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This study presents the development of a framework used to optimise and experimentally validate a novel axial flux direct-drive (DD) permanent magnet generator (PMG) for the offshore wind turbine market. This technology aims to offer significant levelised cost of energy (LCoE) reductions via capital expenditure and operating expense (CAPEX and OPEX) savings – a key objective for the offshore industry. The DD-PMG technology uses ferrite magnets to create the magnetic field, which is a significant source of cost reduction. The use of ferrite could also eliminate an industry wide reliance on neodymium iron boron, the scarce and expensive rare-earth magnet used in existing designs. Another advantage of a ferrite-based design is that it is less sensitive to the cooling problems that currently face existing DD-PMGs. This study describes the development and testing of two prototype machines at nominal 2 and 70 kW power ratings. Moreover, the finite element analysis and analytical steps employed to develop optimised designs together with the experimental verification are presented. The simulated and experimental results show good agreement which provides confidence in the design and modelling work completed. [ABSTRACT FROM AUTHOR]

Free-piston engines have the potential to offer a compact machine capable of delivering electrical power. In this work, the design and modelling of a linear tubular generator are presented and used to investigate the effect of the electrical machine design on engine performance. A cogging-force-reduction technique is presented and used as a case study to demonstrate the importance of the integrated design. [ABSTRACT FROM AUTHOR]

The frequency response test on synchronous generators has been increasing in the last decades, but the high cost of equipment used for conducting the test is still a stumbling block for both manufacturers and end consumers. This study aims to propose a methodology for obtaining parameters, through the use of neural networks. This study treats the results designed through frequency tests, in which the proposal was the use of low-cost equipment to perform them. In addition, a process of optimisation of the neural network was developed during the development of this study. [ABSTRACT FROM AUTHOR]

This article presents a VCO‐based impulse generator, in which all circuit blocks are switched for low power consumption. A switching control pulse generator is employed for adjusting the impulse duration. The drive amplifier can generate triangular‐like impulse with high amount of side‐lobe rejection without any external filter. The experimental results show that the frequency range covers 6.5‐9.3 GHz and 10‐dB bandwidth is tunable from 0.5‐2 GHz, while consuming only 39.6 pJ/pulse at 10 MHz pulse repetition frequency. The impulse generator is fabricated using a 0.13 μm CMOS process and chip size is 1.07 × 1.50 mm2 including ESD pads. [ABSTRACT FROM AUTHOR]

In this paper, we analyzed the periodicity of discrete Logistic and Tent sequences with different computational precision in detail. Further, we found that the process of iterations of the Logistic and Tent mapping is composed of transient and periodic stages. Surprisingly, for the different initial iterative values, we first discovered that all periodic stages have the same periodic limit cycles. This phenomenon has seriously affected the security of chaotic cipher. To solve this problem, we designed a novel discrete chaotic sequence generator based on m-sequence and discrete chaotic mapping. The experimental results indicated that the chaotic sequence generator can generate pseudorandom chaotic sequences with large periodicity and good performance under the condition of limited computational precision. [ABSTRACT FROM AUTHOR]

The paper is about the design and prototyping of directly driven outer rotor permanent magnet generator for small scale wind turbine. In the paper, the initial design of the generator is given. Main issues and phenomena affecting the generator design, such as cogging torque and its reduction possibilities, selection and demagnetization risk assessment of permanent magnets, machine losses and thermal analysis, are described. Test results of prototype generator construction and final parameters are also presented. The necessity of further study is pointed out. [ABSTRACT FROM AUTHOR]

Most factors in chemical science and engineering are quantitative. Therefore, chemists and engineers are more familiar with the notion that factors should necessarily have three levels. Ref. [5] introduced a new class of 3-level screening designs which allows the assessment of curvature of the factor-response relationship. They called these designs definitive screening designs (DSDs). These DSDs are (i) saturated for estimating the intercept, the m main effects and the m quadratic effects; (ii) unlike resolution III designs, all main effects are orthogonal to 2-factor interactions; (iii) unlike resolution IV designs, 2-factor interactions are not fully aliased with one another; and (iv) unlike resolution III and IV designs, the quadratic effects can be estimated and are orthogonal to main effects and not fully aliased with 2-factor interactions; (v) when the design is sufficiently large, it allows efficient estimation of the full quadratic model in any three factors. This paper introduces a new class of DSD-like designs generated by cyclic generators. This new class can be used to study the presence of the second-order effects more efficiently. [ABSTRACT FROM AUTHOR]

