Electric Generator Research Articles

On the Effect of Current Stabilizer on Dynamics of a Small Hybrid Wind Power Generator

The use of small wind power generators remains quite relevant. In particular, they can be efficient for charging batteries in remote locations where there is no centralized power supply (including in the Arctic, Far East, etc.). They can also be used as part of missions to planets with atmospheres. One of the promising design solutions for a small wind power generator with a vertical axis of rotation is a hybrid device. It consists of two wind turbines that have a common axis of rotation: external (Darrieus wind turbine) and internal (Savonius rotor). This scheme represents a compromise between the relatively high power coefficient of the Darrieus turbine and the good startup characteristics the Savonius rotor. It is known that one of the typical battery charging modes is constant current charging. Here we consider a hybrid installation, the generator of which is connected to a current stabilizer. The load is simulated with an active resistance. It is assumed that the generator is a DC generator. A closed mathematical model of the studied system is constructed. The aerodynamic load is described using the quasi-steady approach. It is assumed that the characteristic time of electrical processes is much smaller than the characteristic time of mechanical processes. The influence of load resistance on the behavior of the system is investigated. It is shown that, under certain conditions, several steady modes (up to five) exist in the system. In this case, at least two of them are attracting. Therefore, the hysteresis of the angular speed of the steady mode is possible when the load resistance changes. It should be noted that in a number of situations, an unstable steady mode (which corresponds to a lower angular speed of the turbine than a stable one) may be preferable (for example, to reduce the load on bearings). In this regard, a resistance control strategy has been proposed to ensure stabilization of the unstable stationary regime.

Multi‐operating characteristic analysis and loss optimization of novel large capacity high‐speed permanent magnet generator

AbstractRecently, the development trend of large capacity generator has gradually shifted from electrical excitation generator to permanent magnet generator (PMG). As a result, the large capacity high‐speed permanent magnet generator (HSPMG) with high power density and high efficiency have received widespread attention. This paper aims to analyse the loss optimization of novel large capacity HSPMG under multi‐operating conditions. In terms of the parameter requirements, a 2.5 MW and 7000 rpm HSPMG is designed. To verify the accuracy of simulation model and the rationality of generator design, the output characteristics of large capacity HSPMG which has been combined with prototype experimental data are calculated under both no‐load and load conditions. Based on the load power characteristics of large capacity HSPMG, the optimization range of the magnetization angle under multi‐operating conditions is explored. By analysing the no‐load back electromotive force (EMF) and loss characteristics of large capacity HSPMG, the optimal magnetization angle that corresponds to the minimum loss under three conditions is obtained. The correctness of the analysis and optimization method is verified by comparing the loss distribution and electromagnetic results before and after the optimization. The research results provide a reference for the multi‐operating characteristics analysis and loss optimization of large capacity HSPMG.

Low-Cost Cascade Thermoacoustic Electric Generator for Energy Harvesting

The cascade thermoacoustic heat engine has garnered significant attention for its ability to convert various heat sources into acoustic power without the challenges of acoustic streaming. By integrating it with a commercial loudspeaker, it can be further developed into a novel, low-cost thermoacoustic electric generator. This study aims to design and evaluate a thermoacoustic electric generator capable of producing several watts of electricity. The system consists of a cascade thermoacoustic engine, comprising a standing-wave and a traveling-wave unit, coupled with a B&C 6PS38 loudspeaker in a linear configuration. Atmospheric air is used as the working fluid, and standard market components, such as PVC and steel pipes, are proposed to minimize costs. Unlike traditional thermoacoustic generators, this system uses commercially available loudspeakers and a linear configuration, offering a cost-effective solution for low-wattage power generation, free from the issue of acoustic streaming. This makes it suitable for small-scale, distributed energy systems. The numerical simulation tool DeltaEC is employed to design and assess the system's performance. The optimal configuration is 4 meters long, with the standing-wave and traveling-wave units centrally positioned. Operating at a frequency of 74.56 Hz, the system generates 90.18 W of electrical power with a total heat input of 1046.74 W and an external load resistance of 19.77 ohms. This corresponds to a heat-to-acoustic efficiency of 18.41%, an acoustic-to-electric efficiency of 68.98%, and an overall heat-to-electric efficiency of 8.62%. The study also emphasizes the importance of operating conditions and impedance matching between the cascade engine and the loudspeaker. These findings represent progress toward developing an affordable thermoacoustic generator for energy recovery and other applications.

