Electric Generator Research Articles

The effect of ions on liquid-solid interface investigated by charge sensitive direct current droplet-based electricity generator

The contact electrification (CE) between DI water and SiO2 or fluorinated polymer has been proven to be mainly due to electron transfer, which is significantly influenced by ions in solution. However, how these ions in water affect the charge transfer at the liquid-solid (L-S) interface is still unresolved, especially for the already charged friction layer. Here, a direct current droplet-based electricity generator (DC-DEG) which is sensitive to the change of charge transfer at the L-S interface is adopted to detect the effects of ions in the neutral salt solution on the charged PTFE surface. The distribution of ions on the charged L-S interface (the change of electric potential on the solid surface) and its effects on the output of DC-DEGs have been studied. The results indicate that the charge transfer of droplets and then the output of DC-DEGs are closely related to the concentrations of salt solutions. Anions can enhance the surface potential of PTFE due to their adsorptions on PFTE while cations can reduce it due to their screen effect. At low ionic concentrations, the surface potential enhancement caused by anion adsorption is larger than that surface potential reduction caused by screen effect from cations. At high ionic concentrations, the electrostatic screen effect of cations increases a lot to weaken the surface potential and reducing the charge separation of droplets induced by electrostatic induction (EI). This work explains the redistribution process of ions at the L-S interface and also provides a clever solution for improving the electrical output performance of DEGs.

Possibilities of using a corona electric discharge generator in the processes of water and surface sterilization

Possibilities of using a corona electric discharge generator in the processes of water and surface sterilization

Control Method of Load Sharing between AC Machine and Energy Storage Bank in the DC Grid

The article presents the issues related to load-power sharing in direct-current grid and a novel control method has advantages over known solutions. Unlike many similar-sounding papers, this article shows an attempt at creating fully controllable non-isolated system that allows for load-power sharing between a permanent magnet alternator equipped with machine-side converter (MSC) and a dual active bridge (DAB) tied to batteries or supercapacitor. The current-based load-power sharing is an essential feature of parallel-connected direct-current generators, and all types of voltage sources, in this way are contributing power to the system. To keep the optimal efficiency of the alternator, the rotational speed changes rely on proper mapping of the driving combustion engine. System components include a self-excited synchronous generator (SESG), operating at variable shaft speed, as well as batteries and supercapacitors that provide electricity for sudden electrical-load changes on the distribution grid. The core of the presented system is in a power-distribution method that consists of a programmed-controller structure allowing precise current distribution. A novelty of the proposed method is the use of a cascaded system of current and DC voltage regulators that allows for precise power-distribution control. In contrast with previously presented solutions, the proposed system allows for fast and accurate control of currents, loading parallel-connected DC voltage sources for wide-range generator speed changes. In the presented solution, both converters have been equipped with Schottky diodes, preventing the flow of equalizing currents between closed transistors in the parallel mode of operation. An experimental test-stand of the described system is presented with its theoretical basis and experimental results.

Design and Analysis of a Linear Electric Generator for Harvesting Vibration Energy

This paper provides a proof of concept for a linear electric generator that can be used to harvest energy from various sources of linear motion, such as vibrations, free-piston engines and wave energy. The generator can be used to power small electronic devices, such as sensors, or charge household batteries. The literature was reviewed to develop an understanding about the applications, control methods, excitation methods and mechanics of rotating and linear electric machines. A bidirectional, two-sided linear machine was designed with two stator cores and a single mover core. The stator windings and mover winding can be independently excited, allowing for three modes: no mover excitation, a DC excited mover, and an AC excited mover. Simulation results showed that the magnetic flux generated by DC excited stator cores were concentrated in the centre of the mover core. The use of two stator cores eliminates lateral flux in the mover core when it is not excited, minimising attraction and repulsion forces. Parametric analysis showed that flux cutting occurred in all operation modes, verifying that the generator will produce power when operating. Hardware tests produced an output current when the machine was electrically and mechanically excited, verifying the proposed design.