A magnetically geared machine (MGM) integrates a magnetic gear with a low-torque, high-speed electric machine to create a single compact high-torque, low-speed device with the size advantages of a mechanically geared system and the reliability of a direct drive machine. This work investigates the use of MGMs for wave energy conversion through the development of a large-scale magnetically decoupled inner stator radial flux magnetically geared generator rated for 10 kW at an input speed of 30 r/min. Critical design trends are illustrated using parametric two-dimensional and three-dimensional finite element simulation results. Information is also provided about the prototype's mechanical structure and key magneto-mechanical design considerations, including the impact of modulator bridges and the extent of axially escaping leakage flux. The prototype's experimental stall torque of 3870 Nm represents a 99.1% match with the simulated stall torque and corresponds to volumetric and gravimetric torque densities of 82.8 kNm/m3 and 14.5 Nm/kg, respectively. Additionally, the prototype achieves an experimental efficiency of approximately 90% for operation near rated torque. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is to show, design and test a new piezoelectric-based low-power generator to generate cheap and clean energy. The presented generator can be evaluated as an experimental renewable energy producing system. Obtained results show that presented generator systems can be constructed on a large scale for usable energy production. Power production capacity of presented generator can be increased with technical and physical improvements. Simple structure and cheapness are the most important features of presented generator. This generator includes an unbalanced propeller and a piezoelectric material equipped board. This unbalanced propeller generates mechanical vibration by the variation of wind speed conditions. These vibrations are transferred to a piezoelectric material equipped board. The piezoelectric material equipped board converts these vibrations into electrical power. Some experimental data were collected under different wind speeds and different external load resistances to evaluate presented generator. Changes in output power are shown with graphics related with dependent wind speed and external load resistors. [ABSTRACT FROM AUTHOR]

Summary: Two electromagnetic power generators were designed and built with the purpose of creating a safe, noncarbon emitting, and long‐lasting source of energy. Prototype A has 20 coils and B has 10 coils. Each one has 2 flywheels, a second‐hand ferrite magnet that spins over the horizontal plane (lateral axis), and neodymium magnets (NdFeB). A literature review is provided covering the origins of the first direct current generators up to the most widely used contemporary alternating current power generators, comparing them with both prototypes. These were compared with each other to determine which performs better by making mathematical projections and checking them experimentally. The prototypes are based on an innovative configuration for mechanical energy conversion, which supplies power every time the system is in motion. The harvested energy has shown results—in terms of output power, power density, and specific power—which depend on several factors, such as the mechanical force induced and the period of time they remain spinning by the flywheels. The different parameters of the systems, which include connections, structure details, spinning plane, experimental results, and materials, are specified. Advantages and disadvantages are also analyzed, including some immediate real‐life applications. The designs have been improved by changing the shape of the coils and magnets as a whole to create enduring power systems. [ABSTRACT FROM AUTHOR]

Travelling-wave thermoacoustic heat engine is capable of converting heat to acoustic power which in turn can be used to generate electricity by a linear alternator. The thermoacoustic heat engine can work in a wide range of heat quality, giving it the ability to be used for waste heat recovery. In this paper, a new configuration of looped-tube travelling wave thermoacoustic engine is proposed, which consists of two identical stages each having a power extraction point, and the linear alternator connecting these two points working in “push-pull” mode. This enables a more effective acoustic impedance matching compared to the use of multiple linear alternators known in the literature. The laboratory demonstrator has been designed, built and tested. The applied heat source temperature is similar to that of the internal combustion engine exhaust gases in order to explore the potential of using the device for waste heat recovery from road or marine transport. In experiments, the maximum electric power of 48.6 W at thermal-to-electric efficiency of around 6% was achieved with helium at 28 bar as working fluid and 297 K temperature difference across the regenerator. The performance of the device has been analysed and compared to modelling performed using DeltaEC simulation tool. [ABSTRACT FROM AUTHOR]