A FINANCIAL EVALUATION OF WHEAT PRODUCTION PROJECTS UNDER CENTER PIVOT IRRIGATION SYSTEMS IN ANBAR GOVERNORATE

The research aims to identify the financial feasibility of cultivating the wheat crop under modern irrigation systems in desert areas and to clarify the impact of the capacity of the systems in those projects in achieving the financial feasibility of their establishment, using the economic evaluation criteria for the projects. The research included a study of 60 projects in Anbar Governorate for the 2020-2021 production season. It has been shown that projects that use several systems, despite their high investment costs, can recover the money invested in them within a relatively short period. The projects that use modern irrigation systems covering 60 donums were among the best projects that achieved technical efficiency in the productivity of the wheat crop, and the average net income reached the cash in the sample is about 1.3 billion dinars, while the average net income per donum in the research sample is about 189 thousand dinars. The sample was not able to achieve accounting profits, The research recommended the need to use electric power systems as an alternative to relying on electric power generators, as the average price of solar power systems in the Iraqi market is currently within reach.

Geometric Evaluation of an Oscillating Water Column Wave Energy Converter Device Using Representative Regular Waves of the Sea State Found in Tramandaí, Brazil

Aiming to contribute to studies related to the generation of electrical energy from renewable sources, this study carried out a geometric investigation of an oscillating water column (OWC) wave energy converter (WEC) device. The structure of this device consists of a hydropneumatic chamber and an air duct, where a turbine is coupled to an electrical energy generator. When waves hit the device, the air inside it is pressurized and depressurized, causing the air to flow through the duct, activating the turbine. In this sense, the present study used the constructal design method to evaluate the influence of the ratio between the height and length of the hydropneumatic chamber (H1/L) on the mean available hydropneumatic power (PH(RMS)). Fluent software was used to perform numerical simulations of representative regular waves from the sea state in the municipality of Tramandaí, southern Brazil, impacting the OWC. Thus, it was possible to identify the geometry that maximized the performance of the OWC WEC, with (H1/L)O=0.3430, yielding PH(RMS)=56.66 W. In contrast, the worst geometry was obtained with H1/L=0.1985, where PH(RMS)=28.19 W. Therefore, the best case is 101% more efficient than the worst one.

Water-Triboelectrification-Complemented Moisture Electric Generator.

Energy harvesting from ubiquitous natural water vapor based on moisture electric generator (MEG) technology holds great potential to power portable electronics, the Internet of Things, and wireless transmission. However, most devices still encounter challenges of low output, and a single MEG complemented with another form of energy harvesting for achieving high power has seldom been demonstrated. Herein, we report a flexible and efficient hybrid generator capable of harvesting moisture and tribo energies simultaneously, both from the source of water droplets. The moisture electric and triboelectric layers are based on a water-absorbent citric acid (CA)-mediated polyglutamic acid (PGA) hydrogel and porous electret expanded polytetrafluoroethylene (E-PTFE), respectively. Such a waterproof E-PTFE film not only enables efficient triboelectrification with water droplets' contact but also facilitates water vapor to be transferred into the hydrogel layer for moisture electricity generation. A single hybrid generator under water droplets' impact delivers a DC voltage of 0.55 V and a peak current density of 120 μA cm-2 from the MEG, together with a simultaneous AC output voltage of 300 V and a current of 400 μA from the complementary water-based triboelectric generator (TEG) side. Such a hybrid generator can work even under harsh wild environments with 5 °C cold and saltwater impacts. Significantly, an optical alarm and wireless communication system for wild, complex, and emergency scenarios is demonstrated with power from the hybrid generators. This work expands the applications of water-based electricity generation technologies and provides insight into harvesting multiple potential energies in the natural environment with high output.