THE DEPENDENCE BETWEEN THE OPTIMAL MECHANICAL ANGULAR SPEED AND THE VARIABLE WIND SPEED FROM AN ENERGETIC POINT OF VIEW

This paper examines the fundamental elements required for operating a wind turbine (WT) at its maximum power point (MPP). It focuses on measuring the wind speed and the power output from the electric generator (EG) over time to establish the relationship between the optimal mechanical angular velocity (MAV) and the wind speed, denoted as the function ωOPTIM(V). This function is crucial for controlling the power output of the electric generator, ensuring that the WT operates at its maximum power point. The study analyzes the measurements taken from the turbines in Siliștea in Dobrogea, Romania. The paper concludes by presenting an algorithm to determine the function ωOPTIM(V).

Peningkatan Kapasitas Digester Untuk Kecukupan Produksi Biogas Sebagai Bahan Bakar Generator Listrik

The development of dairy farming in Nagari Lasi District Canduang, Agam Regency, West Sumatra Province, has provided the materials a massive source of biogas production. The number of cattle in Nagari Lasi has reached around 1000 heads, plus other livestock such as Buffaloes and Goats. The manufacture of digesters in the previous year's Community service activities was a success. It produces biogas and is used for cheese production and household supply. However, the amount of biogas produced is still tiny. To realize "Community-Independent Energy," power generator installation is necessary. The biogas supply must be in large quantities and available continuously for the generator to operate. Biogas currently produced by the digester is insufficient to produce the biogas required by the generator. Therefore, biogas production capacity needs to be improved by expanding the volume of the digester that will be processing cow dung into biogas. Increasing digester capacity has significantly increased biogas production, reaching 12 m3 per day. This amount is enough to be used as fuel for an electric generator continuously.

New solutions for mechanized small diameter shaft sinking for residual oil production

The huge losses of oil in the subsurface necessitated the search for ways to extract residual oil, which led to the idea of combined use of the practice of mining and oil production. This involves drilling two vertical wellbores in the side rocks on the lying side of the oil reservoir, which are connected by two inter-hole joints. From the upper joint, a full series of wells pass along the entire strike of the formation at a certain interval with depth into the formation, into which steam supply pipes are placed with plugged ends at the bottom of the wells and lateral dispersed holes along their entire length. At the wellhead, these pipes are connected to individual high-pressure pulsating electric steam generators, and the wells themselves at the wellhead and the steam supply pipes are plugged. The electric steam generators are operated in line with a preset program. The most labor-intensive and costly in the idea of combined use of mining and oil production technologies is the sinking of vertical mine shafts, which requires new solutions in mine development technologies. In this regard, it is planned to reduce the cost of mining operations with the purpose of their use in oil production by means of non-explosive continuous mechanical-hydraulic pulse breaking of rocks of any strength and abrasiveness. Keywords: hydraulic pulse breaking of rocks; residual oil recovery technology; minimum diameter shaft sinking; two-jaw grab.

All-Wood-Based Ionic Power Generator with Dual Functions for Alkaline Wastewater Reuse and Energy Harvesting.

Water-induced electricity harvesting has gained much significance for energy sustainability. Bio-based hydrovoltaic materials increase the attractiveness of this strategy. Although promising, it faces a challenge due to its reliance on fresh water and its inherently low power output. Herein, the energy from alkalinity-gradient power generation demonstrated the feasibility of reuse of alkaline wastewater to develop an all-wood-based water-induced electric generator (WEG) based on ion concentration gradients. The intermittent water droplets bring about uneven distribution of electrolyte and endow delignified wood with the difference of ion concentration along aligned cellulose nanochannels, thus supplying electrical power. The practice of using alkali reservoirs, including industrial wastewater, further contributes to electricity generation. The cubic WEG with a side length of 2 cm can produce an ultrahigh open-circuit voltage of about 1.1 V and a short-circuit current of up to 320 μA. A power output of 6.75 μW cm-2 is correspondingly realized. Series-connected WEGs can be used as an energy source for commercial electronics and self-powered systems. Our design provides a double value proposition, allowing for sustainable energy generation and wastewater reuse.

Droplet-Based Direct-Current Electricity Generation Induced by Dynamic Electric Double Layers.

