Research of influence of open-winding faults on properties of brushless permanent magnets motor

Directory of Open Access Journals (Sweden)

Bogusz Piotr

2017-12-01

Full Text Available The paper presents an analysis of influence of selected fault states on properties of brushless DC motor with permanent magnets. The subject of study was a BLDC motor designed by the authors for unmanned aerial vehicle hybrid drive. Four parallel branches per each phase were provided in the discussed 3-phase motor. After open-winding fault in single or few parallel branches, a further operation of the motor can be continued. Waveforms of currents, voltages and electromagnetic torque were determined in discussed fault states based on the developed mathematical and simulation models. Laboratory test results concerning an influence of open-windings faults in parallel branches on properties of BLDC motor were presented.

Harmonic Fluxes and Electromagnetic Forces of Concentric Winding Brushless Permanent Magnet Motor

Science.gov (United States)

Ishibashi, Fuminori; Takemasa, Ryo; Matsushita, Makoto; Nishizawa, Takashi; Noda, Shinichi

Brushless permanent magnet motors have been widely used in home applications and industrial fields. These days, high efficiency and low noise motors are demanded from the view point of environment. Electromagnetic noise and iron loss of the motor are produced by the harmonic fluxes and electromagnetic forces. However, order and space pattern of these have not been discussed in detail. In this paper, fluxes, electromagnetic forces and magneto-motive forces of brushless permanent magnet motors with concentric winding were analyzed analytically, experimentally and numerically. Time harmonic fluxes and time electromagnetic forces in the air gap were measured by search coils on the inner surface of the stator teeth and analyzed by FEM. Space pattern of time harmonic fluxes and time electromagnetic forces were worked out with experiments and FEM. Magneto motive forces due to concentric winding were analyzed with equations and checked by FEM.

Improved ADRC for a Maglev planar motor with a concentric winding structure

NARCIS (Netherlands)

Kou, Baoquan; Xing, Feng; Zhang, Chaoning; Zhang, L.; Zhou, Yiheng; Wang, Tiecheng

2016-01-01

In the semiconductor industry, positioning accuracy and acceleration are critical parameters. To improve the acceleration speed of a motor, this paper proposes the moving-coil maglev planar motor with a concentric winding structure. The coordinate system has been built for the multiple degrees of

Hydraulic Yaw System for Wind Turbines with New Compact Hydraulic Motor Principle

DEFF Research Database (Denmark)

Sørensen, Rasmus Mørk; Hansen, Michael Rygaard; Mouritsen, Ole Ø.

2011-01-01

This paper presents a new hydraulic yaw system for wind turbines. The basic component is a new type of hydraulic motor characterized by an extraordinary high specific displacement yielding high output torque in a compact form. The focus in the paper is the volumetric efficiency of the motor, which...

Theories and control models and motor learning: clinical applications in neuro-rehabilitation.

Science.gov (United States)

Cano-de-la-Cuerda, R; Molero-Sánchez, A; Carratalá-Tejada, M; Alguacil-Diego, I M; Molina-Rueda, F; Miangolarra-Page, J C; Torricelli, D

2015-01-01

In recent decades there has been a special interest in theories that could explain the regulation of motor control, and their applications. These theories are often based on models of brain function, philosophically reflecting different criteria on how movement is controlled by the brain, each being emphasised in different neural components of the movement. The concept of motor learning, regarded as the set of internal processes associated with practice and experience that produce relatively permanent changes in the ability to produce motor activities through a specific skill, is also relevant in the context of neuroscience. Thus, both motor control and learning are seen as key fields of study for health professionals in the field of neuro-rehabilitation. The major theories of motor control are described, which include, motor programming theory, systems theory, the theory of dynamic action, and the theory of parallel distributed processing, as well as the factors that influence motor learning and its applications in neuro-rehabilitation. At present there is no consensus on which theory or model defines the regulations to explain motor control. Theories of motor learning should be the basis for motor rehabilitation. The new research should apply the knowledge generated in the fields of control and motor learning in neuro-rehabilitation. Copyright © 2011 Sociedad Española de Neurología. Published by Elsevier Espana. All rights reserved.

A novel steady state wind turbine simulator using an inverter controlled induction motor

Energy Technology Data Exchange (ETDEWEB)

Kojabadi, H.M.; Liuchen Chang

2005-07-01

This paper presents a new wind turbine simulator for steady state conditions. In order to provide a test platform for wind turbine drive trains, the authors have developed an experimental system to simulate the static characteristics of real wind turbines. This system consists of a 10 hp induction motor (IM), which drives a synchronous generator and is driven by a 10 kW variable-speed drive inverter, and real time control software. A microcontroller, a PC interfaced to a LAB Windows I/O board, and an IGBT inverter-controlled induction motor are used instead of a real wind turbine to supply shaft torque. A control program written in the C language is developed that obtains wind profiles and, by using turbine characteristics and the rotational speed of the IM, calculates the theoretical shaft torque of a real wind turbine. Based on the comparison of the measured torque with this demand torque, the shaft torque of the IM is regulated accordingly by controlling stator current demand and frequency demand of an inverter. In this way, the relationships between shaft rotating speed, shaft torque of the IM and wind speed are made to conform to the characteristics of a real wind turbine. The drive is controlled using the measured shaft torque directly, instead of estimating it as conventional drives do. (author)

Induction generator-induction motor wind-powered pumping system

Energy Technology Data Exchange (ETDEWEB)

Miranda, M.S.; Lyra, R.O.C.; Silva, S.R. [CPDEE - UFMG, Belo Horizonte (Brazil)

1997-12-31

The energy storage matter plays an important role in wind-electric conversion systems for isolated applications. Having that in mind, two different approaches can be basically considered: either the immediate conversion of the generated electric energy, as in a water pumping system or electric energy storage for later use, as in a battery charging system. Due to some features such as no need of an external reactive power source and, sometimes, a gearbox, permanent-magnet synchronous generators have been broadly used in low rated power isolated systems. Despite that, system performance can be affected when the generator is feeding an inductive load (e.g., an induction motor) under variable-speed-variable-frequency operational conditions. Since there is no effective flux control, motor overload may occur at high wind speeds. Thus, good system performance can be obtained through additional control devices which may increase system cost. Although being rugged and cheap, induction machines always work as a reactive power drain; therefore, they demand an external reactive power source. Considering that, reactive static compensators appear as an attractive alternative to the cost x performance problem. In addition to that, different control strategies can be used so that system performance can be improved.

RESONANT PROCESSES IN STARTING MODES OF SYNCHRONOUS MOTORS WITH CAPACITORS IN THE EXCITATION WINDINGS CIRCUIT

Directory of Open Access Journals (Sweden)

V. S. Malyar

2017-08-01

Full Text Available Purpose. Development of a mathematical model that enables to detect resonance modes during asynchronous startup of salient-pole synchronous motors, in which capacitors are switched on to increase the electromagnetic moment in the circuit of the excitation winding. Methodology. The asynchronous mode is described by a system of differential equations of the electric equilibrium of motor circuits written in orthogonal coordinate axes. The basis of the developed algorithm is the mathematical model of the high-level adequacy motor and the projection method for solving the boundary value problem for the equations of the electric equilibrium of the circuits written in orthogonal coordinate axes, taking into account the presence of capacitors in the excitation winding. The coefficients of differential equations are the differential inductances of the motor circuits, which are determined on the basis of the calculation of its magnetic circuit. As a result of the asymmetry of the rotor windings in the asynchronous mode, the current coupling and currents change according to the periodic law. The problem of its definition is solved as a boundary one. Results. A mathematical model for studying the asynchronous characteristics of synchronous motors with capacitors in an excitation winding is developed, by means of which it is possible to investigate the influence of the size of the capacity on the motor's starting properties and the resonance processes which may arise in this case. Scientific novelty. The developed method of mathematical modeling is based on a fundamentally new mathematical basis for the calculation of stationary dynamic modes of nonlinear electromagnetic circuits, which enables to obtain periodic coordinate dependencies, without resorting to the calculation of the transients. The basis of the developed algorithm is based on the approximation of state variables by cubic splines, the projection method of decomposition for the boundary value

Loss of life of induction motors under various operating anomalies

International Nuclear Information System (INIS)

Chugh, Tarun; Varde, P.V.

2016-01-01

Reliability studies conducted to study the various failure modes of all induction motors shows that one of failure modes i.e. winding failure is quite prevalent and accounts for high percentage of failures of motors. Thus, there is a pivotal need to understand the theory of winding failure and know how it can be prognosticated based on the input parameters, current operating environment and maintenance history of a motor. This paper defines loss of motor life as the loss of stator winding insulation life due to thermal and environmental stresses. From the thermal point of view, the stator winding insulation is the weakest part of a squirrel cage induction motor, and equations are developed to estimate the insulation Iife and hence the motor life. In this regard, an integrated model consisting of an electrical model, thermal model and insulation ageing model is developed to evaluate the effect of various anomalies/stressors e.g. overvoltage and voltage unbalance on the life of a motor. This model is used to quantify the loss of life of a 2.3 kW, 415 V induction motor. The electrical model is developed by conducting Open Circuit and Blocked Rotor Test on the motor and thereby deriving its equivalent circuit. Using the model, the stator winding losses are calculated and given as an input to the thermal model to find the temperature rise in the stator winding. The steady state temperature of the stator winding is given as an input to the insulation aging model which predicts the loss of life. This work presents a simple technique for calculating thermal parameters based on motor testing rather than from motor design data. The insulation ageing model is developed based on Eyring Equation considering temperature and humidity as stressors. (author)

Microcontroller based Stator Winding Resistance Determination of Induction Motor Drive on Temperature Variations

OpenAIRE

Siraj Ahmed T; Sukhdeo Sao; K.S.R Anjaneyulu

2014-01-01

In this paper an experiment has been conducted to determine the online stator winding resistance of an induction motor, in industries as well as domestic purpose induction motors is largely utilized, as it has both applications of variable and constant torque operation nature. The major requirement of an electric drive system is its independent control of torque and speed; this is achieved in DC motor Drive but has more disadvantages. With the help of fast acting switching devices it is possi...

The count of losses by eddy currents in the windings of electric motors with hollow anchor

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N. V. Pribylova

2017-01-01

Full Text Available Given the rationale of taking into account losses on eddy currents in the windings of a low-inertia DC motors with offered magnetoelectric systems. Increased in recent years, the power of these motors (through the use of highly coercive magnets permanent caused an increase in the volume of copper in the air gap and the magnetic induction values. All this has values given rise to significant eddy currents in the windings made in the air gap, and hence the necessity of taking into account losses from these currents. The experimentally obtained dependence of the losses on eddy currents on the frequency of rotation for a DC motor with a hollow anchor with a power of 350 watts. The magnitude of these losses can reach 30% of the nominal power of the motor. Described mechanism of occurrence of losses. Eddy currents occur in areas with variable magnetic flux and cause the appearance of force, which is directed toward the velocity vector and inhibits the anchor. The directions of these currents, the vectors of magnetic induction, magnetic field and force acting on the conductor winding and a braking anchor. The proposed methods reduce losses: crushing contours of eddy currents and achieve uniform distribution of magnetic induction in the interpolar space of the motor. Shows their strengths and weaknesses. The crushing circuits of windings occur surge currents. To eliminate the losses on the surge currents it is necessary to apply a transposition of the conductors. Given a refined formula for finding the losses on eddy currents in the armature winding, the conductors of which is made in the form of a harness of several wires. Formula has shown a good convergence with experimental data.

Split-phase motor running as capacitor starts motor and as capacitor run motor

Directory of Open Access Journals (Sweden)

Yahaya Asizehi ENESI

2016-07-01

Full Text Available In this paper, the input parameters of a single phase split-phase induction motor is taken to investigate and to study the output performance characteristics of capacitor start and capacitor run induction motor. The value of these input parameters are used in the design characteristics of capacitor run and capacitor start motor with each motor connected to rated or standard capacitor in series with auxiliary winding or starting winding respectively for the normal operational condition. The magnitude of capacitor that will develop maximum torque in capacitor start motor and capacitor run motor are investigated and determined by simulation. Each of these capacitors is connected to the auxiliary winding of split-phase motor thereby transforming it into capacitor start or capacitor run motor. The starting current and starting torque of the split-phase motor (SPM, capacitor run motor (CRM and capacitor star motor (CSM are compared for their suitability in their operational performance and applications.

The Mechanism Study of Alternating Arc(ACMagnetic Levitation Induction Motor

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Li Zeng

2015-01-01

Full Text Available Magnetic levitation (no bearings motor by using magnetic force to make rotor suspend and drive realize its high or ultra-high speed rotating. The stator’s structure of traditional no bearing magnetic levitation motor is double winding which is polar logarithmic difference 1 of 2 sets of winding (torque winding and suspension winding and embedded in the stator. Using two inverter respectively for the two sets of winding to go into the same frequency current in order to realize the suspension of the rotor and motor’s driven, small carrying capacity of motor’s structure, controlling complex system. This paper based on the traditional motor technology puts forward a kind of arc principle and respectively decorates two arc motors in horizontal and vertical direction symmetric to rotor according to the electromagnetic bearing suspension technology that is constituted the arc magnetic levitation induction motor. Establishing air-gap transformation regular between rotor and stator (air-gap length motor is under the effect of interference. Based on the electromagnetic theory establishing distribution regular of the air-gap magnetic induction intensity. Virtual displacement principle is used to establish electromagnetism mathematical model and motor electromagnetism levitation. By the finite element analysis carrying on simulation research to the magnetic induction intensity, electric magnetic levitation force and distribution features of electromagnetic torque and so on.

Interpretation of basic concepts in theories of human motor abilities

Directory of Open Access Journals (Sweden)

Petrović Adam

2014-01-01

Full Text Available The basic aim of this research is to point to the possible language, logical and knowledge problems in interpretation and understanding of basic concepts in theories of motor abilities (TMA. Such manner of review is not directed only to 'mere understanding', it can lead to a new growth of scientific knowledge. Accordingly, the research question is set, i.e. the research issue: Is there a language, logical and knowledge agreement between basic concepts in the theories of human motor abilities? The answer to the set question direct that a more complete agreement between the basic concepts in the theories of human motor abilities should be searched in a scientific dialog between researchers of various beliefs.

Understanding wind power technology theory, deployment and optimisation

CERN Document Server

Schaffarczyk, Alois

2014-01-01

Wind energy technology has progressed enormously over the last decade. In coming years it will continue to develop in terms of power ratings, performance and installed capacity of large wind turbines worldwide, with exciting developments in offshore installations. Designed to meet the training needs of wind engineers, this introductory text puts wind energy in context, from the natural resource to the assessment of cost effectiveness and bridges the gap between theory and practice. The thorough coverage spans the scientific basics, practical implementations and the modern state of technology

Solar Wind Proton Temperature Anisotropy: Linear Theory and WIND/SWE Observations

Science.gov (United States)

Hellinger, P.; Travnicek, P.; Kasper, J. C.; Lazarus, A. J.

2006-01-01

We present a comparison between WIND/SWE observations (Kasper et al., 2006) of beta parallel to p and T perpendicular to p/T parallel to p (where beta parallel to p is the proton parallel beta and T perpendicular to p and T parallel to p are the perpendicular and parallel proton are the perpendicular and parallel proton temperatures, respectively; here parallel and perpendicular indicate directions with respect to the ambient magnetic field) and predictions of the Vlasov linear theory. In the slow solar wind, the observed proton temperature anisotropy seems to be constrained by oblique instabilities, by the mirror one and the oblique fire hose, contrary to the results of the linear theory which predicts a dominance of the proton cyclotron instability and the parallel fire hose. The fast solar wind core protons exhibit an anticorrelation between beta parallel to c and T perpendicular to c/T parallel to c (where beta parallel to c is the core proton parallel beta and T perpendicular to c and T parallel to c are the perpendicular and parallel core proton temperatures, respectively) similar to that observed in the HELIOS data (Marsch et al., 2004).

Analysis and control of the compaction force in the composite prepreg tape winding process for rocket motor nozzles

Directory of Open Access Journals (Sweden)

Xiaodong He

2017-04-01

Full Text Available In the process of composite prepreg tape winding, the compaction force could influence the quality of winding products. According to the analysis and experiments, during the winding process of a rocket motor nozzle aft exit cone with a winding angle, there would be an error between the deposition speed of tape layers and the feeding speed of the compaction roller, which could influence the compaction force. Both a lack of compaction and overcompaction related to the feeding of the compaction roller could result in defects of winding nozzles. Thus, a flexible winding system has been developed for rocket motor nozzle winding. In the system, feeding of the compaction roller could be adjusted in real time to achieve an invariable compaction force. According to experiments, the force deformation model of the winding tape is a time-varying system. Thus, a forgetting factor recursive least square based parameter estimation proportional-integral-differential (PID controller has been developed, which could estimate the time-varying parameter and control the compaction force by adjusting the feeding of the compaction roller during the winding process. According to the experimental results, a winding nozzle with fewer voids and a smooth surface could be wounded by the invariable compaction force in the flexible winding system.

Split-phase motor running as capacitor starts motor and as capacitor run motor

OpenAIRE

Yahaya Asizehi ENESI; Jacob TSADO; Mark NWOHU; Usman Abraham USMAN; Odu Ayo IMORU

2016-01-01

In this paper, the input parameters of a single phase split-phase induction motor is taken to investigate and to study the output performance characteristics of capacitor start and capacitor run induction motor. The value of these input parameters are used in the design characteristics of capacitor run and capacitor start motor with each motor connected to rated or standard capacitor in series with auxiliary winding or starting winding respectively for the normal operational condition. The ma...

A Micro-scale Wind Turbine Fed BLDC Motor for Electric Vehicle Drive Application

OpenAIRE

Kazraji, Saeed Masoumi; Khanabdal, Saheb; Soflaye, Ramin Bavil; Sabahi, Mehran

2016-01-01

In this paper a permanent magnet brushless dc motor (PMBLDCM) based driver with a wind-generator (WG) in maximum power point tracking (MPPT) condition is proposed. The proposed system has a high efficiency buck-type dc/dc converter and control unit running the MPPT function. The WG optimal power characteristic and wind speed measuring data are not required while the WG works in variable speed mode, therefore higher reliability, simplicity, lower cost and less mechanical Tension of the WG are ...

Understanding Self-Controlled Motor Learning Protocols through the Self-Determination Theory.

Science.gov (United States)

Sanli, Elizabeth A; Patterson, Jae T; Bray, Steven R; Lee, Timothy D

2012-01-01

The purpose of the present review was to provide a theoretical understanding of the learning advantages underlying a self-controlled practice context through the tenets of the self-determination theory (SDT). Three micro-theories within the macro-theory of SDT (Basic psychological needs theory, Cognitive Evaluation Theory, and Organismic Integration Theory) are used as a framework for examining the current self-controlled motor learning literature. A review of 26 peer-reviewed, empirical studies from the motor learning and medical training literature revealed an important limitation of the self-controlled research in motor learning: that the effects of motivation have been assumed rather than quantified. The SDT offers a basis from which to include measurements of motivation into explanations of changes in behavior. This review suggests that a self-controlled practice context can facilitate such factors as feelings of autonomy and competence of the learner, thereby supporting the psychological needs of the learner, leading to long term changes to behavior. Possible tools for the measurement of motivation and regulation in future studies are discussed. The SDT not only allows for a theoretical reinterpretation of the extant motor learning research supporting self-control as a learning variable, but also can help to better understand and measure the changes occurring between the practice environment and the observed behavioral outcomes.

Understanding self-controlled motor learning protocols through the self determination theory

Directory of Open Access Journals (Sweden)

Elizabeth Ann Sanli

2013-01-01

Full Text Available The purpose of the present review was to provide a theoretical understanding of the learning advantages underlying a self-controlled practice context through the tenets of the self-determination theory (SDT. Three micro theories within the macro theory of SDT (Basic psychological needs theory, Cognitive Evaluation Theory & Organismic Integration Theory are used as a framework for examining the current self-controlled motor learning literature. A review of 26 peer-reviewed, empirical studies from the motor learning and medical training literature revealed an important limitation of the self-controlled research in motor learning: that the effects of motivation have been assumed rather than quantified. The SDT offers a basis from which to include measurements of motivation into explanations of changes in behavior. This review suggests that a self-controlled practice context can facilitate such factors as feelings of autonomy and competence of the learner, thereby supporting the psychological needs of the learner, leading to long term changes to behavior. Possible tools for the measurement of motivation and regulation in future studies are discussed. The SDT not only allows for a theoretical reinterpretation of the extant motor learning research supporting self-control as a learning variable, but also can help to better understand and measure the changes occurring between the practice environment and the observed behavioral outcomes.

DETAILED FIT OF 'CRITICAL BALANCE' THEORY TO SOLAR WIND TURBULENCE MEASUREMENTS

International Nuclear Information System (INIS)

Forman, Miriam A.; Wicks, Robert T.; Horbury, Timothy S.

2011-01-01

We derive the reduced spectrum of turbulent magnetic fluctuations at different frequencies f which would be observed by a single spacecraft in the solar wind when the magnetic field was at an angle θ B to the solar wind flow, if the wavevector spectrum in the solar wind frame were in anisotropic 'critical balance' (CB) as proposed by Goldreich and Sridhar in 1995 (GS95). The anisotropic power spectrum in the inertial range, P(f, θ B ), is scaled onto one curve with f- 5/3 behavior at θ B near 90 0 and f -2 behavior at small θ B . The transition between the two limiting spectra depends on the form of the GS95 wavevector spectrum and the CB scaling parameter L. Using wavelet analysis of Ulysses magnetic field data in three 30-day periods in the high-latitude solar wind in 1995, we verify that the scaling of power with angle and frequency is qualitatively consistent with GS95 theory. However, the scale length L required to fit the observed P(f, θ B ) to the original CB theory is rather less than the scale predicted by that theory for the solar wind. Part, possibly all, of this discrepancy is removed when the GS95 theory modified for imbalanced turbulence is used.

Development and fundamental study on a superconducting induction/synchronous motor incorporated with MgB2 cage windings

International Nuclear Information System (INIS)

Nakamura, T; Yamada, Y; Nishio, H; Sugano, M; Amemiya, N; Kajikawa, K; Wakuda, T; Takahashi, M; Okada, M

2012-01-01

In this paper, a fundamental study of the rotating characteristics of a induction/synchronous motor by use of superconducting MgB 2 cage windings is carried out based on analysis and experiment. Current transport properties of the produced monofilamentary MgB 2 wires are firstly characterized, and then utilized for the determination of the current carrying capacity of the rotor bars. Then, the motor model is designed and fabricated with the aid of conventional (copper) stator windings. We successfully observe the synchronous rotation of the fabricated motor at a rotation speed range from 300 to 1800 rpm. We can also realize an almost constant torque versus speed curve, and this characteristic is explained from the steep take-off of the electric field versus the current density curve, based on the nonlinear electrical equivalent circuit. These results are promising for the practical applications of a high efficiency motor for a liquid hydrogen circulation pump.

Theories for the winds from Wolf Rayet stars

International Nuclear Information System (INIS)

Cassinelli, J.P.

1982-01-01

The massive and fast winds of Wolf Rayet stars present a serious momentum problem for the line-driven wind theories that are commonly used to explain the fast winds of early type stars. It is perhaps possible for the winds to be driven by lines, if multiple scattering occurs and if there are a sufficient number of lines in the spectrum so that large fraction of the continuum is blocked by line opacity in the winds. Several other mechanisms are discussed, in particular two that rely on strong magnetic fields: a) Alfven wave driven wind models like those recently developed by Hartmann and MacGregor for late type supergiants and b) the ''Fast Magnetic Rotator'' model that was developed by Belcher and MacGregor for the winds from pre-main sequence stars. In either model, large magnetic fields (approximately equal to 10 4 gauss) are required to drive the massive and fast winds of Wolf Rayet stars. Smaller fields might be possible if the multiple scattering line radiation force can be relied on to provide a final acceleration to terminal velocity. (Auth.)

Improved ADRC for a Maglev Planar Motor with a Concentric Winding Structure

Directory of Open Access Journals (Sweden)

Baoquan Kou

2016-12-01

Full Text Available In the semiconductor industry, positioning accuracy and acceleration are critical parameters. To improve the acceleration speed of a motor, this paper proposes the moving-coil maglev planar motor with a concentric winding structure. The coordinate system has been built for the multiple degrees of freedom movement system. The Lorenz force method has been applied to solve its electromagnetic model. The real-time solving of the generalized inverse matrix of factors can realize the decoupling of the winding current. When the maglev height changes, the electromagnetic force and torque decreases exponentially with the increase of the air gap. To decrease the influence on control system performance by the internal model change and the external disturbance, this paper proposes an improved active disturbance rejection control (ADRC to design the controller. This new controller overcomes the jitter phenomenon due to the turning point for the traditional ADRC, thus it is more suitable for the maglev control system. The comparison between ADRC and the improved ADRC has been conducted, the result of which shows the improved ADRC has greater robustness.

Experimental verification of the effect of cable length on voltage distribution in stator winding of an induction motor under surge condition

Energy Technology Data Exchange (ETDEWEB)

Oyegoke, B.S. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Electromechanics

1997-12-31

This paper presents the results of surge distribution tests performed on a stator of a 6 kV induction motor. The primary aim of these tests was to determine the wave propagation properties of the machine winding fed via cables of different lengths. Considering the measured resorts, conclusions are derived regarding the effect of cable length on the surge distribution within the stator winding of an ac motor. (orig.) 15 refs.

Recognizing speech in a novel accent: the motor theory of speech perception reframed.

Science.gov (United States)

Moulin-Frier, Clément; Arbib, Michael A

2013-08-01

The motor theory of speech perception holds that we perceive the speech of another in terms of a motor representation of that speech. However, when we have learned to recognize a foreign accent, it seems plausible that recognition of a word rarely involves reconstruction of the speech gestures of the speaker rather than the listener. To better assess the motor theory and this observation, we proceed in three stages. Part 1 places the motor theory of speech perception in a larger framework based on our earlier models of the adaptive formation of mirror neurons for grasping, and for viewing extensions of that mirror system as part of a larger system for neuro-linguistic processing, augmented by the present consideration of recognizing speech in a novel accent. Part 2 then offers a novel computational model of how a listener comes to understand the speech of someone speaking the listener's native language with a foreign accent. The core tenet of the model is that the listener uses hypotheses about the word the speaker is currently uttering to update probabilities linking the sound produced by the speaker to phonemes in the native language repertoire of the listener. This, on average, improves the recognition of later words. This model is neutral regarding the nature of the representations it uses (motor vs. auditory). It serve as a reference point for the discussion in Part 3, which proposes a dual-stream neuro-linguistic architecture to revisits claims for and against the motor theory of speech perception and the relevance of mirror neurons, and extracts some implications for the reframing of the motor theory.

An improved efficiency of fuzzy sliding mode control of permanent magnet synchronous motor for wind turbine generator pumping system

International Nuclear Information System (INIS)

Benchabane, F.; Titaouine, A.; Guettaf, A.; Yahia, K.; Taibi, D.; Bennis, O.

2012-01-01

This paper presents an analysis by which the dynamic performances of a permanent magnet synchronous motor (PMSM) motor is controlled through a hysteresis current loop and an outer speed loop with different controllers. The dynamics of the wind turbine pumping drive system with (PI) and a fuzzy sliding mode (FSM) speed controllers are presented. In order to optimize the overall system efficiency, a maximum power point tracker is also used. Simulation is carried out by formatting the mathematical model for wind turbine generator, motor and pump load. The results for such complicated and nonlinear system, with fuzzy sliding mode speed controller show improvement in transient response of the PMSM drive over conventional PI. The effectiveness of the FSM controller is also demonstrated. (author)

An electrical gearbox by means of pole variation for induction and superconducting disc motor

International Nuclear Information System (INIS)

Inacio, S; Inacio, D; Pina, J M; Valtchev, S; Neves, M V; Rodrigues, A L

2008-01-01

In this paper, a poly-phase disc motor innovative feeding and control strategy, based on a variable poles approach, and its application to a HTS disc motor, are presented. The stator windings may be electronically commutated to implement a 2, 4, 6 or 8 poles winding, thus changing the motor's torque/speed characteristics. The motor may be a conventional induction motor with a conductive disc rotor, or a new HTS disc motor, with conventional copper windings at its two iron semi-stators, and a HTS disc as a rotor. The conventional induction motor's operation principle is related with the induced electromotive forces in the conductive rotor. Its behaviour, characteristics (namely their torque/speed characteristics for different number of pole pairs) and modelling through Steinmetz and others theories are well known. The operation principle of the motor with HTS rotor, however, is rather different and is related with vortices' dynamics and pinning characteristics; this is a much more complex process than induction, and its modelling is quite complicated. In this paper, the operation was simulated through finite-elements commercial software, whereas superconductivity was simulated by the E-J power law. The Electromechanical performances of both motors where computed and are presented and compared. Considerations about the systems overall efficiency, including cryogenics, are also discussed

Timoshenko-Wagner-Kappus Torsion Bending Theory and Wind ...

Indian Academy of Sciences (India)

Theory and Wind Tunnel Balance Design. S P Govinda ... The study of torsion and bending has always been a favourite ... Since it was difficult to work quietlyin Petersburg, .... should be stiff and strong to endure shocks and ensure long life.

Detection of Stator Winding Fault in Induction Motor Using Fuzzy Logic with Optimal Rules

Directory of Open Access Journals (Sweden)

Hamid Fekri Azgomi

2013-04-01

Full Text Available Induction motors are critical components in many industrial processes. Therefore, swift, precise and reliable monitoring and fault detection systems are required to prevent any further damages. The online monitoring of induction motors has been becoming increasingly important. The main difficulty in this task is the lack of an accurate analytical model to describe a faulty motor. A fuzzy logic approach may help to diagnose traction motor faults. This paper presents a simple method for the detection of stator winding faults (which make up 38% of induction motor failures based on monitoring the line/terminal current amplitudes. In this method, fuzzy logic is used to make decisions about the stator motor condition. In fact, fuzzy logic is reminiscent of human thinking processes and natural language enabling decisions to be made based on vague information. The motor condition is described using linguistic variables. Fuzzy subsets and the corresponding membership functions describe stator current amplitudes. A knowledge base, comprising rule and data bases, is built to support the fuzzy inference. Simulation results are presented to verify the accuracy of motor’s fault detection and knowledge extraction feasibility. The preliminary results show that the proposed fuzzy approach can be used for accurate stator fault diagnosis.

An induction/synchronous motor with high temperature superconductor/normal conductor hybrid double-cage rotor windings

International Nuclear Information System (INIS)

Nakamura, T; Nagao, K; Nishimura, T; Matsumura, K

2009-01-01

We propose hybrid double-cage rotor windings that consist of a high temperature superconductor (HTS) and a normal conductor, which are introduced into an HTS induction/synchronous motor (HTS-ISM). The motor rotates as a conventional induction motor when the operating temperature of the hybrid rotor is above the critical temperature of the HTS bars, i.e., in the normal conducting state. On the other hand, the HTS-ISM rotates as a synchronous motor when the temperature is below the critical temperature, i.e., in the superconducting (zero resistance) state. In other words, we do not always need to take care of the cooling conditions, if the HTS-ISM is automatically, as well as appropriately, controlled, depending upon the rotation mode. Namely, the above-mentioned hybrid double-cage HTS-ISM is possibly a breakthrough in solving the cooling problems of HTS rotating machines, especially for industrial applications. The experimental results of the aforementioned motor are reported. An example of an operation flowchart of the motor is also presented and discussed.

Effect of power quality on windings temperature of marine induction motors

Energy Technology Data Exchange (ETDEWEB)

Gnacinski, P. [Gdynia Maritime University, Department of Ship Electrical Power Engineering, Morska Str. 83, 81-225 Gdynia (Poland)], E-mail: piotrg@am.gdynia.pl

2009-10-15

Marine induction machines are exposed to various power quality disturbances appearing simultaneously in ship power systems: frequency and voltage rms value deviation, voltage unbalance and voltage waveform distortions. As a result, marine induction motors can be seriously overheated due to lowered supply voltage quality. Improvement of the protection of marine induction machines requires an appropriate method of power quality assessment and modification of the power quality regulations of ship classification societies. This paper presents an analytical model of an induction cage machine supplied with voltage of lowered quality, used in part II of the work (effect of power quality on windings temperature of marine induction motors. Part II. Results of investigations and recommendations for related regulations) for power quality assessment in ship power systems, and for justification of the new power quality regulations proposal. The presented model is suitable for implementation in an on-line measurement system.

Prediction of windings temperature rise in induction motors supplied with distorted voltage

Energy Technology Data Exchange (ETDEWEB)

Gnacinski, P. [Gdynia Maritime University, Department of Ship Electrical Power Engineering, Morska Street 83, 81-225 Gdynia (Poland)

2008-04-15

One of the features of ship power systems is a different level and intensity of disturbances appearing during routine operation - the rms voltage value and frequency deviation, voltage unbalance and waveform voltage distortion. As a result, marine induction machines are exposed to overheating due to the lowered voltage quality. This paper is devoted to windings temperature rise prediction in marine induction cage machines supplied with distorted voltage, which means real voltage conditions. The proposed method of prediction does not require detailed knowledge of the thermal properties of a machine. Although the method was developed for marine induction motors, it is applicable for industry machines supplied with distorted voltage. It can also be generalized and used for estimation of the steady state windings temperature rise of any electrical machinery in various work conditions. (author)

Prediction of windings temperature rise in induction motors supplied with distorted voltage

International Nuclear Information System (INIS)

Gnacinski, P.

2008-01-01

One of the features of ship power systems is a different level and intensity of disturbances appearing during routine operation - the rms voltage value and frequency deviation, voltage unbalance and waveform voltage distortion. As a result, marine induction machines are exposed to overheating due to the lowered voltage quality. This paper is devoted to windings temperature rise prediction in marine induction cage machines supplied with distorted voltage, which means real voltage conditions. The proposed method of prediction does not require detailed knowledge of the thermal properties of a machine. Although the method was developed for marine induction motors, it is applicable for industry machines supplied with distorted voltage. It can also be generalized and used for estimation of the steady state windings temperature rise of any electrical machinery in various work conditions

How Kinesthetic Motor Imagery works: a predictive-processing theory of visualization in sports and motor expertise.

Science.gov (United States)

Ridderinkhof, K Richard; Brass, Marcel

2015-01-01

Kinesthetic Motor Imagery (KMI) is an important technique to acquire and refine motor skills. KMI is widely used by professional athletes as an effective way to improve motor performance without overt motor output. Despite this obvious relevance, the functional mechanisms and neural circuits involved in KMI in sports are still poorly understood. In the present article, which aims at bridging the sport sciences and cognitive neurophysiology literatures, we give a brief overview of relevant research in the field of KMI. Furthermore, we develop a theoretical account that relates KMI to predictive motor control theories assuming that it is based on internal activation of anticipatory images of action effects. This mechanism allows improving motor performance solely based on internal emulation of action. In accordance with previous literature, we propose that this emulation mechanism is implemented in brain regions that partially overlap with brain areas involved in overt motor performance including the posterior parietal cortex, the cerebellum, the basal ganglia and the premotor cortex. Finally, we outline one way to test the heuristic value of our theoretical framework for KMI; we suggest that experience with motor performance improves the ability to correctly infer the goals of others, in particular in penalty blocking in soccer. Copyright © 2015 Elsevier Ltd. All rights reserved.

Adaptive Disturbance Tracking Theory with State Estimation and State Feedback for Region II Control of Large Wind Turbines

Science.gov (United States)

Balas, Mark J.; Thapa Magar, Kaman S.; Frost, Susan A.

2013-01-01

A theory called Adaptive Disturbance Tracking Control (ADTC) is introduced and used to track the Tip Speed Ratio (TSR) of 5 MW Horizontal Axis Wind Turbine (HAWT). Since ADTC theory requires wind speed information, a wind disturbance generator model is combined with lower order plant model to estimate the wind speed as well as partial states of the wind turbine. In this paper, we present a proof of stability and convergence of ADTC theory with lower order estimator and show that the state feedback can be adaptive.

Impulse-variability theory: implications for ballistic, multijoint motor skill performance.

Science.gov (United States)

Urbin, M A; Stodden, David F; Fischman, Mark G; Weimar, Wendi H

2011-01-01

Impulse-variability theory (R. A. Schmidt, H. N. Zelaznik, B. Hawkins, J. S. Frank, & J. T. Quinn, 1979) accounts for the curvilinear relationship between the magnitude and resulting variability of the muscular forces that influence the success of goal-directed limb movements. The historical roots of impulse-variability theory are reviewed in the 1st part of this article, including the relationship between movement speed and spatial error. The authors then address the relevance of impulse-variability theory for the control of ballistic, multijoint skills, such as throwing, striking, and kicking. These types of skills provide a stark contrast to the relatively simple, minimal degrees of freedom movements that characterized early research. However, the inherent demand for ballistic force generation is a strong parallel between these simple laboratory tasks and multijoint motor skills. Therefore, the authors conclude by recommending experimental procedures for evaluating the adequacy of impulse variability as a theoretical model within the context of ballistic, multijoint motor skill performance. Copyright © Taylor & Francis Group, LLC

Field-oriented control of five-phase induction motor with open-end stator winding

Directory of Open Access Journals (Sweden)

Listwan Jacek

2016-09-01

Full Text Available The mathematical model of the five-phase squirrel-cage induction motor and the system of the dual five-phase voltage source inverter have been presented. The control methods and control systems of the field-oriented control of the five-phase induction motor with an open-end stator winding are described. The structures of the direct fieldoriented control system (DFOC and the Indirect Field-oriented control system (IFOC with PI controllers in outer and inner control loops are analyzed. A method of space vector modulation used to control the system of the dual five-phase voltage source inverter has been discussed. The results of simulation studies of the field-oriented control methods are presented. Comparative analysis of the simulation results was carried out.