Experimental implementation of extremum-seeking control: Gas fuel efficiency at electrical generation under power requirements

A current challenge stands for operating the emergency power system (EPS) that involves the challenge of supplying sufficient electrical energy at same time the fuel consumption is minimum. A complication arises as power requirements change during the EPS operation which can be seen as uncertain load disturbances. In such a context, the extremum-seeking (ES) is alternative towards the efficient energy conversion when control goal involves fuel optimization along the time operation. Here, the dynamical response of a gas fueled power plant is identified via Hammerstein model. The model is realized such that an ES control is designed for automatically reaching an extreme in face to distinct (unmeasured and uncertain) power requirements. The ES control is designed and experimentally tested at an electrical generator at distinct power requirements. The results show the minimum gas fuel consumption remains in face to distinct power requirements.

Design and tests of a marine current turbine in low flow velocity

Marine current energy is recognized a promising energy source due to its inherent stability and high predictability. In the past decade, several milestones have been achieved in marine current turbine (MCT) research such as MeyGen and O2. However, compared with high-velocity currents, low velocity currents are more commonly distributed worldwide, which presents new challenges. The demand for low starting velocity and high efficiency necessitates some novel structure in the design of blade, power transmission, etc. To address these issues, taking a 50W MCT as research object, this paper firstly presents the MCT design of a new fan-shaped rotor configuration, a compact non-contact magnetic coupling, a low inertial power train and hollow-cup DC generator for easier starting. Furthermore, to realize the maximum power point tracking (MPPT) and sustainable power supply, the electrical system and its control strategy were designed. The hydrodynamic performance of the fan-shaped rotor was simulated and analyzed using CFD, and a simulation model of the electrical and control systems was constructed and tested to verify the performance. Finally, the tank and sea tests were respectively conducted to validate the performance of proposed MCT. The results indicate that the proposed MCT is capable of starting at velocities around 0.2 m/s and achieving a power coefficient (Cp) exceeding 0.4, making it well-suited for providing a continuous and stable power supply in areas with low flow velocities.

COMPUTER MODELING OF TRANSIENT ELECTROMECHANICAL PROCESSES IN A WIND POWER PLANT WITH A MAGNETIC GEARBOX

In this work, a computer Simulink model of a wind power plant has been developed, which uses a magnetic gearbox instead of a mechanical gearbox and also contains a synchronous permanent magnet generator. A separate Simulink model of a magnetic gearbox built on the basis of a modulated magnetic field in the air gap was developed, which al-lows to study the stability of its operation both in steady-state and transient modes. Calculations of various dynamic modes of the wind power plant’s operation were carried out, based on the developed model, such as the starting mode, an instantaneous increase in the wind speed acting on the wind turbine, and an increase in the load of the electric gen-erator. According to the results of the calculations, it is shown that in transient modes, when short-term overloads oc-cur, both rotors of the magnetic gearbox can fall out of synchronous motion for a certain period of time and then, de-pending on the parameters of the gearbox (as well as its other elements), the electromechanical system either reaches a certain operating steady-state mode or loses the ability to transfer mechanical power from the wind turbine to the gen-erator. It has been shown that the use of a more powerful magnetic gearbox, with an increased value of the maximum magnetic torque, allows of a more overload-resistant operation of both: a gearbox and the wind plant as a whole. Ref-erences 9, figures 10.

Silage harvesting for small farms by using vacuum sealing in flexible polymer containers on a converted trailer

The article presents an analysis of milk production in Kazakhstan and identifies the reason for its low level, which is due to deficient feed, especially in small farms and in the private sector. The difficulty of saving the limited silage volume is due to the lack of preparation technology for preventing spoilage. The objective of this work is to complete the necessary equipment of a mobile tractor-trailer to reduce the specific energy consumption when preparing silage in flexible containers using a vacuum seal to increase the productivity of dairy cattle farming in smallholder and the private sector of the Republic. The basic rational parameters for sealing the silage by vacuum in the field on a mobile tractor-trailer for ease of transport and storage are obtained: silage weight in a flexible container – 769.6 kg, geometric dimensions of the sealed container by height (0.90 m), width (0.85 m) and length (0.85 m). The efficiency of the specific energy consumption of the proposed method for silage preparation is established at 35% compared with the traditional method. The recommended technology of silage preparation in flexible containers will be possible when conventional tractor-trailers are retrofitted with standard portable equipment (internal combustion engine-based (ICE) electric generator, vacuum pump, film welder).