Harvesting energy from water droplets has received tremendous attention due to the pursuit of sustainable and green energy resources. The droplet-based electricity generator (DEG) provides an admirable strategy to harvest energy from droplets into electricity. However, most of the DEGs merely generate electricity of alternating current (AC) output rather than direct current (DC) without the utilization of rectifiers, impeding its practical applications in energy storage and power supply. Here, a direct current droplet-based electricity generator (DC-DEG) is developed by the simple configuration of the electrodes. The DC output originates from the dynamical electric double layer (EDL) formed at two electrodes and droplet interfaces where the charging/discharging process of EDL capacitance occurs. Several experiments are exhibited to demonstrate the rationality of the proposed principle. The influence of some factors on the output is investigated for further insight into the DC-DEG device. This work provides a novel strategy to harvest energy from water droplets directly into DC electricity and may expand the application of DEGs in powering electronic devices without the help of rectifiers.

Noninvertible symmetries and anomalies from gauging 1-form electric centers

We devise a general method for obtaining 0-form noninvertible discrete chiral symmetries in 4-dimensional SU(N)/ℤp and SU(N) × U(1)/ℤp gauge theories with matter in arbitrary representations, where ℤp is a subgroup of the electric 1-form center symmetry. Our approach involves placing the theory on a three-torus and utilizing the Hamiltonian formalism to construct noninvertible operators by introducing twists compatible with the gauging of ℤp. These theories exhibit electric 1-form and magnetic 1-form global symmetries, and their generators play a crucial role in constructing the corresponding Hilbert space. The noninvertible operators are demonstrated to project onto specific Hilbert space sectors characterized by particular magnetic fluxes. Furthermore, when subjected to twists by the electric 1-form global symmetry, these surviving sectors reveal an anomaly between the noninvertible and the 1-form symmetries. We argue that an anomaly implies that certain sectors, characterized by the eigenvalues of the electric symmetry generators, exhibit multi-fold degeneracies. When we couple these theories to axions, infrared axionic noninvertible operators inherit the ultraviolet structure of the theory, including the projective nature of the operators and their anomalies. We discuss various examples of vector and chiral gauge theories that showcase the versatility of our approach.

Freeboard and Trim Measurement: a Case Study of Landing Craft Tank Conversion to Ship Power Plan

In this research, the ship power plan which is the result of a conversion from a landing craft tank is designed to meet the electricity needs in areas affected by a disaster or electricity crisis. So far, the government has chartered a similar ship from Turkey which is used to meet electricity needs in Indonesian areas which have been affected by the disaster and electricity crisis. This ship is modified to carry an electric generator which can later be sent to areas that need it. Two main focuses are the goal of this research, the first is to find the value of the freeboard and the second is the trim of the ship after the redesign. To achieve this goal, in this study a numerical calculation method was used to calculate the freeboard and trim values according to applicable standards. The results of the analysis show that the freeboard value is still safe, with the actual freeboard value being greater than the required freeboard (0.8 m > 0.44 m). For ship trim, the bow trim condition is obtained with a smaller LCG-LCB difference than the 0.05% LPP value (0.912 < 0.923). By looking at the results of these measurements, the condition of the ship's freeboard and trim is still in a fairly good category even though it has been converted from a landing craft tank to a ship power plant. This study can provide a reference for ship design before converting the actual ship so that it can carry out trim and freeboard tests to prevent build failures.

Анализ электромагнитных процессов блока возбуждения трехкаскадного стартер-генератора для авиационной энергосистемы

This article discusses the excitation system of a three-stage synchronous generator for aviation use in two distinctive modes of operation: as an electric power generator for an on-board power supply system and an electric starter for gas turbine engines of the aircraft. The article presents the calculation of the starter and generator operating modes of the excitation system. The basic design relations for the semiconductor converter circuit have been obtained and confirmed by simulation modeling in the PowerSIM environment. The problem of synthesizing an automatic control system for the TSG excitation unit operating as part of an on-board power supply system using a method for calculating the parameters of regulators based on the motion separation method has been solved. A two-circuit control system has been created for the generator mode of operation, including PI and PID regulators with output voltage regulation of the main generating stage. To control the excitation unit in the electric star¬ter mode of operation, a single-circuit control system for the current of the excitation winding with the addition of a resonant component has been designed. The evaluation of the efficiency of the designed control systems was carried out on the basis of simulation modeling using PowerSIM and MATLAB/Simulink application software packages for a generator feeding a three-phase AC network in accordance with the requirements of GOST R 54073-2017.The results of mathematical modeling formed the basis for the design of an experimental sample of the power unit in a hybrid integrated design for the TSG voltage regulation system.