Homopolar dc motor and trapped flux brushless dc motor using high temperature superconductor materials

Science.gov (United States)

Crapo, Alan D.; Lloyd, Jerry D.

1991-03-01

Two motors have been designed and built for use with high-temperature superconductor (HTSC) materials. They are a homopolar dc motor that uses HTSC field windings and a brushless dc motor that uses bulk HTSC materials to trap flux in steel rotor poles. The HTSC field windings of the homopolar dc motor are designed to operate at 1000 A/sq cm in a 0.010-T field. In order to maximize torque in the homopolar dc motor, an iron magnetic circuit with small air gaps gives maximum flux for minimum Ampere turns in the field. A copper field winding version of the homopolar dc motor has been tested while waiting for 575 A turn HTSC coils. The trapped flux brushless dc motor has been built and is ready to test melt textured bulk HTSC rings that are currently being prepared. The stator of the trapped flux motor will impress a magnetic field in the steel rotor poles with warm HTSC bulk rings. The rings are then cooled to 77 K to trap the flux in the rotor. The motor can then operate as a brushless dc motor.

Halbach array DC motor/generator

Science.gov (United States)

Merritt, B.T.; Dreifuerst, G.R.; Post, R.F.

1998-01-06

A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An ``inside-out`` design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then ``switched`` or ``commutated`` to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives. 17 figs.

Halbach array DC motor/generator

Science.gov (United States)

Merritt, Bernard T.; Dreifuerst, Gary R.; Post, Richard F.

1998-01-01

A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An "inside-out" design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then "switched" or "commutated" to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives.

Nonlinear aeroelastic modelling for wind turbine blades based on blade element momentum theory and geometrically exact beam theory

International Nuclear Information System (INIS)

Wang, Lin; Liu, Xiongwei; Renevier, Nathalie; Stables, Matthew; Hall, George M.

2014-01-01

Due to the increasing size and flexibility of large wind turbine blades, accurate and reliable aeroelastic modelling is playing an important role for the design of large wind turbines. Most existing aeroelastic models are linear models based on assumption of small blade deflections. This assumption is not valid anymore for very flexible blade design because such blades often experience large deflections. In this paper, a novel nonlinear aeroelastic model for large wind turbine blades has been developed by combining BEM (blade element momentum) theory and mixed-form formulation of GEBT (geometrically exact beam theory). The nonlinear aeroelastic model takes account of large blade deflections and thus greatly improves the accuracy of aeroelastic analysis of wind turbine blades. The nonlinear aeroelastic model is implemented in COMSOL Multiphysics and validated with a series of benchmark calculation tests. The results show that good agreement is achieved when compared with experimental data, and its capability of handling large deflections is demonstrated. Finally the nonlinear aeroelastic model is applied to aeroelastic modelling of the parked WindPACT 1.5 MW baseline wind turbine, and reduced flapwise deflection from the nonlinear aeroelastic model is observed compared to the linear aeroelastic code FAST (Fatigue, Aerodynamics, Structures, and Turbulence). - Highlights: • A novel nonlinear aeroelastic model for wind turbine blades is developed. • The model takes account of large blade deflections and geometric nonlinearities. • The model is reliable and efficient for aeroelastic modelling of wind turbine blades. • The accuracy of the model is verified by a series of benchmark calculation tests. • The model provides more realistic aeroelastic modelling than FAST (Fatigue, Aerodynamics, Structures, and Turbulence)

Theory of radiatively driven stellar winds. I. A physical interpretation

International Nuclear Information System (INIS)

Abbott, D.C.

1980-01-01

This series of papers extends the line-driven wind theory of Castor, Abbott, and Klein (CAK). The present paper develops a physical interpretation of line-driven flows using analytic methods. Numerical results will follow in two subsequent papers

Psycholinguistic and motor theories of apraxia of speech.

Science.gov (United States)

Ziegler, Wolfram

2002-11-01

This article sketches the relationships between modern conceptions of apraxia of speech (AOS) and current models of neuromotor and neurolinguistic disorders. The first section is devoted to neurophysiological perspectives of AOS, and its relation to dysarthrias and to limb apraxia is discussed. The second section introduces the logogen model and considers AOS in relation to supramodal aspects of aphasia. In the third section, AOS with the background of psycholinguistic models of spoken language production, including the Levelt model and connectionist models, is discussed. In the fourth section, the view of AOS as a disorder of speech motor programming is discussed against the background of theories from experimental psychology. The final section considers two models of speech motor control and their relation to AOS. The article discusses the strengths and weaknesses of these approaches.

The modern portfolio theory applied to wind farm financing

Energy Technology Data Exchange (ETDEWEB)

Chaves-Schwinteck, P. [DEWI GmbH, Oldenburg (Germany)

2011-02-15

An alternative to the application of the principles of the Modern Portfolio Theory as a strategy to the reduction of the risks around the energy production of wind farms was presented in the last sections. The potential of geographical diversification to reduce the risks related to the availability of wind as a primary resource was demonstrated by the results of the first case study. Furthermore, the results of the second case study have shown that, once a sufficient history of technical performance data is available, a reduction of the risks linked to the technical performance of the wind turbines can be achieved in a similar way. Nevertheless, the existence of 'non-diversifiable' risks still presents a challenge for the financing of wind farms. In this sense, it is important to point out that the financing performance of a portfolio of wind farms is extremely dependent on the individual performance of the single projects. In other words, a portfolio analysis is not a miracle. A 'bad' project remains a 'bad' project even when this project is bundled with a 'good' one. For this reason, other risk management strategies, as for example, a well performed technical due diligence should be always taken into consideration. (orig.)

Nuevo procedimiento para la evaluación de los motores monofásicos de inducción; New approach to single–phase induction motors performance evaluation

Directory of Open Access Journals (Sweden)

Marcos A.- de Armas Teyra y otros

2013-01-01

Full Text Available En el presente trabajo se desarrolló un algoritmo basado en el método del torque en elentrehierro que evalúa el comportamiento de los motores monofásicos de inducción y determinala potencia desarrollada, la eficiencia y otros parámetros operacionales a partir de las medicionesobtenidas de un analizador de redes instalado en los terminales del motor. Los resultados poseenadecuada precisión independientemente de si existen variaciones de tensión y de frecuencia, o silas tensiones están desfasadas o no e incluso donde la disposición espacial de los devanadospueda ser arbitraria con distinto número de vueltas en las bobinas así como diferentes calibres en los conductores. La solución se alcanza sin necesidad de conocer los parámetros del circuitoequivalente. Como casos de estudio se muestra su aplicación a motores de fase dividida, capacitor permanente y asimétrico comparando los resultados con el método tradicional basado en la teoría de los campos rotatorios.In this paper was developed an algorithm based in air gap torque method to evaluate theperformance of single phase induction motors. The developed shaft power, efficiency and otherparameters are determined using a power analyzer installed in motor terminals in field conditions.Results are adequate independently if there exist voltage or frequency deviation, voltageunbalance or different voltage phase between main and auxiliary winding and different spatial disposition of windings, wire size or winding distribution. The solution is obtained withoutknowledge of motor equivalent circuit’s parameters. As cases its application to split phase, permanent capacitor and asymmetric motors are exposed comparing the results with the classic rotating field theory.

Integrated motor drive and non-isolated battery charger based on the split-phase PM motors for plug-in vehicles

Directory of Open Access Journals (Sweden)

Saeid Haghbin

2014-06-01

Full Text Available A novel integrated motor drive and non-isolated battery charger based on a split-phase permanent magnet (PM motor is presented and described for a plug-in vehicle. The motor windings are reconfigured by a relay for the traction and charging operation. In traction mode, the motor is like a normal three-phase motor, whereas in the charging mode, after windings reconnection, the system is a three-phase Boost rectifier. One important challenge to use the motor as three inductors in charger circuit is to have it in standstill during the battery charging. Based on the presented mathematical model of a split-phase PM motor, the zero-torque condition of the motor is explained which led to a proper windings reconnection for the charging. Simulation and experimental results of two separate practical systems are provided to verify the proposed integrated battery charger. Some practical limitations and design recommendations are provided to achieve a more realistic practical system.

Enhanced gauge symmetry and winding modes in double field theory

Energy Technology Data Exchange (ETDEWEB)

Aldazabal, G. [Centro Atómico Bariloche,8400 S.C. de Bariloche (Argentina); Instituto Balseiro (CNEA-UNC) and CONICET,8400 S.C. de Bariloche (Argentina); Graña, M. [Institut de Physique Théorique, CEA/ Saclay,91191 Gif-sur-Yvette Cedex (France); Iguri, S. [Instituto de Astronomía y Física del Espacio (CONICET-UBA), Universidad de Buenos Aires,1428 Buenos Aires (Argentina); Mayo, M. [Centro Atómico Bariloche,8400 S.C. de Bariloche (Argentina); Instituto Balseiro (CNEA-UNC) and CONICET,8400 S.C. de Bariloche (Argentina); Nuñez, C. [Instituto de Astronomía y Física del Espacio (CONICET-UBA), Universidad de Buenos Aires,1428 Buenos Aires (Argentina); Departamento de Física, FCEN, Universidad de Buenos Aires,C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina); Rosabal, J.A. [Departamento de Física, FCEN, Universidad de Buenos Aires,C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina)

2016-03-15

We provide an explicit example of how the string winding modes can be incorporated in double field theory. Our guiding case is the closed bosonic string compactified on a circle of radius close to the self-dual point, where some modes with non-zero winding or discrete momentum number become massless and enhance the U(1)×U(1) symmetry to SU(2)×SU(2). We compute three-point string scattering amplitudes of massless and slightly massive states, and extract the corresponding effective low energy gauge field theory. The enhanced gauge symmetry at the self-dual point and the Higgs-like mechanism arising when changing the compactification radius are examined in detail. The extra massless fields associated to the enhancement are incorporated into a generalized frame with ((O(d+3,d+3))/(O(d+3)×O(d+3))) structure, where d is the number of non-compact dimensions. We devise a consistent double field theory action that reproduces the low energy string effective action with enhanced gauge symmetry. The construction requires a truly non-geometric frame which explicitly depends on both the compact coordinate along the circle and its dual.

A Model for Analyzing a Five-Phase Fractional-Slot Permanent Magnet Tubular Linear Motor with Modified Winding Function Approach

Directory of Open Access Journals (Sweden)

Bo Zhang

2016-01-01

Full Text Available This paper presents a model for analyzing a five-phase fractional-slot permanent magnet tubular linear motor (FSPMTLM with the modified winding function approach (MWFA. MWFA is a fast modeling method and it gives deep insight into the calculations of the following parameters: air-gap magnetic field, inductances, flux linkages, and detent force, which are essential in modeling the motor. First, using a magnetic circuit model, the air-gap magnetic density is computed from stator magnetomotive force (MMF, flux barrier, and mover geometry. Second, the inductances, flux linkages, and detent force are analytically calculated using modified winding function and the air-gap magnetic density. Finally, a model has been established with the five-phase Park transformation and simulated. The calculations of detent force reveal that the end-effect force is the main component of the detent force. This is also proven by finite element analysis on the motor. The accuracy of the model is validated by comparing with the results obtained using semianalytical method (SAM and measurements to analyze the motor’s transient characteristics. In addition, the proposed method requires less computation time.

Three-phase AC synchronous motor with high-temperature superconductor (HTS) rotor windings and HTS bearings. Final report

International Nuclear Information System (INIS)

Neumueller, H.W.; Nick, W.; Frank, M.; Massek, P.; Hasselt, P. van; Thummes, G.; Haefner, H.U.; Kummeth, P.; Werfel, F.; Frauenhofer, J.; Senger, R.; Schmidt, W.

2003-06-01

The project involved the design, construction and testing of a 3000 kW converter-fed synchronous motor as a development prototype with - HTS rotor windings, - closed-circuit cooling system, - stator air-gap winding and - high-gradient HTS magnetic bearing. The project objective was to create the conditions necessary for the construction of an application-oriented model(∼2 MW) that would be suitable for field tests and provide a starting point for subsequent series expansion. The main focus was fixed on feasibility and function issues relating to the various components, particularly during operation of the overall system in the test bay. These ambitious targets were achieved within the scope of project-based cooperation. This has been demonstrated especially in test bed operation of the machine since spring 2001, in the course of which the motor produced a maximum continuous rating of 450 kW - significantly above the specified value - while the short-time rating could be increased up to 600 kW. Throughout testing the motor demonstrated excellent performance characteristics that are markedly indifferent to load fluctuations and indicative of important operating advantages to subsequent users of such HTS motors. Loss calculations showed that, in terms of efficiency, this prototype already represents an approximately 1% improvement over the conventional motors or generators currently available. The robustness of the cooling concept developed as part of the project was also convincingly demonstrated during the comprehensive test phase, which has been ongoing since spring 2001. The innovative pulse-tube coolers developed by our partner companies Leybold and TransMIT promise further advantages over current commercial GM-coolers. Despite considerable problems with materials the team successfully built and operated a contactless HTS magnet bearing (based on YBCO stator cylinders from partner company ATZ) that is currently one of the world's largest in terms of bearing

A Neo-Piagetian Theory of Constructive Operators: Applications to Perceptual-Motor Development and Learning.

Science.gov (United States)

Todor, John I.

The author presents an overview of Pascual-Leone's Theory of Constructive Operators, a process-structural theory based upon Piagetian constructs which has evolved to both explain and predict the temporal unfolding of behavior. An application is made of the theory to the demands of a discrete motor task and prediction of (a) the minimal age…

Improved blade element momentum theory for wind turbine aerodynamic computations

DEFF Research Database (Denmark)

Sun, Zhenye; Chen, Jin; Shen, Wen Zhong

2016-01-01

Blade element momentum (BEM) theory is widely used in aerodynamic performance predictions and design applications for wind turbines. However, the classic BEM method is not quite accurate which often tends to under-predict the aerodynamic forces near root and over-predict its performance near tip....... for the MEXICO rotor. Results show that the improved BEM theory gives a better prediction than the classic BEM method, especially in the blade tip region, when comparing to the MEXICO measurements. (C) 2016 Elsevier Ltd. All rights reserved....

Application of Portfolio Theory to Minimization of Generation Variability in a System with Wind plants

International Nuclear Information System (INIS)

Sabolic, D.

2016-01-01

This paper evaluates validity of modern portfolio theory (MPT) for planning of installation of new wind plants with the lowest possible generation variability for given expected yearly generation. Suppose a Planner had historic meteorological data on wind speeds at a finite number of locations over longer time periods, and that they were technically convertible to time series of forecasted generation powers per megawatt of installed capacity. Suppose further that she intended to upgrade existing system with certain fixed amount of new wind plant capacity. Then she would be able to allocate shares in that total capacity to the available locations in a way that suits her policy goals regarding relation between total expected annual generation and total variability of generation best. Minimization of variability is a legitimate policy goal because it increases total costs of energy supply, so that leaving generation to vary more than technically necessary is economically inefficient. This article focuses on applicability of portfolio theory to such a problem. In the presented research, measured 15-minute data of wind generation in existing Croatian wind plants were used.(author).

Calibrated Blade-Element/Momentum Theory Aerodynamic Model of the MARIN Stock Wind Turbine: Preprint

Energy Technology Data Exchange (ETDEWEB)

Goupee, A.; Kimball, R.; de Ridder, E. J.; Helder, J.; Robertson, A.; Jonkman, J.

2015-04-02

In this paper, a calibrated blade-element/momentum theory aerodynamic model of the MARIN stock wind turbine is developed and documented. The model is created using open-source software and calibrated to closely emulate experimental data obtained by the DeepCwind Consortium using a genetic algorithm optimization routine. The provided model will be useful for those interested in validating interested in validating floating wind turbine numerical simulators that rely on experiments utilizing the MARIN stock wind turbine—for example, the International Energy Agency Wind Task 30’s Offshore Code Comparison Collaboration Continued, with Correlation project.

Windmills and wind motors how to build and run them

CERN Document Server

Powell, F E

2011-01-01

Free, clean, and sustainable energy: wind power is an essential resource everyone can harness. This comprehensive and compact historical work provides everything you need to learn about the theory and construction of everyday windmills, from small ones intended solely as models to those large enough to generate electricity. Powell provides all the necessities to get you on your way, including detailed, step-by-step instructions, illustrations, and designs for every part of the project.Types of windmill projects include:A model windmill with sails two feet acrossA

Probabilistic stability and "tall" wind profiles: theory and method for use in wind resource assessment

DEFF Research Database (Denmark)

Kelly, Mark C.; Troen, Ib

2016-01-01

A model has been derived for calculating the aggregate effects of stability and the finite height of the planetary boundary layer upon the long-term mean wind profile. A practical implementation of this probabilistic extended similarity-theory model is made, including its incorporation within...... to the methodology. Results of the modeling are shown for a number of sites, with discussion of the models’ efficacy and the relative improvement shown by the new model, for situations where a user lacks local heat flux information, as well as performance of the new model using measured flux statistics. Further...... the European Wind Atlas (EWA) methodology for site-to-site application. Theoretical and practical implications of the EWA methodology are also derived and described, including unprecedented documentation of the theoretical framework encompassing vertical extrapolation, as well as some improvement...

Asynchronous slip-ring motor synchronized with permanent magnets

Directory of Open Access Journals (Sweden)

Glinka Tadeusz

2017-03-01

Full Text Available The electric LSPMSM motor presented in the paper differs from standard induction motor by rotor design. The insulated start-up winding is located in slots along the rotor circumference. The winding ends are connected to the slip-rings. The rotor core contains permanent magnets. The electromechanical characteristics for synchronous operation were calculated, as were the start-up characteristics for operation with a short-circuited rotor winding. Two model motors were used for the calculations, the V-shaped Permanent Magnet (VPM – Fig. 3, and the Linear Permanent Magnet (IPM – Fig. 4, both rated at 14.5 kW. The advantages of the investigated motor are demonstrated in the conclusions.

Cryogenic Electric Motor Tested

Science.gov (United States)

Brown, Gerald V.

2004-01-01

Technology for pollution-free "electric flight" is being evaluated in a number of NASA Glenn Research Center programs. One approach is to drive propulsive fans or propellers with electric motors powered by fuel cells running on hydrogen. For large transport aircraft, conventional electric motors are far too heavy to be feasible. However, since hydrogen fuel would almost surely be carried as liquid, a propulsive electric motor could be cooled to near liquid hydrogen temperature (-423 F) by using the fuel for cooling before it goes to the fuel cells. Motor windings could be either superconducting or high purity normal copper or aluminum. The electrical resistance of pure metals can drop to 1/100th or less of their room-temperature resistance at liquid hydrogen temperature. In either case, super or normal, much higher current density is possible in motor windings. This leads to more compact motors that are projected to produce 20 hp/lb or more in large sizes, in comparison to on the order of 2 hp/lb for large conventional motors. High power density is the major goal. To support cryogenic motor development, we have designed and built in-house a small motor (7-in. outside diameter) for operation in liquid nitrogen.

Using Achievement Goal Theory in Motor Skill Instruction: A Systematic Review.

Science.gov (United States)

Palmer, Kara K; Chinn, Katherine M; Robinson, Leah E

2017-12-01

Over the past two decades, achievement goal theory (AGT) has been used as a theoretical framework to design and implement motor skill programming in young children. The purpose of this systematic review was to examine the effects of AGT in motor skill interventions and programming in children aged 0-12 years. This systematic literature search was conducted using three databases: Google Scholar, PubMed, and EBSCOhost. Studies were included if they met the following four inclusion criteria: (1) had an intervention with a gross motor outcome, (2) used an intervention grounded in AGT, (3) included young children (aged 0-12 years), and (4) were written in English. Studies were rated according to methodological reporting quality. All literature searches and reporting were consistent with the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) protocol. A total of 12 studies met all inclusion criteria and were included in the sample. All studies reported that AGT motor skill interventions were effective for improving motor skills in young children. Studies varied in regard to intervention groups, duration, dosage, and the personnel responsible for implementing the intervention. None of the included studies met the requirements to be considered as having high methodological quality. Based on these findings, AGT is an effective theoretical approach for designing and implementing motor skill interventions for young children.

Assessment of wind speed and wind power through three stations in Egypt, including air density variation and analysis results with rough set theory

International Nuclear Information System (INIS)

Essa, K.S.M.; Embaby, M.; Marrouf, A.A.; Koza, A.M.; Abd El-Monsef, M.E.

2007-01-01

It is well known that the wind energy potential is proportional to both air density and the third power of the wind speed average over a suitable time period. The wind speed and air density have random variables depending on both time and location. The main objective of this work is to derive the most general wind energy potential of the wind formulation putting into consideration the time variable in both wind speed and air density. The correction factor is derived explicitly in terms of the cross-correlation and the coefficients of variation.The application is performed for environmental and wind speed measurements at the Cairo Airport, Kosseir and Hurguada, Egypt. Comparisons are made between Weibull, Rayleigh, and actual data distributions of wind speed and wind power of one year 2005. A Weibull distribution is the best match to the actual probability distribution of wind speed data for most stations. The maximum wind energy potential was 373 W/m 2 in June at Hurguada (Red Sea coast) where the annual mean value was 207 W/m 2 . By Using Rough Set Theory, We Find That the Wind Power Depends on the Wind Speed with greater than air density

78 FR 38455 - Energy Conservation Program: Test Procedures for Electric Motors

Science.gov (United States)

2013-06-26

... windings, which protects them from condensation, moisture, dirt, and debris. This insulation typically... and Moisture Resistant Windings 4. Inverter-Capable Electric Motors 5. Totally Enclosed Non-Ventilated... set. [cir] Definite-purpose inverter- fed electric motor. [cir] Electric motor with moisture resistant...

Motor control for a brushless DC motor

Science.gov (United States)

Peterson, William J. (Inventor); Faulkner, Dennis T. (Inventor)

1985-01-01

This invention relates to a motor control system for a brushless DC motor having an inverter responsively coupled to the motor control system and in power transmitting relationship to the motor. The motor control system includes a motor rotor speed detecting unit that provides a pulsed waveform signal proportional to rotor speed. This pulsed waveform signal is delivered to the inverter to thereby cause an inverter fundamental current waveform output to the motor to be switched at a rate proportional to said rotor speed. In addition, the fundamental current waveform is also pulse width modulated at a rate proportional to the rotor speed. A fundamental current waveform phase advance circuit is controllingly coupled to the inverter. The phase advance circuit is coupled to receive the pulsed waveform signal from the motor rotor speed detecting unit and phase advance the pulsed waveform signal as a predetermined function of motor speed to thereby cause the fundamental current waveform to be advanced and thereby compensate for fundamental current waveform lag due to motor winding reactance which allows the motor to operate at higher speeds than the motor is rated while providing optimal torque and therefore increased efficiency.

Electric Motor Thermal Management Research: Annual Progress Report

Energy Technology Data Exchange (ETDEWEB)

Bennion, Kevin S. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-10-19

Past work in the area of active convective cooling provided data on the average convective heat transfer coefficients of circular orifice automatic transmission fluid (ATF) jets impinging on stationary targets intended to represent the wire bundle surface of the motor end-winding. Work during FY16 focused on the impact of alternative jet geometries that could lead to improved cooling over a larger surface of the motor winding. Results show that the planar jet heat transfer coefficients over a small (12.7-mm-diameter) target surface are not too much lower than for the circular orifice jet in which all of the ATF from the jet impinges on the target surface. The planar jet has the potential to achieve higher heat transfer over a larger area of the motor end winding. A new test apparatus was constructed to measure the spatial dependence of the heat transfer relative to the jet nozzle over a larger area representative of a motor end-winding. The tested planar flow geometry has the potential to provide more uniform cooling over the full end-winding surface versus the conventional jet configuration. The data will be used by motor designers to develop thermal management strategies to improve motor power density. Work on passive thermal design in collaboration with Oak Ridge National Laboratory to measure the thermal conductivity of wire bundle samples representative of end-winding and slot-winding materials was completed. Multiple measurement techniques were compared to determine which was most suitable for measuring composite wire bundle samples. NREL used a steady-state thermal resistance technique to measure the direction-dependent thermal conductivity. The work supported new interactions with industry to test new materials and reduce passive-stack thermal resistance in motors, leading to motors with increased power density. NREL collaborated with Ames Laboratory in the area of material characterization. The work focused on measuring the transverse rupture strength of

Effect of power quality on windings temperature of marine induction motors. Part I: Machine model

Energy Technology Data Exchange (ETDEWEB)

Gnacinski, P. [Gdynia Maritime Univ., Dept. of Ship Electrical Power Engineering, Morska Str. 83, 81-225 Gdynia (Poland)

2009-10-15

Marine induction machines are exposed to various power quality disturbances appearing simultaneously in ship power systems: frequency and voltage rms value deviation, voltage unbalance and voltage waveform distortions. As a result, marine induction motors can be seriously overheated due to lowered supply voltage quality. Improvement of the protection of marine induction machines requires an appropriate method of power quality assessment and modification of the power quality regulations of ship classification societies. This paper presents an analytical model of an induction cage machine supplied with voltage of lowered quality, used in part II of the work (effect of power quality on windings temperature of marine induction motors. Part II. Results of investigations and recommendations for related regulations) for power quality assessment in ship power systems, and for justification of the new power quality regulations proposal. The presented model is suitable for implementation in an on-line measurement system. (author)

Application and Perspectives of Multiphase Induction Motors

Directory of Open Access Journals (Sweden)

Benas Kundrotas

2012-04-01

Full Text Available The article considers the areas of applying multiphase induction motors. Their advantages against three phase motors have become the main reason for employing them in multiphase drives. The paper deals with the six-phase induction motor having two similar three phase windings in the stator shifted by 30 degrees in space and three phase windings in the rotor. Differential equations for this motor are presented and transformed to dq synchronous reference frame. The transformed equations are expressed in a matrix form and solved by MATLAB software using the Dormand-Prince (ode45 method. The transient characteristics of the torque, speed and current of the six-phase induction motor are calculated and discussed.Article in Lithuanian

The optimization model for multi-type customers assisting wind power consumptive considering uncertainty and demand response based on robust stochastic theory

International Nuclear Information System (INIS)

Tan, Zhongfu; Ju, Liwei; Reed, Brent; Rao, Rao; Peng, Daoxin; Li, Huanhuan; Pan, Ge

2015-01-01

Highlights: • Our research focuses on demand response behaviors of multi-type customers. • A wind power simulation method is proposed based on the Brownian motion theory. • Demand response revenue functions are proposed for multi-type customers. • A robust stochastic optimization model is proposed for wind power consumptive. • Models are built to measure the impacts of demand response on wind power consumptive. - Abstract: In order to relieve the influence of wind power uncertainty on power system operation, demand response and robust stochastic theory are introduced to build a stochastic scheduling optimization model. Firstly, this paper presents a simulation method for wind power considering external environment based on Brownian motion theory. Secondly, price-based demand response and incentive-based demand response are introduced to build demand response model. Thirdly, the paper constructs the demand response revenue functions for electric vehicle customers, business customers, industry customers and residential customers. Furthermore, robust stochastic optimization theory is introduced to build a wind power consumption stochastic optimization model. Finally, simulation analysis is taken in the IEEE 36 nodes 10 units system connected with 650 MW wind farms. The results show the robust stochastic optimization theory is better to overcome wind power uncertainty. Demand response can improve system wind power consumption capability. Besides, price-based demand response could transform customers’ load demand distribution, but its load curtailment capacity is not as obvious as incentive-based demand response. Since price-based demand response cannot transfer customer’s load demand as the same as incentive-based demand response, the comprehensive optimization effect will reach best when incentive-based demand response and price-based demand response are both introduced.

Non-isolated integrated motor drive and battery charger based on the split-phase PM motor for plug-in vehicles

OpenAIRE

Serrano Guillén, Isabel; Bermejo Fernández, Álvaro

2013-01-01

In electric vehicles and plug-in hybrid electric vehicles, the utility grid charges the vehicle battery through a battery charger. Different solutions have been proposed to reduce the size and cost of the charger. One solution to achieve this is to include the devices used in the traction circuit in the charger circuit; this is called an integrated motor drive and battery charger. A split-phase PM motor, a motor with double set of windings, gives the opportunity to implement different wind...

Research on Control Strategies of an Open-End Winding Permanent Magnet Synchronous Driving Motor (OW-PMSM-Equipped Dual Inverter with a Switchable Winding Mode for Electric Vehicles

Directory of Open Access Journals (Sweden)

Liang Chu

2017-05-01

Full Text Available An open-end winding permanent magnet synchronous motor (PMSM has a larger range of speed regulation than normal PMSM with the same DC voltage, and the control method is more flexible. It can also manage energy distribution between two power sources without a DC/DC converter. This paper aims at an electric vehicle equipped with OW-PMSM drive system with dual power sources and dual inverters; based on analyzing the external characteristics of each winding mode, we propose a winding mode switching strategy whose torque saturation judgmental algorithm, which is insensitive to motor’s parameters, could automatically realize upswitching of the winding mode. The proposed multi-level current hysteresis modulation algorithm could set the major power source and switch it at any time in independent mode, which accomplishes energy distribution between two power sources; its two control methods, low switching frequency method and high power difference method, could achieve different energy distribution effects. Simulation results confirm the validity and effectiveness of the winding mode switching strategy and current modulation method. They also show that an electric vehicle under the proposed control methods has better efficiency than one equipped with a traditional OW-PMSM drive system under traditional control.

Development of Interior Permanent Magnet Motors with Concentrated Windings for Reducing Magnet Eddy Current Loss

Science.gov (United States)

Yamazaki, Katsumi; Kanou, Yuji; Fukushima, Yu; Ohki, Shunji; Nezu, Akira; Ikemi, Takeshi; Mizokami, Ryoichi

In this paper, we present the development of interior magnet motors with concentrated windings, which reduce the eddy current loss of the magnets. First, the mechanism of the magnet eddy current loss generation is investigated by a simple linear magnetic circuit. Due to the consideration, an automatic optimization method using an adaptive finite element method is carried out to determine the stator and rotor shapes, which decrease the eddy current loss of the magnet. The determined stator and rotor are manufactured in order to proof the effectiveness by the measurement.

On the stringy nature of winding modes in noncommutative thermal field theories

CERN Document Server

Arcioni, G; Gomis, J P; Vázquez-Mozo, Miguel Angel; Gomis, Joaquim

2000-01-01

We show that thermal noncommutative field theories admit a version of `channel duality' reminiscent of open/closed string duality, where non-planar thermal loops can be replaced by an infinite tower of tree-level exchanges of effective fields. These effective fields resemble closed strings in three aspects: their mass spectrum is that of closed-string winding modes, their interaction vertices contain extra moduli, and they can be regarded as propagating in a higher-dimensional `bulk' space-time. In noncommutative models that can be embedded in a D-brane, we show the precise relation between the effective `winding fields' and closed strings propagating off the D-brane. The winding fields represent the coherent coupling of the infinite tower of closed-string oscillator states. We derive a sum rule that expresses this effective coupling in terms of the elementary couplings of closed strings to the D-brane. We furthermore clarify the relation between the effective propagating dimension of the winding fields and t...

Compressor motor for air conditioners realizing high efficiency and low cost; Kokoritsu tei cost wo jitsugenshita eakonyo asshukuki motor

Energy Technology Data Exchange (ETDEWEB)

Inaba, Y.; Kawamura, K.; Imazawa, K. [Toshiba Corp., Tokyo (Japan)

2000-01-01

The compressor motor accounts for most of the consumption of electric power in an air conditioner. To promote energy-saving, Toshiba has been progressively changing the compressor motors in its air conditioners to high-efficiency brushless DC motors. We have now developed a new compressor motor in order to achieve even greater energy-saving. A concentrated winding system was adopted featuring direct winding on the teeth of the stator core, for the first time in the industry. As a result, it was possible to realize a high-efficiency, compact, lightweight, and low-cost motor. Moreover, by constructing a new system for production, we were able to improve productivity and quality. The newly developed motor is expected to contribute to the further diffusion of energy-saving air conditioners. (author)

Investigation of Perceptual-Motor Behavior Across the Expert Athlete to Disabled Patient Skill Continuum can Advance Theory and Practical Application.

Science.gov (United States)

Müller, Sean; Vallence, Ann-Maree; Winstein, Carolee

2017-12-14

A framework is presented of how theoretical predictions can be tested across the expert athlete to disabled patient skill continuum. Common-coding theory is used as the exemplar to discuss sensory and motor system contributions to perceptual-motor behavior. Behavioral and neural studies investigating expert athletes and patients recovering from cerebral stroke are reviewed. They provide evidence of bi-directional contributions of visual and motor systems to perceptual-motor behavior. Majority of this research is focused on perceptual-motor performance or learning, with less on transfer. The field is ripe for research designed to test theoretical predictions across the expert athlete to disabled patient skill continuum. Our view has implications for theory and practice in sports science, physical education, and rehabilitation.

Modular PM Motor Drives for Automotive Traction Applications

International Nuclear Information System (INIS)

Su, G.J.

2001-01-01

This paper presents modular permanent magnet (PM) motor drives for automotive traction applications. A partially modularized drive system consisting of a single PM motor and multiple inverters is described. The motor has multiple three-phase stator winding sets and each winding set is driven with a separate three-phase inverter module. A truly modularized inverter and motor configuration based on an axial-gap PM motor is then introduced, in which identical PM motor modules are mounted on a common shaft and each motor module is powered by a separate inverter module. The advantages of the modular approach for both inverter and motor include: (1) power rating scalability-one design meets different power requirements by simply stacking an adequate number of modules, thus avoiding redesigning and reducing the development cost, (2) increased fault tolerance, and (3) easy repairing. A prototype was constructed by using two inverters and an axial-gap PM motor with two sets of three-phase stat or windings, and it is used to assist the diesel engine in a hybrid electric vehicle converted from a Chevrolet Suburban. The effect of different pulse-width-modulation strategies for both motoring and regenerative modes on current control is analyzed. Torque and regenerative control algorithms are implemented with a digital signal processor. Analytical and initial testing results are included in the paper

Direct-phase-variable model of a synchronous reluctance motor including all slot and winding harmonics

International Nuclear Information System (INIS)

Obe, Emeka S.; Binder, A.

2011-01-01

A detailed model in direct-phase variables of a synchronous reluctance motor operating at mains voltage and frequency is presented. The model includes the stator and rotor slot openings, the actual winding layout and the reluctance rotor geometry. Hence, all mmf and permeance harmonics are taken into account. It is seen that non-negligible harmonics introduced by slots are present in the inductances computed by the winding function procedure. These harmonics are usually ignored in d-q models. The machine performance is simulated in the stator reference frame to depict the difference between this new direct-phase model including all harmonics and the conventional rotor reference frame d-q model. Saturation is included by using a polynomial fitting the variation of d-axis inductance with stator current obtained by finite-element software FEMAG DC (registered) . The detailed phase-variable model can yield torque pulsations comparable to those obtained from finite elements while the d-q model cannot.

Design and AC loss analysis of a superconducting synchronous motor

Energy Technology Data Exchange (ETDEWEB)

Jiang, Q [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Majoros, M [Department of Materials Science and Engineering, Ohio State University (United States); Hong, Z [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Campbell, A M [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Coombs, T A [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

2006-11-15

This paper gives a conceptual design of a superconducting synchronous motor consisting of both high-temperature superconducting rotating field winding and armature winding. The AC losses of the armature winding of the motor have been investigated experimentally and numerically, by considering the self-field of the superconducting coils and the rotating magnetic field exposed on the armature winding. The recent developments of YBCO-coated conductors present the possibility of achieving a wholly superconducting machine of significantly smaller size and weight than a conventional machine. Both the rotating field winding and the armature winding are composed of YBCO high-temperature superconducting (HTS) coils. A low AC loss armature winding design has been developed for this superconducting synchronous motor. The performance of the machine was investigated by modelling with the finite-element method. The machine's torque is calculated from first principles by considering the angle between the field and the armature main flux lines.

Using a micromachined magnetostatic relay in commutating a DC motor

Science.gov (United States)

Tai, Yu-Chong (Inventor); Wright, John A. (Inventor); Lilienthal, Gerald (Inventor)

2004-01-01

A DC motor is commutated by rotating a magnetic rotor to induce a magnetic field in at least one magnetostatic relay in the motor. Each relay is activated in response to the magnetic field to deliver power to at least one corresponding winding connected to the relay. In some cases, each relay delivers power first through a corresponding primary winding and then through a corresponding secondary winding to a common node. Specific examples include a four-pole, three-phase motor in which each relay is activated four times during one rotation of the magnetic rotor.

Remote Sensing Wind and Wind Shear System.

Science.gov (United States)

Contents: Remote sensing of wind shear and the theory and development of acoustic doppler; Wind studies; A comparison of methods for the remote detection of winds in the airport environment; Acoustic doppler system development; System calibration; Airport operational tests.

Control of Surface Mounted Permanent Magnet Motors with Special Application to Fractional-Slot Concentrated Windings

Energy Technology Data Exchange (ETDEWEB)

Lawler, J.S.