Combined cooling, heat, and power (CCHP) system offers numerous potential advantages for the supply of energy to residential buildings in the sense of improved energy efficiency and reduced environmental burdens. To realize the potential for being more beneficial, however, such systems must reduce total costs relative to conventional systems. In this study, a linear programming optimization model was presented for optimum planning and sizing of CCHP systems. The purpose of the model is to give the design of the CCHP system by considering electrical chiller and absorption chiller simultaneously in economic viewpoint. A numerical study was conducted in Tehran to evaluate the CCHP system model. The linear programming (LP) model determines the optimal sizes of the CCHP equipment by considering capital cost of the system. It showed that by considering electricity buyback, the optimum size of the electrical chiller decrease and the optimum size of the combined heat and power (CHP) unit and the absorption chiller increase dramatically with respect to without electricity buyback. Also, the LP model determines the optimal operation strategy of the system by neglecting capital cost. The optimally operated CCHP system encompassing electrical and absorption chiller could result in an 18% decrease in operating cost when compared to a CHP system encompassing electrical chiller only. Without electricity buyback, the profitability of CCHP was 23%, while with electricity buyback, profitability became 39%. Furthermore, a sensitivity analysis was conducted to show how the important parameters affect the entire system performance. [ABSTRACT FROM AUTHOR]

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The concept of harvesting energy in the ambient environment arouses great interest because of the demand for wireless sensing devices and low-power electronics without external power supply. Harvesting energy by vibration with piezoelectric materials can be used to convert mechanical energy into electrical energy that can be stored and used to power other devices. This conversion of vibrations (mechanical energy) to electrical energy using piezoelectric materials is an exciting and rapidly developing area of research with a widening range of applications constantly materialising. In this context, the goal of this paper is to develop a comprehensive prototype generator that can harvest vibration energy and convert it to electrical energy by providing the output power for optimisation and its performance. Two setups of prototype are used: a cantilever beam with tip mass at the end, and a cantilever beam without tip mass at the end. Data from the experiment is compared and analysed using MatLab. The results show that the power output of the prototype with the tip mass is greater than the power output without the tip mass. The experimental results led to a power optimisation from that prototype by different characteristic of piezoelectric ceramic plate. [ABSTRACT FROM AUTHOR]

Out-of-step detection methods for generators depend on impedance measurements that are mapped from the angular difference between the generator source and the Thévenin equivalent of the interconnected system. Though implemented successfully with decades of operating experience, the mapping is not the most accurate due to a simplified model. This paper proposes an improved out-of-step detection method for generators by means of the most direct indicator—angular difference. The generator's rotor angle is estimated with a particle filter-based dynamic state estimator and the angular separation is then calculated by combining the raw local phasor measurements with this estimate. The method is also enhanced with the real-time stability analysis that is able to predict marginally unstable swings. The approach is illustrated via dynamic simulations on the New England 10-generator, 39-bus system. While consistent with the traditional schemes for out-of-step detection, the proposed method is advantageous in that it does not make any simplifying assumptions in its formulation, and provides early detection for unstable swings resulting in reduced stresses on the breaker and generator. The proposed approach shows great potential to supervise the conventional relay with availability of synchrophasor measurements and computational power. [ABSTRACT FROM PUBLISHER]

A modular approach to designing generators of high-power high-voltage nanosecond pulses on the basis of a two-level wave summator and transistor formers of partial pulses is considered. The design and parameters of the modules that are oriented at the development of generators of voltage pulses of up to 300 kV at a current of up to 4 kA are described. The capabilities of these modules are demonstrated based on the example of a pulse generator with a power of 10 MW, a varied pulse duration of 50-150 ns, and a pulse repetition rate of up to 2 kHz. [ABSTRACT FROM AUTHOR]

Six types of gas generators based on guanidinium azotetrazolate (GZT) were designed into six formulations having different oxidants: GZT-LiNO3 (1), GZT-NaNO3 (2), GZT-KNO3 (3), GZT-Mg(NO3)2 (4), GZT-Sr(NO3)2 (5) and GZT-KMnO4 (6), respectively. The properties of these formulations were investigated in terms from gas production, appropriate combustion temperature and nontoxic gaseous emission. REAL software calculation program [1] was used to calculate the combustion heat at constant pressure, combustion heat at constant volume and specific volume in standard state. It showed that gas generators based on GZT with nitrate salts as oxidant exhibited better performance. Thus its thermal behavior and combustion temperature were studied further and the experimental results were consistent with the theoretical calculation results. Therefore, it can be concluded that formulation 3 has comprehensive optimal performance: low moisture content, insensitivity to friction, heightened vacuum stability, high combustion heat and specific volume. Namely, formulation 3 exhibited the most promising indications of commercial application, such as using in air bags of motor vehicles. [ABSTRACT FROM AUTHOR]