Analysis of Energy Efficiency Parameters of a Hybrid Vehicle Powered by Fuel with a Liquid Catalyst

A notable trend in the modern automotive market is the increased interest in hybrid cars. Hybrid cars combine a standard internal combustion engine with an electric motor solution. Research into increasing the energy efficiency of a conventional unit while meeting increasingly stringent exhaust emission standards is becoming a key postulate in this matter. This article discusses an analysis of modifying the fuel used by hybrid vehicles using the example of a selected drive unit equipped with a spark-ignition engine. This effect was tested after the Eco Fuel Shot liquid catalyst was added to the fuel. The research process was carried out in two stages, as follows: in road conditions using the Dynomet road dynamometer; and on the V-tech VT4/B2 chassis dynamometer. Tests were carried out to replicate road tests with a catalytic additive in the fuel. A mathematical model was created and the following energy efficiency parameters of the hybrid vehicle were calculated: the torque of the internal combustion engine, electric motor, and generator; the rotational speeds of the internal combustion engine, electric motor, and generator; the power of the internal combustion engine, electric motor, and generator; the equivalent fuel consumption of the electric motor and generator; the fuel consumption of the internal combustion engine, electric motor, and generator; and the mileage fuel consumption of the internal combustion engine, electric motor, and generator. The results of the tests made it possible to identify the benefits of using the tested liquid catalyst on the operation of the drive system of the analyzed hybrid vehicle. This research will be of benefit to both the demand side in the form of users of this category of vehicles, and the supply side represented by the manufacturers of power units.

Design of Moisture-Enabled Electric Generators Utilizing sp- and sp2-Hybridized Two-Dimensional Carbon Materials: A Minireview and Perspectives

Design of Moisture-Enabled Electric Generators Utilizing sp- and sp²-Hybridized Two-Dimensional Carbon Materials: A Minireview and Perspectives

Wave-to-wire modelling and hydraulic PTO optimization of a dense point absorber WEC array

We investigate the hydrodynamic interactions and power extraction efficiency of a dense array of Point Absorber (PA) Wave Energy Converters (WECs) clustered around the fixed pillar of a wind turbine –the Ocean Grazer device– with a standard hydraulic Power Take-Off (PTO) system. Using potential flow theory, a detailed wave-to-wire model is developed in WEC-Sim with four distinct hydraulic PTO designs: i) Multi PTO-with individual hydraulic PTO systems for each buoy, ii) Shared PTO V1-with a unified PTO system for the entire array, iii) Shared PTO V2-with the accumulator volume split into two segments, and iv) Shared PTO V3-with four strategically distributed segments. Key parameters such as the diameter of the hydraulic pistons, volume and pre-charged pressure of the high-pressure accumulators, hydraulic motor displacement and the speed of the electric generator are optimized with a genetic algorithm and a parametric analysis across various sea states. The results highlight that strategically allocating the accumulators across the floaters of a dense WEC array can yield significantly higher power production and should be considered at the early design stages.

Sustainable solution to the critical challenges of an oceanic wave farm for maximizing power generation

In this paper, a general wave farm design procedure has been presented. For example, the design procedure is applied to the Bay of Bengal, Bangladesh. Firstly, the most effective site is selected to construct a wave farm considering various techno-economic factors. A coordinated drawing for the proposed site selection procedure is presented, which includes a coastal area map and sea, grid map, wave height, and different assorted factors. Transmission line cost is analyzed for nearly equipotential locations. Then wave height, time period, wave power, and vertical speed are observed for the selected location. In the next step, a wave farm layout has been designed considering point absorber type device and the oceanic wave dataset with statistical analysis. Further, a linear electrical generator (LEG) is designed and analyzed for the wave farm. The generator is simulated in the ANSYS/Maxwell environment. Since the wave parameters vary from time to time, the LEG is simulated for several vertical speeds. To find the highest output power, the load profiles are analyzed for each speed separately. In the next step, the LEG is optimized. Simulation result shows that the flux distribution of optimized LEG is better than its initially designed counterpart. Efficiency of the optimized LEG is 7 % greater than its initial design. The proposed method of site selection, statistical analysis of the wave dataset, and the optimized LEG design are combined in this paper for maximum wave energy extraction.