2005-12-21

It is well known that the ability of the permanent magnet synchronous machine (PMSM) to operate over a wide constant power speed range (CPSR) is dependent upon the machine inductance [1,2,3,4,5]. Early approaches for extending CPSR operation included adding supplementary inductance in series with the motor [1] and the use of anti-parallel thyristor pairs in series with the motor-phase windings [5]. The increased inductance method is compatible with a voltage-source inverter (VSI) controlled by pulse-width modulation (PWM) which is called the conventional phase advance (CPA) method. The thyristor method has been called the dual mode inverter control (DMIC). Neither of these techniques has met with wide acceptance since they both add cost to the drive system and have not been shown to have an attractive cost/benefit ratio. Recently a method has been developed to use fractional-slot concentrated windings to significantly increase the machine inductance [6]. This latest approach has the potential to make the PMSM compatible with CPA without supplemental external inductance. If the performance of such drive is acceptable, then the method may make the PMSM an attractive option for traction applications requiring a wide CPSR. A 30 pole, 6 kW, 6000 maximum revolutions per minute (rpm) prototype of the fractional-slot PMSM design has been developed [7]. This machine has significantly more inductance than is typical of regular PMSMs. The prototype is to be delivered in late 2005 to the Oak Ridge National Laboratory (ORNL) for testing and development of a suitable controller. In advance of the test/control development effort, ORNL has used the PMSM models developed over a number of previous studies to study the steady-state performance of high-inductance PMSM machines with a view towards control issues. The detailed steady-state model developed includes all motor and inverter-loss mechanisms and will be useful in assessing the performance of the dynamic controller to be

Mountain Plains Learning Experience Guide: Electric Motor Repair.

Science.gov (United States)

Ziller, T.

This Electric Motor Repair Course is designed to provide the student with practical information for winding, repairing, and troubleshooting alternating current and direct current motors, and controllers. The course is comprised of eight units: (1) Electric Motor Fundamentals, (2) Rewinding, (3) Split-phase Induction Motors, (4) Capacitor Motors,…

Kinetic Theory and Fast Wind Observations of the Electron Strahl

Science.gov (United States)

Horaites, Konstantinos; Boldyrev, Stanislav; Wilson, Lynn B., III; Viñas, Adolfo F.; Merka, Jan

2018-02-01

We develop a model for the strahl population in the solar wind - a narrow, low-density and high-energy electron beam centred on the magnetic field direction. Our model is based on the solution of the electron drift-kinetic equation at heliospheric distances where the plasma density, temperature and the magnetic field strength decline as power laws of the distance along a magnetic flux tube. Our solution for the strahl depends on a number of parameters that, in the absence of the analytic solution for the full electron velocity distribution function (eVDF), cannot be derived from the theory. We however demonstrate that these parameters can be efficiently found from matching our solution with observations of the eVDF made by the Wind satellite's SWE strahl detector. The model is successful at predicting the angular width (FWHM) of the strahl for the Wind data at 1 au, in particular by predicting how this width scales with particle energy and background density. We find that the strahl distribution is largely determined by the local temperature Knudsen number γ ∼ |T dT/dx|/n, which parametrizes solar wind collisionality. We compute averaged strahl distributions for typical Knudsen numbers observed in the solar wind, and fit our model to these data. The model can be matched quite closely to the eVDFs at 1 au; however, it then overestimates the strahl amplitude at larger heliocentric distances. This indicates that our model may be improved through the inclusion of additional physics, possibly through the introduction of 'anomalous diffusion' of the strahl electrons.

Intelligent robust control law for induction motors based on field-oriented control theory

Energy Technology Data Exchange (ETDEWEB)

Barambones, O.; Alcorta, P.; Sevillano, G.; Garrido, A.; Garrido, I. [Univ. del Pais Vasco, Bilbao (Spain). Dpto. Ingenieri a de Sistemas y Automatica

2009-07-01

A sensorless adaptive control law was developed to improve the trajectory tracking performance of induction motors. The law used an integral sliding mode algorithm to avoid the necessity of calculating an upper bound for system uncertainties. The vector control theory was used to develop the induction motor drives. The sliding mode control law incorporated an adaptive switching gain and included a method of estimating rotor speeds. Rotor speed estimation errors were presented as a first order simple function based on the difference between real stator currents and estimated stator currents. The Lyapunov stability theory was used to analyze the controller under different load disturbances and parameter uncertainties. Results of the study showed that the control signal of the scheme was smaller than signals obtained using traditional variable structure control schemes. It was concluded that speed tracking objectives can be obtained under various parameter and torque uncertainties. 9 refs., 7 figs.

Modal Analysis of In-Wheel Motor-Driven Electric Vehicle Based on Bond Graph Theory

Directory of Open Access Journals (Sweden)

Di Tan

2017-01-01

Full Text Available A half-car vibration model of an electric vehicle driven by rear in-wheel motors was developed using bond graph theory and the modular modeling method. Based on the bond graph model, modal analysis was carried out to study the vibration characteristics of the electric vehicle. To verify the effectiveness of the established model, the results were compared to ones computed on the ground of modal analysis and Newton equations. The comparison shows that the vibration model of the electric vehicle based on bond graph theory not only is able to better compute the natural frequency but also can easily determine the deformation mode, momentum mode, and other isomorphism modes and describe the dynamic characteristics of an electric vehicle driven by in-wheel motors more comprehensively than other modal analysis methods.

High-Tc superconducting electric motors

International Nuclear Information System (INIS)

Schiferl, R.; Stein, J.

1992-01-01

In this paper, the advantages and limitations of using superconductors in motors are discussed. A synchronous motor with a high temperature superconducting field winding for pump and fan drive applications is described and some of its unique design features are identified. A 10,000 horsepower superconducting motor design is presented. The critical field and current density requirements for high temperature superconducting wire in motors is discussed. Finally, recent progress in superconducting wire performance is presented

Dual power, constant speed electric motor system

Science.gov (United States)

Kirschbaum, H.S.

1984-07-31

A dual capacity permanent split capacitor electric motor system is provided with a stator having main and auxiliary windings. The main stator winding includes two winding sections which are connected in parallel with each other and across a pair of line terminals while the auxiliary winding is connected in series with a capacitor to form a circuit branch which is connected between the line terminals for operation at a first output power level. Switching means are provided to reconnect the main stator winding sections in series with each other and in series with a second capacitor to form a circuit branch which is connected between the line terminals while the stator auxiliary winding is connected directly between the line terminals for operation at a second output power level. Automatic rotation reversal occurs when the motor switches from the first to the second output power level. 6 figs.

Dual power, constant speed electric motor system

Science.gov (United States)

Kirschbaum, Herbert S.

1984-01-01

A dual capacity permanent split capacitor electric motor system is provided with a stator having main and auxiliary windings. The main stator winding includes two winding sections which are connected in parallel with each other and across a pair of line terminals while the auxiliary winding is connected in series with a capacitor to form a circuit branch which is connected between the line terminals for operation at a first output power level. Switching means are provided to reconnect the main stator winding sections in series with each other and in series with a second capacitor to form a circuit branch which is connected between the line terminals while the stator auxiliary winding is connected directly between the line terminals for operation at a second output power level. Automatic rotation reversal occurs when the motor switches from the first to the second output power level.

Wind Turbine Generator Efficiency Based on Powertrain Combination and Annual Power Generation Prediction

Directory of Open Access Journals (Sweden)

Dongmyung Kim

2018-05-01

Full Text Available Wind turbine generators are eco-friendly generators that produce electric energy using wind energy. In this study, wind turbine generator efficiency is examined using a powertrain combination and annual power generation prediction, by employing an analysis model. Performance testing was conducted in order to analyze the efficiency of a hydraulic pump and a motor, which are key components, and so as to verify the analysis model. The annual wind speed occurrence frequency for the expected installation areas was used to predict the annual power generation of the wind turbine generators. It was found that the parallel combination of the induction motors exhibited a higher efficiency when the wind speed was low and the serial combination showed higher efficiency when wind speed was high. The results of predicting the annual power generation considering the regional characteristics showed that the power generation was the highest when the hydraulic motors were designed in parallel and the induction motors were designed in series.

System and method to determine electric motor efficiency using an equivalent circuit

Science.gov (United States)

Lu, Bin [Kenosha, WI; Habetler, Thomas G [Snellville, GA

2011-06-07

A system and method for determining electric motor efficiency includes a monitoring system having a processor programmed to determine efficiency of an electric motor under load while the electric motor is online. The determination of motor efficiency is independent of a rotor speed measurement. Further, the efficiency is based on a determination of stator winding resistance, an input voltage, and an input current. The determination of the stator winding resistance occurs while the electric motor under load is online.

Design of large permanent magnetized synchronous electric machines: Low speed, high torque machines - generator for direct driven wind turbine - motor for rim driven thruster

Energy Technology Data Exchange (ETDEWEB)

Kroevel, Oeystein

2011-02-15

This work presents the design of two prototype permanent magnetized electric machines for two different applications where large permanent magnet machines might be used. Existing technology have been used as the fundament for new design and adapted to new applications, contributing, hopefully, to the development of better and more environmental friendly energy conversion. The first application presented is represented with a prototype made in cooperation with the industry in which a PM-motor is integrated into a propeller unit. Both because of the industrial connection, and the integration between the PM-motor and the propeller, the choices made for the PM-motor are conservative trying to reduce the risk. The direct rim driven thruster prototype includes a surface mounted radial flux permanent magnet machine (SM RFPM) with fractional slot winding with a q around 1. Other engineering features were introduced to make the integration of propeller and motor feasible, but without the PM-machine the thruster would not have reached the performance demand. An important part of the project was to show that the SM RFPM enables this solution, providing high performance with a large air gap. The prototype has been tested in sea, under harsh conditions, and even though the magnets have been exposed directly to sea water and been visible corroded, the electric motor still performs well within the specifications. The second application is represented with a prototype PM-generator for wind turbines. This is an example of a new, very low speed high torque machine. The generator is built to test phenomena regarding concentrated coils, and as opposed to the first application, being a pure academic university project, its success is not connected to its performance, but with the prototype's ability to expose the phenomena in question. The prototype, or laboratory model, of the generator for direct driven wind turbines features SM RFPM with concentrated coils (CC). An opportunity

The theory of radiation driven stellar winds and the Wolf-Rayet phenomenon

International Nuclear Information System (INIS)

Abbott, D.C.

1982-01-01

The author considers the question of whether the mass loss observed from Wolf-Rayet stars can be explained by a version of wind theory which is scaled to the conditions found in the envelopes of Wolf-Rayet stars. He discusses the following topics: - The calculated radiation pressure in OB stars, and its dependence on temperature, density, and chemical composition. - A comparison between predicted and observed mass loss rates and terminal velocities for OB stars. - The applicability of the standard radiation driven wind models to Wolf-Rayet stars. - Speculations on how Wolf-Rayet stars achieve their enormous mass loss rates within the context of the radiation pressure mechanism. (Auth.)

Induction motor for superconducting synchronous/asynchronous motor

International Nuclear Information System (INIS)

Litz, D.C.; Haller, H.E. III.

1975-01-01

An induction motor structure for use on the outside of a superconducting rotor comprising a cylindrical shell of solid and laminated, magnetic iron with squirrel cage windings embedded in the outer circumference of said shell is described. The sections of the shell between the superconducting windings of the rotor are solid magnetic iron. The sections of the shell over the superconducting windings are made of laminations of magnetic iron. These laminations are parallel to the axis of the machine and are divided in halves with the laminations in each half oriented in diagonal opposition so that the intersection of the laminations forms a V. This structure presents a relatively high reluctance to leakage flux from the superconducting windings in the synchronous operating mode, while presenting a low reluctance path to the stator flux during asynchronous operation

Non-Cooperative Regulation Coordination Based on Game Theory for Wind Farm Clusters during Ramping Events

DEFF Research Database (Denmark)

Qi, Yongzhi; Liu, Yutian; Wu, Qiuwei

2017-01-01

With increasing penetration of wind power in power systems, it is important to track scheduled wind power output as much as possible during ramping events to ensure security of the system. In this paper, a non‐cooperative coordination strategy based on the game theory is proposed for the regulation...... of the regulation revenue function according to the derived Nash equilibrium condition, the ER strategy is the Nash equilibrium of the regulation competition. Case studies were conducted with the power output data of wind farms from State Grid Jibei Electric Power Company Limited of China to demonstrate...

Thermal analysis of linear pulse motor for SMART control element drive mechanism

International Nuclear Information System (INIS)

Hur, H.; Kim, J. H.; Kim, J. I.; Jang, K. C.; Kang, D. H.

1999-01-01

It is important that the temperature of the motor windings be maintained within the allowable limit of the insulation, since the linear pulse motor of CEDM is always supplied with current during the reactor operation. In this study three motor windings were fabricated with three different diameters of coil wires, and the temperatures inside the windings were measured with different current values. As the insulation of the windings is composed of teflon, glass fiber, and air, it is not an easy task to determine experimentally the thermal properties of the complex insulation. In this study, the thermal properties of the insulation were obtained by comparing the results of finite element thermal analyses and those of experiment. The thermal properties obtained here will be used as input for the optimization analysis of the motor

Electromagnetic Performance Calculation of HTS Linear Induction Motor for Rail Systems

Science.gov (United States)

Liu, Bin; Fang, Jin; Cao, Junci; Chen, Jie; Shu, Hang; Sheng, Long

2017-07-01

According to a high temperature superconducting (HTS) linear induction motor (LIM) designed for rail systems, the influence of electromagnetic parameters and mechanical structure parameters on the electromagnetic horizontal thrust, vertical force of HTS LIM and the maximum vertical magnetic field of HTS windings are analyzed. Through the research on the vertical field of HTS windings, the development regularity of the HTS LIM maximum input current with different stator frequency and different thickness value of the secondary conductive plate is obtained. The theoretical results are of great significance to analyze the stability of HTS LIM. Finally, based on theory analysis, HTS LIM test platform was built and the experiment was carried out with load. The experimental results show that the theoretical analysis is correct and reasonable.

Electromagnetic Performance Calculation of HTS Linear Induction Motor for Rail Systems

International Nuclear Information System (INIS)

Liu, Bin; Fang, Jin; Cao, Junci; Chen, Jie; Shu, Hang; Sheng, Long

2017-01-01

According to a high temperature superconducting (HTS) linear induction motor (LIM) designed for rail systems, the influence of electromagnetic parameters and mechanical structure parameters on the electromagnetic horizontal thrust, vertical force of HTS LIM and the maximum vertical magnetic field of HTS windings are analyzed. Through the research on the vertical field of HTS windings, the development regularity of the HTS LIM maximum input current with different stator frequency and different thickness value of the secondary conductive plate is obtained. The theoretical results are of great significance to analyze the stability of HTS LIM. Finally, based on theory analysis, HTS LIM test platform was built and the experiment was carried out with load. The experimental results show that the theoretical analysis is correct and reasonable. (paper)

Electronically commutated serial-parallel switching for motor windings

Science.gov (United States)

Hsu, John S [Oak Ridge, TN

2012-03-27

A method and a circuit for controlling an ac machine comprises controlling a full bridge network of commutation switches which are connected between a multiphase voltage source and the phase windings to switch the phase windings between a parallel connection and a series connection while providing commutation discharge paths for electrical current resulting from inductance in the phase windings. This provides extra torque for starting a vehicle from lower battery current.

A new wind power prediction method based on chaotic theory and Bernstein Neural Network

International Nuclear Information System (INIS)

Wang, Cong; Zhang, Hongli; Fan, Wenhui; Fan, Xiaochao

2016-01-01

The accuracy of wind power prediction is important for assessing the security and economy of the system operation when wind power connects to the grids. However, multiple factors cause a long delay and large errors in wind power prediction. Hence, efficient wind power forecasting approaches are still required for practical applications. In this paper, a new wind power forecasting method based on Chaos Theory and Bernstein Neural Network (BNN) is proposed. Firstly, the largest Lyapunov exponent as a judgment for wind power system's chaotic behavior is made. Secondly, Phase Space Reconstruction (PSR) is used to reconstruct the wind power series' phase space. Thirdly, the prediction model is constructed using the Bernstein polynomial and neural network. Finally, the weights and thresholds of the model are optimized by Primal Dual State Transition Algorithm (PDSTA). The practical hourly data of wind power generation in Xinjiang is used to test this forecaster. The proposed forecaster is compared with several current prominent research findings. Analytical results indicate that the forecasting error of PDSTA + BNN is 3.893% for 24 look-ahead hours, and has lower errors obtained compared with the other forecast methods discussed in this paper. The results of all cases studying confirm the validity of the new forecast method. - Highlights: • Lyapunov exponent is used to verify chaotic behavior of wind power series. • Phase Space Reconstruction is used to reconstruct chaotic wind power series. • A new Bernstein Neural Network to predict wind power series is proposed. • Primal dual state transition algorithm is chosen as the training strategy of BNN.

Operating of Small Wind Power Plants with Induction Generators

OpenAIRE

Jakub Nevrala; Stanislav Misak

2008-01-01

This paper describes different systems of small wind power plants with induction generators used in the Czech Republic. Problems of wind power plants running with induction generators are solved within partial target of the research project MSM 6198910007. For small wind power plants is used induction motor as a generator. Parameters of the name plate of motor must be resolved for generator running on measuring base. These generators are running as a separately working generators or generator...

Tensions between Scottish National Policies for onshore wind energy and local dissatisfaction - insights from regulation theory

Energy Technology Data Exchange (ETDEWEB)

Parkhill, Karen [School of Psychology, Tower Building, Cardiff University, Cardiff, (United Kingdom)

2007-09-15

Although best described as a meta theory addressing the endurance of capitalism, regulation theory can successfully be used to explore not only the economic dimensions, but also the political, socio-cultural and environmental dimensions of particular developmental strategies. Thus, it offers a framework for embedding abstract debates about social attitudes to new technologies within debates about real regulation - the economic, social and cultural relationships operating through particular places. This paper uses regulation theory and qualitative, interview-based data to analyse Scotland's drive for onshore wind energy. This approach teases out how responses to wind farms are bound up with wider debates about how rural spaces are, and should be, regulated; the tensions within and between national political objectives, local political objectives and local communities' dissatisfaction; and the connections between local actors and more formal dimensions of renewable energy policy. (Author)

Controller for computer control of brushless dc motors. [automobile engines

Science.gov (United States)

Hieda, L. S. (Inventor)

1981-01-01

A motor speed and torque controller for brushless d.c. motors provides an unusually smooth torque control arrangement. The controller provides a means for controlling a current waveform in each winding of a brushless dc motor by synchronization of an excitation pulse train from a programmable oscillator. Sensing of torque for synchronization is provided by a light beam chopper mounted on the motor rotor shaft. Speed and duty cycle are independently controlled by controlling the frequency and pulse width output of the programmable oscillator. A means is also provided so that current transitions from one motor winding to another is effected without abrupt changes in output torque.

Design and Experimental Analysis of an Exhaust Air Energy Recovery Wind Turbine Generator

Directory of Open Access Journals (Sweden)

Ahmad Fazlizan

2015-06-01

Full Text Available A vertical axis wind turbine (VAWT was positioned at the discharge outlet of a cooling tower electricity generator. To avoid a negative impact on the performance of the cooling tower and to optimize the turbine performance, the determination of the VAWT position in the discharge wind stream was conducted by experiment. The preferable VAWT position is where the higher wind velocity matches the positive torque area of the turbine rotation. With the proper matching among the VAWT configurations (blade number, airfoil type, operating tip-speed-ratio, etc. and exhaust air profile, the turbine system was not only able to recover the wasted kinetic energy, it also reduced the fan motor power consumption by 4.5% and increased the cooling tower intake air flow-rate by 11%. The VAWT had a free running rotational speed of 479 rpm, power coefficient of 10.6%, and tip-speed-ratio of 1.88. The double multiple stream tube theory was used to explain the VAWT behavior in the non-uniform wind stream. For the actual size of a cooling tower with a 2.4 m outlet diameter and powered by a 7.5 kW fan motor, it was estimated that a system with two VAWTs (side-by-side can generate 1 kW of power which is equivalent to 13% of energy recovery.

The Mechanical Transient Process at Asynchronous Motor Oscillating Mode

Science.gov (United States)

Antonovičs, Uldis; Bražis, Viesturs; Greivulis, Jānis

2009-01-01

The research object is squirrel-cage asynchronous motor connected to single-phase sinusoidal. There are shown, that by connecting to the stator windings a certain sequence of half-period positive and negative voltage, a motor rotor is rotated, but three times slower than in the three-phase mode. Changing the connecting sequence of positive and negative half-period voltage to stator windings, motor can work in various oscillating modes. It is tested experimentally. The mechanical transient processes had been researched in rotation and oscillating modes.

Motor of the future - superconducting

International Nuclear Information System (INIS)

Moen, Odd

2001-01-01

High-temperature superconductors count as the most innovative and future-oriented technology for electric motors. When these materials are used, the engine rating can be doubled and at the same time the losses halved while retaining the same size of construction. Siemens have recently developed a synchronous motor based on a high-temperature superconducting excitation winding. The rated power of the motor is 380 kW. The high-temperature superconductor that is used in this motor requires considerably less cooling outfit than low-temperature superconductors

Design of an HTS motor

Energy Technology Data Exchange (ETDEWEB)

Jiang, Y; Pei, R; Hong, Z; Jiang, Q; Coombs, T A [Cambridge University engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)], E-mail: yj222@cam.ac.uk

2008-02-01

This paper gives a detailed description of the design of a high temperature superconducting (HTS) motor. The stator of the motor consists of six air cored HTS racetrack windings, together with an iron shield. The rotor is made of 80 superconducting YBCO pucks, which can be magnetized and equates to a four-pole permanent magnet. The whole HTS motor is cooled by liquid nitrogen to 77K, and acts as a permanent magnet synchronous motor with the power rate of 15.7 kW.

Wind accretion: Theory and observations

Science.gov (United States)

Shakura, N. I.; Postnov, K. A.; Kochetkova, A. Yu.; Hjalmarsdotter, L.; Sidoli, L.; Paizis, A.

2015-07-01

A review of wind accretion in high-mass X-ray binaries is presented. We focus on different regimes of quasi-spherical accretion onto the neutron star (NS): the supersonic (Bondi) accretion, which takes place when the captured matter cools down rapidly and falls supersonically towards the NS magnetosphere, and subsonic (settling) accretion which occurs when plasma remains hot until it meets the magnetospheric boundary. These two regimes of accretion are separated by an X-ray luminosity of about 4 × 1036 erg s-1. In the subsonic case, which sets in at lower luminosities, a hot quasi-spherical shell must form around the magnetosphere, and the actual accretion rate onto NS is determined by the ability of the plasma to enter the magnetosphere due to Rayleigh-Taylor instability. In turn, two regimes of subsonic accretion are possible, depending on plasma cooling mechanism (Compton or radiative) near the magnetopshere. The transition from the high-luminosity with Compton cooling to the lowluminosity (Lx ≲ 3 × 1035 erg s-1) with radiative cooling can be responsible for the onset of the off states repeatedly observed in several low-luminosity slowly accreting pulsars, such as Vela X-1, GX 301-2, and 4U 1907+09. The triggering of the transitionmay be due to a switch in the X-ray beam pattern in response to a change in the optical depth in the accretion column with changing luminosity. We also show that in the settling accretion theory, bright X-ray flares (~1038-1040 erg) observed in supergiant fast X-ray transients (SFXT) can be produced by sporadic capture of magnetized stellar wind plasma. At sufficiently low accretion rates, magnetic reconnection can enhance the magnetospheric plasma entry rate, resulting in copious production of X-ray photons, strong Compton cooling and ultimately in unstable accretion of the entire shell. A bright flare develops on the free-fall time scale in the shell, and the typical energy released in an SFXT bright flare corresponds to the mass

Diagnostics of Electric Equipment Windings

Directory of Open Access Journals (Sweden)

I. I. Branovitsky

2007-01-01

Full Text Available The paper presents methodology and results of the investigations pertaining to study of influence of short-circuited turns on transient electrical processes in electric motor windings. Dependence of their damped speed and value of the difference signal, obtained at reciprocal subtraction of damped oscillation curves in absence and in presence of short-circuited turns, on number of turns in the tested windings. It has been determined that damped oscillation curves, immediately attributed to short-circuited turns, have peak values along temporary axis which are areas of the largest transient process sensitivity to КЗ turns.Methodology for diagnostics of single- and three-phase electric motor windings and also other electric equipment, being realized in DO-1 device, has been developed in the paper. The men­tioned device makes it possible to carry out visual comparison and quantitative analysis of damped oscillation curves in the tested windings with standard ones which are set in the device memory and their difference signals.

A Principle and Winding Design of Consequent-Pole Bearingless Motors

Science.gov (United States)

Takenaga, Tomohiro; Kubota, Yutaka; Chiba, Akira; Fukao, Tadashi

Recently, bearingless motors have been developed to enhance motor drive systems with magnetic suspension. Several types of motors have been proposed as bearingless motors, such as induction, surface mounted permanent magnet, inset permanent magnet, interior permanent magnet, buried permanent magnet, homopolar, hybrid, and switched reluctance bearingless motors. Permanent magnet bearingless motors have been attracting more interests in these years because of the high efficiency. In this paper, a consequent-pole bearingless motor is proposed. A rotor has buried permanent magnets, of which polarities are like. The radial force of a consequent-pole bearingless motor is generated by dc current. Thus, rotational angular position is not needed in a magnetic suspension controller. Radial force variations caused by a rotor rotation are minimized by improving arrangement of stator suspension conductors. A prototype bearingless motor and its controller are built. In experiment, principles of magnetic suspension in the proposed consequent-pole bearingless drive are confirmed.

Wind Energy

International Nuclear Information System (INIS)

Rodriguez D, J.M.

1998-01-01

The general theory of the wind energy conversion systems is presented. The availability of the wind resource in Colombia and the ranges of the speed of the wind in those which is possible economically to use the wind turbines are described. It is continued with a description of the principal technological characteristics of the wind turbines and are split into wind power and wind-powered pumps; and its use in large quantities grouped in wind farms or in autonomous systems. Finally, its costs and its environmental impact are presented

DC Motor control using motor-generator set with controlled generator field

Science.gov (United States)

Belsterling, Charles A.; Stone, John

1982-01-01

A d.c. generator is connected in series opposed to the polarity of a d.c. power source supplying a d.c. drive motor. The generator is part of a motor-generator set, the motor of which is supplied from the power source connected to the motor. A generator field control means varies the field produced by at least one of the generator windings in order to change the effective voltage output. When the generator voltage is exactly equal to the d.c. voltage supply, no voltage is applied across the drive motor. As the field of the generator is reduced, the drive motor is supplied greater voltage until the full voltage of the d.c. power source is supplied when the generator has zero field applied. Additional voltage may be applied across the drive motor by reversing and increasing the reversed field on the generator. The drive motor may be reversed in direction from standstill by increasing the generator field so that a reverse voltage is applied across the d.c. motor.

Detectable states, cycle fluxes, and motility scaling of molecular motor kinesin: An integrative kinetic graph theory analysis

Science.gov (United States)

Ren, Jie

2017-12-01

The process by which a kinesin motor couples its ATPase activity with concerted mechanical hand-over-hand steps is a foremost topic of molecular motor physics. Two major routes toward elucidating kinesin mechanisms are the motility performance characterization of velocity and run length, and single-molecular state detection experiments. However, these two sets of experimental approaches are largely uncoupled to date. Here, we introduce an integrative motility state analysis based on a theorized kinetic graph theory for kinesin, which, on one hand, is validated by a wealth of accumulated motility data, and, on the other hand, allows for rigorous quantification of state occurrences and chemomechanical cycling probabilities. An interesting linear scaling for kinesin motility performance across species is discussed as well. An integrative kinetic graph theory analysis provides a powerful tool to bridge motility and state characterization experiments, so as to forge a unified effort for the elucidation of the working mechanisms of molecular motors.

The electric motor handbook

Energy Technology Data Exchange (ETDEWEB)

Hurst, R.W.; Feltham, P. (eds.)

2004-05-01

This handbook outlines the important role that electric motors play in modern society. It covers the field of motor applications from various motor types to their use and repair. It also presents practical applications of electric motors and methods on motor efficiency. More than half of all electricity generated, and 75 per cent of all industrial electricity consumption is consumed by electric motors. Electrical personnel must be aware of all factors involved in electric motors in order to choose and apply the appropriate size of electric motor. These factors include efficiency, sizing and proper application. The efficient use and maximum life expectancy of electric motors depends on proper motor protection, control and maintenance. This handbook includes articles from leading experts on electric motors in modern electrical systems. The content includes: design considerations; proper electric motor sizing techniques; optimal electric motor application; electric motor protection technology; electric motor control principles; electric motor maintenance and troubleshooting; induction electric motors; electric motor bearing currents; electric motor bearing lubrication; electromagnetism; electric motor enclosures; electric motor testing; electric motor repair; DC electric motor; electric motor starters; electric motor brushes; industrial electric motors; electric motor diagrams; AC electric motors; electric motor wiring; electric motor service; electric motor rewinding; electric motor winding; diagram of electric motor wiring; electric motor kit; and, troubleshooting electric motors. A directory of motor manufacturers and suppliers was also included. refs., tabs., figs.

Concurrent word generation and motor performance: further evidence for language-motor interaction.

Directory of Open Access Journals (Sweden)

Amy D Rodriguez

Full Text Available Embodied/modality-specific theories of semantic memory propose that sensorimotor representations play an important role in perception and action. A large body of evidence supports the notion that concepts involving human motor action (i.e., semantic-motor representations are processed in both language and motor regions of the brain. However, most studies have focused on perceptual tasks, leaving unanswered questions about language-motor interaction during production tasks. Thus, we investigated the effects of shared semantic-motor representations on concurrent language and motor production tasks in healthy young adults, manipulating the semantic task (motor-related vs. nonmotor-related words and the motor task (i.e., standing still and finger-tapping. In Experiment 1 (n = 20, we demonstrated that motor-related word generation was sufficient to affect postural control. In Experiment 2 (n = 40, we demonstrated that motor-related word generation was sufficient to facilitate word generation and finger tapping. We conclude that engaging semantic-motor representations can have a reciprocal influence on motor and language production. Our study provides additional support for functional language-motor interaction, as well as embodied/modality-specific theories.

Advanced dc-Traction-Motor Control System

Science.gov (United States)

Vittone, O.

1985-01-01

Motor-control concept for battery-powered vehicles includes stateof-the-art power-transistor switching and separate excitation of motor windings in traction and regenerative braking. Switching transistors and other components of power-conditioning subsystem operate under control of computer that coordinates traction, braking, and protective functions.

System and Method for Determining Rate of Rotation Using Brushless DC Motor

Science.gov (United States)

Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

2000-01-01

A system and method are provided for measuring rate of rotation. A brushless DC motor is rotated and produces a back electromagnetic force (emf) on each winding thereof. Each winding's back-emf is squared. The squared outputs associated with each winding are combined, with the square root being taken of such combination, to produce a DC output proportional only to the rate of rotation of the motor's shaft.

Linear motor coil assembly and linear motor

NARCIS (Netherlands)

2009-01-01

An ironless linear motor (5) comprising a magnet track (53) and a coil assembly (50) operating in cooperation with said magnet track (53) and having a plurality of concentrated multi-turn coils (31 a-f, 41 a-d, 51 a-k), wherein the end windings (31E) of the coils (31 a-f, 41 a-e) are substantially

Application of a ray theory model to the prediction of noise emissions from isolated wind turbines and wind parks

International Nuclear Information System (INIS)

Prospathopoulos, John M.; Voutsinas, Spyros G.

2006-01-01

Various propagation models have been developed to estimate the level of noise near residential areas. Predictions and measurements have proven that proper modelling of the propagation medium is of particular importance. In the present work, calculations are performed using a ray theory methodology. The ray trajectory and transport equations are derived from the linear acoustics equations for a moving medium in three dimensions. Ground and atmospheric absorption, wave refraction and diffraction and atmospheric turbulence are taken into account by introducing appropriate coefficients in the equations. In the case of a wind turbine (W/T) it is assumed that noise is produced by a point source located at the rotor centre. Given the sound power spectrum, the noise spectrum at the receiver is obtained by solving the axisymmetric propagation problem. The procedure consists of (a) finding the eigenrays, (b) calculating the energy losses along the eigenrays and (c) synthesizing the sound pressure level (SPL) by superposing the contributions of the eigenrays. In the case of a wind park the total SPL is calculated by superposing the contributions of all W/Ts. Application is made to five cases of isolated W/Ts in terrains of varying complexity. In flat or even smooth terrain the predictions agree well with the measurements. In complex terrain the predictions can be considered satisfactory, taking into account the assumption of constant wind velocity profile. Application to a wind park shows clearly the influence of the terrain on the wind velocity and consequently on the SPL. (Author)

Developmental Differences in Motor Task Integration: A Test of Pascual-Leone's Theory of Constructive Operators.

Science.gov (United States)

Todor, John I.

1979-01-01

Assesses the ability of Pascual-Leone's Theory of Constructive Operators to predict the minimum age or maturational level at which integration of a motor task could be achieved. Subjects were 114 elementary school children ranging in age from 5 to 12. (Author/MP)

Numerical investigation of refrigeration machine compressor operation considering single-phase electric motor dynamic characteristics

Science.gov (United States)

Baidak, Y.; Smyk, V.

2017-08-01

Using as the base the differential equations system which was presented in relative units for generalized electric motor of hermetic refrigeration compressor, mathematical model of the software for dynamic performance calculation of refrigeration machine compressors drive low-power asynchronous motors was developed. Performed on its ground calculations of the basic model of two-phase electric motor drive of hermetic compressor and the proposed newly developed model of the motor with single-phase stator winding, which is an alternative to the industrial motor winding, have confirmed the benefits of the motor with innovative stator winding over the base engine. Given calculations of the dynamic characteristics of compressor drive motor have permitted to determine the value of electromagnetic torque swinging for coordinating compressor and motor mechanical characteristics, and for taking them into consideration in choosing compressor elements construction materials. Developed and used in the process of investigation of refrigeration compressor drive asynchronous single-phase motor mathematical and software can be considered as an element of computer-aided design system for design of the aggregate of refrigeration compression unit refrigerating machine.

Test results of a 5 kW fully superconducting homopolar motor

Energy Technology Data Exchange (ETDEWEB)

Lee, J. K. [Woosuk University, Wanju (Korea, Republic of); Park, S. H.; Kim, Y.; Lee, S.; Joo, H. G.; Kim, W. S.; Choi, K. [Korea Polytechnic University,Siheong (Korea, Republic of); Hahm, S. Y. [Electrical Engineering and Science Research Institute,Seoul (Korea, Republic of)

2013-05-15

The superconducting Homopolar motor is manufactured and tested. Homopolar motor system is simple and solid as the field coil of the motor is fixed near the stator coil without rotating system. In this paper, a 5 kW fully superconducting homopolar motor which has high temperature superconducting armature and field coils is manufactured and tested in liquid nitrogen. The critical current test results of the used 2G superconducting wire, pancake coil for rotor winding and race-track coils for armature winding are reported. Also, the test result of rotating and operating performance is presented. The operating frequency is to be 5 Hz for low-speed rotating. The developed fully superconducting Homopolar motor is the world's first.

Test results of a 5 kW fully superconducting homopolar motor

International Nuclear Information System (INIS)

Lee, J. K.; Park, S. H.; Kim, Y.; Lee, S.; Joo, H. G.; Kim, W. S.; Choi, K.; Hahm, S. Y.

2013-01-01

The superconducting Homopolar motor is manufactured and tested. Homopolar motor system is simple and solid as the field coil of the motor is fixed near the stator coil without rotating system. In this paper, a 5 kW fully superconducting homopolar motor which has high temperature superconducting armature and field coils is manufactured and tested in liquid nitrogen. The critical current test results of the used 2G superconducting wire, pancake coil for rotor winding and race-track coils for armature winding are reported. Also, the test result of rotating and operating performance is presented. The operating frequency is to be 5 Hz for low-speed rotating. The developed fully superconducting Homopolar motor is the world's first.

Laboratory development of wind turbine simulator using variable ...

African Journals Online (AJOL)

user

1*Department of Electronics Engineering, Prof. ... In this paper variable speed induction motor drive using scalar control is interfaced in wind energy conversion ... the wind turbine simulator is used as a necessary tool in research laboratories.

Cerebellar motor learning versus cerebellar motor timing: the climbing fibre story

Science.gov (United States)

Llinás, Rodolfo R

2011-01-01

Abstract Theories concerning the role of the climbing fibre system in motor learning, as opposed to those addressing the olivocerebellar system in the organization of motor timing, are briefly contrasted. The electrophysiological basis for the motor timing hypothesis in relation to the olivocerebellar system is treated in detail. PMID:21486816

Motor control theories and their applications.

Science.gov (United States)

Latash, Mark L; Levin, Mindy F; Scholz, John P; Schöner, Gregor

2010-01-01

We describe several influential hypotheses in the field of motor control including the equilibrium-point (referent configuration) hypothesis, the uncontrolled manifold hypothesis, and the idea of synergies based on the principle of motor abundance. The equilibrium-point hypothesis is based on the idea of control with thresholds for activation of neuronal pools; it provides a framework for analysis of both voluntary and involuntary movements. In particular, control of a single muscle can be adequately described with changes in the threshold of motor unit recruitment during slow muscle stretch (threshold of the tonic stretch reflex). Unlike the ideas of internal models, the equilibrium-point hypothesis does not assume neural computations of mechanical variables. The uncontrolled manifold hypothesis is based on the dynamic system approach to movements; it offers a toolbox to analyze synergic changes within redundant sets of elements related to stabilization of potentially important performance variables. The referent configuration hypothesis and the principle of abundance can be naturally combined into a single coherent scheme of control of multi-element systems. A body of experimental data on healthy persons and patients with movement disorders are reviewed in support of the mentioned hypotheses. In particular, movement disorders associated with spasticity are considered as consequences of an impaired ability to shift threshold of the tonic stretch reflex within the whole normal range. Technical details and applications of the mentioned hypo-theses to studies of motor learning are described. We view the mentioned hypotheses as the most promising ones in the field of motor control, based on a solid physical and neurophysiological foundation.

