Control of Electrodialysis Desalination Systems as Smart Loads in Microgrids with High Penetration of Renewable Generation

Water desalination systems connected to microgrids with high penetration of renewable energy generation are frequently used to promote the development of remote areas. These microgrids often have power quality and even stability problems. This work shows that electrodialysis desalination systems can be managed as smart loads, that is, they can contribute to the power balance and voltage regulation of the microgrid without neglecting its main function of water desalination. For this, a model of multiple inputs and multiple outputs for a desalination system is proposed where the variables to control are the treated water concentration and the active and reactive powers demanded by the desalination system. Based on this model, a control law is proposed that allows to face the complexity of the non-linear system in a simple and precise way. The proposed control guarantees the low salt concentration of the drinking water and favors the energy balance of the microgrid, allowing better control of the power quality and greater penetration of renewable energy generation

Sliding-mode controller for a photovoltaic system based on a Cuk converter

The wide range of step-up and step-down input-output voltage characteristic of the Cuk converter makes it a good candidate to interface photovoltaic arrays in both classical and distributed maximum power point tracking systems. Because its two inductor structure, Cuk converters have continuous input and output currents, which reduce the additional filtering elements usually required for interfacing dc/dc converter topologies. However, PV systems based on Cuk converters usually do not provide formal proofs of global stability under realistic conditions, which makes impossible to ensure a safe operation of the PV installation. Therefore, this paper proposes a high performance sliding-mode controller for PV systems based on Cuk converters, which regulates the PV voltage in agreement with the commands imposed by a MPPT algorithm, rejecting both load and environmental perturbations, and ensuring global stability for real operation conditions. Finally, the performance of the regulated PV system is tested using both simulations and experiments

Simulation-based coyote optimization algorithm to determine gains of PI controller for enhancing the performance of solar PV water-pumping system

In this study, a simulation-based coyote optimization algorithm (COA) to identify the gains of PI to ameliorate the water-pumping system performance fed from the photovoltaic system is presented. The aim is to develop a stand-alone water-pumping system powered by solar energy, i.e., without the need of electric power from the utility grid. The voltage of the DC bus was adopted as a good candidate to guarantee the extraction of the maximum power under partial shading conditions. In such a system, two proportional-integral (PI) controllers, at least, are necessary. The adjustment of (Proportional-Integral) controllers are always carried out by classical and tiresome trials and errors techniques which becomes a hard task and time-consuming. In order to overcome this problem, an optimization problem was reformulated and modeled under functional time-domain constraints, aiming at tuning these decision variables. For achieving the desired operational characteristics of the PV water-pumping system for both rotor speed and DC-link voltage, simultaneously, the proposed COA algorithm is adopted. It is carried out through resolving a multiobjective optimization problem employing the weighted-sum technique. Inspired on theCanis latransspecies, the COA algorithm is successfully investigated to resolve such a problem by taking into account some constraints in terms of time-domain performance as well as producing the maximum power from the photovoltaic generation system. To assess the efficiency of the suggested COA method, the classical Ziegler-Nichols and trial-error tuning methods for the DC-link voltage and rotor speed dynamics, were compared. The main outcomes ensured the effectiveness and superiority of the COA algorithm. Compared to the other reported techniques, it is superior in terms of convergence rapidity and solution qualities

Analysis of Grid-Interactive PV-Fed BLDC Pump Using Optimized MPPT in DC–DC Converters

In solar photovoltaic (PV) system-based Brushless DC (BLDC) motors for water pumping application, the role of DC/DC converters is very important. In order to extract the maximum power from the PV array, an efficient DC/DC converter is essential at the intermediate stage. In this work, different DC/DC converter topologies suitable for BLDC motors are proposed. The converters are supported by an optimized maximum power point tracking system to provide a reliable operation. Recent optimization algorithms such as fuzzy logic, perturb and observe, grey wolf, and whale optimization are implemented with the PI controller in maximum power point tracking to maximize the conversion efficiency. The obtained results using SEPIC, LUO, and interleaved LUO converters provide a comparative study in the case of converter output, motor parameters, and grid output. The performance analysis on three different converters and multiple optimization methods are carried out. By analyzing the performance of different converter topologies, the interleaved LUO converter outperforms the other two converters with the results of a voltage gain ratio of 1:22, conversion efficiency of 98.3%, and grid current THD of 2.9%. Moreover, regarding the power quality aspect, the total harmonic distortion of the grid current is maintained below the IEEE-519 standard. In addition, the developed system has an advantage of operating both in stand-alone and grid-connected operation modes.publishedVersio

Fuzzy maximum power point tracking compared to sliding mode technique for photovoltaic systems based on DC-DC boost converter