THE NATURE OF ELECTRICITY

Definition: Electricity is one of the seven aggregate states of space, its elementary quanta, which exist in the form of two separate components – electrical and magnetic. In electric current generators, the quanta of space are split into electrical and magnetic parts with energy absorption. In current consumers, quanta of electricity combine with quanta of magnetism into elementary quanta of space with the release of energy.

Visualizing the Maximum Energy Zone of Wind Turbines Operating at Time-Varying Wind Speeds

Wind turbines are one of the leading renewable sources of electricity. They are located in areas where the energy potential of the wind is high and more or less permanent. Their efficient operation depends on certain technical characteristics of the entire wind system (wind turbines, generator, automation system, regulation, and control). This paper analyses experimental data from wind turbines, WT, in the Dobrogea area: wind speed, v, velocity, n, and power, PEG, at the electric generator, EG. These are used to identify the local maxima of wind turbine power at different wind speeds. Based on this, a mathematical model for wind turbines and the power losses caused by inefficient control are determined. The mathematical model is used to visualize the maximum energy zones. At the end of this study, an algorithm is given that allows for the visualization of the optimal energy zone. The algorithm resulting from the analyzed case studies can be implemented by the control system in order to maximize the produced electricity with any variation in wind speed.

Electrical pruning of Pinus radiata epicormic growths

A novel method for pruning epicormic growths with high voltage energy pulses is presented. This method could be utilized in autonomous forest management, for example by a drone carrying an electrical pulse generator and applicator pruning device. In a laboratory setting, short duration, high voltage pulses of electricity were generated using a capacitor network and a current source. These pulses were applied to Pinus radiata needles and the relative tissue injury to the needles was assessed by estimating electrolyte leakage from the needles in deionised water using electrical conductivity (EC) measurements. EC was positively correlated with the electrical energy applied. This validated the theory that electrical stimuli can cause increased cell death in plant matter. The cell damage, based on electrolyte leakage, caused by stimulating a Pinus radiata needle with a single 1.5 J pulse of energy was 21 % of the maximum, where the maximum was found to result in an EC of 333 µS/cm per gramme of needle in a 45 ml solution. These results from testing on needles removed from the tree confirm the potential of electrical pruning of epicormic growths. Future testing on live in-situ needles will be implemented to determine the level at which cell death induced by the application of high voltage pulses is sufficient to prune epicormic growths, given that mechanical and biotic factors of needles removed from the tree may enhance the rate of cell death in harvested samples.

Simulation methodology and numerical comparison of boxer and opposed free piston linear generator configuration in 0D/1D environment

Free Piston Linear Generators (FPLGs) are thermal machines suitable for both stationary power generation unit (PU) and vehicle propulsion. They convert chemical energy from the fuel into electric energy to charge a battery using a linear electric generator. Due to the reduction of friction losses and the ability to work with different compression ratios, FPLGs are potentially characterized by high overall global efficiency with respect to a conventional alternative internal combustion engine. Like conventional internal combustion engines, FPLGs have several configurations: single piston, dual piston, opposed piston and boxer are the configurations considered in this work. Two configurations are compared in this paper from a functional and energetic perspective: opposed piston (Opposed) and Boxer. This is done with the aim to highlights pro and cons of these configurations. They are modelled using the 0D/1D modelling coupling GT-Power® and Simulink®. The comparison between the two configurations was done modelling the architecture with the same size and in two-strokes operating mode. The comparison of the two configurations highlights differences between them in terms of scavenging process, thermodynamic efficiency and global energy efficiency, putting in evidence what aspects need to be improved for each configuration and what are their advantageous features. Boxer configuration can provide less power due to lower volumetric efficiency compared to the Opposed configuration. Boxer configuration can provide 102.2 kW while Opposed can provide 110.0 kW at full load with a frequency of 20 Hz (equivalent to 1200 rpm). The Opposed configuration results in lower heat loss but higher energy lost at the exhaust. The final balance shows that Boxer configuration has a slightly higher brake efficiency (equal to 28.9 %) compared to the value found for Opposed (27.6 %).

