There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

A new fuzzy-logic controller for maximum power point tracking of photovoltaic (PV) systems is proposed. PV modeling is discussed. Conventional hill-climbing maximum power-point tracker structures and features are investigated. The new controller improves the hill-climbing search method by fuzzifying the rules of such techniques and eliminates their drawbacks. Fuzzy-logic-based hill climbing offers fast and accurate converging to the maximum operating point during steady-state and varying weather conditions compared to conventional hill climbing. Simulation and experimentation results are provided to demonstrate the validity of the proposed fuzzy-logic-based controller.

Fuzzy-Logic-Control Approach of a Modified Hill-Climbing Method for Maximum Power Point in Microgrid Standalone Photovoltaic System

Energy storages introduce many advantages such as balancing generation and demand, power quality improvement, smoothing the renewable resource’s intermittency, and enabling ancillary services like frequency and voltage regulation in microgrid (MG) operation. Hybrid energy storage systems (HESSs) characterized by coupling of two or more energy storage technologies are emerged as a solution to achieve the desired performance by combining the appropriate features of different technologies. A single ESS technology cannot fulfill the desired operation due to its limited capability and potency in terms of lifespan, cost, energy and power density, and dynamic response. Hence, different configurations of HESSs considering storage type, interface, control method, and the provided service have been proposed in the literature. This paper comprehensively reviews the state of the art of HESSs system for MG applications and presents a general outlook of developing HESS industry. Important aspects of HESS utilization in MGs including capacity sizing methods, power converter topologies for HESS interface, architecture, controlling, and energy management of HESS in MGs are reviewed and classified. An economic analysis along with design methodology is also included to point out the HESS from investor and distribution systems engineers view. Regarding literature review and available shortcomings, future trends of HESS in MGs are proposed.

Hybrid energy storage system for microgrids applications: A review

This paper proposes an intelligent control method for the maximum power point tracking (MPPT) of a photovoltaic system under variable temperature and insolation conditions This method uses a fuzzy logic controller applied to a DC–DC converter device The different steps of the design of this controller are presented together with its simulation The PV system that I chose to simulate to apply my techniques on it is stand-alone PV water pumping system Results of this simulation are compared to those obtained by the system without MPPT They show that the system with MPPT using fuzzy logic controller increase the efficiency of energy production from PV

Maximum Power Point Tracking Using Fuzzy Logic Control

To increase the efficiency of photovoltaic (PV) systems, maximum power point (MPP) tracking of the solar arrays is needed. Solar arrays output power depends on the solar irradiance and temperature. Also the mismatch phenomenon caused by partial shade will affect the output power of solar systems and lead to the incorrect operation of conventional MPP tracker. Under partially shaded conditions, the solar array power–current characteristic has multiple maximum. This paper presents a maximum power point tracking (MPPT) with particle swarm optimization method for PV systems under partially shaded condition. The performance of the proposed method is compared with perturb and observe (P&O), improved P&O, voltage-based maximum power point tracking and current-based maximum power point tracking algorithms, especially, under partially shaded condition. Simulation results confirm that proposed MPPT algorithm with high accuracy can track the peak power point under different insolation, temperature and partially shaded conditions, and it has the best performance in comparison with four mentioned MPPT algorithms. Also under rapidly changing atmospheric conditions, the P&O algorithm is diverged. Copyright © 2013 John Wiley & Sons, Ltd.

A PSO‐based maximum power point tracking for photovoltaic systems under environmental and partially shaded conditions

Optimal reconfiguration and capacitor placement are used to reduce power losses and keep the voltage within its allowable interval in power distribution systems considering voltage, current, and radial condition constraints. It is needed to solve two nonlinear discrete optimization problems simultaneously, so an intelligent algorithm is used to reach an optimum solution for network power losses. An effective method and a new optimization algorithm using ‘improved binary PSO’ is presented and discussed to minimize power losses in distribution network by simultaneous network reconfiguration and capacitor placement. The proposed model uses binary strings which represent the state of the network switches and capacitors. The algorithm is applied and tested on 16- and 33-bus IEEE test systems to find the optimum configuration of the network with regard to power losses. Five different cases are considered, and the effectiveness of the proposed technique is also demonstrated with improvements in power loss reduction compared to other previously researched methods, through MATLAB under steady-state conditions.

/pdf/optimal-reconfiguration-and-capacitor-placement-for-power-15rbq5grfa.pdf

Optimal reconfiguration and capacitor placement for power loss reduction of distribution system using improved binary particle swarm optimization

This article presents an efficient hybrid big bang–big crunch optimization algorithm to solve the multi-objective reconfiguration of balanced and unbalanced distribution systems in a fuzzy framework. The objectives considered are the minimization of total real power losses, the minimization of buses voltage deviation, and load balancing in the feeders. First, each objective is fuzzified, and then the overall fuzzy satisfaction function formed is considered as a fitness function and maximized during the optimization process. The hybrid big bang–big crunch algorithm is an effective and powerful method that has high accuracy and fast convergence, and its implementation is easy. This algorithm using particle swarm optimization capacities improves the capability of the big bang–big crunch algorithm for better exploration. In addition, the hybrid big bang–big crunch uses a mutation operator after position updating to avoid local optimum and to explore new search areas. The effectiveness of the proposed...

An Efficient Hybrid Big Bang–Big Crunch Algorithm for Multi-objective Reconfiguration of Balanced and Unbalanced Distribution Systems in Fuzzy Framework

One of the most available energy sources in the world is solar energy, while in the category of renewable and nonrenewable energies is in the first group. Power generation of a photovoltaic (PV) system is a technique which is possible by using solar cells. Since photovoltaic systems cannot force solar cells to operate at MPP, a controller is needed to do so. If the controller can operate more accurately, or in other words, be optimized, the system will have an appropriate output. Many papers have been presented on maximum power point tracking algorithms. This paper intends to review the previous articles and provide a proper division, performance method. This explains the performance, application, advantages and disadvantages of algorithms to be a good reference for selecting the appropriate algorithm. Algorithms in this paper are divided into four categories methods based on measurement, calculation, intelligent schemes and hybrid schemes. The exhibition of new algorithms and the optimization of previous algorithms have led to the number of articles in this field over the years. In order to review the methods a comparative table is also provided. Finally, a PV system has been controlled by using three algorithms P&O, IC and Fuzzy-PI. The outputs control signals from the MPPT have been applied by Boost and SEPIC converters, and the outputs have been compared. Simulations have been performed in MATLAB/Simulink software.

A comprehensive review and classified comparison of MPPT algorithms in PV systems

(Δ ) are used to generate the optimal MPPT converter duty cycle, such that solar panel maximum power is generated under different operating conditions. A photovoltaic system including a solar panel, a fuzzy MPP tracker and a resistive load is designed, simulated and constructed. The fuzzy MPP tracker includes a buck dc/dc converter, fuzzy controller and interfacing circuits. Theoretical and experimental results are used to indicate the advantages and limitations of the proposed technique.

/pdf/a-new-fuzzy-based-maximum-power-point-tracker-for-14xnt4l1yo.pdf

Mohammad Sarvi

Papers

A PSO‐based maximum power point tracking for photovoltaic systems under environmental and partially shaded conditions

Optimal reconfiguration and capacitor placement for power loss reduction of distribution system using improved binary particle swarm optimization

An Efficient Hybrid Big Bang–Big Crunch Algorithm for Multi-objective Reconfiguration of Balanced and Unbalanced Distribution Systems in Fuzzy Framework

A comprehensive review and classified comparison of MPPT algorithms in PV systems

A new fuzzy-based maximum power point tracker for photovoltaic applications