In this paper, a 70 Hz pulse tube micro cryocooler (PTMC) driven by two opposite linear generators has been studied using linear theory of thermoacoustic. In contrast to conventional thermodynamic calculation method the results of a small-scale PTC as a thermoacoustic system were obtained. Numerical simulation was conducted to design the system and optimum structure parameters were obtained. With operating condition of 2.5 MPa mean pressure and 70 Hz operating frequency, a cooling power of 8 W at 77 K and a relative Carnot efficiency of 21% were achieved. In order to prove the applicability of numerical simulation using linear theory of thermoacoustic to such small-scale cooling system and to better understand the energy conversion characteristics of the system, distributions of key parameters such as acoustic work, exergy were presented and discussed. [ABSTRACT FROM AUTHOR]

The free piston linear generator is a new range extender concept for the application in a full electric vehicle. The free piston engine driven linear generators can achieve high efficiency at part and full load which is suitable for the range extender application. This paper presents requirements for designing a linear generator deduced from a basic analysis of a free piston linear generator. [ABSTRACT FROM AUTHOR]

Hydropower has long been recognized as a renewable power source. Due to economic reasons, high and medium head potentials have been primarily developed. Later, low-head potentials became a feasible solution with the application of modern Bulb generators. Although Bulb generators have been developed and applied since the 1930s, new techniques and materials have been used to overcome technical and design challenges, which are described herein. [ABSTRACT FROM AUTHOR]

In this paper, the design and development of a double-sided air-cored tubular generator (DSTG) is presented. The characteristics of air-cored slot-less structures are investigated in terms of power density and efficiency. This is highly desirable for small- and medium-sized renewable energy conversion systems. In this paper, an analytical tool based on the magnetic vector potential method is built in order to achieve a fast but accurate method by which the machine is analyzed. The analytical model is validated by finite-element (FE) analysis. Further design improvements based on the analytical and FE models are then suggested in order to enhance the performance of the DSTG. The final design of the DSTG is validated by the test results from a developed prototype of the DSTG. [ABSTRACT FROM AUTHOR]

In order to fully analyze the characteristics of an excitation assistance switched reluctance generator (EASRG) applied in wind power generation, a static model and a dynamic model are proposed. The static model is based on the 3-D finite-element method (FEM), which can be used to obtain the static magnetization and torque characteristics. The dynamic model, consisting of two lookup tables to describe the EASRG under different current and rotor positions, is built in Simulink to avoid the long computation time of a 3-D FEM model. The dynamic model is able to provide a more realistic assessment of the performance of the EASRG by considering the transient current, while the static model can only consider one constant current. The torque characteristics of the EASRG with different phase currents and commutation angles are studied. The turn-ON angle is found to have a more significant impact on the EASRG performance than the turn-OFF angle. Furthermore, the impact of the width of the rotor pole on the characteristics of the EASRG is studied with the help of the dynamic model. The design with the highest average torque can be achieved if the rotor pole width equals the stator pole width. [ABSTRACT FROM AUTHOR]

This paper proposes a new adaptive filter for wind generators that combines instantaneous reactive power compensation technology and current prediction controller, and therefore this system is characterized by low harmonic distortion, high power factor, and small DC-link voltage variations during load disturbances. The performance of the system was first simulated using MATLAB/Simulink, and the possibility of an adaptive digital low-pass filter eliminating current harmonics was confirmed in steady and transient states. Subsequently, a digital signal processor was used to implement an active power filter. The experimental results indicate, that for the rated operation of 2 kVA, the system has a total harmonic distortion of current less than 5.0% and a power factor of 1.0 on the utility side. Thus, the transient performance of the adaptive filter is superior to the traditional digital low-pass filter and is more economical because of its short computation time compared with other types of adaptive filters. [ABSTRACT FROM AUTHOR]