Application of stepping motor

International Nuclear Information System (INIS)

1980-10-01

This book is divided into three parts, which is about practical using of stepping motor. The first part has six chapters. The contents of the first part are about stepping motor, classification of stepping motor, basic theory og stepping motor, characteristic and basic words, types and characteristic of stepping motor in hybrid type and basic control of stepping motor. The second part deals with application of stepping motor with hardware of stepping motor control, stepping motor control by microcomputer and software of stepping motor control. The last part mentions choice of stepping motor system, examples of stepping motor, measurement of stepping motor and practical cases of application of stepping motor.

Aerodynamic loads calculation and analysis for large scale wind turbine based on combining BEM modified theory with dynamic stall model

Energy Technology Data Exchange (ETDEWEB)

Dai, J.C. [College of Mechanical and Electrical Engineering, Central South University, Changsha (China); School of Electromechanical Engineering, Hunan University of Science and Technology, Xiangtan (China); Hu, Y.P.; Liu, D.S. [School of Electromechanical Engineering, Hunan University of Science and Technology, Xiangtan (China); Long, X. [Hara XEMC Windpower Co., Ltd., Xiangtan (China)

2011-03-15

The aerodynamic loads for MW scale horizontal-axis wind turbines are calculated and analyzed in the established coordinate systems which are used to describe the wind turbine. In this paper, the blade element momentum (BEM) theory is employed and some corrections, such as Prandtl and Buhl models, are carried out. Based on the B-L semi-empirical dynamic stall (DS) model, a new modified DS model for NACA63-4xx airfoil is adopted. Then, by combing BEM modified theory with DS model, a set of calculation method of aerodynamic loads for large scale wind turbines is proposed, in which some influence factors such as wind shear, tower, tower and blade vibration are considered. The research results show that the presented dynamic stall model is good enough for engineering purpose; the aerodynamic loads are influenced by many factors such as tower shadow, wind shear, dynamic stall, tower and blade vibration, etc, with different degree; the single blade endures periodical changing loads but the variations of the rotor shaft power caused by the total aerodynamic torque in edgewise direction are very small. The presented study approach of aerodynamic loads calculation and analysis is of the university, and helpful for thorough research of loads reduction on large scale wind turbines. (author)

Electromagnetic Design and Losses Analysis of a High-Speed Permanent Magnet Synchronous Motor with Toroidal Windings for Pulsed Alternator

Directory of Open Access Journals (Sweden)

Yuan Wan

2018-03-01

Full Text Available The configuration of conventional high-speed Permanent Magnet Synchronous Motors (PMSMs is usually long and thin, with overlong axial end winding lengths, which is not suitable for those applications that place severe restrictions on the axial length, such as pulsed alternators. This paper first studied the key design aspects of a flat-structure high-speed PMSM. The toroidal-windings, low-conductivity material of the retaining sleeve, large airgap and segmentation of magnets were studied to reduce the axial length of the motor. The division of the stator and the employment of a non-magnetic outer stator were used to improve overall performance. Then the losses of the prototype were calculated and the factors having an influence on the losses were also investigated, after which, their effects on the total loss were evaluated. The total loss could be effectively reduced by the decrease of strand number of conductors and the division of stator, while only being slightly reduced by epoxy resin pole fillers. Metal-stack pole fillers have the same effect on the reduction of rotor loss as epoxy resin, while maintaining the good thermal-conductivity of metal. In addition, the influence of the carrier frequency of the inverter on the losses was analyzed, and it was found that high carrier frequency was helpful to reduce rotor losses. Finally, a small-scale prototype was manufactured and the experimental results were provided.

Wind, Wave, and Tidal Energy Without Power Conditioning

Science.gov (United States)

Jones, Jack A.

2013-01-01

Most present wind, wave, and tidal energy systems require expensive power conditioning systems that reduce overall efficiency. This new design eliminates power conditioning all, or nearly all, of the time. Wind, wave, and tidal energy systems can transmit their energy to pumps that send high-pressure fluid to a central power production area. The central power production area can consist of a series of hydraulic generators. The hydraulic generators can be variable displacement generators such that the RPM, and thus the voltage, remains constant, eliminating the need for further power conditioning. A series of wind blades is attached to a series of radial piston pumps, which pump fluid to a series of axial piston motors attached to generators. As the wind is reduced, the amount of energy is reduced, and the number of active hydraulic generators can be reduced to maintain a nearly constant RPM. If the axial piston motors have variable displacement, an exact RPM can be maintained for all, or nearly all, wind speeds. Analyses have been performed that show over 20% performance improvements with this technique over conventional wind turbines

The role of capacitance in a wind-electric water pumping system

Energy Technology Data Exchange (ETDEWEB)

Ling, Shitao [West Texas A& M Univ., Canyon, TX (United States); Clark, R.N. [Conservation and Production Research Lab., Bushland, TX (United States)

1997-12-31

The development of controllers for wind-electric water pumping systems to enable the use of variable voltage, variable frequency electricity to operate standard AC submersible pump motors has provided a more efficient and flexible water pumping system to replace mechanical windmills. A fixed capacitance added in parallel with the induction motor improves the power factor and starting ability of the pump motor at the lower cut-in frequency. The wind-electric water pumping system developed by USDA-Agricultural Research Service, Bushland, TX, operated well at moderate wind speeds (5-12 m/s), but tended to lose synchronization in winds above 12 m/s, especially if they were gusty. Furling generally did not occur until synchronization had been lost and the winds had to subside before synchronization could be reestablished. The frequency needed to reestablish synchronization was much lower (60-65 Hz) than the frequency where synchronization was lost (70-80 Hz). As a result, the load (motor and pump) stayed off an excessive amount of time thus causing less water to be pumped and producing a low system efficiency. The controller described in this paper dynamically connects additional capacitance of the proper amount at the appropriate time to keep the system synchronized (running at 55 to 60 Hz) and pumping water even when the wind speed exceeds 15 m/s. The system efficiency was improved by reducing the system off-line time and an additional benefit was reducing the noise caused by the high speed blade rotation when the load was off line in high winds.

Impact Study of PMSG-Based Wind Power Penetration on Power System Transient Stability Using EEAC Theory

Directory of Open Access Journals (Sweden)

Zhongyi Liu

2015-11-01

Full Text Available Wind turbines with direct-driven permanent magnet synchronous generators (PMSGs are widely used in wind power generation. According to the dynamic characteristics of PMSGs, an impact analysis of PMSG-based wind power penetration on the transient stability of multi-machine power systems is carried out in this paper based on the theory of extended equal area criterion (EEAC. Considering the most severe PMSG integration situation, the changes in the system’s equivalent power-angle relationships after integrating PMSGs are studied in detail. The system’s equivalent mechanical input power and the fault period electrical output power curves are found to be mainly affected. The analysis demonstrates that the integration of PMSGs can cause either detrimental or beneficial effects on the system transient stability. It is determined by several factors, including the selection of the synchronous generators used to balance wind power, the reactive power control mode of PMSGs and the wind power penetration level. Two different simulation systems are also adopted to verify the analysis results.

Pragmatics in action: indirect requests engage theory of mind areas and the cortical motor network.

Science.gov (United States)

van Ackeren, Markus J; Casasanto, Daniel; Bekkering, Harold; Hagoort, Peter; Rueschemeyer, Shirley-Ann

2012-11-01

motor areas reliably more than comprehension of sentences devoid of any implicit motor information. This is true despite the fact that IR sentences contain no lexical reference to action. (2) Comprehension of IR sentences also reliably activates substantial portions of the theory of mind network, known to be involved in making inferences about mental states of others. The implications of these findings for embodied theories of language are discussed.

Influence analysis of structural parameters on electromagnetic properties of HTS linear induction motor

International Nuclear Information System (INIS)

Zhao, J.; Zheng, T.Q.; Zhang, W.; Fang, J.; Liu, Y.M.

2011-01-01

A new type high temperature superconductor linear induction motor is designed and analyzed as a prototype to ensure applicability aimed at industrial motors. Made of Bi-2223/Ag, primary windings are distributed with the double-layer concentrated structure. The motor is analyzed by 2D electromagnetic Finite Element Method to get magnetic field distribution, thrust force, vertical force and so on. The critical current of motor and the electromagnetic force are mostly decided by the leakage flux density of primary slot and by the main magnetic flux and eddy current respectively. The structural parameters of motor have a great influence on the distribution of magnetic field. Under constant currents, the properties of motor are analyzed with different slot widths, slot heights and winding turns. The properties of motor, such as the maximum slot leakage flux density, motor thrust and motor vertical force, are analyzed with different structural parameters.

Brushless DC motor control system responsive to control signals generated by a computer or the like

Science.gov (United States)

Packard, Douglas T. (Inventor); Schmitt, Donald E. (Inventor)

1987-01-01

A control system for a brushless DC motor responsive to digital control signals is disclosed. The motor includes a multiphase wound stator and a permanent magnet rotor. The rotor is arranged so that each phase winding, when energized from a DC source, will drive the rotor through a predetermined angular position or step. A commutation signal generator responsive to the shaft position provides a commutation signal for each winding. A programmable control signal generator such as a computer or microprocessor produces individual digital control signals for each phase winding. The control signals and commutation signals associated with each winding are applied to an AND gate for that phase winding. Each gate controls a switch connected in series with the associated phase winding and the DC source so that each phase winding is energized only when the commutation signal and the control signal associated with that phase winding are present. The motor shaft may be advanced one step at a time to a desired position by applying a predetermined number of control signals in the proper sequence to the AND gates and the torque generated by the motor may be regulated by applying a separate control signal to each AND gate which is pulse width modulated to control the total time that each switch connects its associated winding to the DC source during each commutation period.

Permanent split capacitor single phase electric motor system

Science.gov (United States)

Kirschbaum, H.S.

1984-08-14

A permanent split capacitor single phase electric motor achieves balanced operation at more than one operating point by adjusting the voltage supplied to the main and auxiliary windings and adjusting the capacitance in the auxiliary winding circuit. An intermediate voltage tap on an autotransformer supplies voltage to the main winding for low speed operation while a capacitive voltage divider is used to adjust the voltage supplied to the auxiliary winding for low speed operation. 4 figs.

Extended cage adjustable speed electric motors and drive packages

Science.gov (United States)

Hsu, John S.

1999-01-01

The rotor cage of a motor is extended, a second stator is coupled to this extended rotor cage, and the windings have the same number of poles. The motor torque and speed can be controlled by either injecting energy into or extracting energy out from the rotor cage. The motor produces less harmonics than existing doubly-fed motors. Consequently, a new type of low cost, high efficiency drive is produced.

Analytical prediction of the electromagnetic torques in single-phase and two-phase ac motors

Energy Technology Data Exchange (ETDEWEB)

Popescu, M.

2004-07-01

The single-phase and two-phase versions of AC motors can be modelled by means of the two-axis (d-q) theory with sufficient accuracy when the equivalent circuit parameters are correctly estimated. This work attempts to present a unified approach to the analytical prediction of the electromagnetic torque of these machines. Classical d-q axes formulation requires that the reference frame should be fixed on the frame where the asymmetries arise, i.e. the stator and rotor. The asynchronous torques that characterize the induction motors are modelled in a stationary reference frame, where the d-q axes coincide with the physical magnetic axes of the stator windings. For the permanent magnet motors, that may exhibit asymmetries on both stator and rotor, the proposed solution includes: a series of frame transformations, followed by symmetrical components decomposition. As in single-phase and two-phase systems the homopolar component is zero; each symmetrical component - negative and positive - is further analysed using d-q axes theory. The superposition principle is employed to consider the magnets and rotor cage effects. The developed models account for the most important asymmetries of the motor configuration. These are, from the stator point of view, different distribution, conductors' dimensions and number of effective turns, non-orthogonal magnetic axes windings and from the rotor point of view, asymmetrical rotor cage, variable reluctance, and permanent magnets effect. The time and space harmonics effect is ignored. Test data are compared with the computed data in order to observe how the simplifying assumptions affect the level of accuracy. The analytical prediction methods make possible torque computation according to the nature of the torque being computed, namely, induction, reluctance and excitation (permanent magnet). The results are available for quasi steady-state, steady-state (rated or synchronous speed) and dynamic analyses. All the developed

Brushless dc motor uses electron beam switching tube as commutator

Science.gov (United States)

Studer, P.

1965-01-01

Electron beam switching tube eliminates physical contact between rotor and stator in brushless dc motor. The tube and associated circuitry control the output of a dc source to sequentially energize the motor stator windings.

Modernization of gas-turbine engines with high-frequency induction motors

Science.gov (United States)

Abramovich, B. N.; Sychev, Yu A.; Kuznetsov, P. A.

2018-03-01

Main tendencies of growth of electric energy consumption in general and mining industries were analyzed in the paper. A key role of electric drive in this process was designated. A review about advantages and disadvantages of unregulated gearboxes with mechanical units that are commonly used in domestically produced gas-turbine engines was made. This review allows one to propose different gas-turbine engines modernization schemes with the help of PWM-driven high-frequency induction motors. Induction motors with the double rotor winding were examined. A simulation of high-frequency induction motors with double rotor windings in Matlab-Simulink software was carried out based on equivalent circuit parameters. Obtained characteristics of new motors were compared with serially produced analogues. After the simulation, results were implemented in the real prototype.

Operating of Small Wind Power Plants with Induction Generators

Directory of Open Access Journals (Sweden)

Jakub Nevrala

2008-01-01

Full Text Available This paper describes different systems of small wind power plants with induction generators used in the Czech Republic. Problems of wind power plants running with induction generators are solved within partial target of the research project MSM 6198910007. For small wind power plants is used induction motor as a generator. Parameters of the name plate of motor must be resolved for generator running on measuring base. These generators are running as a separately working generators or generators connected to the power grid. Methods of control these systems as a separately working, directly connecting to power grid, control by frequency converter and wiring by synchronous cascade are confronted on the measuring base too.

Increasing Mud Pump Motor Reliability against Malfunctions of DC Motor Excitation System

Science.gov (United States)

Nikulin, O. V.; Shabanov, V. A.

2017-10-01

The most widely used drilling machinery, such as mud pumps, draw-works, and rotors, use direct-current (DC) motors with independent excitation as the electric drive. Drilling machinery drives operate in harsh ambient conditions, including those with the presence of moisture, dust and vibration, which increases the malfunction rate of both drilling equipment and their electric drives. One of the frequently encountered malfunctions are DC motor excitation coil faults, which disrupt the normal functioning of electric drives, often leading to shutdown of the drilling process. In a four-pole DC motor, the malfunction of one coil leads to lack of excitation current in just one coil pair, while the other pair remains functional. In this case, DC motors and drilling equipment can remain operational, which would allow for continuing the drilling process. This paper considers the possibility of operation of a DC motor on a drilling rig in those cases when one pair of excitation coils is non-functional, and describes the device for switching between the excitation coils and the auxiliary winding in a DC motor with independent excitation.

Fettered aircraft for using wind energy

Energy Technology Data Exchange (ETDEWEB)

Hoeppner, H.; Horvath, E.; Ulrich, S.

1980-08-28

The invention concerns an aircraft tethered by cables, whose balloon-shaped central body produces static and aerodynamic upthrust and which carries turbines, which are used to convert wind energy and to drive the aircraft. The purpose of the invention is to provide an aircraft, which will keep wind energy plant at the optimum height. A new type of aircraft is used to solve the problem, which, according to the invention, combines static upthrust, the production of aerodynamic upthrust, wind energy conversion, energy transport and forward drive in a technically integrated aircraft. If the use of windpower is interrupted, then if necessary the drive together with a remote control system provides controlled free flight of the aircraft. One variant of the object of the invention consists of a central, balloon-shaped body for upthrust, in which there are wind turbines driving electrical generators. According to the invention the motors required to start the wind turbines are of such dimensions that they will drive the turbines in free flight of the aircraft and thus provide forward drive of the aircraft. A power generating unit, consisting of an internal combustion engine and the starter motors switched over to generator operation is used to provide house service supplies for control and regulation of the aircraft.

Brief Overview of Motor Learning and It's Application to Rehabilitation: Part Ⅰ: Motor Learning Theory

Institute of Scientific and Technical Information of China (English)

Christopher A Zaino

2003-01-01

@@ 1 DEFINITION OF MOTOR LEARNING Motor learning is the study of how we acquire and modify movements.1 The acquisition of motor skills is the process of learning how to do a particular movement (performance), but the real key to therapeutic intervention is being able to affect permanent changes in motor skills via the process of motor learning. Therefore, motor learning is defined as the ability to retain the ability to perform a motor task at a later time. In rehabilitation, it is important to be cognizant of the concepts of acquisition and retention. We can facilitate acquisition,but do little to assist in the retention of the task (learning). Conversely, we can arrange practice such that acquisition is slowed, but we can actually be assisting learning the task. It is important to have a clear goal in mind and work towards the eventual learning of the task to allow full functional use of that skill.

Speed Control of Multiphase Cage Induction Motors Incorporating Supply Sequence

Directory of Open Access Journals (Sweden)

Drozdowski Piotr

2014-12-01

Full Text Available The subject of this paper is the control possibility of the multiphase cage induction motors having number of phases greater than 3. These motors have additional properties for speed control that distinguish them from the standard 3 phase motors: operation at various sequences of supplying voltages due to the inverter control and possible operation with few open-circuited phases. For each supply sequence different no load speeds at the same frequency can be obtained. This feature extends the motor application for miscellaneous drive demands including vector or scalar control. This depends mainly on the type of the stator winding for a given number of phases, since the principle of motor operation is based on co-operation of higher harmonics of magnetic field. Examples of operation are presented for a 9-phase motor, though general approach has been discussed. This motor was fed by a voltage source inverter at field oriented control with forced currents. The mathematical model of the motor was reduced to the form incorporating all most important physical features and appropriate for the control law formulation. The operation was illustrated for various supply sequences for “healthy” motor and for the motor operating at one phase broken. The obtained results have shown that parasitic influence of harmonic fields interaction has negligible influence on motor operation with respect to the useful coupling for properly designed stator winding.

Model of the double-rotor induction motor in terms of electromagnetic differential

Directory of Open Access Journals (Sweden)

Adamczyk Dominik

2016-12-01

Full Text Available The paper presents a concept, a construction, a circuit model and experimental results of the double-rotor induction motor. This type of a motor is to be implemented in the concept of the electromagnetic differential. At the same time it should fulfill the function of differential mechanism and the vehicle drive. One of the motor shafts is coupled to the direction changing mechanical transmission. The windings of the external rotor are powered by slip rings and brushes. The inner rotor has the squirrel-cage windings. The circuit model parameters were calculated based on the 7.5 kW real single-rotor induction motor (2p = 4. Experimental verification of the model was based on comparison between the mentioned single-rotor motor and double-rotor model with the outer rotor blocked. The presented results showed relatively good compliance between the model and real motor.

Controls of Hydraulic Wind Turbine

Directory of Open Access Journals (Sweden)

Zhang Yin

2016-01-01

Full Text Available In this paper a hydraulic wind turbine generator system was proposed based on analysis the current wind turbines technologies. The construction and principles were introduced. The mathematical model was verified using MATLAB and AMsim. A displacement closed loop of swash plate of motor and a speed closed loop of generator were setup, a PID control is introduced to maintain a constant speed and fixed frequency at wind turbine generator. Simulation and experiment demonstrated that the system can connect grid to generate electric and enhance reliability. The control system demonstrates a high performance speed regulation and effectiveness. The results are great significant to design a new type hydraulic wind turbine system.

How Kinesthetic Motor Imagery works: A predictive-processing theory of visualization in sports and motor expertise

NARCIS (Netherlands)

Ridderinkhof, K.R.; Brass, M.

2015-01-01

Kinesthetic Motor Imagery (KMI) is an important technique to acquire and refine motor skills. KMI is widely used by professional athletes as an effective way to improve motor performance without overt motor output. Despite this obvious relevance, the functional mechanisms and neural circuits

Dynamic eccentricity fault diagnosis in round rotor synchronous motors

International Nuclear Information System (INIS)

Ebrahimi, Bashir Mahdi; Etemadrezaei, Mohammad; Faiz, Jawad

2011-01-01

Research highlights: → We have presented a novel approach to detect dynamic eccentricity in round rotor synchronous motors. → We have introduced an efficient index based on processing torque using time series data mining method. → The stator current spectrum of the motor under different levels of fault and load are computed. → Winding function method has been employed to model healthy and faulty synchronous motors. -- Abstract: In this paper, a novel approach is presented to detect dynamic eccentricity in round rotor synchronous motors. For this, an efficient index is introduced based on processing developed torque using time series data mining (TSDM) method. This index can be utilized to diagnose eccentricity fault and its degree. The capability of this index to predict dynamic eccentricity is illustrated by investigation of load variation impacts on the nominated index. Stator current spectrum of the faulty synchronous motor under different loads and dynamic eccentricity degrees are computed. Effects of the dynamic eccentricity and load variation simultaneously are scrutinized on the magnitude of 17th and 19th harmonic components as traditional indices for eccentricity fault diagnosis in synchronous motors. Necessity signals and parameters for processing and feature extraction are evaluated by winding function method which is employed to model healthy and faulty synchronous motors.

Blowing against the wind-An exploratory application of actor network theory to the analysis of local controversies and participation processes in wind energy

International Nuclear Information System (INIS)

Jolivet, Eric; Heiskanen, Eva

2010-01-01

This paper analyses the deployment of wind power and the related local controversies using actor-network theory (ANT). ANT provides conceptual instruments for a fine-tuned analysis of the contingencies that condition a project's success or failure by focusing on the micro-decisions that intertwine the material aspects of the technology, the site where it is implemented, the participation process, and the social relations in which they are embedded. By considering controversies as alternative efforts of competing networks of actors to 'frame' the reality and enroll others, ANT sheds light on the complex and political nature of planning a wind farm project, insofar as it consist in aligning material and human behaviours into a predictable scenario. 'Overflows' occur when actors do not conform to expectations, adopt conflicting positions and develop their own interpretations of the project, thus obliging designers to adapt their frames and change their plans. To demonstrate this framework, we apply it to the case of a wind farm project in the South of France, near Albi. Our analysis suggests a new approach to examining wind power projects in terms of the interaction between globally circulating technologies, unique characteristics of the site, the participation process and the social dynamics that emerge when these are combined.

Study of different effectives on wind energy by using mathematical methods and rough set theory

International Nuclear Information System (INIS)

Marrouf, A.A.

2009-01-01

introduction about concept of rough set and effect of air density on wind energy. Section 2-2 focus es on the concept of rough set and its properties and generalization of approximation of rough set theory by using topological space. Random structure of wind energy has been discussed in section 2-3 Chapter 3: In this chapter we focus on the concept of variable precision rough set (VPRS), its properties and its generalization using general relation into estimating the best locations in Egypt to construct wind power stations. In Section 3-1 we introduce a general introduction to Variable Precision Rough Set (VPRS) and wind energy. In Section 3-2 we have focused on the concept and properties of VPRS. In Section 3-3 we have introduced a generalization of VPRS using General relation which introduced by the Egyptian topological group [16]. In Section 3-4 we have introduced the Weibull parameters, In Section 3-5 we have introduced wind power estimation and analysis, electricity generation and cost analysis are introduced in Section 3-6.

Stepping motors a guide to theory and practice

CERN Document Server

Acarnely, Paul

2002-01-01

This book provides an introductory text which will enable the reader to both appreciate the essential characteristics of stepping motor systems and understand how these characteristics are being exploited in the continuing development of new motors, drives and controllers. A basic theoretical approach relating to the more significant aspects of performance is presented, although it is assumed throughout that the reader has no previous experience of electrical machines and is primarily interested in the applications of stepping motors.

Design and analysis of full pitch winding and concentrated stator ...

Indian Academy of Sciences (India)

magnet machine with flux linkage reversal in the stator concentrated winding. The existing ... Section 7 compares steady state motor ... flux linking the stator winding is sinusoidal, the induced emf is also sinusoidal as shown in figure 3.

Extreme wind estimate for Hornsea wind farm

DEFF Research Database (Denmark)

Larsén, Xiaoli Guo

The purpose of this study is to provide estimation of the 50-year winds of 10 min and 1-s gust value at hub height of 100 m, as well as the design parameter shear exponent for the Hornsea offshore wind farm. The turbulence intensity required for estimating the gust value is estimated using two...... approaches. One is through the measurements from the wind Doppler lidar, WindCube, which implies serious uncertainty, and the other one is through similarity theory for the atmospheric surface layer where the hub height is likely to belong to during strong storms. The turbulence intensity for storm wind...... strength is taken as 0.1. The shear exponents at several heights were calculated from the measurements. The values at 100 m are less than the limit given by IEC standard for all sectors. The 50-year winds have been calculated from various global reanalysis and analysis products as well as mesoscale models...

Calculation of Cogging Torque in Hybrid Stepping Motors | Agber ...

African Journals Online (AJOL)

When the windings of a hybrid stepping motor are unexcited the permanent magnet's flux produces cogging torque. This torque has both desirable and undesirable features depending on the application that the motor is put into. This paper formulates an analytical method for predicting cogging torque using measured ...

Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor

Science.gov (United States)

Coffey, Howard T.

1993-01-01

A propulsion and suspension system for an inductive repulsion type magnetically levitated vehicle which is propelled and suspended by a system which includes propulsion windings which form a linear synchronous motor and conductive guideways, adjacent to the propulsion windings, where both combine to partially encircling the vehicle-borne superconducting magnets. A three phase power source is used with the linear synchronous motor to produce a traveling magnetic wave which in conjunction with the magnets propel the vehicle. The conductive guideway combines with the superconducting magnets to provide for vehicle leviation.

Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor

Science.gov (United States)

Coffey, H.T.

1993-10-19

A propulsion and suspension system for an inductive repulsion type magnetically levitated vehicle which is propelled and suspended by a system which includes propulsion windings which form a linear synchronous motor and conductive guideways, adjacent to the propulsion windings, where both combine to partially encircling the vehicle-borne superconducting magnets. A three phase power source is used with the linear synchronous motor to produce a traveling magnetic wave which in conjunction with the magnets propel the vehicle. The conductive guideway combines with the superconducting magnets to provide for vehicle levitation. 3 figures.

Lidar-based reconstruction of wind fields and application for wind turbine control

OpenAIRE

Kapp, Stefan

2017-01-01

In this thesis horizontal, upwind scanning lidar systems of the focused continuous-wave type are regarded for wind turbines. The theory of wind field reconstruction is extended to a five parameter model describing the inflow in non-uniform conditions more accurately. Sensor requirements are derived. A new approach to spherically scan the inflow area is studied experimentally. Expected inaccuracies of the averaged wind direction signal in a wind farm environment are quantified and spatial inho...

Controlling chaos in permanent magnet synchronous motor based on finite-time stability theory

International Nuclear Information System (INIS)

Du-Qu, Wei; Bo, Zhang

2009-01-01

This paper reports that the performance of permanent magnet synchronous motor (PMSM) degrades due to chaos when its systemic parameters fall into a certain area. To control the undesirable chaos in PMSM, a nonlinear controller, which is simple and easy to be constructed, is presented to achieve finite-time chaos control based on the finite-time stability theory. Computer simulation results show that the proposed controller is very effective. The obtained results may help to maintain the industrial servo driven system's security operation. (general)

Aerodynamics of wind turbines emerging topics

CERN Document Server

Amano, R S

2014-01-01

Focusing on Aerodynamics of Wind Turbines with topics ranging from Fundamental to Application of horizontal axis wind turbines, this book presents advanced topics including: Basic Theory for Wind turbine Blade Aerodynamics, Computational Methods, and Special Structural Reinforcement Technique for Wind Turbine Blades.

Generalized two axes model of a squirrel-cage induction motor for rotor fault diagnosis

Directory of Open Access Journals (Sweden)

Samir Hamdani

2008-01-01

Full Text Available A generalized two axes model of a squirrel-cage induction motor is developed This model is based on a winding function approach and the coupled magnetic circuit theory and takes into account the stator and the rotor asymmetries due to faults. This paper presents a computer simulation and experimental dynamic characteristics for a healthy induction machine, machine with one broken bar and a machine with two broken bars. The results illustrate good agreement between both simulated and experimental results. Also, the power spectral density PSD was performed to obtain a stator current spectrum.

Novel rotating characteristics of a squirrel-cage-type HTS induction/synchronous motor

International Nuclear Information System (INIS)

Nakamura, T; Ogama, Y; Miyake, H; Nagao, K; Nishimura, T

2007-01-01

This paper describes the rotating characteristics of a high-T c superconducting induction/synchronous motor, which possesses both asynchronous and synchronous torques even though its structure is exactly the same as the squirrel-cage-type induction motor. Two kinds of Bi-2223/Ag multifilamentary tapes were utilized for the secondary windings. A commercialized motor (1.5 kW) was subjected to this study. A conventional (normal conducting) stator (three-phase, four-pole) was directly utilized, and only the squirrel-cage windings were replaced with the superconducting tapes. The tests were performed after the fabricated motor was immersed in liquid nitrogen. The operating temperature was also varied by pumping out the liquid nitrogen. It is shown that the motor is successfully synchronized for the temperature range from 65 to 77 K. Detailed discussions for such novel rotating characteristics are reported based on the electrical equivalent circuit

High frequency electromagnetic processes in induction motors supplied from PWM inverters

Directory of Open Access Journals (Sweden)

Ioan Ţilea

2010-12-01

Full Text Available The paper presents the electromagnetic interference between induction motors and inverters when at high frequency electromagnetic process appears in induction motors having a parallel resonant effect because of parasitic capacitive coupling between windings and ground, using a numerical model in simulink and a high frequency induction motor equivalent circuit model this effect is shown.

INTENSITY SETTER FOR A DEVICE OF SMOOTH START OF SUBMERSIBLE PUMP ELECTRIC MOTOR

Directory of Open Access Journals (Sweden)

V.I. Lobov

2016-06-01

Full Text Available Purpose. Development of an intensity setter, which in a rational law changes the opening thyristor the voltage regulator and effectively to changing power supply voltage stator windings of the electric pump deepening, ensuring a smooth start in a wide range. Methodology. Electric submersible pump belongs to the small inertia electric, since it is not significant total moment of inertia, not exceeding two moments of inertia of the motor and static moment on the shaft does not exceed forty percent of the nominal torque. For technical requirements that electric acceleration time should have no less than twenty seconds or more. Office starting modes of electric submersible pumps economically justified using thyristor voltage regulator by forming the dial changes the intensity of the necessary legislation in time voltage feeding the stator windings. This ensures a smooth start right rotor of the electric submersible pump. Results. A block diagram of the intensity setter that is: with control unit, two units that form the exponential voltage supply emitter follower and regulatory elements. The mathematical expressions for voltage at the stator windings of the motor, changing exponentially, opening the angle of thyristor power unit thyristor the voltage regulator, which is determined through the initial angle of opening. Provided formula for pick-up voltage and minimum voltage, time constants, which are determined from the basic equations of motion and mechanical characteristics of the electric motor. Analytical investigated by the voltage dependence violation by changing the time constant flowing and growing exhibitor supply voltage stator electric circuit deepening pump. Originality. Proposed in the initial time on the stator windings of the electric pick-up voltage is applied. Under the influence of this voltage, motor rotor begins to accelerate. At the same time, pick-up voltage decreases the minimum startup voltage varies exponentially in which

High Power Density Motors

Science.gov (United States)

Kascak, Daniel J.

2004-01-01

With the growing concerns of global warming, the need for pollution-free vehicles is ever increasing. Pollution-free flight is one of NASA's goals for the 21" Century. , One method of approaching that goal is hydrogen-fueled aircraft that use fuel cells or turbo- generators to develop electric power that can drive electric motors that turn the aircraft's propulsive fans or propellers. Hydrogen fuel would likely be carried as a liquid, stored in tanks at its boiling point of 20.5 K (-422.5 F). Conventional electric motors, however, are far too heavy (for a given horsepower) to use on aircraft. Fortunately the liquid hydrogen fuel can provide essentially free refrigeration that can be used to cool the windings of motors before the hydrogen is used for fuel. Either High Temperature Superconductors (HTS) or high purity metals such as copper or aluminum may be used in the motor windings. Superconductors have essentially zero electrical resistance to steady current. The electrical resistance of high purity aluminum or copper near liquid hydrogen temperature can be l/lOO* or less of the room temperature resistance. These conductors could provide higher motor efficiency than normal room-temperature motors achieve. But much more importantly, these conductors can carry ten to a hundred times more current than copper conductors do in normal motors operating at room temperature. This is a consequence of the low electrical resistance and of good heat transfer coefficients in boiling LH2. Thus the conductors can produce higher magnetic field strengths and consequently higher motor torque and power. Designs, analysis and actual cryogenic motor tests show that such cryogenic motors could produce three or more times as much power per unit weight as turbine engines can, whereas conventional motors produce only 1/5 as much power per weight as turbine engines. This summer work has been done with Litz wire to maximize the current density. The current is limited by the amount of heat it

Design and control of a superconducting permanent magnet synchronous motor

International Nuclear Information System (INIS)

Jiang, Y; Pei, R; Hong, Z; Song, J; Fang, F; Coombs, T A

2007-01-01

This paper gives a detailed description of the design of a superconducting permanent magnet synchronous motor. The parameters of the motor have been identified, and the torque equation has been stated. A direct torque control algorithm is introduced and applied to a traditional permanent magnet synchronous motor and the superconducting permanent magnet synchronous motor described in this paper. The motor performance shows that the direct torque control algorithm provides excellent control to the superconducting motor, and guarantees that the magnitude of the operational armature currents is smaller than the value of the critical current of the superconducting tape used for stator winding

Design and control of a superconducting permanent magnet synchronous motor

Energy Technology Data Exchange (ETDEWEB)

Jiang, Y [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Pei, R [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Hong, Z [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Song, J [Huazhong University of Science of Technology, Wuhan 430074 (China); Fang, F [Huazhong University of Science of Technology, Wuhan 430074 (China); Coombs, T A [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

2007-07-15

This paper gives a detailed description of the design of a superconducting permanent magnet synchronous motor. The parameters of the motor have been identified, and the torque equation has been stated. A direct torque control algorithm is introduced and applied to a traditional permanent magnet synchronous motor and the superconducting permanent magnet synchronous motor described in this paper. The motor performance shows that the direct torque control algorithm provides excellent control to the superconducting motor, and guarantees that the magnitude of the operational armature currents is smaller than the value of the critical current of the superconducting tape used for stator winding.

Effects of a Memory and Visual-Motor Integration Program for Older Adults Based on Self-Efficacy Theory.

Science.gov (United States)

Kim, Eun Hwi; Suh, Soon Rim

2017-06-01

This study was conducted to verify the effects of a memory and visual-motor integration program for older adults based on self-efficacy theory. A non-equivalent control group pretest-posttest design was implemented in this quasi-experimental study. The participants were 62 older adults from senior centers and older adult welfare facilities in D and G city (Experimental group=30, Control group=32). The experimental group took part in a 12-session memory and visual-motor integration program over 6 weeks. Data regarding memory self-efficacy, memory, visual-motor integration, and depression were collected from July to October of 2014 and analyzed with independent t-test and Mann-Whitney U test using PASW Statistics (SPSS) 18.0 to determine the effects of the interventions. Memory self-efficacy (t=2.20, p=.031), memory (Z=-2.92, p=.004), and visual-motor integration (Z=-2.49, p=.013) increased significantly in the experimental group as compared to the control group. However, depression (Z=-0.90, p=.367) did not decrease significantly. This program is effective for increasing memory, visual-motor integration, and memory self-efficacy in older adults. Therefore, it can be used to improve cognition and prevent dementia in older adults. © 2017 Korean Society of Nursing Science

Lost for emotion words: What motor and limbic brain activity reveals about autism and semantic theory

Science.gov (United States)

Moseley, Rachel L.; Shtyrov, Yury; Mohr, Bettina; Lombardo, Michael V.; Baron-Cohen, Simon; Pulvermüller, Friedemann

2015-01-01

Autism spectrum conditions (ASC) are characterised by deficits in understanding and expressing emotions and are frequently accompanied by alexithymia, a difficulty in understanding and expressing emotion words. Words are differentially represented in the brain according to their semantic category and these difficulties in ASC predict reduced activation to emotion-related words in limbic structures crucial for affective processing. Semantic theories view ‘emotion actions’ as critical for learning the semantic relationship between a word and the emotion it describes, such that emotion words typically activate the cortical motor systems involved in expressing emotion actions such as facial expressions. As ASC are also characterised by motor deficits and atypical brain structure and function in these regions, motor structures would also be expected to show reduced activation during emotion-semantic processing. Here we used event-related fMRI to compare passive processing of emotion words in comparison to abstract verbs and animal names in typically-developing controls and individuals with ASC. Relatively reduced brain activation in ASC for emotion words, but not matched control words, was found in motor areas and cingulate cortex specifically. The degree of activation evoked by emotion words in the motor system was also associated with the extent of autistic traits as revealed by the Autism Spectrum Quotient. We suggest that hypoactivation of motor and limbic regions for emotion word processing may underlie difficulties in processing emotional language in ASC. The role that sensorimotor systems and their connections might play in the affective and social-communication difficulties in ASC is discussed. PMID:25278250

Electrical stimulation and motor recovery.