Numerical study of [formula omitted]-fuelled micro-free piston CHP system, coupled with thermophotovoltaic (TPV) and battolyser units

Hydrogen (H2) fuelled internal combustion engines (ICEs) can play an important role in small-scale applications despite low efficiency, short reactant residence time and pre-combustion issues. In this study, a hybrid green H2 production and utilisation system covering renewable-powered H2O electrolysis, micro-CHP (combined heat and power) and thermoelectric units was developed. The solar or wind powered battolyser system stores electricity and utilises it to produce H2. The produced green H2 combusts with air in the cylinder to drive the turbine and the electric generator. While the thermophotovoltaic (TPV) unit converts the heat radiation into electrical energy to maximise the power efficiency of the developed hybrid system. The result showed a better temperature distribution, higher pressure discharge on both pistons’ walls and increased energy efficiency by replacing a single-piston with the opposed piston cylinder combustor and using cylinder exit gas to generate more electricity. Steam coolant reduced the thermal stress on the cylinder wall. The mounted TPV unit on the cylinder wall converted the absorbed heat flux to 3.9 kW. The maximum power output of the solar PV and wind turbine systems was reached at an irradiance of 1200 W/m2 under ambient temperature conditions and a wind speed of 17 m/s. By using the exhaust gas from the cylinder to drive the gas turbine, 8.8 kW power output and an electrical efficiency of 31.9 % were recorded. NOx emissions <6 ppm and a CHP efficiency of 93.5 % were achieved for the developed hybrid system. The proposed system can substitute the current domestic gas boiler which is in the phase-out state.

Assessing the Impact of CO2 Emissions from Transport and Power on Health and Environment in Duhok, Kurdistan Region, Iraq

This study investigates the carbon dioxide (CO2) emissions generated by transportation and power generation in Duhok Governorate, Kurdistan Region of Iraq. The research highlights the alarming levels of CO2 emissions resulting from the region's 270,315 vehicles and 1,814 private electric power generators, which consume approximately 1,500,000 liters of gasoline and 650,000 liters of diesel daily. These activities contribute to a total daily CO2 emission of 1,741,188 kg, amounting to over 626,827,680 kg annually. The findings reveal the significant environmental and public health threats posed by these emissions, emphasizing the urgent need for targeted mitigation strategies. Comparisons with other urban regions such as Cairo, Tehran, New Delhi, Lagos, and Nairobi reveal a similar pattern of high vehicular and generator-induced CO2 emissions, underscoring the global nature of this environmental challenge. The study underscores the importance of addressing CO2 emissions through improved regulations, modernized infrastructure, and sustainable energy practices to protect both the environment and public health.

A Direct Current Self-Sustained Moisture-Electric Generator with 1D/2D Hierarchical Nanostructure for Continuous Operation of Off-Grid Electronics.

Ubiquitous moisture is a colossal reservoir of clean energy, and the emergence of moisture-electric generators (MEGs) is expected to provide direct power support for off-grid electronic devices anytime and anywhere. However, most MEGs rely on auxiliary energy storage devices and rectifier circuits to drive small electronic devices, which hinder scalability and widespread deployment, and the development of direct current (DC) MEGs with high power output that can directly drive off-grid electronic devices is highly promising but challenging. Herein, a self-sustained moisture-electric generator (SMEG) with a hierarchical nanostructure based on one-dimensional (1D) negatively charged nanofibers and two-dimensional (2D) conductive nanosheets was demonstrated to generate continuous DC electricity from atmospheric humidity. Sulfation of bacterial cellulose nanofibers lowers the surface potential and increases the surface charge energy, and reduced graphene oxide (rGO) provides a conduction pathway for electrons. The hierarchical nanostructures constructed by the combination of 1D nanofibers and 2D nanosheets endow the SMEG with self-sustained moisture gradients and structural anisotropy, which force the generation of a pseudocurrent. This combination also constructs microcapacitors that further enhance the moisture-electric power output. The SMEG can generate a continuous voltage in excess of 0.54 V for over 2160 h, with a power density of about 822 μW cm-3, demonstrating excellent operational durability. This research provides a feasible solution for the development of sustainable, versatile, and efficient power supplies for off-grid self-powered devices.