Distributed Generators (DG or embedded generators) are generators that are connected to the distribution network. Their advantages are the ability to reduce or postpone the need for investment in the transmission and distribution infrastructure when optimally located; the ability to reduce technical losses within the transmission and distribution networks as well as general improvement in power quality and system reliability. This paper highlights the benefits of distributed generation by using a 15-bus radial distribution network, modelled in the DIgSILENT Power Factory software, to demonstrate the improvement in voltage profile as well as the reduction in technical losses. [ABSTRACT FROM AUTHOR]

This paper presents a study, design and testing of a Linear Oscillating Generator. There are presented the main steps of the magnetic and electric calculations for a permanent magnet linear alternator of fixed coil and moving magnets type. Finally it has been shown the comparative analysis between the linear oscillating generator with moving permanent magnets in no load operation and load operation. [ABSTRACT FROM AUTHOR]

The article explains the working of hand-cranked dc electric generator Genecon. Photograph of the voltage across the oscillator is given. The frequency at which its handle has to be turned is also given in a tabular form. The ways in which Genecon functions both as generator and a motor is also mentioned.

This paper attempts to present the necessary steps in designing a electrical generator represented in 2D, 3D, finite element analysis software of Ansoft Maxwell magnetic fields. This work includes modeling form of generator, boundaries, excitations, parameterization, the analysis of the mesh, optimization, performance and representation fields: A (Flux Vector Lines and A), H (Mag_H and H Vector), B (Mag_B and B vector) J (Jz and J vector) and the energy and other analyzes as CoreLoss, Ohmic_Loss and Total_Loss. [ABSTRACT FROM AUTHOR]

This paper concerns a three-phase self-excited induction generator used for autonomous power generation. It presents a robust control strategy which makes it possible to maintain the frequency quasi constant during the voltage regulation without any control loop on this variable. This strategy, which also prevents the machine disengagement, uses as power converter a simple dimmer. The obtained theoretical and/or numerical results are validated on a laboratory test bench that allows the analysis of this control law effectiveness. [ABSTRACT FROM AUTHOR]

This article presents the design, fabrication and characterization of a micromachined energy harvester utilizing aluminium nitride (AlN) as a piezoelectric thin film material for energy conversion of random vibrational excitations. The harvester was designed and fabricated using silicon micromachining technology where AlN is sandwiched between two electrodes on top of a silicon cantilever beam which is terminated by a silicon seismic mass. The harvester generates electric power when subjected to mechanical vibrations. The generated electrical response of the device was experimentally evaluated at various acceleration levels. A maximum power of 34.78 μW was obtained for the device with a seismic mass of 5.6 × 5.6 mm at an acceleration value of 2 g. Various fabricated devices were tested and evaluated in terms of the generated electrical power as well as the resonant frequency. [ABSTRACT FROM AUTHOR]

Due to the lack of mature design programfor the tubular permanentmagnet linear wave generator (TPMLWG) and poor sinusoidal characteristics of the air gap flux density for the traditional surface-mounted TPMLWG, a design method and a new secondary structure of TPMLWG are proposed. An equivalent mathematical model of TPMLWG is established to adopt the transformation relationship between the linear velocity of permanentmagnet rotary generator and the operating speed of TPMLWG, to determine the structure parameters of the TPMLWG. The new secondary structure of the TPMLWG contains surface-mounted permanent magnets and the interior permanent magnets, which form a series-parallel hybrid magnetic circuit, and their reasonable structure parameters are designed to get the optimum pole-arc coefficient. The electromagnetic field and temperature field of TPMLWG are analyzed using finite element method. It can be included that the sinusoidal characteristics of air gap flux density of the new secondary structure TPMLWG are improved, the cogging force as well as mechanical vibration is reduced in the process of operation, and the stable temperature rise of generator meets the design requirements when adopting the new secondary structure of the TPMLWG. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to design a good tracking controller for the generator automatic voltage regulator (AVR) system. It uses an iterative learning control (ILC) algorithm as a control rule and tries to keep voltage error as low as possible, while replying to set point changes as fast as possible. Two models of ILC are discussed: P-type learning and linear quadratic (LQ) optimal design. The results of designing by LQ optimal method are compared with a Ziegler-Nichols proportional-integral-derivative (PID) controller. The effects of changing different parameters are investigated and illustrated by simulation. In order to provide better robustness for the design, a PID-ILC parallel structure is designed and simulated under system parameter changes. [ABSTRACT FROM AUTHOR]

