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

Power electronics

This research study explores the Global Positioning System (GPS), its history, and the process of discovery needed to create the most accurate GPS possible, as well as the contemporary applications of GPS technology. Starting with the first satellite in space, GPS has been a work in progress. Originally pursued by the military for improvements to military tactics, GPS has become integrated into the everyday lives of millions of people around the world. How GPS determines location is a dichotomy, with simplistic theory and complex application. Many factors go into GPS to provide a consistent, accurate location. The orbital planes the satellites are placed in provide 24/7 coverage globally, the L-band frequencies used were chosen specifically for the characteristics they possess, and the multiple atomic clocks installed on each satellite provide incredible accuracy down to the nanoseconds, which is quintessential in GPS accuracy. The applications in GPS are far reaching and more applications are continually being discovered. With as far as GPS technology has progressed, there are still several factors that degrade the signal and are a challenge to overcome. Many of these challenges can be corrected efficiently, however, others, such as scintillation and total electron content variability in the ionosphere, create major hurdles to overcome. Luckily, there are many programs that aid in the correction process of these hurdles. The History of GPS According to R. Saunders’ article ​A Short History of GPS Development,​ The Global Positioning System (GPS) has a long history of trial and error and refinement and improvement. It’s purpose has shifted from being a military strategic asset to commonplace among the general public with its use in traveling, farming, and even banking. The beginning of GPS, introduced with a simple idea, can be traced back to the Soviet Union in the late 1950’s. In 1957, the Soviet Union made history with successfully launching the first satellite in space. To track the satellite Sputnik, Physicists and Scientists at John Hopkins University’s Applied Physics Laboratory listened to the beeps Sputnik’s signals produced. They noticed that the beeps had a Doppler Effect or Doppler Shift as the satellite passed by. Much like the sound a siren makes as a fire truck approaches, then as it passes, the sound of the siren seems different. The change in timing between the beeps let the scientist know Sputnik’s location. This led to the idea of reversing that process, to give a location on the Earth. Using radio frequencies to determine location in a two dimensional plane had been around since WWII, but using satellites would push this technology into the three dimensional realm. The United States Navy, Army, and Air Force all began developing their own GPS satellites in the 1960’s, but this was no small task. In the early 1960’s, the Navy launched its first Transit Satellite. The failure of this satellite, however, was due to

/pdf/the-global-positioning-system-30ag469ov3.pdf

The Global Positioning System

Review on Energy Storage Systems Control Methods in Microgrids

A novel statistical performance evaluation of most modern optimization-based global MPPT techniques for partially shaded PV system is presented in this paper. In recent years, there has been a growing attention toward mitigation of partial shading effect of the PV system through using modern optimization. The field of tracking MPP of the PV system attracts huge attention from the researchers, as it is the best way to increase PV plant efficiency. Under non-uniform solar irradiance, the power against voltage characteristics of PV array have more than one MPP. This condition leads to extra complications to track MPP and decreases the efficiency of the PV system. Traditional MPPT methods are typically used to increase the harvested energy of PV under normal conditions without any problems. The key drawback of such methods is failing extraction of global MPP under actual weather conditions that sometimes under shadowing condition. Several global MPPT methods based on modern optimization are presented for extracting global MPP in case of shadowing condition. The essential target of this work is not limited to present an integrated specific review on the state-of-the-art of these techniques; but also a comprehensive statistical evaluation of twenty optimizers that represent high percent of all the reported techniques is performed with changing shading scenarios. This work serves as a source of valuable information for researchers and engineers working with PV systems to keep abreast with the modern advance in the field of tracking MPP of PV system.