Aim. This paper presents the amelioration of maximum power point tracking using fuzzy logic methods for photovoltaic system supplying a standalone system. Method. The main role of the maximum power tracking is to force the system for working at the maximum point for each change of meteorological conditions. The classic technique Perturb and Observe is more attractive due to its simple and high efficiency. Sliding mode is a non-linear control technique; characterised by robustness against the parameters change or disturbances, it gives a good maximum power operation under different conditions such as changing solar radiation and photovoltaic cell temperature. Novelty. Fuzzy logic tracking technique is treated. Fuzzy rules construction is based on Perturb and Observe behaviour when the appropriate disturbance step is produced in order to obtain a fast system with an acceptable precision. We use in our study 60 W photovoltaic panel associated to boost chopper converter in order to supply a standalone system. Results. As show in results figures using fuzzy maximum power point tracking the ameliorate performances especially the very low oscillation rate (nearly 0.6 W), and very acceptable response time 0.1 s.Мета. У цій роботі представлено покращення відстеження точки максимальної потужності з використанням методів нечіткої логіки для фотоелектричної системи, що постачає електроенергію до автономної системи. Метод. Основна роль відстеження максимальної потужності – примусити систему працювати в максимальній точці при кожній зміні метеорологічних умов. Класична техніка збурення та спостереження є більш привабливою завдяки своїй простоті та високій ефективності. Режим ковзання – це нелінійний метод керування; характеризується стійкістю до зміни параметрів або порушень, дає хорошу максимальну потужність роботи в різних умовах, таких як зміна сонячного випромінювання та температури фотоелектричних елементів. Новизна. Використовується методика відстеження з використанням нечіткої логіки. Побудова нечітких правил базується на поведінці збурення та спостереження, коли виробляється відповідний крок збурення, щоб отримати швидку систему з прийнятною точністю. У цьому дослідженні використовується фотоелектрична панель потужністю 60 Вт, підключена до перетворювача, що підвищує, для постачання електроенергії до автономної системи. Результати. Як показують результати, дані використовують нечітку максимальну точку потужності, яка відстежує покращені характеристики, особливо дуже низьку швидкість коливань (майже 0,6 Вт) і дуже прийнятний час відгуку 0,1 с

Fuzzy maximum power point tracking compared to sliding mode technique for photovoltaic systems based on DC-DC boost converter

Aim. This paper presents the amelioration of maximum power point tracking using fuzzy logic methods for photovoltaic system supplying a standalone system. Method. The main role of the maximum power tracking is to force the system for working at the maximum point for each change of meteorological conditions. The classic technique Perturb and Observe is more attractive due to its simple and high efficiency. Sliding mode is a non-linear control technique; characterised by robustness against the parameters change or disturbances, it gives a good maximum power operation under different conditions such as changing solar radiation and photovoltaic cell temperature. Novelty. Fuzzy logic tracking technique is treated. Fuzzy rules construction is based on Perturb and Observe behaviour when the appropriate disturbance step is produced in order to obtain a fast system with an acceptable precision. We use in our study 60 W photovoltaic panel associated to boost chopper converter in order to supply a standalone system. Results. As show in results figures using fuzzy maximum power point tracking the ameliorate performances especially the very low oscillation rate (nearly 0.6 W), and very acceptable response time 0.1 s.Мета. У цій роботі представлено покращення відстеження точки максимальної потужності з використанням методів нечіткої логіки для фотоелектричної системи, що постачає електроенергію до автономної системи. Метод. Основна роль відстеження максимальної потужності – примусити систему працювати в максимальній точці при кожній зміні метеорологічних умов. Класична техніка збурення та спостереження є більш привабливою завдяки своїй простоті та високій ефективності. Режим ковзання – це нелінійний метод керування; характеризується стійкістю до зміни параметрів або порушень, дає хорошу максимальну потужність роботи в різних умовах, таких як зміна сонячного випромінювання та температури фотоелектричних елементів. Новизна. Використовується методика відстеження з використанням нечіткої логіки. Побудова нечітких правил базується на поведінці збурення та спостереження, коли виробляється відповідний крок збурення, щоб отримати швидку систему з прийнятною точністю. У цьому дослідженні використовується фотоелектрична панель потужністю 60 Вт, підключена до перетворювача, що підвищує, для постачання електроенергії до автономної системи. Результати. Як показують результати, дані використовують нечітку максимальну точку потужності, яка відстежує покращені характеристики, особливо дуже низьку швидкість коливань (майже 0,6 Вт) і дуже прийнятний час відгуку 0,1 с

Comparative Study of P&O and Fuzzy MPPT Controllers and Their Optimization Using PSO and GA to Improve Wind Energy System

Many academics have recently focused on wind energy installations. WECS (wind energy conversion system) is a renewable energy source that has seen significant development in recent years. Furthermore, compared to the use of power grid supply, the use of the WECS in the water pumping field is a cost-free option (economically). The purpose of this study is to demonstrate a wind-powered pumping mechanism. To obtain the best option, it considers and contrasts four distinct approaches. This research aims to improve the system\u27s performance and the quality of the generated power. The objective of the control of WECS with a permanent magnet synchronous generator (PMSG) is to carefully maximize power generation. Finally, this research employed the fuzzy logic control (FLC) and particle swarm optimization (PSO) algorithms improved using a genetic algorithm (GA). The proposed system\u27s performance was tested using the generated output voltage, current, and power waveforms, as well as the intermediate circuit voltage waveform and generator speed. The provided data show that the control technique used in this study was effective

Current-Sensorless Control Strategy for the MPPT of a PV Cell:An Energy-Based Approach

A novel energy-based modelling and control strategy is developed and implemented to solve the maximum power point tracking problem when a photovoltaic cell array is connected to consumption loads. A mathematical model that contains key characteristic parameters of an energy converter stage connected to a photovoltaic cell array is proposed and recast using the port-Hamiltonian framework. The system consists of input-output power port pairs and storage and dissipating elements. Then, a current-sensorless control loop for a maximum power point tracking is designed, acting over the energy converter stage and following an interconnection and damping assignment passivity-based strategy. The performance of the proposed strategy is compared to a (classical) sliding mode control law. Our energy-based strategy is implemented in a hardware platform with a sampling rate of 122 Hz, resulting in lower dynamic power consumption compared to other maximum power point tracking control strategies. Numerical simulations and experimental results validate the performance of the proposed energy-based modelling and the novel control law approach