The recent work in literature has shown the potential of energy harvesting as means to power wireless sensors. An energy harvester typically consists of a transducer and low-power management circuits. However, current systems suffer from crude design methodology with no synergy between these two stages. In this work, the authors present two design modules of a modified electromagnetic microgenerator system, which aid in the performance of the associated power converter. Startup is a critical issue for such systems, since the transducer voltage is quite low (a few hundred millivolts AC). For the first design module, a thin piezoelectric strip is added to the electromagnetic microgenerator to provide the start-up power for the converter system. The second module unifies the design of the input filter for the converter with the microgenerator. The microgenerator parasitics are utilised to satisfy the input filter requirements of the converter. Such an approach reduces the overall inductive losses in the system compared with other set-ups reported in the literature. Both the microgenerator and the input filter are fabricated along with a suitable AC-DC boost converter using discrete components. Both simulation and experimental results are shown to demonstrate the start-up capability of such a system and efficacy of the input filter design. [ABSTRACT FROM AUTHOR]

A simple analogue technique called auxiliary envelope tracking, or AET, is presented, which is shown to be capable of improving the efficiency of a radio frequency power amplifier (RFPA). This AET signal is an amplified envelope signal that supplies the drain port of the RFPA. The concept of AET is explained and a theoretical background for the technique is presented. The main feature of this technique lies in the separation of the DC and AC components of the tracking signal. This allows for a very simple and low-cost tracking generator design that consists of a simple source follower amplifier and an RF broadband transformer. A practical system has been implemented and the measured results are obtained for WCDMA signals. A measurement on the realised system shows a 50% improvement in the drain efficiency at average output power of 33 dBm of a 25 W GaN. This substantial improvement is achieved at a competitive WCDMA signal with peak-to-average envelope power ratio of 9.17 dB. [ABSTRACT FROM AUTHOR]

This study proposes a novel application of the differential voltage current conveyor (DVCC) in realising relaxation generators. This is the first report of a relaxation generator constructed with a DVCC device. The proposed circuits employ a single DVCC with a minimum number of passive components. The first circuit is a typical topology that can generate a symmetrical square wave with a fixed duty cycle. The second circuit can further control the duty cycle of a square wave by adjusting the tuning factor of the potentiometer. This study also presents an improved topology that features dual frequency operation modes within the same scheme, describes the operation of the circuits, and discusses the non-ideal effects and other considerations of the proposed circuits. This study simulates the proposed circuits using Is-Spice to verify their workability, and further uses commercially available ICs and discrete components for circuit implementation and testing. Simulation and experimental results correspond with the theoretical analysis. [ABSTRACT FROM AUTHOR]

This paper introduces a new voltage-mode second-order sinusoidal generator circuit with four active elements and six passive elements, including grounded capacitors. The frequency and condition of oscillation can be independently controlled. The effect of active element's nonidealities and parasitic effects is also studied; the proposed topology is good in absorbing several parasitic elements involved with the active elements. The circuit is advantageous for generating high frequency signals which is demonstrated for 25 MHz outputs. Several circuit extensions are also given which makes the new proposal useful for real circuit adoption. The proposed theory is validated through simulation results. [ABSTRACT FROM AUTHOR]

The term local generator as used in this paper is intended to describe a generator supply dedicated to a specific facility which would have a more limited and specific capacity and loading than a broader and higher capacity utility supply. These systems, particularly when there is a large nonlinear component, require additional coordination and design considerations as a result. Generator suppliers obviously understand their equipment in great detail and have well-defined application guidelines for the more typical linear loads which they are expecting to supply. Adjustable-speed drives (ASDs) and other nonlinear loads bring additional factors into play such as harmonics, possible requirement for harmonic filters, and the specifics of their topology design such as the inherent capacitance involved in all drive designs. The intent of this paper is to address the necessary application considerations when applying nonlinear loads on local generation starting at the basics of sizing and progressing through topics such as alternator sizing, voltage and speed regulation, etc. Specific focus will be with respect to an application issue which arose for a recent offshore application involving a high component of nonlinear ASD loading on their offshore distribution system per the author's experience. [ABSTRACT FROM AUTHOR]