Science.gov (United States)

Young, Wise

2015-01-01

In recent years, several investigators have successfully regenerated axons in animal spinal cords without locomotor recovery. One explanation is that the animals were not trained to use the regenerated connections. Intensive locomotor training improves walking recovery after spinal cord injury (SCI) in people, and >90% of people with incomplete SCI recover walking with training. Although the optimal timing, duration, intensity, and type of locomotor training are still controversial, many investigators have reported beneficial effects of training on locomotor function. The mechanisms by which training improves recovery are not clear, but an attractive theory is available. In 1949, Donald Hebb proposed a famous rule that has been paraphrased as "neurons that fire together, wire together." This rule provided a theoretical basis for a widely accepted theory that homosynaptic and heterosynaptic activity facilitate synaptic formation and consolidation. In addition, the lumbar spinal cord has a locomotor center, called the central pattern generator (CPG), which can be activated nonspecifically with electrical stimulation or neurotransmitters to produce walking. The CPG is an obvious target to reconnect after SCI. Stimulating motor cortex, spinal cord, or peripheral nerves can modulate lumbar spinal cord excitability. Motor cortex stimulation causes long-term changes in spinal reflexes and synapses, increases sprouting of the corticospinal tract, and restores skilled forelimb function in rats. Long used to treat chronic pain, motor cortex stimuli modify lumbar spinal network excitability and improve lower extremity motor scores in humans. Similarly, epidural spinal cord stimulation has long been used to treat pain and spasticity. Subthreshold epidural stimulation reduces the threshold for locomotor activity. In 2011, Harkema et al. reported lumbosacral epidural stimulation restores motor control in chronic motor complete patients. Peripheral nerve or functional electrical

Voltage dip caused by the sequential energization of wind turbine transformers

DEFF Research Database (Denmark)

Arana Aristi, Iván; Holbøll, Joachim; Sørensen, T.

2009-01-01

motors, this recommendation automatically applies to the wind turbine transformers in a wind farm, regardless of the fact that wind turbine transformers are rarely energized and the investment of timed relays might be significant. At the design stage of the collection grid of large offshore wind farms...... farms in Denmark and the UK. However, there is still work to be done to optimize the investment and protection system of the internal grid of the wind power plants....

Optimal current waveforms for brushless permanent magnet motors

Science.gov (United States)

Moehle, Nicholas; Boyd, Stephen

2015-07-01

In this paper, we give energy-optimal current waveforms for a permanent magnet synchronous motor that result in a desired average torque. Our formulation generalises previous work by including a general back-electromotive force (EMF) wave shape, voltage and current limits, an arbitrary phase winding connection, a simple eddy current loss model, and a trade-off between power loss and torque ripple. Determining the optimal current waveforms requires solving a small convex optimisation problem. We show how to use the alternating direction method of multipliers to find the optimal current in milliseconds or hundreds of microseconds, depending on the processor used, which allows the possibility of generating optimal waveforms in real time. This allows us to adapt in real time to changes in the operating requirements or in the model, such as a change in resistance with winding temperature, or even gross changes like the failure of one winding. Suboptimal waveforms are available in tens or hundreds of microseconds, allowing for quick response after abrupt changes in the desired torque. We demonstrate our approach on a simple numerical example, in which we give the optimal waveforms for a motor with a sinusoidal back-EMF, and for a motor with a more complicated, nonsinusoidal waveform, in both the constant-torque region and constant-power region.

Scheduled power tracking control of the wind-storage hybrid system based on the reinforcement learning theory

Science.gov (United States)

Li, Ze

2017-09-01

In allusion to the intermittency and uncertainty of the wind electricity, energy storage and wind generator are combined into a hybrid system to improve the controllability of the output power. A scheduled power tracking control method is proposed based on the reinforcement learning theory and Q-learning algorithm. In this method, the state space of the environment is formed with two key factors, i.e. the state of charge of the energy storage and the difference value between the actual wind power and scheduled power, the feasible action is the output power of the energy storage, and the corresponding immediate rewarding function is designed to reflect the rationality of the control action. By interacting with the environment and learning from the immediate reward, the optimal control strategy is gradually formed. After that, it could be applied to the scheduled power tracking control of the hybrid system. Finally, the rationality and validity of the method are verified through simulation examples.

Small Wind Energy Systems

DEFF Research Database (Denmark)

Simões, Marcelo Godoy; Farret, Felix Alberto; Blaabjerg, Frede

2017-01-01

considered when selecting a generator for a wind power plant, including capacity of the AC system, types of loads, availability of spare parts, voltage regulation, technical personal and cost. If several loads are likely inductive, such asphase-controlled converters, motors and fluorescent lights......This chapter intends to serve as a brief guide when someone is considering the use of wind energy for small power applications. It is discussed that small wind energy systems act as the major energy source for residential or commercial applications, or how to make it part of a microgrid...... as a distributed generator. In this way, sources and loads are connected in such a way to behave as a renewable dispatch center. With this regard, non-critical loads might be curtailed or shed during times of energy shortfall or periods of high costs of energy production. If such a wind energy system is connected...

Exploitation of wind energy and its potential in Czechoslovakia

International Nuclear Information System (INIS)

Rychetnik, V.

1990-01-01

Examples from over the world are shown to demonstrate the potential of wind energy in power generation. The basic types of wind motors and the installed capacities are given. In Czechoslovakia the wind conditions are rather complex. Wind energy can be economically exploited at sites where the mean wind velocity at 10 m above the ground exceeds 4 m/s. This can cover about 2% of annual power generation in Czechoslovakia. The amount of electricity generated and its cost are estimated. The investment into a wind power plant would pay back in several years. The use of small wind power plants to supply, e.g., individual houses will be of limited importance. (M.D.). 4 figs., 8 refs

Design, implementation, and application of 150-degree commutation VSI to improve speed range of sensored BLDC motor.

Science.gov (United States)

Ozgenel, Mehmet Cihat

2017-09-01

Permanent magnet brushless dc (BLDC) motors are very convenient for many applications such as industrial, medical, robotic, aerospace, small electric vehicles, and home applications because of their inherent satisfying dynamic characteristics. There are numerous studies about these motors and their control schemes such as sensorless control and different speed and torque control schemes. All electric motors need commutation in order to produce speed and torque. Commutation in brushed DC motors is performed by means of a brush and collector. In BLDC motors, commutation is provided electronically in contrast to the brushed dc motors. In BLDC motors, motor phase windings are energized according to the information of the rotor position by inverter transistors. Rotor position information is used for commutation. Therefore, rotor position information is required to produce speed and torque for BLDC motors. The easiest and cheapest way to obtain rotor position information is to use Hall-effect or optical sensors. BLDC motor manufacturers generally produce BLDC motors equipped with three Hall-effect position sensors. Having three position sensors on BLDC motors provides six-step commutation which ensures two phase windings are energized in each moment. The third phase is empty. In this study, all phase windings are energized in the same time. This commutation method is twelve-step or 150 degrees commutation. So that more speed can be achieved from the same BLDC motor by comparison with six-step commutation. In this paper, both six-step and twelve-step commutation methods applied to the same BLDC motor and obtained experimental results from this study were presented, examined, and discussed.

Design, implementation, and application of 150-degree commutation VSI to improve speed range of sensored BLDC motor

Science.gov (United States)

Ozgenel, Mehmet Cihat

2017-09-01

Permanent magnet brushless dc (BLDC) motors are very convenient for many applications such as industrial, medical, robotic, aerospace, small electric vehicles, and home applications because of their inherent satisfying dynamic characteristics. There are numerous studies about these motors and their control schemes such as sensorless control and different speed and torque control schemes. All electric motors need commutation in order to produce speed and torque. Commutation in brushed DC motors is performed by means of a brush and collector. In BLDC motors, commutation is provided electronically in contrast to the brushed dc motors. In BLDC motors, motor phase windings are energized according to the information of the rotor position by inverter transistors. Rotor position information is used for commutation. Therefore, rotor position information is required to produce speed and torque for BLDC motors. The easiest and cheapest way to obtain rotor position information is to use Hall-effect or optical sensors. BLDC motor manufacturers generally produce BLDC motors equipped with three Hall-effect position sensors. Having three position sensors on BLDC motors provides six-step commutation which ensures two phase windings are energized in each moment. The third phase is empty. In this study, all phase windings are energized in the same time. This commutation method is twelve-step or 150 degrees commutation. So that more speed can be achieved from the same BLDC motor by comparison with six-step commutation. In this paper, both six-step and twelve-step commutation methods applied to the same BLDC motor and obtained experimental results from this study were presented, examined, and discussed.

Half century of wind power generation memoir. Part 1; Furyoku hatsuden hanseiki sono omoide. 1

Energy Technology Data Exchange (ETDEWEB)

Nakata, H.

1995-12-01

This article may be deemed an autobiography of an individual on his development of wind power generation devices. The author began to be interested in electricity while he was a pupil of primary school and during his time of middle school student, when he walked against the strong wind on an embankment, he got an idea to utilize the wind power and succeeded to generate electricity with his handmade wind power generator using a bicycle generator. Afterwards he kept interested in devices utilizing the wind power, in 1973, energy saving was widely promoted due to the oil crises, and taking that opportunity, he established single-handedly a laboratory for development of utilization of the breeze power. Since his retirement from teaching profession in the spring of 1980, he has coped with earnestly the development of wind power generators. He acquired and installed various machine tools for metal works for generators and various machines for wood works for making propellers. In this article, wind power generators using bicycle generators (direct connection type and speed increasing type), small D.C. motors (motors for driving tape recorder, motors for automobile radiator and windshield wiper, etc.) and automobile generators (D.C. generators and alternators) are explained. 11 figs.

Drive of a rail locomotive using linear motors. Antrieb eines schienengebundenen Triebfahrzeuges mit Hilfe von Linearmotoren

Energy Technology Data Exchange (ETDEWEB)

Kagischke, W; Steffen, U

1977-12-08

The purpose of the invention is to avoid the disadvantages of asynchronous linear motors, for example for need for reactive current for excitation, where driving on a normal section and driving on a branch line should be possible without losing the saving in weight on the inductor. According to the invention, the common inductor on a synchronous linear motor consists of 2 parallel packets of laminations surrounded by DC excitation windings and the secondary systems consists of unwound and spaced magnetic sections covering the two packets of laminations on the normal section. In the direction of thrust, their length extends nearly over the pole pitch of the multi-phase AC winding. According to the invetnion, this drive therefore consists of a synchronous linear motor combined into a double motor, with an external, rail shaped fixed secondary system, which has a multi-phase AC winding opposite it.

Atmospheric diffusion wind tunnel with automatic measurement

Energy Technology Data Exchange (ETDEWEB)

Maki, S; Sakai, J; Murata, E

1974-01-01

A wind tunnel which permits estimates of atmospheric diffusion is described. Smoke from power plant smoke stacks, for example, can be simulated and traced to determine the manner of diffusion in the air as well as the grade of dilution. The wind tunnel is also capable of temperature controlled diffusion tests in which temperature distribution inside the wind tunnel is controlled. A minimum wind velocity of 10 cm can be obtained with accuracy within plus or minus 0.05 percent using a controlled direct current motor; diffusion tests are often made at low wind velocity. Fully automatic measurements can be obtained by using a minicomputer so that the operation and reading of the measuring instruments can be remotely controlled from the measuring chamber. (Air Pollut. Abstr.)

A new method for wind speed forecasting based on copula theory.

Science.gov (United States)

Wang, Yuankun; Ma, Huiqun; Wang, Dong; Wang, Guizuo; Wu, Jichun; Bian, Jinyu; Liu, Jiufu

2018-01-01

How to determine representative wind speed is crucial in wind resource assessment. Accurate wind resource assessments are important to wind farms development. Linear regressions are usually used to obtain the representative wind speed. However, terrain flexibility of wind farm and long distance between wind speed sites often lead to low correlation. In this study, copula method is used to determine the representative year's wind speed in wind farm by interpreting the interaction of the local wind farm and the meteorological station. The result shows that the method proposed here can not only determine the relationship between the local anemometric tower and nearby meteorological station through Kendall's tau, but also determine the joint distribution without assuming the variables to be independent. Moreover, the representative wind data can be obtained by the conditional distribution much more reasonably. We hope this study could provide scientific reference for accurate wind resource assessments. Copyright © 2017 Elsevier Inc. All rights reserved.

Wind energy utilization: A bibliography with abstracts - Cumulative volume 1944/1974

Science.gov (United States)

1975-01-01

Bibliography, up to 1974 inclusive, of articles and books on utilization of wind power in energy generation. Worldwide literature is surveyed, and short abstracts are provided in many cases. The citations are grouped by subject: (1) general; (2) utilization; (3) wind power plants; (4) wind power generators (rural, synchronous, remote station); (5) wind machines (motors, pumps, turbines, windmills, home-built); (6) wind data and properties; (7) energy storage; and (8) related topics (control and regulation devices, wind measuring devices, blade design and rotors, wind tunnel simulation, aerodynamics). Gross-referencing is aided by indexes of authors, corporate sources, titles, and keywords.

Estimates of oceanic surface wind speed and direction using orthogonal beam scatterometer measurements and comparison of recent sea scattering theories

Science.gov (United States)

Moore, R. K.; Fung, A. K.; Dome, G. J.; Birrer, I. J.

1978-01-01

The wind direction properties of radar backscatter from the sea were empirically modelled using a cosine Fourier series through the 4th harmonic in wind direction (referenced to upwind). A comparison with 1975 JONSWAP (Joint North Sea Wave Project) scatterometer data, at incidence angles of 40 and 65, indicates that effects to third and fourth harmonics are negligible. Another important result is that the Fourier coefficients through the second harmonic are related to wind speed by a power law expression. A technique is also proposed to estimate the wind speed and direction over the ocean from two orthogonal scattering measurements. A comparison between two different types of sea scatter theories, one type presented by the work of Wright and the other by that of Chan and Fung, was made with recent scatterometer measurements. It demonstrates that a complete scattering model must include some provisions for the anisotropic characteristics of the sea scatter, and use a sea spectrum which depends upon wind speed.

Producing Turbulent Wind Tunnel Inflows Relevant to Wind Turbines using an Active Grid

Science.gov (United States)

Rumple, Christopher; Welch, Matthew; Naughton, Jonathan

2017-11-01

The rise of industries like wind energy have provided motivation for generating realistic turbulent inflows in wind tunnels. Facilities with the ability to produce such inflows can study the interaction between the inflow turbulence and the flow of interest such as a wind turbine wake. An active grid - a system of actively driven elements - has gained increasing acceptance in turbulence research over the last 20 years. The ability to tailor the inflow turbulence quantities (e.g. turbulence intensities, integral length scale, and turbulence spectrum) is a driving reason for the growing use of active grids. An active grid with 40 independent axes located within the forward contraction of a low speed wind tunnel is used to explore the range of turbulent inflows possible using hot-wire anemometry to characterize the turbulence. Motor control algorithms (i.e. user waveform inputs) used to produce various turbulent inflows will be presented. Wind data available from meteorological towers are used to develop relevant inflows for wind turbines to demonstrate the usefulness of the active grid. This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award # DE-SC0012671.

Dynamic analysis of horizontal axis wind turbine by thin-walled beam theory

Science.gov (United States)

Wang, Jianhong; Qin, Datong; Lim, Teik C.

2010-08-01

A mixed flexible-rigid multi-body mathematical model is applied to predict the dynamic performance of a wind turbine system. Since the tower and rotor are both flexible thin-walled structures, a consistent expression for their deformations is applied, which employs a successive series of transformations to locate any point on the blade and tower relative to an inertial coordinate system. The kinetic and potential energy terms of each flexible body and rigid body are derived for use in the Lagrange approach to formulate the wind turbine system's governing equation. The mode shapes are then obtained from the free vibration solution, while the distributions of dynamic stress and displacement of the tower and rotor are computed from the forced vibration response analysis. Using this dynamic model, the influence of the tower's stiffness on the blade tip deformation is studied. From the analysis, it is evident that the proposed model not only inherits the simplicity of the traditional 1-D beam element, but also able to provide detailed information about the tower and rotor response due to the incorporation of the flexible thin-walled beam theory.

Theory of mind performance in Parkinson's disease is associated with motor and cognitive functions, but not with symptom lateralization.

Science.gov (United States)

Nobis, Lisa; Schindlbeck, Katharina; Ehlen, Felicitas; Tiedt, Hannes; Rewitzer, Charlotte; Duits, Annelien A; Klostermann, Fabian

2017-09-01

Next to the typical motor signs, Parkinson's disease (PD) goes along with neuropsychiatric symptoms, amongst others affecting social cognition. Particularly, Theory of Mind (ToM) impairments have mostly been associated with right hemispherical brain dysfunction, so that it might prevail in patients with left dominant PD. Fourty-four PD patients, twenty-four with left and twenty with right dominant motor symptoms, engaged in the Reading the Mind in the Eyes (RME) and the Faux Pas Detection Test (FPD) to assess affective and cognitive ToM. The results were correlated with performance in further cognitive tests, and analyzed with respect to associations with the side of motor symptom dominance and severity of motor symptoms. No association of ToM performance with right hemispheric dysfunction was found. RME results were inversely correlated with motor symptom severity, while FPD performance was found to correlate with the performance in verbal fluency tasks and the overall cognitive evaluation. Affective ToM was found associated with motor symptom severity and cognitive ToM predominantly with executive function, but no effect of PD lateralization on this was identified. The results suggest that deficits in social cognition occur as a sequel of the general corticobasal pathology in PD, rather than as a result of hemisphere-specific dysfunction.

Observer-based estimation of stator-winding faults in delta-connected induction motors

DEFF Research Database (Denmark)

Skovemose Kallesøe, Carsten; Izadi-Zamanabadi, Roozbeh; Vadstrup, Pierre

2007-01-01

This paper addresses the subject of interturn short circuit estimation in the stator of a delta-connected induction motor. In this paper, an adaptive observer scheme is proposed. The proposed observer is capable of simultaneously estimating the speed of the motor, the amount turns involved...... in the short circuit, and an expression of the current in the short circuit. Moreover, the currents are made available even though a fault has occurred in the motor. To be able to develop this observer, a model that is particularly suitable for the chosen observer design, is also derived. The effeciency...... of the proposed observer is demonstrated by tests performed on a test setup with a customized designed induction motor. With this motor it is possible to simulate interturn short-circuit faults....

Quantitative analysis of a wind energy conversion model

International Nuclear Information System (INIS)

Zucker, Florian; Gräbner, Anna; Strunz, Andreas; Meyn, Jan-Peter

2015-01-01

A rotor of 12 cm diameter is attached to a precision electric motor, used as a generator, to make a model wind turbine. Output power of the generator is measured in a wind tunnel with up to 15 m s −1 air velocity. The maximum power is 3.4 W, the power conversion factor from kinetic to electric energy is c p = 0.15. The v 3 power law is confirmed. The model illustrates several technically important features of industrial wind turbines quantitatively. (paper)

Control of a Dual-Stator Flux-Modulated Motor for Electric Vehicles

Directory of Open Access Journals (Sweden)

Xinhua Guo

2016-07-01

Full Text Available This paper presents the control strategies for a novel dual-stator flux-modulated (DSFM motor for application in electric vehicles (EVs. The DSFM motor can be applied to EVs because of its simple winding structure, high reliability, and its use of two stators and rotating modulation steels in the air gap. Moreover, it outperforms conventional brushless doubly-fed machines in terms of control performance. Two stator-current-oriented vector controls with different excitation in the primary winding, direct and alternating current excitation, are designed, simulated, and evaluated on a custom-made DSFM prototype allowing the decoupled control of torque. The stable speed response and available current characteristics strongly validate the feasibility of the two control methods. Furthermore, the proposed control methods can be employed in other applications of flux-modulated motors.

Pathogenesis of motor neuron disease

Institute of Scientific and Technical Information of China (English)

Xuefei Wang

2006-01-01

OBJECTIVE: To summarize and analyze the factors and theories related to the attack of motor neuron disease, and comprehensively investigate the pathogenesis of motor neuron disease.DATA SOURCES: A search of Pubmed database was undertaken to identify articles about motor neuron disease published in English from January 1994 to June 2006 by using the keywords of "neurodegenerative diseases". Other literatures were collected by retrieving specific journals and articles.STUDY SELECTION: The data were checked primarily, articles related to the pathogenesis of motor neuron disease were involved, and those obviously irrelated to the articles were excluded.DATA EXTRACTION: Totally 54 articles were collected, 30 of them were involved, and the other 24 were excluded.DATA SYNTHESIS: The pathogenesis of motor neuron disease has multiple factors, and the present related theories included free radical oxidation, excitotoxicity, genetic and immune factors, lack of neurotrophic factor,injury of neurofilament, etc. The studies mainly come from transgenic animal models, cell culture in vitro and patients with familial motor neuron disease, but there are still many restrictions and disadvantages.CONCLUSION: It is necessary to try to find whether there is internal association among different mechanisms,comprehensively investigate the pathogenesis of motor neuron diseases, in order to provide reliable evidence for the clinical treatment.

Preliminary Design of Reluctance Motors for Light Electric Vehicles Driving

Directory of Open Access Journals (Sweden)

TRIFA, V.

2009-02-01

Full Text Available The paper presents the aspects regarding FEM analysis of a reluctant motor for direct driving of the light electric vehicles. The reluctant motor take into study is of special construction suitable for direct drive of a light electric vehicle. It is an inverse radial reluctant motor, with a fixed stator mounted on front wheel shaft and an external toothed rotor fixed on the front wheel itself. A short presentation of preliminary design is continued with the FEM analysis in order to provide the optimal geometry of the motor and adequate windings.

Detection of Failure in Asynchronous Motor Using Soft Computing Method

Science.gov (United States)

Vinoth Kumar, K.; Sony, Kevin; Achenkunju John, Alan; Kuriakose, Anto; John, Ano P.

2018-04-01

This paper investigates the stator short winding failure of asynchronous motor also their effects on motor current spectrums. A fuzzy logic approach i.e., model based technique possibly will help to detect the asynchronous motor failure. Actually, fuzzy logic similar to humanoid intelligent methods besides expected linguistic empowering inferences through vague statistics. The dynamic model is technologically advanced for asynchronous motor by means of fuzzy logic classifier towards investigate the stator inter turn failure in addition open phase failure. A hardware implementation was carried out with LabVIEW for the online-monitoring of faults.

Controlling a Four-Quadrant Brushless Three-Phase dc Motor

Science.gov (United States)

Nola, F. J.

1986-01-01

Control circuit commutates windings of brushless, three-phase, permanent-magnet motor operating from power supply. With single analog command voltage, controller makes motor accelerate, drive steadily, or brake regeneratively, in clockwise or counterclockwise direction. Controller well suited for use with energy-storage flywheels, actuators for aircraft-control surfaces, cranes, industrial robots, and other electromechanical systems requiring bidirectional control or sudden stopping and reversal.

Applying Dynamical Systems Theory to Optimize Libration Point Orbit Stationkeeping Maneuvers for WIND

Science.gov (United States)

Brown, Jonathan M.; Petersen, Jeremy D.

2014-01-01

NASA's WIND mission has been operating in a large amplitude Lissajous orbit in the vicinity of the interior libration point of the Sun-Earth/Moon system since 2004. Regular stationkeeping maneuvers are required to maintain the orbit due to the instability around the collinear libration points. Historically these stationkeeping maneuvers have been performed by applying an incremental change in velocity, or (delta)v along the spacecraft-Sun vector as projected into the ecliptic plane. Previous studies have shown that the magnitude of libration point stationkeeping maneuvers can be minimized by applying the (delta)v in the direction of the local stable manifold found using dynamical systems theory. This paper presents the analysis of this new maneuver strategy which shows that the magnitude of stationkeeping maneuvers can be decreased by 5 to 25 percent, depending on the location in the orbit where the maneuver is performed. The implementation of the optimized maneuver method into operations is discussed and results are presented for the first two optimized stationkeeping maneuvers executed by WIND.

The study of transient processes in the asynchronous starting of the synchronous motor

OpenAIRE

Alexandru Bârlea; Olivian Chiver

2012-01-01

Starting synchronous motors can be achieved by several ethods: starting with an auxiliary motor launch, starting in asynchronous regim, by feeding from a variable frequency source, auto-synchronization with the network.. In our case we study the transient processes in a asynchronous regim . In this case the synchronous motor is started like a squirrel cage induction motor . To start, the synchronous motor is equipped with a starting winding cage placed in the pole pieces of polar inducers; la...

Special-Purpose High-Torque Permanent-Magnet Motors

Science.gov (United States)

Doane, George B., III

1995-01-01

Permanent-magnet brushless motors that must provide high commanded torques and satisfy unusual heat-removal requirement are developed. Intended for use as thrust-vector-control actuators in large rocket engines. Techniques and concepts used to design improved motors for special terrestrial applications. Conceptual motor design calls for use of rotor containing latest high-energy-product rare-earth permanent magnets so that motor produces required torque while drawing smallest possible currents from power supply. Torque generated by electromagnetic interaction between stator and permanent magnets in rotor when associated electronic circuits applied appropriately temporally and spatially phased currents to stator windings. Phase relationships needed to produce commanded torque computed in response to torque command and to electronically sensed angular position of rotor relative to stator.

Further development in theory/data closure of the photoelectron-driven polar wind and day-night transition of the outflow

Directory of Open Access Journals (Sweden)

S. W. Y. Tam

Full Text Available Recent in situ observations have revealed novel features in the polar wind. Measurements between 5000 and 9000 km altitude by the Akebono satellite indicate that both H⁺ and O⁺ ions can have remarkably higher outflow velocities in the sunlit region than on the nightside. Electrons also display an asymmetric behavior: the dayside difference in energy spread, greater for upward-moving than downward-moving electrons, is absent on the nightside. Here, we discuss the further development of a theory by Tam et al. that can explain most of these observed peculiar properties by properly taking into account the global, kinetic, collisional effects of the sunlit photoelectrons, on the background polar wind and the electric field. Quantitative comparisons of the calculated results with actual data will be described. In addition, transition from the daytime photoelectron-driven polar wind to the night-time polar wind will be discussed.

Motor current signature analysis for determining operational readiness of motor-operated valves (MOVs)

International Nuclear Information System (INIS)

Kryter, R.C.; Haynes, H.D.

1987-01-01

Motor current signature analysis (MCSA) is a novel diagnostic process for condition monitoring of electric-motor-driven mechanical equipment (e.g., pumps, motor-operated valves, compressors, and processing machinery). The MCSA process identifies, characterizes, and trends over time the instantaneous load variations of mechanical equipment in order to diagnose changes in the condition of the equipment (e.g., due to degradation or service wear), which, if allowed to continue, may lead to failure. It monitors the instantaneous variations (noise content) in the electric current flowing through the power leads to the electric motor that drives the equipment. The motor itself thereby acts as a transducer, sensing both large and small, long-term and rapid, mechanical load variations and converting them to variations in the induced current generated in the motor windings. This motor current noise signature is detected, amplified, and further processed as needed to examine its time domain and frequency domain (spectral) characteristics. The operational principles of MCSA and the nonintrusive data collection apparatus and procedure used with MOVs will be described. Data collected from MOVs in both laboratory and in-plant environments will also be shown to illustrate the ability of MCSA to ''see'' the detailed inner workings of the valve and operator and thus to detect degraded performance at an incipient stage. (Set of 18 vugraphs)

Information-Measuring System to Control the Electrical and Mechanical Motor Parameters

Directory of Open Access Journals (Sweden)

K. S. Ermakov

2015-01-01

Full Text Available The article considers the issue of creating an information-measuring system for an asynchronous motor. The presented system allows ensuring the failure-free protection of electromotor, considerably reducing costs of its unplanned repair, and reduced economical loss from idle time of the electric motor.The developed system comprises a mathematical model and two subsystems to measure electrical and mechanical parameters of the asynchronous motor.The electrical subsystem comprises a FLUKE company recording multi-meter a signal from which passes through the block of intervals and coding and comes to PC.The mechanical subsystem uses technical tools of phase-chronometric method. This method developed at the department of Metrology and Interchangeability allows an increasing efficiency of developed informative-measuring system. Mathematical modeling is used to link information from subsystems (electrical and mechanical to electromotor construction.The work conducted mathematical modeling of some defects of electric motor, namely: rupture of rotor winding and line surge.The mathematical model in Mathcad was based on a modified formula of Kloss. It allows us to tie the average current value of the torque of the induction motor with shaft speed and take into account the effect of the frequency and voltage.The Matlab Simulink (the package for visual programming environment was used to simulate a rupture of the rotor winding. Simulation results showed how the phase currents of the electric motor changed with the winding rupture.The developed information-measuring system has a number of advantages over traditional systems used in this field (vibration-based diagnostics systems. It will allow an increasing efficiency of the system for diagnostics of electrical machines created on the basis of this information-measuring system.

Performance analysis of a composite dual-winding reluctance machine

International Nuclear Information System (INIS)

Anih, Linus U.; Obe, Emeka S.

2009-01-01

The electromagnetic energy conversion process of a composite dual-winding asynchronous reluctance machine is presented. The mechanism of torque production is explained using the magnetic fields distributions. The dynamic model developed in dq-rotor reference frame from first principles depicts the machine operation and response to sudden load change. The device is self-starting in the absence of rotor conductors and its starting current is lower than that of a conventional induction machine. Although the machine possesses salient pole rotors, it is clearly shown that its performance is that of an induction motor operating at half the synchronous speed. Hence the device produces synchronous torque while operating asynchronously. Simple tests were conducted on a prototype demonstration machine and the results obtained are seen to be in tune with the theory and the steady-state calculations.

Arrangement for matching a wind rotor to an electrical generator

Energy Technology Data Exchange (ETDEWEB)

Beusse, H

1978-04-06

The invention concerns an arrangement for matching a wind power machine to an electrical generator, which feeds a consumer network. According to the invention first generator using the shaft horsepower of the wind power machine feeds an electric water, which is coupled to a second generator, whose power is taken to the consumer network. The output signal of a computer which has the annemometer feeding into it controls the excitation of the motor at sufficient wind speed, so that the speed of rotation of the second generator is practically constant, and a spted regulator takes excess energy via a controlled rectifier (thyristor) to a shunt circuit of the motor, if the wind power exceeds the load taken from the output of the second generator. As an extension of the arrangement according to the invention it is proposed to arrange a Diesel engine in the shaft of the second generator, which can be controlled at constant speed by the control device, so that it takes over the missing output if the wind power is less than the load at the generator output. Apart from this, it is proposed that the loading of the wind rotor should be controlled by the control device so that it only comes in if the wind rotor has reached a stable working point after accelerating on no load.

Linear Parameter Varying Control of Induction Motors

DEFF Research Database (Denmark)

Trangbæk, Klaus

The subject of this thesis is the development of linear parameter varying (LPV) controllers and observers for control of induction motors. The induction motor is one of the most common machines in industrial applications. Being a highly nonlinear system, it poses challenging control problems...... for high performance applications. This thesis demonstrates how LPV control theory provides a systematic way to achieve good performance for these problems. The main contributions of this thesis are the application of the LPV control theory to induction motor control as well as various contributions...

A brushless dc spin motor for momentum exchange altitude control

Science.gov (United States)

Stern, D.; Rosenlieb, J. W.

1972-01-01

Brushless dc spin motor is designed to use Hall effect probes as means of revolving rotor position and controlling motor winding currents. This results in 3 to 1 reduction in watt-hours required for wheel acceleration, a 2 to 1 reduction in power to run wheel, and a 10 to 1 reduction in the electronics size and weight.

Comparison of the lifting-line free vortex wake method and the blade-element-momentum theory regarding the simulated loads of multi-MW wind turbines

International Nuclear Information System (INIS)

Hauptmann, S; Bülk, M; Cheng, P W; Schön, L; Erbslöh, S; Boorsma, K; Grasso, F; Kühn, M

2014-01-01

Design load simulations for wind turbines are traditionally based on the blade- element-momentum theory (BEM). The BEM approach is derived from a simplified representation of the rotor aerodynamics and several semi-empirical correction models. A more sophisticated approach to account for the complex flow phenomena on wind turbine rotors can be found in the lifting-line free vortex wake method. This approach is based on a more physics based representation, especially for global flow effects. This theory relies on empirical correction models only for the local flow effects, which are associated with the boundary layer of the rotor blades. In this paper the lifting-line free vortex wake method is compared to a state- of-the-art BEM formulation with regard to aerodynamic and aeroelastic load simulations of the 5MW UpWind reference wind turbine. Different aerodynamic load situations as well as standardised design load cases that are sensitive to the aeroelastic modelling are evaluated in detail. This benchmark makes use of the AeroModule developed by ECN, which has been coupled to the multibody simulation code SIMPACK

Comparison of the lifting-line free vortex wake method and the blade-element-momentum theory regarding the simulated loads of multi-MW wind turbines

Science.gov (United States)

Hauptmann, S.; Bülk, M.; Schön, L.; Erbslöh, S.; Boorsma, K.; Grasso, F.; Kühn, M.; Cheng, P. W.

2014-12-01

Design load simulations for wind turbines are traditionally based on the blade- element-momentum theory (BEM). The BEM approach is derived from a simplified representation of the rotor aerodynamics and several semi-empirical correction models. A more sophisticated approach to account for the complex flow phenomena on wind turbine rotors can be found in the lifting-line free vortex wake method. This approach is based on a more physics based representation, especially for global flow effects. This theory relies on empirical correction models only for the local flow effects, which are associated with the boundary layer of the rotor blades. In this paper the lifting-line free vortex wake method is compared to a state- of-the-art BEM formulation with regard to aerodynamic and aeroelastic load simulations of the 5MW UpWind reference wind turbine. Different aerodynamic load situations as well as standardised design load cases that are sensitive to the aeroelastic modelling are evaluated in detail. This benchmark makes use of the AeroModule developed by ECN, which has been coupled to the multibody simulation code SIMPACK.

Airfoil characteristics for wind turbines

OpenAIRE

Bak, C.; Fuglsang, P.; Sørensen, Niels N.; Aagaard Madsen, Helge; Shen, W.Z.; Sørensen, Jens Nørkær

1999-01-01

Airfoil characteristics for use in the Blade Element Momentum (BEM) method calculating the forces on Horizontal Axis Wind Turbines (HAWT) are derived by use of systematic methods. The investigation and derivation of the airfoil characteristics are basedon four different methods: 1) Inverse momentum theory, 2) Actuator disc theory, 3) Numerical optimisation and 4) Quasi-3D CFD computations. The two former methods are based on 3D CFD computations and wind tunnel measurements on a 41-m full-scal...

Permanently split capacitor motor-study of the design parameters

Science.gov (United States)

Sarac, Vasilija; Stefanov, Goce

2017-09-01

Paper analyzes the influence of various design parameters on torque of permanently split capacitor motor. Motor analytical model is derived and it is used for calculating the performance characteristics of basic motor model. The acquired analytical model is applied in optimization software that uses genetic algorithms (GA) as an optimization method. Optimized motor model with increased torque is derived by varying three motor parameters in GA program: winding turns ratio, average air gap flux density and motor stack length. Increase of torque has been achieved for nominal operation but also at motor starting. Accuracy of the derived models is verified by Simulink. The acquired values of several motor parameters from transient characteristics of Simulink models are compared with the corresponding values obtained from analytical models of both motors, basic and optimized. Numerical analysis, based on finite element method (FEM), is also performed for both motor models. As a result of the FEM analysis, magnetic flux density in motor cross-section is calculated and adequate conclusions are derived in relation to core saturation and air gap flux density in both motor models.

LQR Feedback Control Development for Wind Turbines Featuring a Digital Fluid Power Transmission System

DEFF Research Database (Denmark)

Pedersen, Niels Henrik; Johansen, Per; Andersen, Torben O.

2016-01-01

with a DFP motor, which has been combined with the NREL 5-MW reference wind turbine model. A classical variable speed control strategy for wind speeds below rated is proposed for the turbine, where the pump displacement is fixed and the digital motor displacement is varied for pressure control. The digital...... for such digital systems are complicated by its non-smooth behavior. In this paper a control design approach for a digital displacement machine® is proposed and a performance analysis of a wind turbine using a DFP transmission is presented. The performance evaluation is based on a dynamic model of the transmission...... invariant model. Using full-field flow wind profiles as input, the design approach and control performance is verified by simulation in the dynamic model of the wind turbine featuring the DFP transmission. Additionally, the performance is compared to that of the conventional NREL reference turbine...