Multi-modal safety analysis of the more electric aircraft starter generator system

Multi-modal safety analysis of the more electric aircraft starter generator system

Semi-supervised diagnosis of wind-turbine gearbox misalignment and imbalance faults

Both wear-induced bearing failure and misalignment of the powertrain between the rotor and the electrical generator are common failure modes in wind-turbine motors. In this study, Semi-Supervised Learning (SSL) is applied to a fault detection and diagnosis solution. Firstly, a dataset is generated containing both normal operating patterns and seven different failure classes of the two aforementioned failure modes that vary in intensity. Several datasets are then generated, maintaining different numbers of labeled instances and unlabeling the others, in order to evaluate the number of labeled instances needed for the desired accuracy level. Subsequently, different types of SSL algorithms and combinations of algorithms are trained and then evaluated with the test data. The results showed that an SSL approach could improve the accuracy of trained classifiers when a small number of labeled instances were used together with many unlabeled instances to train a Co-Training algorithm or combinations of such algorithms. When a few labeled instances (fewer than 10% or 327 instances, in this case) were used together with unlabeled instances, the SSL algorithms outperformed the result obtained with the Supervised Learning (SL) techniques used as a benchmark. When the number of labeled instances was sufficient, the SL algorithm (using only labeled instances) performed better than the SSL algorithms (accuracy levels of 87.04% vs. 86.45%, when labeling 10% of instances). A competitive accuracy of 97.73% was achieved with the SL algorithm processing a subset of 40% of the labeled instances.Graphical abstractSteps and processes for approaching semi-supervised FDD of wind-turbine gearbox misalignment and imbalance faults

Efficient control of the fully passive oscillating foil in 2D confined flows with adjustment of the heave damping

A foil that is free to pitch and heave in an upstream flow can oscillate very regularly and with large amplitudes given that its inertial properties and support stiffness in pitch and heave are well adapted to the flow velocity. Useful energy can be extracted from these oscillations via an appropriate damping in heave that models the presence of an electric generator. In recent years, the structural parameters of such a fully passive oscillating-foil turbine (OFT) have been optimized, yielding a maximum energy extraction efficiency of 51.0% under the assumptions of 2D and unconfined flow. However, the turbine is normally deployed in channels with finite cross-sectional area, thus impacting the flow rate passing through the turbine via the blockage effect. In this work, we extend the applicability of the 2D optimized structural parameters to 2D confined scenarios with a simple tuning of the viscous heave damping coefficient. Performance is determined via a fluid-structure interaction solver based on an unsteady Reynolds-averaged Navier–Stokes approach. As expected, confining the turbine increases the heave amplitude and the power, up to a point where the motions become chaotic, and thus require an increase in the heave damping coefficient. This study shows that in all confined 2D scenarios, reasonably good performances of the fully passive OFT can be maintained when using its optimal structural parameters obtained in 2D unconfined conditions, given that the generator is adjusted accordingly.

Future Scope and Current Energy Situation of Wind Energy, with a Simulation of Small Wind Farm in Matrix Laboratory (MATLAB)

When the world is going through extreme energy shortage, mainly the non-renewable energies, wind energy is the hope along with solar energy, hydro energy, nuclear energy and bio mass energy to meet the energy demand. In the end of 2021, in India only, the wind capacity was 40 GWatt [8]. By the end of 2030, new 30 GWatt offshore wind capacity will be installed [8]. Wind turbines may be of various shapes and sizes. When more than one wind turbines are working together to create electrical power, they form a wind farm. The aim of this particular project is to make a simulation of a small wind farm of 4.5 MW in the simulation part of MATLAB software. Here squirrel cage induction generators are used as the electrical generators connected to the turbines. It generates power for the grid. SVC is connected to the wind turbines to control the overall reactive power. The aim is to make a MATLAB Simulink phasor model of a 4.5 MW wind farm with SVC with three fully functioning wind turbines.