This paper deals with a design of an axial flux permanent magnet (AFPM) generator which is a key element of a compact size portable and manual generator system composed of a gear system, a generator, a rectifier, and a battery charger. The design objects of the AFPM generator are its compact size, light weight, and high efficiency, and the three design objects are the main criteria to select the value of design variables. A soft magnetic composite core is used instead of a silicon steel core in the AFPM generator to achieve a compact size. In this paper, the overall design process to meet the design goals and the design results are presented with experiment results. [ABSTRACT FROM PUBLISHER]

Abstract: Ocean waves, in addition to generating direct forces on fixed and floating offshore wind generator structures, also have significant indirect effects via their influence on the atmospheric and oceanic boundary layers above and below the water surface. In the atmospheric boundary layer the waves act as roughness elements, influencing the turbulent flow and the vertical wind speed profile, and induce oscillatory motions in the airflow. Spray droplets from breaking wave crests enhance structure corrosion, and may lead to icing under low-temperature conditions. Below the water surface, the air-sea momentum flux and mechanical energy flux, mediated by the waves and wave-generated turbulence, affect the vertical profiles of ocean current, temperature, and salinity. Effects include modifying the structural forces and dynamics, and the movement and dispersion of marine organisms, pollutants, and air bubbles generated by breaking waves, with consequences for fouling, corrosion, and environmental impact. Measurement of relevant airflow and ocean dynamical variables is also challenging, as near the water surface it is often necessary to use instruments mounted on moving measurement platforms. Modelling such boundary-layer effects is a complex task, as a result of feedbacks between the airflow, wave field, current field, and turbulence in the atmosphere and the ocean. We present results from a coupled model study of the North Sea and Norwegian Sea area. We employ a mesoscale atmosphere model (WRF) and a spectral wave model (WAM), running simultaneously and coupled using the open-source coupler MCEL which can interpolate between different model grids and time steps. To investigate the ocean boundary layer, one-dimensional model experiments were performed for an idealized Ekman layer and for locations in the North Sea, Atlantic Ocean, and the northern Pacific, using a version of the GOTM turbulence model, modified to take wave dynamics into account. Results show how the wave field alters the ocean''s aerodynamic roughness and the air–sea momentum flux, depending on the relation between the surface wind speed and the propagation speed of the wave crests (the wave age). These effects will feed back into the airflow, wind speed and turbulence profile in the boundary layer. The ocean dynamics experiments showed results which compare favourably with field observations from the LOTUS3 and PROVESS experiments in the north Atlantic and North Sea, and Ocean Weather Station Papa in the Pacific Ocean. [Copyright &y& Elsevier]

In this paper the design and manufacturing processes for coreless axial flux permanent magnet generators are described for low cost rural electrification applications, where local production of small wind turbines is considered. The process is based on already existing open source design and construction manuals, while a systematic approach to designing generators of varying nominal power and for grid connection or direct battery charging schemes is described. The manufacturing process of a 3 kW small wind turbine generator for grid connection is used as a case study. Emphasis is given to the use of simple tools and techniques to achieve a lower cost, while intricate steps in the manufacturing process are described in more detail. The generator design is simulated and the constructed machine is tested in the laboratory. [ABSTRACT FROM AUTHOR]

In 2004, Cuba begin a new program, which consists of a pattern of power generation sites by installing batteries composed of Electrics Groups Generators, which operate with diesel or fuel oil, constituting one of the more profound conceptual changes in this area. This work aims to obtain a mathematical model for criticality analysis that make possible the hierarchy classification of systems, subsystems and equipment in the process of generating electricity from generators at the sites of fuel-oil technology. To carry out this objective it was necessary: The study of different models of criticality and the potential feasibility of their use in the field of research. The identification of systems and subsystems that make up the generators. The realization of a documentary analysis of the most common faults incurred by systems and equipment for generators. Model validation and finally was classified the documentation according to asset criticality index against complexity index. We developed an instrument approach from experts to determine the variables to consider in the model of criticality in progress for a study model of reliability. The resulting model was applied to several plants of generators providing satisfactory results. [ABSTRACT FROM AUTHOR]