A novel statistical performance evaluation of most modern optimization-based global MPPT techniques for partially shaded PV system

Classical wind energy conversion systems are usually passive generators. The generated power does not depend on the grid requirement but entirely on the fluctuant wind condition. A dc-coupled wind/hydrogen/super capacitor hybrid power system is studied in this paper. The purpose of the control system is to coordinate these different sources, particularly their power exchange, in order to make controllable the generated power. As a result, an active wind generator can be built to provide some ancillary services to the grid. The control system should be adapted to integrate the power management strategies. Two power management strategies are presented and compared experimentally. We found that the “source-following” strategy has better performances on the grid power regulation than the “grid-following” strategy.

https://www.jetir.org/papers/JETIR1604051.pdf

Energy Management and Power Control of a Hybrid Active Wind Generator for Distributed Power Generation and Grid Integration

In this work, an improved Particle Swarm Optimization (PSO) algorithm is employed to perform the Maximum Power Point Tracking (MPPT) of a 1.2 MW Photovoltaic farm under Partial Shading Conditions (PSC). High efficiency, low complexity and reduced tracking time are the main features achieved by integrating the ability to ensure a Global Maximum Power Point (GMPP) operation provided by PSO and the fast convergence of Perturb and Observe (P&O) algorithm. In addition, Sliding-Mode Control (SMC) is used on a cascade scheme on the DC-DC power converters in order to achieve a suitable energy conversion. Thus, the design of the SMC is achieved by using the space state representation of the power converters. Finally, photovoltaic system performance is analyzed for different solar radiation profiles. The obtained results show the proper dynamic and steady-state responses.

Improved particle swarm optimization based MPPT for PV systems under Partial Shading Conditions

This work presents the implementation of a system capable of emulating the production curve of a wind turbine using a DC machine. The system consists of an asynchronous machine-ASM controlled by a variable frequency drive which receives the speed set point from a computer. This ASM was mechanically coupled to a DC generator. A DC/DC power converter was implemented for field weakening control over the DC generator in order to manipulate the generated voltage. The speed produced by the ASM emulates the wind resource. For each speed point, a voltage is generated according to the emulated production curve. Finally, the generated voltage delivered by the DC machine is regulated to a constant 48Vdc bus. This paper describes also the models of the DC generator and of the DC/DC power converters.

Wind generation emulator using a DC machine

This work presents a Battery Energy Storage System (BESS) incorporated to a hybrid generation system — grid connected (Solar Photovoltaic and Eolic) applied in a specific facility located in Quito — Ecuador. For controlling the state of charge and discharge of the battery bank, a supervisory controller based on peak shifting principle is used. A bidirectional converter controls the power flux from the battery into the DC bus and vice versa, whereas the inverter controls the amount of power injected into the AC bus. In order to manage the energy from the inverter, active and reactive (P-Q) control is applied. The control structure involves two cascade loops formed by an internal current control and a superimposed voltage control. Fuzzy logic combined with proportional-integral controllers is applied, ensuring thus, robustness to the system. In this document, the results for two main operating modes, charging and discharging batteries are presented and discussed.

Battery energy storage system for a hybrid generation system grid connected using fuzzy controllers

This work presents an extended study of the work published in the magazine INCISCOS 2018 titled “Improving of the Photovoltaic High Power Plant Generation Using DC/DC Micro Converters”, and intented to increase the amount of electrical energy generation of a Photovoltaic Plant located in Salinas, Imbabura Province, Ecuador through the implementation of DC/DC converters in the solar panel arrays and tracking techniques of the maximum power point. The results show that the insertion of the DC/DC converters in the system causes an increase in the amount of active power. The system is analiced in variation of solar radiation or changes in the ambient temperature as well.

/pdf/analisis-del-uso-de-micro-convertidores-dc-dc-enfocados-en-2igoac57rn.pdf

Análisis del uso de micro convertidores DC/DC enfocados en la extracción máxima de energía en una granja fotovoltaica

This work presents a test method used in a simulation environment to increase the amount of electrical energy produced by the generation stage of the Photovoltaic Plant located in Salinas, Imbabura Province, Ecuador through the inclusion of DC-DC converters in the solar panel arrays and tracking techniques of the maximum power point. The results indicate that the insertion of the DC-DC converters in the system causes an increase in the amount of active power, when the system is exposed to the variation of solar radiation or changes in the ambient temperature.

Nataly Pozo

Papers

Improved particle swarm optimization based MPPT for PV systems under Partial Shading Conditions

Wind generation emulator using a DC machine

Battery energy storage system for a hybrid generation system grid connected using fuzzy controllers

Análisis del uso de micro convertidores DC/DC enfocados en la extracción máxima de energía en una granja fotovoltaica

Improving of the Photovoltaic High Power Plant Generation Using DC/DC Micro Converters