Influence of magnetic saturation effects on the fault detection of induction motors

Directory of Open Access Journals (Sweden)

Drozdowski Piotr

2014-09-01

Full Text Available In this paper, the influence of impact damage to the induction motors on the zero-sequence voltage and its spectrum is presented. The signals detecting the damages result from a detailed analysis of the formula describing this voltage component which is induced in the stator windings due to core magnetic saturation and the discrete displacement of windings. Its course is affected by the operation of both the stator and the rotor. Other fault detection methods, are known and widely applied by analysing the spectrum of stator currents. The presented method may be a complement to other methods because of the ease of measurements of the zero voltage for star connected motors. Additionally, for converter fed motors the zero sequence voltage eliminates higher time harmonics displaced by 120 degrees. The results of the method application are presented through measurements and explained by the use of a mathematical model of the slip-ring induction motor

Estimation of Stator winding faults in induction motors using an adaptive observer scheme

DEFF Research Database (Denmark)

Kallesøe, C. S.; Vadstrup, P.; Rasmussen, Henrik

2004-01-01

This paper addresses the subject of inter-turn short circuit estimation in the stator of an induction motor. In the paper an adaptive observer scheme is proposed. The proposed observer is capable of simultaneously estimating the speed of the motor, the amount turns involved in the short circuit...... and an expression of the current in the short circuit. Moreover the states of the motor are estimated, meaning that the magnetizing currents are made available even though a fault has happened in the motor. To be able to develop this observer, a model particular suitable for the chosen observer design, is also...... derived. The efficiency of the proposed observer is demonstrated by tests performed on a test setup with a customized designed induction motor. With this motor it is possible to simulate inter-turn short circuit faults....

Estimation of Stator Winding Faults in Induction Motors using an Adaptive Observer Scheme

DEFF Research Database (Denmark)

Kallesøe, C. S.; Vadstrup, P.; Rasmussen, Henrik

2004-01-01

This paper addresses the subject of inter-turn short circuit estimation in the stator of an induction motor. In the paper an adaptive observer scheme is proposed. The proposed observer is capable of simultaneously estimating the speed of the motor, the amount turns involved in the short circuit...... and an expression of the current in the short circuit. Moreover the states of the motor are estimated, meaning that the magnetizing currents are made available even though a fault has happened in the motor. To be able to develop this observer, a model particular suitable for the chosen observer design, is also...... derived. The efficiency of the proposed observer is demonstrated by tests performed on a test setup with a customized designed induction motor. With this motor it is possible to simulate inter-turn short circuit faults....

Aberrant supplementary motor complex and limbic activity during motor preparation in motor conversion disorder.

Science.gov (United States)

Voon, Valerie; Brezing, Christina; Gallea, Cecile; Hallett, Mark

2011-11-01

Conversion disorder (CD) is characterized by unexplained neurological symptoms presumed related to psychological issues. The main hypotheses to explain conversion paralysis, characterized by a lack of movement, include impairments in either motor intention or disruption of motor execution, and further, that hyperactive self-monitoring, limbic processing or top-down regulation from higher order frontal regions may interfere with motor execution. We have recently shown that CD with positive abnormal or excessive motor symptoms was associated with greater amygdala activity to arousing stimuli along with greater functional connectivity between the amygdala and supplementary motor area. Here we studied patients with such symptoms focusing on motor initiation. Subjects performed either an internally or externally generated 2-button action selection task in a functional MRI study. Eleven CD patients without major depression and 11 age- and gender-matched normal volunteers were assessed. During both internally and externally generated movement, conversion disorder patients relative to normal volunteers had lower left supplementary motor area (SMA) (implicated in motor initiation) and higher right amygdala, left anterior insula, and bilateral posterior cingulate activity (implicated in assigning emotional salience). These findings were confirmed in a subgroup analysis of patients with tremor symptoms. During internally versus externally generated action in CD patients, the left SMA had lower functional connectivity with bilateral dorsolateral prefrontal cortices. We propose a theory in which previously mapped conversion motor representations may in an arousing context hijack the voluntary action selection system, which is both hypoactive and functionally disconnected from prefrontal top-down regulation. Copyright © 2011 Movement Disorder Society.

Aberrant supplementary motor complex and limbic activity during motor preparation in motor conversion disorder

Science.gov (United States)

Voon, V; Brezing, C; Gallea, C; Hallett, M

2014-01-01

Background Conversion disorder is characterized by unexplained neurological symptoms presumed related to psychological issues. The main hypotheses to explain conversion paralysis, characterized by a lack of movement, include impairments in either motor intention or disruption of motor execution, and further, that hyperactive self-monitoring, limbic processing or top-down regulation from higher order frontal regions may interfere with motor execution. We have recently shown that conversion disorder with positive abnormal or excessive motor symptoms was associated with greater amygdala activity to arousing stimuli along with greater functional connectivity between the amgydala and supplementary motor area. Here we studied patients with such symptoms focusing on motor initiation. Methods Subjects performed either an internally or externally generated two-button action selection task in a functional MRI study. Results Eleven conversion disorder patients without major depression and 11 age- and gender-matched normal volunteers were assessed. During both internally and externally generated movement, conversion disorder patients relative to normal volunteers had lower left supplementary motor area (SMA) (implicated in motor initiation) and higher right amygdala, left anterior insula and bilateral posterior cingulate activity (implicated in assigning emotional salience). These findings were confirmed in a subgroup analysis of patients with tremor symptoms. During internally versus externally generated action in CD patients, the left SMA had lower functional connectivity with bilateral dorsolateral prefrontal cortices. Conclusion We propose a theory in which previously mapped conversion motor representations may in an arousing context hijack the voluntary action selection system which is both hypoactive and functionally disconnected from prefrontal top-down regulation. PMID:21935985

Correlation of theory to wind-tunnel data at Reynolds numbers below 500,000

Science.gov (United States)

Evangelista, Raquel; Mcghee, Robert J.; Walker, Betty S.

1989-01-01

This paper presents results obtained from two airfoil analysis methods compared with previously published wind tunnel test data at chord Reynolds numbers below 500,000. The analysis methods are from the Eppler-Somers airfoil design/analysis code and from ISES, the Drela-Giles Airfoil design/analysis code. The experimental data are from recent tests of the Eppler 387 airfoil in the NASA Langley Low Turbulence Pressure Tunnel. For R not less than 200,000, lift and pitching moment predictions from both theories compare well with experiment. Drag predictions from both theories also agree with experiment, although to different degrees. However, most of the drag predictions from the Eppler-Somers code are accompanied with separation bubble warnings which indicate that the drag predictions are too low. With the Drela-Giles code, there is a large discrepancy between the computed and experimental pressure distributions in cases with laminar separation bubbles, although the drag polar predictions are similar in trend to experiment.

Mathematical models of flat linear induction motors used in mining drives

Energy Technology Data Exchange (ETDEWEB)

Tall, M

1984-01-01

Design parameters are calculated for electric flat linear induction motors, widely employed in the coal and ore mining industries in Poland. A mathematical model of this motor with a single-layer ferromagnetic secondary part is presented. A three-dimensional electromagnetic field analysis is carried out, taking relative magnetic permeability variation, discrete winding distribution, influence of armature grooving and pulsating field influence into account. A computer calculation algorithm is proposed for determining motor characteristics. 17 refs.

Design and Study of a Low-Cost Laboratory Model Digital Wind Power Meter

Science.gov (United States)

Radhakrishnan, Rugmini; Karthika, S.

2010-01-01

A vane-type low-cost laboratory model anemometer cum power meter is designed and constructed for measuring low wind energy created from accelerating fluids. The constructed anemometer is a device which records the electrical power obtained by the conversion of wind power using a wind sensor coupled to a DC motor. It is designed for its…

Magnetic Circuit Model of PM Motor-Generator to Predict Radial Forces

Science.gov (United States)

McLallin, Kerry (Technical Monitor); Kascak, Peter E.; Dever, Timothy P.; Jansen, Ralph H.

2004-01-01

A magnetic circuit model is developed for a PM motor for flywheel applications. A sample motor is designed and modeled. Motor configuration and selection of materials is discussed, and the choice of winding configuration is described. A magnetic circuit model is described, which includes the stator back iron, rotor yoke, permanent magnets, air gaps and the stator teeth. Iterative solution of this model yields flux linkages, back EMF, torque, power, and radial force at the rotor caused by eccentricity. Calculated radial forces are then used to determine motor negative stiffness.

Analyzing solvency with extreme value theory: an application to the Spanish motor liability insurance market

Directory of Open Access Journals (Sweden)

María José Pérez-Fructuoso

2010-04-01

Full Text Available An accurate estimation of extreme claims is fundamental to assess solvency capital requirements (SCR established by Solvency II. Basing on the Extreme Value Theory (EVT, this paper performs a parametric estimation to fit the motor liability insurance historical datasets of two significant and representative companies operating within the Spanish market to a Generalized Pareto Distribution. We illustrate how EVT improves classical adjustments, as it considers outliers apart from mass risks, what leads to optimize the pricing decision-making and fix a risk transfer position.

Multiobjective Design of Turbo Injection Mode for Axial Flux Motor in Plastic Injection Molding Machine by Particle Swarm Optimization

Directory of Open Access Journals (Sweden)

Jian-Long Kuo

2015-01-01

Full Text Available This paper proposes a turbo injection mode (TIM for an axial flux motor to apply onto injection molding machine. Since the injection molding machine requires different speed and force parameters setting when finishing a complete injection process. The interleaved winding structure in the motor provides two different injection levels to provide enough injection forces. Two wye-wye windings are designed to switch two control modes conveniently. Wye-wye configuration is used to switch two force levels for the motor. When only one set of wye-winding is energized, field weakening function is achieved. Both of the torque and speed increase under field weakening operation. To achieve two control objectives for torque and speed of the motor, fuzzy based multiple performance characteristics index (MPCI with particle swarm optimization (PSO is used to find out the multiobjective optimal design solution. Both of the torque and speed are expected to be maximal at the same time. Three control factors are selected as studied factors: winding diameter, winding type, and air-gap. Experimental results show that both of the torque and speed increase under the optimal condition. This will provide enough large torque and speed to perform the turbo injection mode in injection process for the injection molding machine.

Stand-alone excitation synchronous wind power generators with power flow management strategy

Directory of Open Access Journals (Sweden)

Tzuen-Lih Chern

2014-09-01

Full Text Available This study presents a stand-alone excitation synchronous wind power generator (SESWPG with power flow management strategy (PFMS. The rotor speed of the excitation synchronous generator tracks the utility grid frequency by using servo motor tracking technologies. The automatic voltage regulator governs the exciting current of generator to achieve the control goals of stable voltage. When wind power is less than the needs of the consumptive loading, the proposed PFMS increases motor torque to provide a positive power output for the loads, while keeping the generator speed constant. Conversely, during the periods of wind power greater than output loads, the redundant power of generator production is charged to the battery pack and the motor speed remains constant with very low power consumption. The advantage of the proposed SESWPG is that the generator can directly output stable alternating current (AC electricity without using additional DC–AC converters. The operation principles with software simulation for the system are described in detail. Experimental results of a laboratory prototype are shown to verify the feasibility of the system.

Motor control is decision-making.

Science.gov (United States)

Wolpert, Daniel M; Landy, Michael S

2012-12-01

Motor behavior may be viewed as a problem of maximizing the utility of movement outcome in the face of sensory, motor and task uncertainty. Viewed in this way, and allowing for the availability of prior knowledge in the form of a probability distribution over possible states of the world, the choice of a movement plan and strategy for motor control becomes an application of statistical decision theory. This point of view has proven successful in recent years in accounting for movement under risk, inferring the loss function used in motor tasks, and explaining motor behavior in a wide variety of circumstances. Copyright © 2012 Elsevier Ltd. All rights reserved.

Social Motor Synchronization: Insights for Understanding Social Behavior in Autism.

Science.gov (United States)

Fitzpatrick, Paula; Romero, Veronica; Amaral, Joseph L; Duncan, Amie; Barnard, Holly; Richardson, Michael J; Schmidt, R C

2017-07-01

Impairments in social interaction and communication are critical features of ASD but the underlying processes are poorly understood. An under-explored area is the social motor synchronization that happens when we coordinate our bodies with others. Here, we explored the relationships between dynamical measures of social motor synchronization and assessments of ASD traits. We found (a) spontaneous social motor synchronization was associated with responding to joint attention, cooperation, and theory of mind while intentional social motor synchronization was associated with initiating joint attention and theory of mind; and (b) social motor synchronization was associated with ASD severity but not fully explained by motor problems. Findings suggest that objective measures of social motor synchronization may provide insights into understanding ASD traits.

Tidal analysis of Met rocket wind data

Science.gov (United States)

Bedinger, J. F.; Constantinides, E.

1976-01-01

A method of analyzing Met Rocket wind data is described. Modern tidal theory and specialized analytical techniques were used to resolve specific tidal modes and prevailing components in observed wind data. A representation of the wind which is continuous in both space and time was formulated. Such a representation allows direct comparison with theory, allows the derivation of other quantities such as temperature and pressure which in turn may be compared with observed values, and allows the formation of a wind model which extends over a broader range of space and time. Significant diurnal tidal modes with wavelengths of 10 and 7 km were present in the data and were resolved by the analytical technique.

Arrangement for adapting a wind wheel to an electric power generator

Energy Technology Data Exchange (ETDEWEB)

Beusse, H

1977-08-11

The invention is concerned with a device for adapting a wind wheel to an electric power generator in such a way that the wind wheel will always be operated with a maximum performance coefficient, that another source of energy, e.g. a prime mover, can supply the power deficit if the wind power is not sufficient, and that the generator at the output of the facility is kept mains-synchronous of constant speed and constant voltage. According to the invention, the shaft power of the wind power engine is transmitted to a first generator driving an electromotor. The motor is coupled to a second generator feeding into a consumer grid. By means of an anemometer the excitation output of the motor is controled in such manner that the speed of the generator is practically constant-provided a sufficient supply of wind is available. On the shaft of the output generator a prinse mover, e.g. a Diesel engine, is mounted being controllable for contant speed by means of a controll device in such a way that the prime mover takes over the missing amount of power if the wind supply falls short of the power taken off at the generator output.

Hall devices improve electric motor efficiency

Science.gov (United States)

Haeussermann, W.

1979-01-01

Efficiency of electric motors and generators is reduced by radial magnetic forces created by symmetric fields within device. Forces are sensed and counteracted by Hall devices on excitation or control windings. Hall generators directly measure and provide compensating control of anu asymmetry, eliminating additional measurements needed for calibration feedback control loop.

Application of high temperature superconductivity to electric motor design

International Nuclear Information System (INIS)

Edmonds, J.S.; Sharma, D.K.; Jordan, H.E.; Edick, J.D.; Schiferl, R.F.

1992-01-01

This paper reports on progress made in a joint project conducted by the Electric Power Research Institute and Reliance Electric Company to study the possible application of High Temperature Super Conductors (HTSC), materials to electric motors. Specific applications are identified which can be beneficially served by motors constructed with HTSC materials. A summary is presented of the components and design issues related to HTSC motors designed for these applications. During the course of this development program, a three tier HTSC wire performance specification has evolved. The three specifications and the rationale behind these three levels of performance are explained. A description of a test motor that has been constructed to verify the electromagnetic analytical techniques of HTSC motor design is given. Finally, a DC motor with an HTSC field coil is described. Measured data with the motor running is presented showing that the motor is operating with the field winding in the superconducting state

Speed controller for an alternating - current motor

International Nuclear Information System (INIS)

Bolie, V.W.

1984-01-01

A controller for a multi-phase ac motor that is subject to a large inertial load, e.g. an induction motor driving a heavy spinning rotor of a neutron chopper that must be rotated in phase-locked synchronism with a reference pulse train that is representative of an ac power supply signal Esub(L) having a meandering line frequency, includes a sensor which provides a feedback pulse train representative of the actual speed of the motor which is compared (by counting clock pulses between feedback pulses) with a reference clock signal in a computing unit to provide a motor control signal Esub(c). The motor control signal is a weighted linear sum of a speed error signal, a phase error signal, and a drift error signal, the magnitudes of which are recalculated and updated with each revolution of the motor shaft. The speed error signal is constant for large speed errors but highly sensitive to small speed errors. The stator windings of the motor are driven by variable-frequency power amplifiers which are controlled by the motor control signal Esub(c) via PROMs which store digital representations of sine and cosine waveforms in quadrature. (author)

Testing of motor unit synchronization model for localized muscle fatigue.

Science.gov (United States)

Naik, Ganesh R; Kumar, Dinesh K; Yadav, Vivek; Wheeler, Katherine; Arjunan, Sridhar

2009-01-01

Spectral compression of surface electromyogram (sEMG) is associated with onset of localized muscle fatigue. The spectral compression has been explained based on motor unit synchronization theory. According to this theory, motor units are pseudo randomly excited during muscle contraction, and with the onset of muscle fatigue the recruitment pattern changes such that motor unit firings become more synchronized. While this is widely accepted, there is little experimental proof of this phenomenon. This paper has used source dependence measures developed in research related to independent component analysis (ICA) to test this theory.

3000 Horsepower super conductive field acyclic motor

International Nuclear Information System (INIS)

Marshall, R.

1983-01-01

A 3000 hp acyclic motor was assembled and tested utilizing superconducting field coils. The magnet assembly is designed as a quadrupole magnet, utilizing a multifilamentary niobium titanium superconductor. Each magnet coil is 18 inches in diameter and 10 inches long, and operates at rated current of 200 amperes, providing 5.8 tesla in the bore of the coils in the motor configuration. The average winding current density is 10,600 A/cm 2 . The acyclic motor is of a drum-type design with liquid metal current collectors, and is designed to model full-scale machinery for ship propulsion applications. Laboratory test data verified the electrical and electromagnetic design to be within three percent of the calculated values

Weather-power station. Solar energy, wind energy, water energy

Energy Technology Data Exchange (ETDEWEB)

Schatta, M

1975-10-02

A combined power station is described, which enables one to convert solar energy and wind energy into other forms of energy. The plant consists of a water-filled boiler, in which solar energy heats the water by concentration, solar cells, and finally wind rotors, which transform wind energy into electrical energy. The transformed energy is partly available as steam heat, partly as mechanical or electrical energy. The plant can be used for supplying heating systems or electrolysis equipment. Finally, by incorporating suitable motors, a mobile version of the system can be produced.

The Relationship between Social and Motor Cognition in Primary School Age-Children

Science.gov (United States)

Kenny, Lorcan; Hill, Elisabeth; Hamilton, Antonia F. de C.

2016-01-01

There is increased interest in the relationship between motor skills and social skills in child development, with evidence that the mechanisms underlying these behaviors may be linked. We took a cognitive approach to this problem, and examined the relationship between four specific cognitive domains: theory of mind, motor skill, action understanding, and imitation. Neuroimaging and adult research suggest that action understanding and imitation are closely linked, but are somewhat independent of theory of mind and low-level motor control. Here, we test if a similar pattern is shown in child development. A sample of 101 primary school aged children with a wide ability range completed tests of IQ (Raven’s matrices), theory of mind, motor skill, action understanding, and imitation. Parents reported on their children’s social, motor and attention performance as well as developmental concerns. The results showed that action understanding and imitation correlate, with the latter having a weak link to motor control. Theory of mind was independent of the other tasks. These results imply that independent cognitive processes for social interaction (theory of mind) and for motor control can be identified in primary school age children, and challenge approaches that link all these domains together. PMID:26941685

Extrapolating Satellite Winds to Turbine Operating Heights

DEFF Research Database (Denmark)

Badger, Merete; Pena Diaz, Alfredo; Hahmann, Andrea N.

2016-01-01

Ocean wind retrievals from satellite sensors are typically performed for the standard level of 10 m. This restricts their full exploitation for wind energy planning, which requires wind information at much higher levels where wind turbines operate. A new method is presented for the vertical...... extrapolation of satellitebased wind maps. Winds near the sea surface are obtained from satellite data and used together with an adaptation of the Monin–Obukhov similarity theory to estimate the wind speed at higher levels. The thermal stratification of the atmosphere is taken into account through a long...

Computer simulation of a 3-phase induction motor

International Nuclear Information System (INIS)

Memon, N.A.; Unsworth, P.J.

2004-01-01

Computer Simulation of a 3-phase squirrel-cage induction motor is presented in Microsoft QBASIC for understanding trends and various operational modes of an induction motor. Thyristor fed, phase controlled induction motor (three-wire) model has been simulated. In which voltage is applied to the motor stator winding through back-to-back connected thyristors as controlled switches in series with the stator. The simulated induction motor system opens up towards a wide range of investigation/analysis options for research and development work in the field. Key features of the simulation performed are highlighted for development of better understanding of the work done. Complete study of an Induction Motor, starting modes in terms the voltage/current, torque/speed characteristics and their graphical representation produced is presented. Ideal agreement of the simulation results with the notional outcome encourages users to go ahead for various hardware development projects based on the study through the simulation. (author)

Diode Laser Assisted Filament Winding of Thermoplastic Matrix Composites

Science.gov (United States)

Quadrini, Fabrizio; Squeo, Erica Anna; Prosperi, Claudia

2010-01-01

A new consolidation method for the laser-assisted filament winding of thermoplastic prepregs is discussed: for the first time a diode laser is used, as well as long glass fiber reinforced polypropylene prepregs. A consolidation apparatus was built by means of a CNC motion table, a stepper motor and a simple tensioner. Preliminary tests were performed in a hoop winding configuration: only the winding speed was changed, and all the other process parameters (laser power, distance from the laser focus, consolidation force) were kept constant. Small wound rings with an internal diameter of 25 mm were produced and compression tests were carried out to evaluate the composite agglomeration in dependence of the winding speed. At lower winding speeds, a strong interpenetration of adjacent layers was observed.

Theoretical and Experimental Research of Synchronous Reluctance Motor

Science.gov (United States)

Dobriyan, R.; Vitolina, S.; Lavrinovicha, L.; Dirba, J.

2017-10-01

The paper presents the research on evaluation of accuracy of magnetic field calculations of synchronous reluctance motor in comparison with the results obtained in experiments. Magnetic field calculations are performed with the finite element method to determine values of the magnetic flux and electromagnetic torque according to the current value in motor stator and load angle between the rotor direct-axis and axis of stator magnetomotive force (MMF). Experimental values of magnetic flux and electromagnetic torque are obtained on motor with locked rotor while equivalent direct current is applied to the stator windings. The research shows that the results obtained from the magnetic field calculations coincide well with the experimental data.

UNIFIED CONTROL STRUCTURE OF MULTI-TYPE INTERIOR PERMANENT MAGNET MOTOR

Directory of Open Access Journals (Sweden)

M. NORHISAM

2015-03-01

Full Text Available This paper presents the control strategy structure to extract the speed torque characteristic for the newly designed three phase Multi Type Interior Permanent Magnet Motor. The proposed structure with the driving circuits exhibit the performance of torque characteristics of the stepper motor and brushless motor with independent coil winding per phase especially used as an in-wheel motor in agricultural applications. Brushless Direct Current motors exhibit characteristics of generating high torque at high speed while the Permanent Magnet Stepper motors has characteristic of generating high torque at low speed. The typical characteristics of the above two are integrated in the proposed structure with a complex control structure that handle the switching complexity and speed control in real time. Thus, a specially designed driving system is essential to drive and control this special motor. The evaluation of the motor mechanical characteristics when applying load torque is also presented. The result determines the practical torque range applicable for each motor configuration and as combined machine.

Blade-element/momentum theory

DEFF Research Database (Denmark)

Sørensen, Jens Nørkær

2016-01-01

Although there exists a large variety of methods for predicting performance and loadings of wind turbines, the only approach used today by wind turbine manufacturers is based on the blade-element/momentum (BEM) theory by Glauert (Aerodynamic theory. Springer, Berlin, pp. 169-360, 1935). A basic...... assumption in the BEM theory is that the flow takes place in independent stream tubes and that the loading is determined from two-dimensional sectional airfoil characteristics....

Theory of mind, emotional and social functioning, and motor severity in children and adolescents with dystonic cerebral palsy.

Science.gov (United States)

Adegboye, Dolapo; Sterr, Annette; Lin, Jean-Pierre; Owen, Tamsin J

2017-05-01

This cross-sectional study aimed to investigate whether children and adolescents with dystonic cerebral palsy (CP) present with emotional and social difficulties along side motor limitations. Twenty-two verbal and nonverbal children and adolescents with dystonic CP were compared with a normative sample of twenty children and adolescents on measures of theory of mind (ToM), emotion regulation (ER), and social difficulties (SD). Higher social and emotional difficulties were found in the dystonic CP group compared to the control group. Nonverbal participants with dystonic CP were found to present with greater social impairment and lower ToM ability than their verbal counterparts. Emotional regulation and hyperactivity and attentional difficulties (HAD) significantly predicted ToM ability and social difficulties. Lower Gross Motor Function Classification System (GMFCS) level and IQ also contributed to differences in ToM ability. Findings support the need for greater attention to the emotional health and social development of children/adolescents with dystonic CP, along with assessments of motor difficulties in the planning and implementation of interventions and individual care plans. Further research is needed to explore links between motor disorder and mental state understanding in this clinical group. Copyright © 2017 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

A short history of ideo-motor action.

Science.gov (United States)

Stock, Armin; Stock, Claudia

2004-04-01

The ideo-motor theory, which is currently receiving heightened interest in cognitive psychology, looks back on a long history. Essentially two historical roots can be presented. A British one, initiated by Laycock (1845) and Carpenter (1852), which was developed in order to explain ideo-motor phenomena by means of cerebral reflex actions. A second and older root is the German one by Herbart (1816, 1825), Lotze (1852), and Harless (1861), which considered the ideo-motor principle a fundamental mechanism of all intentional human behaviour. Both roots converged in James' (1890) Principles of Psychology before they fell into oblivion due to the dominance of behaviorism in the first half of the 20th century. The few empirical ideo-motor studies of the early 20th century are briefly described. Finally, similarities and differences in the history of the ideo-motor theory are delineated and a perspective is given covering research questions that could be examined in the future. Copyright 2003 Springer-Verlag

Turbulent wind at the equatorial segment of an operating Darrieus wind turbine blade

Science.gov (United States)

Connell, J. R.; Morris, V. R.

1989-09-01

Six turbulent wind time series, measured at equally spaced equator-height locations on a circle 3 m outside a 34-m Darrieus rotor, are analyzed to approximate the wind fluctuations experienced by the rotor. The flatwise lower root-bending stress of one blade was concurrently recorded. The wind data are analyzed in three ways: wind components that are radial and tangential to the rotation of a blade were rotationally sampled; induction and wake effects of the rotor were estimated from the six Eulerian time series; and turbulence spectra of both the measured wind and the modeled wind from the PNL theory of rotationally sampled turbulence. The wind and the rotor response are related by computing the spectral response function of the flatwise lower root-bending stress. Two bands of resonant response that surround the first and second flatwise modal frequencies shift with the rotor rotation rate.

Electrical motor/generator drive apparatus and method

Science.gov (United States)

Su, Gui Jia

2013-02-12

The present disclosure includes electrical motor/generator drive systems and methods that significantly reduce inverter direct-current (DC) bus ripple currents and thus the volume and cost of a capacitor. The drive methodology is based on a segmented drive system that does not add switches or passive components but involves reconfiguring inverter switches and motor stator winding connections in a way that allows the formation of multiple, independent drive units and the use of simple alternated switching and optimized Pulse Width Modulation (PWM) schemes to eliminate or significantly reduce the capacitor ripple current.

A new two-phase homopolar switched reluctance motor for electric vehicle applications

Science.gov (United States)

Tsai, Mi-Ching; Huang, Chien-Chin; Huang, Zheng-Yi

2003-12-01

This paper presents a novel 2-phase homopolar switched reluctance motor (SRM), whose design successfully avoids dead-zone problems that afflict low cost 1- and/or 2-phase SRMs. Unlike conventional radial-winding-radial-gap motors, the proposed SRM has an interior stator that is of the pancake type with axial winding. Such a design allows for a high slot-fill factor and is suitable for implementation as a flat pancake-shaped stator. An efficient, compact prototype was produced with TMS320F240 DSP driving control unit. Experimental results indicate that the present SRM design has the potential to be used for electric bicycles and scooters.

Cycle kinetics, steady state thermodynamics and motors-a paradigm for living matter physics

International Nuclear Information System (INIS)

Qian, Hong

2005-01-01

An integration of the stochastic mathematical models for motor proteins with Hill's steady state thermodynamics yields a rather comprehensive theory for molecular motors as open systems in the nonequilibrium steady state. This theory, a natural extension of Gibbs' approach to isothermal molecular systems in equilibrium, is compared with other existing theories with dissipative structures and dynamics. The theory of molecular motors might be considered as an archetype for studying more complex open biological systems such as biochemical reaction networks inside living cells

Using Video Game Telemetry Data to Research Motor Chunking, Action Latencies, and Complex Cognitive-Motor Skill Learning.

Science.gov (United States)

Thompson, Joseph J; McColeman, C M; Stepanova, Ekaterina R; Blair, Mark R

2017-04-01

Many theories of complex cognitive-motor skill learning are built on the notion that basic cognitive processes group actions into easy-to-perform sequences. The present work examines predictions derived from laboratory-based studies of motor chunking and motor preparation using data collected from the real-time strategy video game StarCraft 2. We examined 996,163 action sequences in the telemetry data of 3,317 players across seven levels of skill. As predicted, the latency to the first action (thought to be the beginning of a chunked sequence) is delayed relative to the other actions in the group. Other predictions, inspired by the memory drum theory of Henry and Rogers, received only weak support. Copyright © 2017 Cognitive Science Society, Inc.

THE ROLE OF DYNAMIC SYSTEMS IN MOTOR DEVELOPMENT RESEARCH. JUST A METAPHOR OR A NOTABLE REALITY?

OpenAIRE

Ivan Šerbetar

2015-01-01

In the present article an application of a new theory of motor control in the context of motor development theories and research has been discussed. In a brief overview of traditional theories of motor development a neuro-maturational theory is mentioned along with the two prominent proponents - McGraw & Gesell. Bernstein’s fundamental insights in motor control were emphasized, such as the concepts of degrees of freedom and synergies, along with his contribution to the measurement technology ...

Transformers and motors

CERN Document Server

Shultz, George

1991-01-01

Transformers and Motors is an in-depth technical reference which was originally written for the National Joint Apprenticeship Training Committee to train apprentice and journeymen electricians. This book provides detailed information for equipment installation and covers equipment maintenance and repair. The book also includes troubleshooting and replacement guidelines, and it contains a minimum of theory and math.In this easy-to-understand, practical sourcebook, you'll discover:* Explanations of the fundamental concepts of transformers and motors* Transformer connections and d

Modeling of wind turbines with doubly fed generator system

CERN Document Server

Fortmann, Jens

2014-01-01

Jens Fortmann describes the deduction of models for the grid integration of variable speed wind turbines and the reactive power control design of wind plants. The modeling part is intended as background to understand the theory, capabilities and limitations of the generic doubly fed generator and full converter wind turbine models described in the IEC 61400-27-1 and as 2nd generation WECC models that are used as standard library models of wind turbines for grid simulation software. Focus of the reactive power control part is a deduction of the origin and theory behind the reactive current requ

Wind energy conversion. Volume II. Aerodynamics of horizontal axis wind turbines

Energy Technology Data Exchange (ETDEWEB)

Miller, R.H.; Dugundji, J.; Martinez-Sanchez, M.; Gohard, J.; Chung, S.; Humes, T.

1978-09-01

The basic aerodynamic theory of the wind turbine is presented, starting with the simple momentum theory based on uniform inflow and an infinite number of blades. The basic vortex theory is then developed. Following these basics, the more complete momentum theory, including swirl, non-uniform inflow, the effect of a finite number of blades, and empirical correction for the vortex ring condition is presented. The more complete vortex theory is presented which includes unsteady aerodynamic effects but based on a semi-rigid wake. Methods of applying this theory for performance estimation are discussed as well as for the purpose of computing time varying airloads due to windshear and tower interference.

Limitations and Constraints of Eddy-Current Loss Models for Interior Permanent-Magnet Motors with Fractional-Slot Concentrated Windings

Directory of Open Access Journals (Sweden)

Hui Zhang

2017-03-01

Full Text Available This paper analyzes and compares models for predicting average magnet losses in interior permanent-magnet motors with fractional-slot concentrated windings due to harmonics in the armature reaction (assuming sinusoidal phase currents. Particularly, loss models adopting different formulations and solutions to the Helmholtz equation to solve for the eddy currents are compared to a simpler model relying on an assumed eddy-current distribution. Boundaries in terms of magnet dimensions and angular frequency are identified (numerically and using an identified approximate analytical expression to aid the machine designer whether the more simple loss model is applicable or not. The assumption of a uniform flux-density variation (used in the loss models is also investigated for the case of V-shaped and straight interior permanent magnets. Finally, predicted volumetric loss densities are exemplified for combinations of slot and pole numbers common in automotive applications.

Wind: French revolutions

International Nuclear Information System (INIS)

Jones, C.

2006-01-01

Despite having the second best wind resources in Europe after the UK, the wind industry in France lags behind its European counterparts with just 6 W of installed wind capacity per person. The electricity market in France is dominated by the state-owned Electricite de France (EdF) and its nuclear power stations. However, smaller renewable generators are now in theory allowed access to the market and France has transposed the EU renewables directive into national law. The French governement has set a target of generating 10,000 MW of renewable capacity by 2010. The announcement of an increased feed-in tariff and the introduction of 'development zones' (ZDEs) which could allow fast-tracking of planning for wind projects are also expected to boost wind projects. But grid access and adminstrative burdens remain major barriers. In addition, French politicians and local authorities remain committed to nuclear, though encouraged by the European Commission, wind is beginning to gain acceptance; some 325 wind farms (representing 1557 MW of capacity) were approved between February 2004 and January 2005. France is now regarded by the international wind energy sector as a target market. One of France's leading independent wind developers and its only listed wind company, Theolia, is expected to be one of the major beneficiaries of the acceleration of activity in France, though other companies are keen to maximise the opportunities for wind. France currently has only one indigenous manufacturer of wind turbines, but foreign suppliers are winning orders

2D analytical modeling of a wholly superconducting synchronous reluctance motor

International Nuclear Information System (INIS)

Male, G; Lubin, T; Mezani, S; Leveque, J

2011-01-01

An analytical computation of the magnetic field distribution in a wholly superconducting synchronous reluctance motor is proposed. The stator of the studied motor consists of three-phase HTS armature windings fed by AC currents. The rotor is made with HTS bulks which have a nearly diamagnetic behavior under zero field cooling. The electromagnetic torque is obtained by the interaction between the rotating magnetic field created by the HTS windings and the HTS bulks. The proposed analytical model is based on the resolution of Laplace's and Poisson's equations (by the separation-of-variables technique) for each sub-domain, i.e. stator windings, air-gap, holes between HTS bulks and exterior iron shield. For the study, the HTS bulks are considered as perfect diamagnetic materials. The boundary and continuity conditions between the sub-domains yield to the global solution. Magnetic field distributions and electromagnetic torque obtained by the analytical method are compared with those obtained from finite element analyses.

2D analytical modeling of a wholly superconducting synchronous reluctance motor

Energy Technology Data Exchange (ETDEWEB)

Male, G; Lubin, T; Mezani, S; Leveque, J, E-mail: gael.male@green.uhp-nancy.fr [Groupe de Recherche en Electrotechnique et Electronique de Nancy, Universite Henri Poincare, Faculte des Sciences et Technologies BP 70239, 54506 Vandoeuvre les Nancy CEDEX (France)

2011-03-15

An analytical computation of the magnetic field distribution in a wholly superconducting synchronous reluctance motor is proposed. The stator of the studied motor consists of three-phase HTS armature windings fed by AC currents. The rotor is made with HTS bulks which have a nearly diamagnetic behavior under zero field cooling. The electromagnetic torque is obtained by the interaction between the rotating magnetic field created by the HTS windings and the HTS bulks. The proposed analytical model is based on the resolution of Laplace's and Poisson's equations (by the separation-of-variables technique) for each sub-domain, i.e. stator windings, air-gap, holes between HTS bulks and exterior iron shield. For the study, the HTS bulks are considered as perfect diamagnetic materials. The boundary and continuity conditions between the sub-domains yield to the global solution. Magnetic field distributions and electromagnetic torque obtained by the analytical method are compared with those obtained from finite element analyses.

Wind tunnel experiments to prove a hydraulic passive rotor speed control concept for variable speed wind turbines (poster)

NARCIS (Netherlands)

Diepeveen, N.F.B.; Jarquin Laguna, A.

2012-01-01

As alternative to geared and direct drive solutions, fluid power drive trains are being developed by several institutions around the world. The common configuration is where the wind turbine rotor is coupled to a hydraulic pump. The pump is connected through a high pressure line to a hydraulic motor

Robust Parameter and Signal Estimation in Induction Motors

DEFF Research Database (Denmark)

Børsting, H.

This thesis deals with theories and methods for robust parameter and signal estimation in induction motors. The project originates in industrial interests concerning sensor-less control of electrical drives. During the work, some general problems concerning estimation of signals and parameters...... in nonlinear systems, have been exposed. The main objectives of this project are: - analysis and application of theories and methods for robust estimation of parameters in a model structure, obtained from knowledge of the physics of the induction motor. - analysis and application of theories and methods...... for robust estimation of the rotor speed and driving torque of the induction motor based only on measurements of stator voltages and currents. Only contimuous-time models have been used, which means that physical related signals and parameters are estimated directly and not indirectly by some discrete...