Abstract: In this study, both materials selection and device configuration design were considered for developing miniature piezoelectric generators with low resonant frequency. Instead of single crystal Si, stainless steel (SUS) was chosen as the substrate of AlN thin films owing to its higher fracture toughness, which made it possible that millimeter-scale generators had resonant frequency of less than 100Hz. The device configuration including the aspect ratio (the length of the cantilever to the width of the cantilever) and the thickness ratio (the substrate layer to the AlN film layer) were analyzed for optimizing transverse electromechanical coupling coefficient of generators. Using AlN thin films deposited on stainless steel, millimeter-scale generators were fabricated and their vibration energy harvesting performance was characterized. Output power and resonant frequency of the devices are, respectively, 5.130μW and 69.8Hz when they were vibrated at 1g acceleration and connected with 0.7MΩ electric loading. [Copyright &y& Elsevier]

The article presents abstracts of studies related to non-destructive testing (NDT) which include the fatigue assessment on the components of nuclear power plants, the methods for the construction of pseudorandom sequences multi-channel generators, and gas metal arc welding monitoring with sound signal.

A linear-generator topology is proposed for wave-energy applications. The main significance of the generator topology is that the relative position of the magnets, copper, and steels has been chosen so that there are no magnetic attraction forces between a stator and a permanent-magnet (PM) translator. The lack of magnetic forces and the modular nature of the generator topology make the manufacture and assembly of the generator easier than a conventional iron-cored PM linear generator. Analytical modeling techniques are described with a genetic-algorithm optimization method. The proposed topology is implemented to an Archimedes-wave-swing wave-energy converter. A 50-kW prototype has been built to prove the concept, and the no-load- and load-test results are presented. [ABSTRACT FROM PUBLISHER]

The article describes an activity program for middle school education which asks students to design an electrical generator by using wire coils and magnet to understand concepts of energy transfer.

Mission critical applications for data centers, financial institutions, telecommunications, and governments typically have generators and uninterruptible power supplies (UPSs) providing backup power to keep their critical information technology loads online. Tier I and tier II topologies according to ANSI/TIA-942 are very simple and straightforward with no redundancy or single distribution path with redundant components. Tier III and tier IV configurations have increasing complexity with multiple distribution paths, concurrent maintainability, and multiple active paths. This paper will explore the high-level compatibility, sizing, and design considerations for generators and UPSs in tiers I, II, III, and IV topologies. [ABSTRACT FROM AUTHOR]

An air-cored tubular linear generator is designed and prototyped, to capture transient bridge vibrations to power wireless sensors on a bridge. The relationship between the moving mass, the spring, and the damping for harvesting sufficient vibration energy is developed. The voltage and power of the linear generator with sinusoidal speed are obtained with a transient electromagnetic field analysis. Finally, the ambient experimental results of the linear generator are obtained and analyzed from actual bridge vibrations. [ABSTRACT FROM AUTHOR]

This paper investigates a novel variable-speed generation system. A new integrated power circuit with voltage clamp protection and self-excitation function is presented. Conventionally, due to the large internal impedance of a generator, oscillations are produced by the resonances of the filter in armature currents which may cause unstable behavior of the generation system. In this paper, an active damping control algorithm cooperated with matrix converter (MC) instantaneous value synthesizing modulation strategy is proposed to suppress oscillations of MC input currents effectively. In addition, a closed-loop voltage control scheme with MC constant transfer ratio and hybrid excitation synchronous generator excitation current regulation is studied. At last, the feasibility of the overall system and schemes has been verified by the experimental results. [ABSTRACT FROM PUBLISHER]

Transverse flux enhanced type superconducting synchronous machines have been studied for large-capacity wind power generation. The generators have multiple circular superconducting field coils in the rotor and copper armature windings in the stator. A parametric design study and electromagnetic characteristic analysis of the superconducting wind turbine generators (WTGs) have been carried out. The target output is 10 MW for a rotational speed of 10 rpm, and the diameter of the whole coil system is 5 m. Superconducting technology is quite effective for compact and lightweight design of large power capacity, low-speed and high torque generators. Armature and field coil dimensions and the number of poles are key parameters in the design study. FEM analysis was carried out to obtain magnetic flux density, magnetic flux linkage, induced voltage, fundamental generator characteristics, etc. Required superconducting wire length was also estimated. [ABSTRACT FROM AUTHOR]