Design, and dynamic evaluation of a novel photovoltaic pumping system emulation with DS1104 hardware setup: Towards innovative in green energy systems.

Diesel engines (DEs) commonly power pumps used in agricultural and grassland irrigation. However, relying on unpredictable and costly fuel sources for DEs pose's challenges related to availability, reliability, maintenance, and lifespan. Addressing these environmental concerns, this study introduces an emulation approach for photovoltaic (PV) water pumping (WP) systems. Emulation offers a promising alternative due to financial constraints, spatial limitations, and climate dependency in full-scale systems. The proposed setup includes three key elements: a PV system emulator employing back converter control to replicate PV panel characteristics, a boost converter with an MPPT algorithm for efficient power tracking across diverse conditions, and a motor pump (MP) emulator integrating an induction motor connected to a DC generator to simulate water pump behaviors. Precise induction motor control is achieved through a controlled inverter. This work innovatively combines PV and WP emulation while optimizing system dynamics, aiming to develop a comprehensive emulator and evaluate an enhanced control algorithm. An optimized scalar control strategy regulates the water MP, demonstrated through MATLAB/Simulink simulations that highlight superior performance and responsiveness to solar irradiation variations compared to conventional MPPT techniques. Experimental validation using the dSPACE control desk DS1104 confirms the emulator's ability to faithfully reproduce genuine solar panel characteristics.

Maintenance Tasks for 20 Kv Medium-Voltage Switchgear Based on Technical Judgment Experience and Manufacturer

A 20 kV medium-voltage switchgear is an important equipment in the electricity system that distributes electricity generated by the 20 kV electric power generator to electricity users. Calor Emag, Merlin Gerin, Alsthom, Fuji, AEG, Schneider, Meidensha, Goldstar, Modalek, Areva, and Siemens are among the companies that make products. This study describes a method for maintaining 20 kV medium-voltage switchgear, an essential equipment in the electricity system. In less technical terms, the failure rate is high at the beginning of an asset's life, which follows the curve of the bathtub. However, the failure rate quickly declines as we identify and discard defective components and eliminate early sources of potential failures, such as installation errors. This study introduces a novel approach by examining the relationship between maintenance tasks, which are based on technical judgment and experiences, and the maintenance tasks provided by the manufacturer for 20 kV medium voltage switchgear. The goal is to develop and deliver the most effective maintenance method for 20 kV medium voltage switchgear, to prevent malfunctions or even catastrophic explosions, while maintaining the lowest possible maintenance costs. Total use of labor over 2 years (24 months) for daily, monthly, 3 monthly, and 2 yearly is 3554-man hours (MH). It provides a comprehensive approach to preventing malfunctions and explosions, resulting in optimal maintenance costs and performance.

Renewable Energy Development Through the Utilization of Palm Oil Mill Effluent (POME) in Indonesia

Abstract This study aims to analyze renewable energy development through the utilization of palm oil waste. Indonesia has significant potential for energy development, particularly from palm oil processing waste, including biomass and biogas energy sources. This study used the qualitative method to provide an overview of the development of scientific research with the theme of renewable energy through the utilization of palm oil waste. The data source was obtained by accessing journals in the Scopus database between 2015 and 2024, with a total of 342 articles. The data is then evaluated with VOS viewer. It was found that palm oil has great potential as renewable energy resources, alternative fuels, electric generator, and for sustainable energy. However, the challenge is related to the understanding of the technology and existing policies. Indicates limitations in the adoption of POME for renewable energy in Indonesia. This study was limited to the articles only from Scopus database. Future studies need to take a comparative analysis approach that uses the Web of Science (WoS) database.