPT algorithm was used to optimize the energy extraction and the system efficiency. Inverter Output Current control to produce an output current (current injected in the power grid) with low Total Harmonic Distortion (THD) implemented in a DSP. Simulation and experimental results verify the correct operation of the proposed system, even with fluctuations in the solar radiation.
We have exploited the dual slope (DS) conversion technique to realize an intelligent system with high resolution that ensures active power measurement and electrical energy consumption. The load power is suited by two Hall effect current and voltage transducers, which are associated upstream with a precision analogue multiplier. A DS analogue-to-digital converter (DS-ADC) performs the conversion by rejecting noise with a conversion time that is multiple frequencies of the ADC's first slope. The digital acquisition is made by a PIC 16F877 using a management algorithm ensuring the control, acquisition, and treatment of information. Results are displayed on a 2-line and 16column LCD. The developed instrument is programmable, which gives it many advantages, such as speed of execution, measurement reliability, and error correction.
The progress of electronics and data processing contributed to the development of the measurement techniques of the virtual instruments. To contribute to this work one carried out an instrumental platform managed by Labview. The conceived measurement system is a multifunction. It ensures the measurement of the active, reactive and apparent power as well as the power-factor and the characterization of the load parameters while making recourse to the Fourier discrete transform. Moreover, one treats and identifies the characteristics of a ferromagnetic substance by the determination of the hysteresis loop, the first magnetization curve as well as the spectral analysis… etc. Indeed, two Hall sensors ensure respectively the adaptation of ) (t u and ) (t i and an analogical process makes it possible to extract the useful output. Via an interface board of the type NI-6024E, one acquires the power using a measurement statistical method which gives an arithmetic mean value that increases the measuring accuracy. This intelligent system makes measurements easy, less cumbersome and it removes the majority of the errors presented by the analogical systems at knowing dispersion and the limitation of the size of the components and the reproducibility. This instrumental platform reduces the experimenter of any long and tiresome calculation. It replaces multiple traditional measuring apparatus while ensuring a better precision. The measurement ranges of this power systems are: an input voltage of 220V and a maximum load current of 10A. The accury is less than 0.2%.
The measurement method used in this paper compares the power measurement on analog wattmeter and digital systems. One analyzes, in the first part, the metrological behavior of an electrodynamics wattmeter and in the second part one uses a multifunction measurement numerical method. This method uses tow Hall sensors and an electronic analog multiplication process to adapt the network voltage and current and also the power measurement. Via an interface board of the type CIGAL M23, one acquires directly the normalized power using a statistical measurement method which increases the accuracy. Using an 8255 timer, one measures the phase angle between the voltage and the current load. The intelligent system allows us to measure the phase angle, the active, reactive and apparent power and to identify the load type (inductive or capacitive one). A comparison in the active power was made between the electrodynamics wattmeter and the smart system. The measurement ranges of this power systems are: An input voltage of 220V and a maximum load current of 5A. The accuracy is less than 0.2%.
In this paper, it is demonstrated the importance of the information concerning the power flow and the state of a building's thermal system for the management and control of electricity consumption. The proposed approach is evaluated simulating the heating exchange behavior of a configurable base model for an isolated and non-thermally insulated habitat in order to determine the influence of the energy losses on the control system. Based on the results obtained with this study, some improvements were carried-out for the management system of the heating flow by introducing appropriated parameters into the control algorithm.
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