Development of helium transfer coupling of 1 MW-class HTS motor for podded ship propulsion system

Energy Technology Data Exchange (ETDEWEB)

Kosuge, Eiji; Gocho, Yoshitsugu; Okumura, Kagao; Yamaguchi, Mitsugi [JapaneseSuperconductivity Organization, 135-8533, Tokyo (Japan); Umemoto, Katsuya; Aizawa, Kiyoshi; Yokoyama, Minoru; Takao, Satoru, E-mail: gocho@jso--new-scm.co.j [Kawasaki Heavy Industries LTD., 673-8666, Hyogo (Japan)

2010-06-01

Research and development of 1 MW superconducting motor are being made aiming at the efficiency improvement for the podded type ship propulsion. The basic machine configuration is similar to steam turbine generators, having a rotating horizontal shaft. As for the motor composed of rotating superconducting field, one of the most critical issues is to provide a technically viable helium transfer coupling (HTC). The field winding of 1 MW motor is cooled with cryogenic helium gas. The HTC needs to supply the cryogenic helium gas with an appropriate flow rate from the stationary part to the rotating field winding region through a hollowed shaft in order not to lose superconducting state of the winding. A full size prototype of HTC was developed prior to the actual one to demonstrate its technical acceptability. The fundamental data with regard to the supply of the refrigerated helium gas were successfully obtained at the rated speed. This work has been supported by New Energy, and Industrial Technology Development Organization (NEDO).

Introduction to wind turbine aerodynamics

CERN Document Server

Schaffarczyk, Alois Peter

2014-01-01

Wind-Turbine Aerodynamics is a self-contained textbook which shows how to come from the basics of fluid mechanics to modern wind turbine blade design. It presents a fundamentals of fluid dynamics and inflow conditions, and gives a extensive introduction into theories describing the aerodynamics of wind turbines. After introducing experiments the book applies the knowledge to explore the impact on blade design.The book is an introduction for professionals and students of very varying levels.

Evaluation of Wall Interference Effects in a Two-Dimensional Transonic Wind Tunnel by Subsonic Linear Theory,

Science.gov (United States)

1979-02-01

tests were conducted on two geometrica lly similar models of each of two aerofoil sections -—t he NA CA 00/ 2 and the BGK- 1 sections -and covered a...and slotted-wall tes t sections are corrected for wind tunnel wall interference efJ~cts by the application of classical linearized theory. For the...solid wall results , these corrections appear to produce data which are very close to being free of the effects of interference. In the case of

Motion makes sense: an adaptive motor-sensory strategy underlies the perception of object location in rats.

Science.gov (United States)

Saraf-Sinik, Inbar; Assa, Eldad; Ahissar, Ehud

2015-06-10

Tactile perception is obtained by coordinated motor-sensory processes. We studied the processes underlying the perception of object location in freely moving rats. We trained rats to identify the relative location of two vertical poles placed in front of them and measured at high resolution the motor and sensory variables (19 and 2 variables, respectively) associated with this whiskers-based perceptual process. We found that the rats developed stereotypic head and whisker movements to solve this task, in a manner that can be described by several distinct behavioral phases. During two of these phases, the rats' whiskers coded object position by first temporal and then angular coding schemes. We then introduced wind (in two opposite directions) and remeasured their perceptual performance and motor-sensory variables. Our rats continued to perceive object location in a consistent manner under wind perturbations while maintaining all behavioral phases and relatively constant sensory coding. Constant sensory coding was achieved by keeping one group of motor variables (the "controlled variables") constant, despite the perturbing wind, at the cost of strongly modulating another group of motor variables (the "modulated variables"). The controlled variables included coding-relevant variables, such as head azimuth and whisker velocity. These results indicate that consistent perception of location in the rat is obtained actively, via a selective control of perception-relevant motor variables. Copyright © 2015 the authors 0270-6474/15/358777-13$15.00/0.

Diode Laser Assisted Filament Winding of Thermoplastic Matrix Composites

Directory of Open Access Journals (Sweden)

Claudia Prosperi

2010-01-01

Full Text Available A new consolidation method for the laser-assisted filament winding of thermoplastic prepregs is discussed: for the first time a diode laser is used, as well as long glass fiber reinforced polypropylene prepregs. A consolidation apparatus was built by means of a CNC motion table, a stepper motor and a simple tensioner. Preliminary tests were performed in a hoop winding configuration: only the winding speed was changed, and all the other process parameters (laser power, distance from the laser focus, consolidation force were kept constant. Small wound rings with an internal diameter of 25 mm were produced and compression tests were carried out to evaluate the composite agglomeration in dependence of the winding speed. At lower winding speeds, a stronginterpenetration of adjacent layers was observed.

Galactic Winds Driven by Supernovae and Radiation Pressure: Theory and Simulations

Science.gov (United States)

Zhang, Dong; Davis, Shane

2018-01-01

Galactic winds are ubiquitous in most rapidly star-forming galaxies. They are crucial to the process of galaxy formation and evolution, regulating star formation, shaping the stellar mass function and the mass-metallicity relation, and enriching the intergalactic medium with metals. Although important, the physics of galactic winds is still unclear. Winds may be driven by many mechanisms including overlapping supernovae explosions, radiation pressure of starlight on dust grains, and cosmic rays. However, the growing observations of multiphase structure in galactic winds in a large number of galaxies have not been well explained by any models. In this talk I will focus on the models of supernova- and radiation-pressure-driven winds. Using the state-of-the-art numerical simulations, I will assess the relative merits of these driving mechanisms for accelerating cold and warm clouds to observed velocities, and momentum flux boost during wind propagation.

On-line diagnosis of inter-turn short circuit fault for DC brushed motor.

Science.gov (United States)

Zhang, Jiayuan; Zhan, Wei; Ehsani, Mehrdad

2018-06-01

Extensive research effort has been made in fault diagnosis of motors and related components such as winding and ball bearing. In this paper, a new concept of inter-turn short circuit fault for DC brushed motors is proposed to include the short circuit ratio and short circuit resistance. A first-principle model is derived for motors with inter-turn short circuit fault. A statistical model based on Hidden Markov Model is developed for fault diagnosis purpose. This new method not only allows detection of motor winding short circuit fault, it can also provide estimation of the fault severity, as indicated by estimation of the short circuit ratio and the short circuit resistance. The estimated fault severity can be used for making appropriate decisions in response to the fault condition. The feasibility of the proposed methodology is studied for inter-turn short circuit of DC brushed motors using simulation in MATLAB/Simulink environment. In addition, it is shown that the proposed methodology is reliable with the presence of small random noise in the system parameters and measurement. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Rotor compound concept for designing an industrial HTS synchronous motor

International Nuclear Information System (INIS)

Kashani, M.; Hosseina, M.; Sarrafan, K.; Darabi, A.

2013-01-01

Highlights: • The superconducting tapes are used in the industrial synchronous motor winding due to their electrical characteristics. • The high magnetic field with no electric loss is obtainable by using the superconducting rotor coils. • The rotor core can be replaced by light non-magnetic materials which drops the rotor total weight up to 50%. • Decreasing the rotor weight was verified by FEM analyses for a sample motor. -- Abstract: Recently, producing power with smaller amount of losses become as a goal in our daily life. Today, large amount of energy waste in power networks all around the world. The main reason is “resistive electric equipments” of power networks. Since early 1980s, simultaneous with the development of high temperature superconductive (HTS) technology, superconductors gently attracted the mankind attentions. Using superconductive equipments instead of conventional resistive ones are result in salient electric loss reduction in power systems. Especially to reduce losses in power networks superconductive industrial rotating machines can potentially perform a significant role. In early recent century, first generation of HTS rotating machines was born. But unfortunately they have long way to penetrate the commercial markets yet. In HTS rotating machines the conventional copper made windings are replaced with the HTS superconductors. In this paper an industrial HTS synchronous motor with YBCO coated conductor field windings was designed. As a new approach, model was equipped with a compound rotor that includes both magnetic and non-magnetic materials. So, large amount of heavy iron made part was replaced by light non-magnetic material such as G-10 fiberglass. Furthermore, in this structure iron loss in rotor could be reduced to its lowest value. Also less weight and more air gap energy density were the additional advantages. Regarding zero electric loss production in field windings and less iron loss in rotor construction, this model

Wind pumps for agriculture: Cost and environmental benefits (comparisons with electric and combustion engine driven pumps)

International Nuclear Information System (INIS)

Piccoli, F.

1991-01-01

After describing initial and running costs of a group of wind-pumps, the author calculates and compares, as far as agricultural and zootechnical purposes are concerned, the costs for each cubic meter of water extracted through wind-powered, electric and internal-combustion engines. The comparisons clearly show, under adequate wind conditions, that wind-pumps are economically more suitable than electric and motor pumps with similar delivery heads

Voltage control of a variable speed wind turbine connected to an isolated load: Experimental study

International Nuclear Information System (INIS)

Masmoudi, Abdelkarim; Krichen, Lotfi; Ouali, Abderrazak

2012-01-01

Highlights: ► We develop an experimental test bench of a wind energy conversion system. ► A DC motor is emulating a variable speed wind turbine using a DS1104 card. ► The production unit is supplying a three-phase load. ► A voltage control is established in order to regulate the DC bus voltage and the line-to-line voltages. - Abstract: This study is interested in the development of an experimental test bench of an autonomous wind energy conversion system (WECS) based on a permanent magnet synchronous generator (PMSG). After the description of the test bench, the elements constituting the WECS are presented. Then, a real time model implemented under a digital signal processor (DSP) system is established. The first objective of this work is to validate the functionality of the test bench leading to experiment some principles developed in theory. The second objective is to control the load connection voltages and the DC bus voltage. For the first control, two resonant controllers are used and for the second one, a dump load, connected to the DC bus, offers the possibility to maintain a balance between production and consumption in spite of wind fluctuations and load variations. The experimental results show the effectiveness of the test bench trying out in real time the behavior of a WECS supplying an isolated load.

Spatial dependence in wind and optimal wind power allocation: A copula-based analysis

International Nuclear Information System (INIS)

Grothe, Oliver; Schnieders, Julius

2011-01-01

The investment decision on the placement of wind turbines is, neglecting legal formalities, mainly driven by the aim to maximize the expected annual energy production of single turbines. The result is a concentration of wind farms at locations with high average wind speed. While this strategy may be optimal for single investors maximizing their own return on investment, the resulting overall allocation of wind turbines may be unfavorable for energy suppliers and the economy because of large fluctuations in the overall wind power output. This paper investigates to what extent optimal allocation of wind farms in Germany can reduce these fluctuations. We analyze stochastic dependencies of wind speed for a large data set of German on- and offshore weather stations and find that these dependencies turn out to be highly nonlinear but constant over time. Using copula theory we determine the value at risk of energy production for given allocation sets of wind farms and derive optimal allocation plans. We find that the optimized allocation of wind farms may substantially stabilize the overall wind energy supply on daily as well as hourly frequency. - Highlights: → Spatial modeling of wind forces in Germany. → A novel way to assess nonlinear dependencies of wind forces by copulas. → Wind turbine allocation by maximizing lower quantiles of energy production. → Optimal results show major increase in reliable part of wind energy.

Wall Correction Model for Wind Tunnels with Open Test Section

DEFF Research Database (Denmark)

Sørensen, Jens Nørkær; Shen, Wen Zhong; Mikkelsen, Robert Flemming

2004-01-01

, the corrections from the model are in very good agreement with the CFD computaions, demonstrating that one-dimensional momentum theory is a reliable way of predicting corrections for wall interference in wind tunnels with closed as well as open cross sections. Keywords: Wind tunnel correction, momentum theory...

Design optimization of brushed permanent magnet D C motor by genetic algorithm

CERN Document Server

Amini, S

2002-01-01

Because of field winding replacement with permanent magnet in brushed permanent magnet D C (PMDC) motors, field losses are eliminated and the structure of the motor is more simple. Efficiency of these motors is therefore increased and the manufacturing process is simplified. Hence, these motors are commonly used in low power applications and their design and optimization is an important consideration. Genetic algorithms are proposed for design optimization of PMD motors because of their independence to objective function structure and its derivative. In this paper genetic algorithms are evaluated for PMDC motor design optimization. an introduction is first presented about PMDC motors, general design procedure and elements of their optimization. Genetic algorithms are then briefly described. Finally results of optimization by genetic algorithms are compared with the one obtained using a conventional method.

Design optimization of brushed permanent magnet D C motor by genetic algorithm

International Nuclear Information System (INIS)

Amini, S.; Oraee, H.

2002-01-01

Because of field winding replacement with permanent magnet in brushed permanent magnet D C (PMDC) motors, field losses are eliminated and the structure of the motor is more simple. Efficiency of these motors is therefore increased and the manufacturing process is simplified. Hence, these motors are commonly used in low power applications and their design and optimization is an important consideration. Genetic algorithms are proposed for design optimization of PMD motors because of their independence to objective function structure and its derivative. In this paper genetic algorithms are evaluated for PMDC motor design optimization. an introduction is first presented about PMDC motors, general design procedure and elements of their optimization. Genetic algorithms are then briefly described. Finally results of optimization by genetic algorithms are compared with the one obtained using a conventional method

Condition monitoring of primary coolant pump-motor units of Indian PHWR

International Nuclear Information System (INIS)

Rshikesan, P.B.; Sharma, S.S.; Mhetre, S.G.

1994-01-01

As the primary coolant pump motor units are located in shut down accessible area, their start up, satisfactory operation and shut down are monitored from control room. As unavailability of one pump in standardised 220 MWe station reduces the station power to about 110 MWe, satisfactory operation of the pump is also important from economic considerations. All the critical parameters of pump shaft, mechanical seal, bearing system, motor winding and shaft displacement (vibrations) are monitored/recorded to ensure satisfactory operation of critical, capital intensive pump-motor units. (author). 2 tabs., 1 fig

The science of making more torque from wind: Diffuser experiments and theory revisited

International Nuclear Information System (INIS)

Bussel, Gerard J W van

2007-01-01

History of the development of DAWT's stretches a period of more than 50 years. So far without any commercial success. In the initial years of development the conversion process was not understood very well. Experimentalists strived at maximising the pressure drop over the rotor disk, but lacked theoretical insight into optimising the performance. Increasing the diffuser area as well as the negative back pressure at the diffuser exit was found profitable in the experiments. Claims were made that performance augmentations with a factor of 4 or more were feasible, but these claims were not confirmed experimentally. With a simple momentum theory, developed along the lines of momentum theory for bare windturbines, it was shown that power augmentation is proportional to the mass flow increase generated at the nozzle of the DAWT. Such mass flow augmentation can be achieved through two basic principles: increase in the diffuser exit ratio and/or by decreasing the negative back pressure at the exit. The theory predicts an optimal pressure drop of 8/9 equal to the pressure drop for bare windturbines independent from the mass flow augmentation obtained. The maximum amount of energy that can be extracted per unit of volume with a DAWT is also the same as for a bare wind turbine. Performance predictions with this theory show good agreement with a CFD calculation. Comparison with a large amount of experimental data found in literature shows that in practice power augmentation factors above 3 have never been achieved. Referred to rotor power coefficients values of C P,rotort = 2.5 might be achievable according to theory, but to the cost of fairly large diffuser area ratio's, typically values of β>4.5

Dynamic model of cage induction motor with number of rotor bars as parameter

Directory of Open Access Journals (Sweden)

Gojko Joksimović

2017-05-01

Full Text Available A dynamic mathematical model, using number of rotor bars as parameter, is reached for cage induction motors through the use of coupled-circuits and the concept of winding functions. The exact MMFs waveforms are accounted for by the model which is derived in natural frames of reference. By knowing the initial motor parameters for a priori adopted number of stator slots and rotor bars model allows change of rotor bars number what results in new model parameters. During this process, the rated machine power, number of stator slots and stator winding scheme remain the same. Although presented model has a potentially broad application area it is primarily suitable for the analysis of the different stator/rotor slot combination on motor behaviour during the transients or in steady-state regime. The model is significant in its potential to provide analysis of dozen of different number of rotor bars in a few tens of minutes. Numerical example on cage rotor induction motor exemplifies this application, including three variants of number of rotor bars.

Motor Skill Learning in Children.

Science.gov (United States)

Gabbard, Carl P.

The purpose of this article is to briefly describe schema theory and indicate its relevance to early childhood development, with specific reference to children's acquisition of motor skills. Schema theory proposes an explanation of how individuals learn and perform a seemingly endless variety of movements. According to Schmidt (1975), goal…

Aerodynamics of Wind Turbines

DEFF Research Database (Denmark)

Hansen, Martin Otto Laver

Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its second edition, it has been entirely updated and substantially extended to reflect advances in technology, research into rotor aerodynamics and the structural...... response of the wind turbine structure. Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element...... Momentum method is also covered, as are eigenmodes and the dynamic behavior of a turbine. The new material includes a description of the effects of the dynamics and how this can be modeled in an aeroelastic code, which is widely used in the design and verification of modern wind turbines. Further...

Thermal analysis simulation for a spin-motor used in the advanced main combustion chamber vacuum plasma spray project using the SINDA computer program

Science.gov (United States)

Mcdonald, Gary H.

1990-01-01

One of the many design challenges of this project is predicting the thermal effects due to the environment inside the vacuum chamber on the turntable and spin motor spindle assembly. The objective of the study is to model the spin motor using the computer program System Improved Numerical Differencing Analyzer (SINDA). By formulating the appropriate input information concerning the motor's geometry, coolant flow path, material composition, and bearing and motor winding characteristics, SINDA should predict temperatures at various predefined nodes. From these temperatures, hopefully, one can predict if the coolant flow rate is sufficient or if certain mechanical elements such as bearings, O ring seals, or motor windings will exceed maximum design temperatures.

Concepts for using trapped-flux bulk high-temperature superconductor in motors and generators

International Nuclear Information System (INIS)

Hull, John R; Strasik, Michael

2010-01-01

We review previous concepts for using bulk high-temperature superconductors (HTSs) in motors and generators and discuss methods for using trapped-flux (TF) HTSs in motors and generators that have been recently investigated in our laboratory. We examine the expected performance of a brushless motor/generator that uses TF bulk HTSs to provide magnetomotive force, where the stator windings are used to create the TF. A key feature is the use of dysprosium for the stator and rotor cores.

Gauge transformations with fractional winding numbers

International Nuclear Information System (INIS)

Abouelsaood, A.

1996-01-01

The role which gauge transformations of noninteger winding numbers might play in non-Abelian gauge theories is studied. The phase factor acquired by the semiclassical physical states in an arbitrary background gauge field when they undergo a gauge transformation of an arbitrary real winding number is calculated in the path integral formalism assuming that a θFF term added to the Lagrangian plays the same role as in the case of integer winding numbers. Requiring that these states provide a representation of the group of open-quote open-quote large close-quote close-quote gauge transformations, a condition on the allowed backgrounds is obtained. It is shown that this representability condition is only satisfied in the monopole sector of a spontaneously broken gauge theory, but not in the vacuum sector of an unbroken or a spontaneously broken non-Abelian gauge theory. It is further shown that the recent proof of the vanishing of the θ parameter when gauge transformations of arbitrary fractional winding numbers are allowed breaks down in precisely those cases where the representability condition is obeyed because certain gauge transformations needed for the proof, and whose existence is assumed, are either spontaneously broken or cannot be globally defined as a result of a topological obstruction. copyright 1996 The American Physical Society

NRC Information No. 88-12: Overgreasing of electric motor bearings

International Nuclear Information System (INIS)

Rossi, C.E.

1992-01-01

NRC personnel observed accumulations of grease on the air vent screens of electric motors used for driving such rotating equipment as fans and pumps at the Millstone and Calvert Cliffs nuclear power plants. The grease appeared to have come from overgreasing of the electric motor bearings. Grease was forced out of the bearing seals, onto the stator windings and rotor, from where it either fell or was thrown onto the inside of the motor housing. Because of these observations, the NRC began an investigation into problems that have been caused in the past, or could be caused in the future, by the overgreasing of electric motor bearings. The NRC staff has solicited technical information and operating experience on the problems caused by the overgreasing of electric motor bearings from motor and bearing manufacturers, as well as from other licensees. Their responses are summarized in this discussion

Evolution of Motor Control: From Reflexes and Motor Programs to the Equilibrium-Point Hypothesis.

Science.gov (United States)

Latash, Mark L

2008-01-01

This brief review analyzes the evolution of motor control theories along two lines that emphasize active (motor programs) and reactive (reflexes) features of voluntary movements. It suggests that the only contemporary hypothesis that integrates both approaches in a fruitful way is the equilibrium-point hypothesis. Physical, physiological, and behavioral foundations of the EP-hypothesis are considered as well as relations between the EP-hypothesis and the recent developments of the notion of motor synergies. The paper ends with a brief review of the criticisms of the EP-hypothesis and challenges that the hypothesis faces at this time.

Design of motors for inverter operation

Energy Technology Data Exchange (ETDEWEB)

Haring, T. [ABB Motors OY, Vaasa (Finland)

2000-07-01

This paper describes very practical principles of how an induction motor should be designed for converter application. The main focus targets the efficiency of the motor and drive. The results presented are based on actual test motors and FEM-calculation simulations. FEM-calculation together with a time-stepping function is a powerful tool for estimating magnetic flux densities, iron losses, current densities and corresponding losses in windings, in other words a tool for optimisation of the motor design. Time-stepping is rather time consuming because all the circuit equations must be solved for each time-step, but it provides a way to estimate the iron losses; hysteresis and eddy current losses as well as current distribution and current losses. The calculation tool also provides the possibility to check if an existing motor is feasible for a converter drive. Alternatively if a motor is only to be supplied by a converter there are many more degrees of freedom in the electrical design and the motor may be optimised for that converter drive by incorporationg rather simple design changes. Additionally a design compromise, ''a general purpose motor'' useable for DOL and feasible for converter drive can be produced following the principles presented herewith. The converter types which are considered are indirect types and mainly voltage source converters since they are the most common on the market and are ''general purpose converters'' and providing a certain freedom to select the motor for the drive. Current source converters require ''matching'' with the motor and therefore need a precise knowledge of the motor equivalent circuit, making the selection of the motor more complicated. (orig.)

Electric drive motors for industrial robots

Science.gov (United States)

Fichtner, K.

1985-04-01

In robotized industrial plants it is possible to use electric motors in the technological process and also for control, assembly, transport, testing, and measurements. Particularly suitable for these applications are permanent-magnet d.c. motors. A new special series was developed for industrial robots with hinge joints in kinematic pairs. The complete drive includes thyristors or transistor controls with regulators and, if necessary, a line transformer as well as a servomotor with tachometer and odometer for speed, current, and position control. The drive is coupled to a robot tong through mechanical torque and force converters. In addition to a 0 to 4000 rpm speed regulation, without wobble at low speeds, and a high torque-to-weight ratio for repetitive short-time heavy duty, these low-inertia motors develop high starting and accelerating torques over the entire speed range. They operate from a 1 to O 220 V a.c. line through a rectifier. The motors are totally enclosed, or of open construction for better ventilation. Their windings have class F insulation for operation at ambient temperatures up to 40 C.

Wind power

Energy Technology Data Exchange (ETDEWEB)

1979-01-01

This publication describes some of the technical, economic, safety and institutional considerations involved in the selection, installation and evaluation of a wind generation system. This information is presented, where possible, in practical, non-technical terms. The first four sections provide background information, theory, and general knowledge, while the remaining six sections are of a more specific nature to assist the prospective owner of a wind generator in his calculations and selections. Meteorological information is provided relating to the wind regime in Nova Scotia. The section on cost analysis discusses some of the factors and considerations which must be examined in order to provide a logical comparison between the alternatives of electricity produced from other sources. The final two sections are brief summaries of the regulations and hazards pertaining to the use of wind generators. The cost of wind-generated electricity is high compared to present Nova Scotia Power Corporation rates, even on Sable Island, Nova Scotia's highest wind area. However, it may be observed that Sable Island is one of the areas of Nova Scotia which is not presently supplied through the power grid and, particularly if there was a significant increase in the price of diesel oil, wind-generated electricity may well be the most economical alternative in that area. Generally speaking, however, where a consumer can purchase electricity at the normal domestic rate, wind generators are not economical, and they will not become economical unless there is a great reduction in their cost, an great increase in electricity rates, or both. Includes glossary. 23 figs., 11 tabs.

Motor planning flexibly optimizes performance under uncertainty about task goals.

Science.gov (United States)

Wong, Aaron L; Haith, Adrian M

2017-03-03

In an environment full of potential goals, how does the brain determine which movement to execute? Existing theories posit that the motor system prepares for all potential goals by generating several motor plans in parallel. One major line of evidence for such theories is that presenting two competing goals often results in a movement intermediate between them. These intermediate movements are thought to reflect an unintentional averaging of the competing plans. However, normative theories suggest instead that intermediate movements might actually be deliberate, generated because they improve task performance over a random guessing strategy. To test this hypothesis, we vary the benefit of making an intermediate movement by changing movement speed. We find that participants generate intermediate movements only at (slower) speeds where they measurably improve performance. Our findings support the normative view that the motor system selects only a single, flexible motor plan, optimized for uncertain goals.

A Bearingless Switched-Reluctance Motor for High Specific Power Applications

Science.gov (United States)

Choi, Benjamin B.; Siebert, Mark

2006-01-01

A 12-8 switched-reluctance motor (SRM) is studied in bearingless (or self-levitated) operation with coil currents limited to the linear region to avoid magnetic saturation. The required motoring and levitating currents are summed and go into a single motor coil per pole to obtain the highest power output of the motor by having more space for motor coil winding. Two controllers are investigated for the bearingless SRM operation. First, a model-based controller using the radial force, which is adjusted by a factor derived from finite element analysis, is presented. Then a simple and practical observation-based controller using a PD (proportional-derivative) control algorithm is presented. Both controllers were experimentally demonstrated to 6500 rpm. This paper reports the initial efforts toward eventual self levitation of a SRM operating into strong magnetic core saturation at liquid nitrogen temperature.

Winding numbers in homotopy theory from integers to reals

International Nuclear Information System (INIS)

Mekhfi, M.

1993-07-01

In Homotopy Theory (HT) we define paths on a given topological space. Closed paths prove to be construction elements of a group (the fundamental group) Π 1 and carry charges, the winding numbers. The charges are integers as they indicate how many times closed paths encircle a given hole (or set of holes). Open paths as they are defined in (HT) do not possess any groups structure and as such they are less useful in topology. In the present paper we enlarge the concept of a path in such a way that both types of paths do possess a group structure. In this broad sense we have two fundamental groups the Π i = Z group and the SO(2) group of rotations but the latter has the global property that there is no periodicity in the rotation angle. There is also two charge operators W and W λ whose eigenvalues are either integers or reals depending respectively on the paths being closed or open. Also the SO(2) group and the real charge operator W λ are not independently defined but directly related respectively to the Π i group and to the integer charge operator W. Thus well defined links can be established between seemingly different groups and charges. (author). 3 refs, 1 fig

Solar wind proton temperature anisotropy: Linear theory and WIND/SWE observations

Czech Academy of Sciences Publication Activity Database

Hellinger, Petr; Trávníček, Pavel; Kasper, J. C.; Lazarus, A. J.

2006-01-01

Roč. 33, č. 9 (2006), L09101/1-L09101/4 ISSN 0094-8276 R&D Projects: GA AV ČR(CZ) IAA3042403 Grant - others:ESA(XE) PECS 98024; NASA (US) NAG-10915 Institutional research plan: CEZ:AV0Z30420517 Keywords : proton temperature anisotropy * solar wind * in situ observations Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 2.602, year: 2006

A simple theory of motor protein kinetics and energetics. II.

Science.gov (United States)

Qian, H

2000-01-10

A three-state stochastic model of motor protein [Qian, Biophys. Chem. 67 (1997) pp. 263-267] is further developed to illustrate the relationship between the external load on an individual motor protein in aqueous solution with various ATP concentrations and its steady-state velocity. A wide variety of dynamic motor behavior are obtained from this simple model. For the particular case of free-load translocation being the most unfavorable step within the hydrolysis cycle, the load-velocity curve is quasi-linear, V/Vmax = (cF/Fmax-c)/(1-c), in contrast to the hyperbolic relationship proposed by A.V. Hill for macroscopic muscle. Significant deviation from the linearity is expected when the velocity is less than 10% of its maximal (free-load) value--a situation under which the processivity of motor diminishes and experimental observations are less certain. We then investigate the dependence of load-velocity curve on ATP (ADP) concentration. It is shown that the free load Vmax exhibits a Michaelis-Menten like behavior, and the isometric Fmax increases linearly with ln([ATP]/[ADP]). However, the quasi-linear region is independent of the ATP concentration, yielding an apparently ATP-independent maximal force below the true isometric force. Finally, the heat production as a function of ATP concentration and external load are calculated. In simple terms and solved with elementary algebra, the present model provides an integrated picture of biochemical kinetics and mechanical energetics of motor proteins.

Resonant inverter supplied Interior Permanent Magnet (IPM) motor ...

African Journals Online (AJOL)

In this paper, rotor position in relation to the resonant frequency component current in the stator winding of DC-voltage link resonant inverter supplied Interior Permanent Magnet (IPM) motor has been developed. Six reference frames are used to relate the rotor position angle to the resonant frequency component current ...

Evolution of Motor Control: From Reflexes and Motor Programs to the Equilibrium-Point Hypothesis

OpenAIRE

Latash, Mark L.

2008-01-01

This brief review analyzes the evolution of motor control theories along two lines that emphasize active (motor programs) and reactive (reflexes) features of voluntary movements. It suggests that the only contemporary hypothesis that integrates both approaches in a fruitful way is the equilibrium-point hypothesis. Physical, physiological, and behavioral foundations of the EP-hypothesis are considered as well as relations between the EP-hypothesis and the recent developments of the notion of m...

Optimizing performance through intrinsic motivation and attention for learning: The OPTIMAL theory of motor learning.

Science.gov (United States)

Wulf, Gabriele; Lewthwaite, Rebecca

2016-10-01

Effective motor performance is important for surviving and thriving, and skilled movement is critical in many activities. Much theorizing over the past few decades has focused on how certain practice conditions affect the processing of task-related information to affect learning. Yet, existing theoretical perspectives do not accommodate significant recent lines of evidence demonstrating motivational and attentional effects on performance and learning. These include research on (a) conditions that enhance expectancies for future performance, (b) variables that influence learners' autonomy, and (c) an external focus of attention on the intended movement effect. We propose the OPTIMAL (Optimizing Performance through Intrinsic Motivation and Attention for Learning) theory of motor learning. We suggest that motivational and attentional factors contribute to performance and learning by strengthening the coupling of goals to actions. We provide explanations for the performance and learning advantages of these variables on psychological and neuroscientific grounds. We describe a plausible mechanism for expectancy effects rooted in responses of dopamine to the anticipation of positive experience and temporally associated with skill practice. Learner autonomy acts perhaps largely through an enhanced expectancy pathway. Furthermore, we consider the influence of an external focus for the establishment of efficient functional connections across brain networks that subserve skilled movement. We speculate that enhanced expectancies and an external focus propel performers' cognitive and motor systems in productive "forward" directions and prevent "backsliding" into self- and non-task focused states. Expected success presumably breeds further success and helps consolidate memories. We discuss practical implications and future research directions.

A thermal and electrical dynamic mathematical model for squirrel cage induction motors; Modelamento matematico dinamico termico e eletrico de motores de inducao

Energy Technology Data Exchange (ETDEWEB)

Sousa, Ronaldo Martins de

1996-01-01

A thermal and electrical dynamic mathematical model for squirrel cage induction motors is presented. The electrical model is described by Park equation and the torque equation, while the thermal model is described by a system of four first order differential equations that represent the motor heat transfer process. The model presented can be used to determine thermal and electrical performance for any operation condition. However, it is suitable mainly for machines operating under continuously transient condition. The presented mathematical model also incorporate variation of rotor winding electrical parameters due to skin effect. (author)

A Breath of Fresh Air in Foraging Theory: The Importance of Wind for Food Size Selection in a Central-Place Forager.

Science.gov (United States)

Alma, Andrea Marina; Farji-Brener, Alejandro G; Elizalde, Luciana

2017-09-01

Empirical data about food size carried by central-place foragers do not often fit with the optimum predicted by classical foraging theory. Traditionally, biotic constraints such as predation risk and competition have been proposed to explain this inconsistency, leaving aside the possible role of abiotic factors. Here we documented how wind affects the load size of a central-place forager (leaf-cutting ants) through a mathematical model including the whole foraging process. The model showed that as wind speed at ground level increased from 0 to 2 km/h, load size decreased from 91 to 30 mm 2 , a prediction that agreed with empirical data from windy zones, highlighting the relevance of considering abiotic factors to predict foraging behavior. Furthermore, wind reduced the range of load sizes that workers should select to maintain a similar rate of food intake and decreased the foraging rate by ∼70% when wind speed increased 1 km/h. These results suggest that wind could reduce the fitness of colonies and limit the geographic distribution of leaf-cutting ants. The developed model offers a complementary explanation for why load size in central-place foragers may not fit theoretical predictions and could serve as a basis to study the effects of other abiotic factors that influence foraging.

An aerodynamic noise propagation model for wind turbines

DEFF Research Database (Denmark)

Zhu, Wei Jun; Sørensen, Jens Nørkær; Shen, Wen Zhong

2005-01-01

A model based on 2-D sound ray theory for aerodynamic noise propagation from wind turbine rotating blades is introduced. The model includes attenuation factors from geometric spreading, sound directivity of source, air absorption, ground deflection and reflection, as well as effects from temperat......A model based on 2-D sound ray theory for aerodynamic noise propagation from wind turbine rotating blades is introduced. The model includes attenuation factors from geometric spreading, sound directivity of source, air absorption, ground deflection and reflection, as well as effects from...... temperature and airflow. At a given receiver point, the sound pressure is corrected by taking into account these propagation effects. As an overall assumption, the noise field generated by the wind turbine is simplified as a point source placed at the hub height of the wind turbine. This assumtion...... is reasonable, for the receiver is located in the far field, at distances from the wind turbine that are much longer than the diameter of the rotor....

The motor system and its disorders

DEFF Research Database (Denmark)

Rowe, James B; Siebner, Hartwig R

2012-01-01

to study safely the processes of neuroplasticity, neural networks and neuropharmacology in stroke and movement disorders and offers a sensitive tool to assess novel therapeutics. In the reverse direction, imaging of clinical populations has promoted innovations in cognitive theory, experimental design...... on the understanding of diverse motor functions, including motor learning, decision making, inhibition and the mirror neuron system. In addition, we show how imaging of the motor system has supported a powerful platform for bidirectional translational neuroscience. In one direction, it has provided the opportunity...

Observer Based Estimation of Stator Winding Faults in Delta-connected Induction Motors, a LMI Approach

DEFF Research Database (Denmark)

Kallesøe, Carsten; Vadstrup, Pierre; Rasmussen, Henrik

2006-01-01

This paper addresses the subject of inter-turn short circuit estimation in the stator of an induction motor. In the paper an adaptive observer scheme is proposed. The proposed observer is capable of simultaneously estimating the speed of the motor, the amount turns involved in the short circuit...... and an expression of the current in the short circuit. Moreover the states of the motor are estimated, meaning that the magnetizing currents are made available even though a fault has happened in the motor. To be able to develop this observer, a model particular suitable for the chosen observer design, is also...... derived. The efficiency of the proposed observer is demonstrated by tests performed on a test setup with a customized designed induction motor. With this motor it is possible to simulate inter-turn short circuit faults....

CALCULATION OF INDUCTANCE OF THE INTERIOR PERMANENT MAGNET SYNCHRONOUS MOTOR

Directory of Open Access Journals (Sweden)

Phyong Le Ngo

2017-01-01

Full Text Available Interior permanent magnet synchronous motor (IPMSM refers to salient-pole synchronous motors, characterized by inequality of inductances of longitudinal (d and transverse (q axes. Electromagnetic torque of IPMSM consists of two components: active torque and reactive torque; the latter depends on inductances of d and q axes. An analytical method to calculate own inductances and mutual inductances of a three-phase IPMSM is presented. Distributed windings of the stator are substituted by equivalent sine distributed windings. An interior permanent magnets rotor is substituted by an equivalent salient-pole rotor. Sections of a magnetic circuit comprising interior permanent magnets, air barriers and steel bridges are substituted by equivalent air-gap. The expressions of the magnetic induction created by current of the stator windings at each point of the air gap as well as of magnetic flux linkage of the stator windings have been obtained. The equations of the self-inductances of phases A, B, C, and of inductance of mutual induction are determined from magnetic flux linkage. The inductance of the d and q axes have been obtained as a result of transformation of the axes abc–dq. The results obtained with the use of the proposed analytical method and the finite element method are presented in the form of a graph; the calculations that have been obtained by these two methods were compared. 

Study of the AC machines winding having fractional q

Science.gov (United States)

Bespalov, V. Y.; Sidorov, A. O.

2018-02-01

The winding schemes with a fractional numbers of slots per pole and phase q have been known and used for a long time. However, in the literature on the low-noise machines design there are not recommended to use. Nevertheless, fractional q windings have been realized in many applications of special AC electrical machines, allowing to improve their performance, including vibroacoustic one. This paper deals with harmonic analysis of windings having integer and fractional q in permanent magnet synchronous motors, a comparison of their characteristics is performed, frequencies of subharmonics are revealed. Optimal winding pitch design is found giving reduce the amplitudes of subharmonics. Distribution factors for subharmonics, fractional and high-order harmonics are calculated, results analysis is represented, allowing for giving recommendations how to calculate distribution factors for different harmonics when q is fractional.

Electromagnetic-Thermal Integrated Design Optimization for Hypersonic Vehicle Short-Time Duty PM Brushless DC Motor

Directory of Open Access Journals (Sweden)

Quanwu Li

2016-01-01

Full Text Available High reliability is required for the permanent magnet brushless DC motor (PM-BLDCM in an electrical pump of hypersonic vehicle. The PM-BLDCM is a short-time duty motor with high-power-density. Since thermal equilibrium is not reached for the PM-BLDCM, the temperature distribution is not uniform and there is a risk of local overheating. The winding is a main heat source and its insulation is thermally sensitive, so reducing the winding temperature rise is the key to the improvement of the reliability. In order to reduce the winding temperature rise, an electromagnetic-thermal integrated design optimization method is proposed. The method is based on electromagnetic analysis and thermal transient analysis. The requirements and constraints of electromagnetic and thermal design are considered in this method. The split ratio and the maximum flux density in stator lamination, which are highly relevant to the windings temperature rise, are optimized analytically. The analytical results are verified by finite element analysis (FEA and experiments. The maximum error between the analytical and the FEA results is 4%. The errors between the analytical and measured windings temperature rise are less than 8%. It can be proved that the method can obtain the optimal design accurately to reduce the winding temperature rise.

Condition monitoring of machinery using motor current signature analysis

International Nuclear Information System (INIS)

Kryter, R.C.; Haynes, H.D.

1989-01-01

Motor current signature analysis (MCSA) is a powerful monitoring tool for motor-driven equipment that provides a nonintrusive means for detecting the presence of mechanical and electrical abnormalities in the motor and the driven equipment, including altered conditions in the process ''downstream'' of the motor-driven equipment. It was developed at the Oak Ridge National Laboratory as a means for determining the effects of aging and service wear systems, but it is applicable to a broad range of machinery. MCSA is based on the recognition that an electric motor (ac or dc) driving a mechanical load acts as an efficient and permanently available transducer by sensing mechanical load variations, large and small, long-term and rapid, and converting them into variations in the induced current generated in the motor windings. These motor current variations are carried by the electrical cables processes as desired. Motor current signatures, obtained in both time and over time to provide early indication of degradation. Successful applications of MCSA technology (patent applied for) include not only motor-operated valves but also pumps of various designs, blowers, and air conditioning systems. Examples are presented briefly, and speculation regarding the applicability of MCSA to a broader range of equipment monitoring and production line testing is also given. 1 ref., 13 figs

Partial discharge as a stator winding evaluation tool

International Nuclear Information System (INIS)

Maughan, C.V.

2005-01-01

This paper has been prepared to illustrate the value of partial discharge (PD) testing in assessing the condition of stator windings on operating generators and motors. The database of one particular PD system vendor was chosen for this study because of the magnitude of data accumulated by this company over the last 15 years. It was felt that sufficient data had been accumulated to allow useful statistical analysis of the capabilities of PD testing. The PD detection technology used by Iris has been installed on about 6000 generators and motors, and has inspection information from about 3600 machines. On these 3600 generators and motors, PD has successfully identified 209 potential problems that were verified by inspection to be present. In most cases, moderate corrective maintenance permitted return of the equipment to service without major repairs. An estimate of the actual number of avoided failures was not possible from the available reports. But it is clear that many potentially serious stator winding failures were avoided as a result of removal of these machines from service because of high PD readings. No attempt has been made in the paper to provide technical background or details of the PD test/analysis processes. There are numerous technical papers and industry guides; the interested reader is referred to IEEE 1434, EPRI Reports, and other documents in the Bibliography. While this paper is based somewhat narrowly on data from only one company, there are several other companies involved in PD testing and evaluation. As described below in this paper, these companies have also been successful in identifying stator winding problems through the use of PD equipment. Clearly, PD testing is a useful tool in monitoring and assessing the condition of stator windings, as well as other associated electrical equipment in the power plant. Because of the power of PD testing, it is expected that the use of PD monitoring will continue to expand at a significant rate in

Numerical modeling of wind turbine aerodynamic noise in the time domain.

Science.gov (United States)

Lee, Seunghoon; Lee, Seungmin; Lee, Soogab

2013-02-01

Aerodynamic noise from a wind turbine is numerically modeled in the time domain. An analytic trailing edge noise model is used to determine the unsteady pressure on the blade surface. The far-field noise due to the unsteady pressure is calculated using the acoustic analogy theory. By using a strip theory approach, the two-dimensional noise model is applied to rotating wind turbine blades. The numerical results indicate that, although the operating and atmospheric conditions are identical, the acoustical characteristics of wind turbine noise can be quite different with respect to the distance and direction from the wind turbine.

Research on High-efficient Remanufacturing Technologies and Application of Electric Motor

Science.gov (United States)

Liu, Ren; Zhao, Yuejin; Yang, Xu; Wang, Gen

2017-09-01

The energy conservation of electric motor system is the key of industrial energy conservation. With the implementation and acceleration of electric motor energy efficiency improvement plan, more and more electric motors are knocked out. High-efficient remanufacturing of electric motor refers to improving the efficiency of electric motor and recycling the resources by replacing the winding, iron core and other components of electric motor on the basis of the low-efficient/outdated electric motors, which conforms to China’s policy of circular economy and resource recovery. The remanufacturing of electric motor not only maximizes the use of resources, but also reduces the energy consumption generated by reprocessing of cast iron, silicon steel sheet and other materials in dismantling of electric motor. However, structures and iron core materials used in design and manufacture of electric motors are different, and the degrees of wear of electric motors are also different under different operating conditions, which further result in diversified design schemes, increased remanufacturing cost and reduced remanufacturing efficiency. This paper analyzes the key process technologies for remanufacturing of electric motors are researched by analyzing the remanufacturing technologies of electric motors, and presents the feasibility to replace the cast-aluminum rotor with cast-copper rotor in high-efficient remanufacturing process of electric motor.

Aeroelastic analysis of an offshore wind turbine: Design and Fatigue Performance of Large Utility-Scale Wind Turbine Blades

OpenAIRE

Fossum, Peter Kalsaas

2012-01-01

Aeroelastic design and fatigue analysis of large utility-scale wind turbine blades are performed. The applied fatigue model is based on established methods and is incorporated in an iterative numerical design tool for realistic wind turbine blades. All aerodynamic and structural design properties are available in literature. The software tool FAST is used for advanced aero-servo-elastic load calculations and stress-histories are calculated with elementary beam theory.According to wind energy ...

Reluctance motor of new design with improved efficiency and power factor

Energy Technology Data Exchange (ETDEWEB)

Hansen-Goos, P; Pieper, W

1981-09-01

Improvement of operating conditions and efficiency by development of new configurations of lamination and production methods for reluctance motors. Investigations during the starting-up period and of the operating behaviour in connection with variable frequency. Reluctance motors are designed in the range from 0,6-4kW with 4-pole winding. They are due to the following identification: 1. The power of motors is in accordance with VDE 42673. 2. The volume of lamination is equal to asynchronous motors of the same IED size. 3. Synchronous pull-out torque is in compliance with VDE 0530: Msub(K)sub(S) > 1,35 Mn (nominal torque). As against standard reluctance motors the following improvements with the new ones have been realized: 4. Increase of nominal power by approx. 100%. 5. Increase of quality factor by approx. 50%. 6. The efficiency is equal to asynchronous motors of the same IEC size.

Optimized Carrier Based Multilevel Generated Modified Dual Three-Phase Open-Winding Inverter for Medium Power Applications

DEFF Research Database (Denmark)

Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Wheeler, Patrick

2016-01-01

This paper presents a novel carrier based multilevel modulation for modified dual three-phase open-winding inverter applicable for low-voltage/high-current applications. A standard three-phase voltage source inverter (VSI) is connected across the open-winding of both ends of the motor. Each VSI i...

Study of linear induction motor characteristics : the Mosebach model

Science.gov (United States)

1976-05-31

This report covers the Mosebach theory of the double-sided linear induction motor, starting with the ideallized model and accompanying assumptions, and ending with relations for thrust, airgap power, and motor efficiency. Solutions of the magnetic in...

Study of linear induction motor characteristics : the Oberretl model

Science.gov (United States)

1975-05-30

The Oberretl theory of the double-sided linear induction motor (LIM) is examined, starting with the idealized model and accompanying assumptions, and ending with relations for predicted thrust, airgap power, and motor efficiency. The effect of varyin...

Fatigue distribution optimization for offshore wind farms using intelligent agent control

DEFF Research Database (Denmark)

Zhao, Rongyong; Shen, Wen Zhong; Knudsen, Torben

2012-01-01

with its neighbouring downwind turbines and organizes them adaptively into a wind delivery group along the wind direction. The agent attributes and the event structure are designed on the basis of the intelligent agent theory by using the unified modelling language. The control strategy of the intelligent......A novel control approach is proposed to optimize the fatigue distribution of wind turbines in a large‐scale offshore wind farm on the basis of an intelligent agent theory. In this approach, each wind turbine is considered to be an intelligent agent. The turbine at the farm boundary communicates...... coefficient for every wind turbine. The optimization is constrained such that the average fatigue for every turbine is smaller than what would be achieved by conventional dispatch and such that the total power loss of the wind farm is restricted to a few percent of the total power. This intelligent agent...

Probing the string winding sector

Energy Technology Data Exchange (ETDEWEB)

Aldazabal, Gerardo; Mayo, Martín [G. Física CAB-CNEA and CONICET, Centro Atómico Bariloche,Av. Bustillo 9500, Bariloche (Argentina); Instituto Balseiro, Centro Atómico Bariloche,Av. Bustillo 9500, Bariloche (Argentina); Nuñez, Carmen [Instituto de Astronomía y Física del Espacio (CONICET-UBA),C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina); Departamento de Física, FCEN, Universidad de Buenos Aires,C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina)

2017-03-17

We probe a slice of the massive winding sector of bosonic string theory from toroidal compactifications of Double Field Theory (DFT). This string subsector corresponds to states containing one left and one right moving oscillators. We perform a generalized Kaluza Klein compactification of DFT on generic 2n-dimensional toroidal constant backgrounds and show that, up to third order in fluctuations, the theory coincides with the corresponding effective theory of the bosonic string compactified on n-dimensional toroidal constant backgrounds, obtained from three-point amplitudes. The comparison between both theories is facilitated by noticing that generalized diffeomorphisms in DFT allow to fix generalized harmonic gauge conditions that help in identifying the physical degrees of freedom. These conditions manifest as conformal anomaly cancellation requirements on the string theory side. The explicit expression for the gauge invariant effective action containing the physical massless sector (gravity+antisymmetric+gauge+ scalar fields) coupled to towers of generalized Kaluza Klein massive states (corresponding to compact momentum and winding modes) is found. The action acquires a very compact form when written in terms of fields carrying O(n,n) indices, and is explicitly T-duality invariant. The global algebra associated to the generalized Kaluza Klein compactification is discussed.

Reactor Coolant Pump Motor Maintenance Experience in Krsko NPP

International Nuclear Information System (INIS)

Vukovic, J.; Besirevic, A.; Boljat, Z.

2016-01-01

After thirty years of service as well as maintenance in Krsko NPP both original Reactor Coolant Pump (RCP) motors are remanufactured by original vendor Westinghouse and a new one was purchased. Design function of the RCP motor is to drive Reactor Coolant Pump and for coast-down feature during Design Basis Accident. This paper will give a view on maintenance issues of RCP motor during the thirty years of service and maintenance in Krsko NPP to be kept functionally operational. During the processes of remanufacturing inspection and disassembly it was made possible to get a deeper perspective in the motor condition and the wear or fatigue of the motor parts. Parameters like bearing & winding temperature, absolute and relative vibration greatly affect motor operation if not kept inside design margins. Rotational speed causes heat generation at the bearings which is then associated with oil temperatures and as a consequence bearing temperatures. That is why the most critical parts of the motor are the components of upper and lower bearing assembly. The condition of motor stator and rotor assembly technical characteristics shall be explained with respect to influence of demanding environmental conditions that the motor is exposed. Assessment shall be made how does the wear of critical RCP motor parts can influence reliable performance of the motor if not maintained in proper way. Information on upgrades that were done on RCP motor shall be shared: Oil Spillage Protection System (OSPS), Stator upgrades, Dynamic Port, etc. (author).

Upper Limb Immobilisation: A Neural Plasticity Model with Relevance to Poststroke Motor Rehabilitation

OpenAIRE

Furlan, Leonardo; Conforto, Adriana Bastos; Cohen, Leonardo G.; Sterr, Annette

2016-01-01

Advances in our understanding of the neural plasticity that occurs after hemiparetic stroke have contributed to the formulation of theories of poststroke motor recovery. These theories, in turn, have underpinned contemporary motor rehabilitation strategies for treating motor deficits after stroke, such as upper limb hemiparesis. However, a relative drawback has been that, in general, these strategies are most compatible with the recovery profiles of relatively high-functioning stroke survivor...

Novel Modified Elman Neural Network Control for PMSG System Based on Wind Turbine Emulator

OpenAIRE

Lin, Chih-Hong

2013-01-01

The novel modified Elman neural network (NN) controlled permanent magnet synchronous generator (PMSG) system, which is directly driven by a permanent magnet synchronous motor (PMSM) based on wind turbine emulator, is proposed to control output of rectifier (AC/DC power converter) and inverter (DC/AC power converter) in this study. First, a closed loop PMSM drive control based on wind turbine emulator is designed to generate power for the PMSG system according to different wind speeds. Then, t...

Dynamic aeroelastic stability of vertical-axis wind turbines under constant wind velocity

Science.gov (United States)

Nitzsche, Fred

1994-05-01

The flutter problem associated with the blades of a class of vertical-axis wind turbines called Darrieus is studied in detail. The spinning blade is supposed to be initially curved in a particular shape characterized by a state of pure tension at the blade cross section. From this equilibrium position a three-dimensional linear perturbation pattern is superimposed to determine the dynamic aeroelastic stability of the blade in the presence of free wind speed by means of the Floquet-Lyapunov theory for periodic systems.

Aerodynamics of wind turbines

DEFF Research Database (Denmark)

Hansen, Martin Otto Laver

Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its third edition, it has been substantially updated with respect to structural dynamics and control. The new control chapter now includes details on how to design...... Turbines (VAWT). Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element Momentum method...... is also covered, as are eigenmodes and the dynamic behaviour of a turbine. The book describes the effects of the dynamics and how this can be modelled in an aeroelastic code, which is widely used in the design and verification of modern wind turbines. Furthermore, it examines how to calculate...

MOTOR ACCELERATION TIME OPTIMIZATION BY THE CHANGE OF THE SUPPLY VOLTAGE VALUE

Directory of Open Access Journals (Sweden)

G. K. Aslanov

2016-01-01

Full Text Available Abstract. It is proved that the deviation of the voltage from the nominal values, often leads to overheating of the motor windings, which reduces the insulation life to a great extent.The task of determining the change in the acceleration time of the motor depending on the switching time of its supply voltage is set. The modeling of DC motor 2ПН132М operation in the short- run changes in starting voltage from 380 V to 220 V - which is its nominal value-is carried out. By sweep method is determined the optimum time for switching the supply voltage of the motor. Mathematical dependencies and simulation results are presented. 

OPEN-LOOP CONTROL OF A BIPOLAR STEPPER MOTORS USING THE SPECIALIZED INTEGRATED CIRCUITS

Directory of Open Access Journals (Sweden)

Gheorghe BALUTA

2004-12-01

Full Text Available This paper describes the open-loop control of a stepper motors. Bipolar stepper motors can be driven with an L297, an L298N bridge driver and very few external components. With an L298N this configuration drives motors with winding currents up to 2.5A. If very high powers are required an equivalent circuit made with discrete transistors replaces the bridge driver. Together these two chips form a complete microprocessor-to-stepper motor interface. The command signals for the controller L297 are generated through an IBM-PC486 interface. It was developed an open-loop command program written in BorlandC programming language.

Performance Analysis of Permanent Magnet Motors for Electric Vehicles (EV Traction Considering Driving Cycles

Directory of Open Access Journals (Sweden)

Thanh Anh Huynh

2018-05-01

Full Text Available This paper evaluates the electromagnetic and thermal performance of several traction motors for electric vehicles (EVs. Two different driving cycles are employed for the evaluation of the motors, one for urban and the other for highway driving. The electromagnetic performance to be assessed includes maximum motor torque output for vehicle acceleration and the flux weakening capability for wide operating range under current and voltage limits. Thermal analysis is performed to evaluate the health status of the magnets and windings for the prescribed driving cycles. Two types of traction motors are investigated: two interior permanent magnet motors and one permanent magnet-assisted synchronous reluctance motor. The analysis results demonstrate the benefits and disadvantages of these motors for EV traction and provide suggestions for traction motor design. Finally, experiments are conducted to validate the analysis.

Reluctance motor employing superconducting magnetic flux switches

International Nuclear Information System (INIS)

Spyker, R.L.; Ruckstadter, E.J.

1992-01-01

This paper reports that superconducting flux switches controlling the magnetic flux in the poles of a motor will enable the implementation of a reluctance motor using one central single phase winding. A superconducting flux switch consists of a ring of superconducting material surrounding a ferromagnetic pole of the motor. When in the superconducting state the switch will block all magnetic flux attempting to flow in the ferromagnetic core. When switched to the normal state the superconducting switch will allow the magnetic flux to flow freely in that pole. By using one high turns-count coil as a flux generator, and selectively channeling flux among the various poles using the superconducting flux switch, 3-phase operation can be emulated with a single-hase central AC source. The motor will also operate when the flux generating coil is driven by a DC current, provided the magnetic flux switches see a continuously varying magnetic flux. Rotor rotation provides this varying flux due to the change in stator pole inductance it produces

Reactor coolant pump testing using motor current signatures analysis

Energy Technology Data Exchange (ETDEWEB)

Burstein, N.; Bellamy, J.

1996-12-01

This paper describes reactor coolant pump motor testing carried out at Florida Power Corporation`s Crystal River plant using Framatome Technologies` new EMPATH (Electric Motor Performance Analysis and Trending Hardware) system. EMPATH{trademark} uses an improved form of Motor Current Signature Analysis (MCSA), technology, originally developed at Oak Ridge National Laboratories, for detecting deterioration in the rotors of AC induction motors. Motor Current Signature Analysis (MCSA) is a monitoring tool for motor driven equipment that provides a non-intrusive means for detecting the presence of mechanical and electrical abnormalities in the motor and the driven equipment. The base technology was developed at the Oak Ridge National Laboratory as a means for determining the affects of aging and service wear specifically on motor-operated valves used in nuclear power plant safety systems, but it is applicable to a broad range of electric machinery. MCSA is based on the recognition that an electric motor (ac or dc) driving a mechanical load acts as an efficient and permanently available transducer by sensing mechanical load variations, large and small, long-term and rapid, and converting them into variations in the induced current generated in the motor windings. The motor current variations, resulting from changes in load caused by gears, pulleys, friction, bearings, and other conditions that may change over the life of the motor, are carried by the electrical cables powering the motor and are extracted at any convenient location along the motor lead. These variations modulate the 60 Hz carrier frequency and appear as sidebands in the spectral plot.

Flywheel Energy Storage Drive System for Wind Applications

Directory of Open Access Journals (Sweden)

Marius Constantin Georgescu

2014-09-01

Full Text Available This paper presents a wind small power plant with a Smart Storage Modular Structure (SSMS, as follows: a Short Time Storage Module (STSM based on a flywheel with Induction Motor (IM and a Medium/Long Time Storage Module (MLTSM based on a Vanadium Redox flow Battery (VRB. To control the speed and torque of the IM are used a nonlinear sensorless solution and a direct torque solution which have been compared. Now, the author proposes to replace the IM by a dc motor with permanent magnet energy injection. In this aim, are accomplished some laboratory tests.

Reliability-Based Design and Planning of Inspection and Monitoring of Offshore Wind Turbines

DEFF Research Database (Denmark)

Marquez-Dominguez, Sergio

Maintaining and developing a sustainable wind industry is the main motivation of this PhD thesis entitled “Reliability-based design and planning of inspection and monitoring of offshore wind turbines”. In this thesis, statistical methods and probability theory are important mathematical tools used...... and offshore wind turbine foundations with the aim of improving the design, decreasing structural costs and increasing benefits. Recently, wind energy technology has started to adopt risk and reliability based inspection planning (RBI) as a methodology based on Bayesian decision theories together...

Optimization of the flux in induction motors; Optymalizacja strumienia w silniku indukcyjnym

Energy Technology Data Exchange (ETDEWEB)

Gruszczynski, P.B. [Centralny Urzad Planowania, Warszawa (Poland); Gnacinski, P. [Wyzsza Szkola Morska, Gdynia (Poland)

1995-06-01

The article discusses possibilities of reducing the temperature of windings through optimization of flux (voltage). A method is presented of statically optimizing the flux at a periodically variable load and also conditions are given for its being applicable. Power criteria of the flux optimization are compared. Advantages of the optimal control are shown, i.e.: reduction of windings temperature and also increasing the life and overload capacity of motor. (author). 6 refs., 7 figs.

NASA Glenn Research Center Program in High Power Density Motors for Aeropropulsion

Science.gov (United States)

Brown, Gerald V.; Kascak, Albert F.; Ebihara, Ben; Johnson, Dexter; Choi, Benjamin; Siebert, Mark; Buccieri, Carl

2005-01-01

Electric drive of transport-sized aircraft propulsors, with electric power generated by fuel cells or turbo-generators, will require electric motors with much higher power density than conventional room-temperature machines. Cryogenic cooling of the motor windings by the liquid hydrogen fuel offers a possible solution, enabling motors with higher power density than turbine engines. Some context on weights of various systems, which is required to assess the problem, is presented. This context includes a survey of turbine engine weights over a considerable size range, a correlation of gear box weights and some examples of conventional and advanced electric motor weights. The NASA Glenn Research Center program for high power density motors is outlined and some technical results to date are presented. These results include current densities of 5,000 A per square centimeter current density achieved in cryogenic coils, finite element predictions compared to measurements of torque production in a switched reluctance motor, and initial tests of a cryogenic switched reluctance motor.

The sensory-motor theory of rhythm and beat induction 20 years on: A new synthesis and future perspectives.

Directory of Open Access Journals (Sweden)

Neil Philip Todd

2015-08-01

Full Text Available Some 20 years ago Todd and colleagues proposed that rhythm perception is mediated by the conjunction of a sensory representation of the auditory input and a motor representation of the body (Todd 1994, 1995, and that a sense of motion from sound is mediated by the vestibular system (Todd 1992, 1993. These ideas were developed into a sensory-motor theory of rhythm and beat induction (Todd et al. 1999. A neurological substrate was proposed which might form the biological basis of the theory (Todd et al. 2002. The theory was implemented as a computational model and a number of experiments conducted to test it. In the following time there have been several key developments. One is the demonstration that the vestibular system is primal to rhythm perception, and in related work several experiments have provided further evidence that rhythm perception is body dependent. Another is independent advances in imaging, which have revealed the brain areas associated with both vestibular processing and rhythm perception. A third is the finding that vestibular receptors contribute to auditory evoked potentials (Todd et al. 2014ab. These behavioural and neurobiological developments demand a theoretical overview which could provide a new synthesis over the domain of rhythm perception. In this paper we suggest four propositions as the basis for such a synthesis. (1 Rhythm perception is a form of vestibular perception; (2 Rhythm perception evokes both external and internal guidance of somatotopic representations; (3 A link from the limbic system to the internal guidance pathway mediates the dance habit; (4 The vestibular reward mechanism is innate. The new synthesis provides an explanation for a number of phenomena not often considered by rhythm researchers. We discuss these along with possible computational implementations and alternative models and propose a number of new directions for future research.

Mathematical Model and Computational Analysis of Selected Transient States of Cylindrical Linear Induction Motor Fed via Frequency Converter

Directory of Open Access Journals (Sweden)

Andrzej Rusek

2008-01-01

Full Text Available The mathematical model of cylindrical linear induction motor (C-LIM fed via frequency converter is presented in the paper. The model was developed in order to analyze numerically the transient states. Problems concerning dynamics of ac-machines especially linear induction motor are presented in [1 – 7]. Development of C-LIM mathematical model is based on circuit method and analogy to rotary induction motor. The analogy between both: (a stator and rotor windings of rotary induction motor and (b winding of primary part of C-LIM (inductor and closed current circuits in external secondary part of C-LIM (race is taken into consideration. The equations of C-LIM mathematical model are presented as matrix together with equations expressing each vector separately. A computational analysis of selected transient states of C-LIM fed via frequency converter is presented in the paper. Two typical examples of C-LIM operation are considered for the analysis: (a starting the motor at various static loads and various synchronous velocities and (b reverse of the motor at the same operation conditions. Results of simulation are presented as transient responses including transient electromagnetic force, transient linear velocity and transient phase current.

Studying Environmental Influence on Motor Development in Children

Science.gov (United States)

Gabbard, Carl; Krebs, Ruy

2012-01-01

There is a good argument that in order to truly understand the influences that shape child motor development, one must consider environmental influences that reflect the multilevel ecological contexts that interact with the changing biological characteristics of the child. Although there are theories typically associated with motor development…

Variable Ratio Hydrostatic Transmission Simulator for Optimal Wind Power Drivetrains

Directory of Open Access Journals (Sweden)

Jose M. Garcia-Bravo

2017-01-01

Full Text Available This work presents a hydromechanical transmission coupled to an electric AC motor and DC generator to simulate a wind power turbine drive train. The goal of this project was to demonstrate and simulate the ability of a hydrostatic variable ratio system to produce constant electric power at varying wind speeds. The experimental results show that the system can maintain a constant voltage when a 40% variation in input speed is produced. An accompanying computer simulation of the system was built and experimentally validated showing a discrete error no larger than 12%. Both the simulation and the experimental results show that the electrical power output can be regulated further if an energy storage device is used to absorb voltage spikes produced by abrupt changes in wind speed or wind direction.

An Enhanced Three-Level Voltage Switching State Scheme for Direct Torque Controlled Open End Winding Induction Motor

Science.gov (United States)

Kunisetti, V. Praveen Kumar; Thippiripati, Vinay Kumar

2018-01-01

Open End Winding Induction Motors (OEWIM) are popular for electric vehicles, ship propulsion applications due to less DC link voltage. Electric vehicles, ship propulsions require ripple free torque. In this article, an enhanced three-level voltage switching state scheme for direct torque controlled OEWIM drive is implemented to reduce torque and flux ripples. The limitations of conventional Direct Torque Control (DTC) are: possible problems during low speeds and starting, it operates with variable switching frequency due to hysteresis controllers and produces higher torque and flux ripple. The proposed DTC scheme can abate the problems of conventional DTC with an enhanced voltage switching state scheme. The three-level inversion was obtained by operating inverters with equal DC-link voltages and it produces 18 voltage space vectors. These 18 vectors are divided into low and high frequencies of operation based on rotor speed. The hardware results prove the validity of proposed DTC scheme during steady-state and transients. From simulation and experimental results, proposed DTC scheme gives less torque and flux ripples on comparison to two-level DTC. The proposed DTC is implemented using dSPACE DS-1104 control board interface with MATLAB/SIMULINK-RTI model.

Hand rim wheelchair propulsion training using biomechanical real-time visual feedback based on motor learning theory principles.

Science.gov (United States)

Rice, Ian; Gagnon, Dany; Gallagher, Jere; Boninger, Michael

2010-01-01

As considerable progress has been made in laboratory-based assessment of manual wheelchair propulsion biomechanics, the necessity to translate this knowledge into new clinical tools and treatment programs becomes imperative. The objective of this study was to describe the development of a manual wheelchair propulsion training program aimed to promote the development of an efficient propulsion technique among long-term manual wheelchair users. Motor learning theory principles were applied to the design of biomechanical feedback-based learning software, which allows for random discontinuous real-time visual presentation of key spatiotemporal and kinetic parameters. This software was used to train a long-term wheelchair user on a dynamometer during 3 low-intensity wheelchair propulsion training sessions over a 3-week period. Biomechanical measures were recorded with a SmartWheel during over ground propulsion on a 50-m level tile surface at baseline and 3 months after baseline. Training software was refined and administered to a participant who was able to improve his propulsion technique by increasing contact angle while simultaneously reducing stroke cadence, mean resultant force, peak and mean moment out of plane, and peak rate of rise of force applied to the pushrim after training. The proposed propulsion training protocol may lead to favorable changes in manual wheelchair propulsion technique. These changes could limit or prevent upper limb injuries among manual wheelchair users. In addition, many of the motor learning theory-based techniques examined in this study could be applied to training individuals in various stages of rehabilitation to optimize propulsion early on.

Methodology for wind turbine blade geometry optimization

Energy Technology Data Exchange (ETDEWEB)

Perfiliev, D.

2013-11-01

Nowadays, the upwind three bladed horizontal axis wind turbine is the leading player on the market. It has been found to be the best industrial compromise in the range of different turbine constructions. The current wind industry innovation is conducted in the development of individual turbine components. The blade constitutes 20-25% of the overall turbine budget. Its optimal operation in particular local economic and wind conditions is worth investigating. The blade geometry, namely the chord, twist and airfoil type distributions along the span, responds to the output measures of the blade performance. Therefore, the optimal wind blade geometry can improve the overall turbine performance. The objectives of the dissertation are focused on the development of a methodology and specific tool for the investigation of possible existing wind blade geometry adjustments. The novelty of the methodology presented in the thesis is the multiobjective perspective on wind blade geometry optimization, particularly taking simultaneously into account the local wind conditions and the issue of aerodynamic noise emissions. The presented optimization objective approach has not been investigated previously for the implementation in wind blade design. The possibilities to use different theories for the analysis and search procedures are investigated and sufficient arguments derived for the usage of proposed theories. The tool is used for the test optimization of a particular wind turbine blade. The sensitivity analysis shows the dependence of the outputs on the provided inputs, as well as its relative and absolute divergences and instabilities. The pros and cons of the proposed technique are seen from the practical implementation, which is documented in the results, analysis and conclusion sections. (orig.)

NRC Information No. 88-72: Inadequacies in the design of dc motor-operated valves

International Nuclear Information System (INIS)

Rossi, C.E.

1992-01-01

On July 1, 1988, a high pressure coolant injection (HPCI) steam admission valve failed to open during a post-maintenance test at the Brunswick nuclear power plant, Unit 1. The same valve had failed in December 1987 and on May 28, 1988. The licensee, Carolina Power and Light Company, established a team to investigate the cause of failure, and the team identified the most probable cause as a dc motor failure due to a shunt-winding to series-winding short circuit. The team believed that this condition was precipitated by thermal binding of the valve internals. The previous failure in May was also diagnosed as having been caused by thermal binding. As a result of these failures, the licensee reviewed the design of the dc motor-operated valves for both the HPCI and the reactor core isolation cooling (RCIC) systems. This review identified a number of significant design deficiencies going well beyond the problems with thermal binding. The deficiencies constitute a potential common cause failure mechanism for safety system valves. Unit 1 was shut down on July 14, 1988 to replace the failed HPCI valve motor and to implement design modifications to other motor-operated valves

An Asymmetrical Space Vector Method for Single Phase Induction Motor

DEFF Research Database (Denmark)

Cui, Yuanhai; Blaabjerg, Frede; Andersen, Gert Karmisholt

2002-01-01

Single phase induction motors are the workhorses in low-power applications in the world, and also the variable speed is necessary. Normally it is achieved either by the mechanical method or by controlling the capacitor connected with the auxiliary winding. Any above method has some drawback which...

HTS axial flux induction motor with analytic and FEA modeling

Energy Technology Data Exchange (ETDEWEB)

Li, S., E-mail: alexlee.zn@gmail.com; Fan, Y.; Fang, J.; Qin, W.; Lv, G.; Li, J.H.

2013-11-15

Highlights: •A high temperature superconductor axial flux induction motor and a novel maglev scheme are presented. •Analytic method and finite element method have been adopted to model the motor and to calculate the force. •Magnetic field distribution in HTS coil is calculated by analytic method. •An effective method to improve the critical current of HTS coil is presented. •AC losses of HTS coils in the HTS axial flux induction motor are estimated and tested. -- Abstract: This paper presents a high-temperature superconductor (HTS) axial-flux induction motor, which can output levitation force and torque simultaneously. In order to analyze the character of the force, analytic method and finite element method are adopted to model the motor. To make sure the HTS can carry sufficiently large current and work well, the magnetic field distribution in HTS coil is calculated. An effective method to improve the critical current of HTS coil is presented. Then, AC losses in HTS windings in the motor are estimated and tested.

HTS axial flux induction motor with analytic and FEA modeling

International Nuclear Information System (INIS)

Li, S.; Fan, Y.; Fang, J.; Qin, W.; Lv, G.; Li, J.H.

2013-01-01

Highlights: •A high temperature superconductor axial flux induction motor and a novel maglev scheme are presented. •Analytic method and finite element method have been adopted to model the motor and to calculate the force. •Magnetic field distribution in HTS coil is calculated by analytic method. •An effective method to improve the critical current of HTS coil is presented. •AC losses of HTS coils in the HTS axial flux induction motor are estimated and tested. -- Abstract: This paper presents a high-temperature superconductor (HTS) axial-flux induction motor, which can output levitation force and torque simultaneously. In order to analyze the character of the force, analytic method and finite element method are adopted to model the motor. To make sure the HTS can carry sufficiently large current and work well, the magnetic field distribution in HTS coil is calculated. An effective method to improve the critical current of HTS coil is presented. Then, AC losses in HTS windings in the motor are estimated and tested

Economic decision-making compared with an equivalent motor task.

Science.gov (United States)

Wu, Shih-Wei; Delgado, Mauricio R; Maloney, Laurence T

2009-04-14

There is considerable evidence that human economic decision-making deviates from the predictions of expected utility theory (EUT) and that human performance conforms to EUT in many perceptual and motor decision tasks. It is possible that these results reflect a real difference in decision-making in the 2 domains but it is also possible that the observed discrepancy simply reflects typical differences in experimental design. We developed a motor task that is mathematically equivalent to choosing between lotteries and used it to compare how the same subject chose between classical economic lotteries and the same lotteries presented in equivalent motor form. In experiment 1, we found that subjects are more risk seeking in deciding between motor lotteries. In experiment 2, we used cumulative prospect theory to model choice and separately estimated the probability weighting functions and the value functions for each subject carrying out each task. We found no patterned differences in how subjects represented outcome value in the motor and the classical tasks. However, the probability weighting functions for motor and classical tasks were markedly and significantly different. Those for the classical task showed a typical tendency to overweight small probabilities and underweight large probabilities, and those for the motor task showed the opposite pattern of probability distortion. This outcome also accounts for the increased risk-seeking observed in the motor tasks of experiment 1. We conclude that the same subject distorts probability, but not value, differently in making identical decisions in motor and classical form.

Studying Action Representation in Children via Motor Imagery

Science.gov (United States)

Gabbard, Carl

2009-01-01

The use of motor imagery is a widely used experimental paradigm for the study of cognitive aspects of action planning and control in adults. Furthermore, there are indications that motor imagery provides a window into the process of action representation. These notions complement internal model theory suggesting that such representations allow…

Power fluctuation and power loss of wind turbines due to wind shear and tower shadow

Institute of Scientific and Technical Information of China (English)

Binrong WEN; Sha WEI; Kexiang WEI; Wenxian YANG; Zhike PENG; Fulei CHU

2017-01-01

The magnitude and stability of power output are two key indices of wind turbines.This study investigates the effects of wind shear and tower shadow on power output in terms of power fluctuation and power loss to estimate the capacity and quality of the power generated by a wind turbine.First,wind speed models,particularly the wind shear model and the tower shadow model,are described in detail.The widely accepted tower shadow model is modified in view of the cone-shaped towers of modem large-scale wind turbines.Power fluctuation and power loss due to wind shear and tower shadow are analyzed by performing theoretical calculations and case analysis within the framework of a modified version of blade element momentum theory.Results indicate that power fluctuation is mainly caused by tower shadow,whereas power loss is primarily induced by wind shear.Under steady wind conditions,power loss can be divided into wind farm loss and rotor loss.Wind farm loss is constant at 3α(3α-1)R2/(8H2).By contrast,rotor loss is strongly influenced by the wind turbine control strategies and wind speed.That is,when the wind speed is measured in a region where a variable-speed controller works,the rotor loss stabilizes around zero,but when the wind speed is measured in a region where the blade pitch controller works,the rotor loss increases as the wind speed intensifies.The results of this study can serve as a reference for accurate power estimation and strategy development to mitigate the fluctuations in aerodynamic loads and power output due to wind shear and tower shadow.

Wind turbine design : with emphasis on Darrieus concept

Energy Technology Data Exchange (ETDEWEB)

Paraschivoiu, I. [Ecole Polytechnique, Montreal, PQ (Canada)

2002-07-01

This book described software applications designed to model the aerodynamic performance of the Darrieus vertical-axis wind turbine. The book also provided a comprehensive review of current vertical-axis wind turbine (VAWT) technology, and discussed recent advances in understanding the physics of flow associated with the Darrieus type of turbine. The principal theories and aerodynamic models for calculating the performance of the turbines were presented, as well as results from experimental data derived from prototypes as well as laboratory measurements. The book was divided into 10 chapters: (1) wind definition and characteristics; (2) a review of the Madaras rotor concept along with an introduction to vortex modelling; (3) an introduction to the geometry of the Darrieus rotor; (4) a single streamtube model; (5) dynamic-stall phenomenon and numerical simulations; (6) double actuator risk theory; (7) details of water channel experiments; (8) modelling of turbine components; (9) wind turbine design parameters; and (10) issues related to socio-economic and environmental impacts. refs., tabs., figs.

Optimal Design of an Axial-Flux Permanent-Magnet Middle Motor Integrated in a Cycloidal Reducer for a Pedal Electric Cycle

Directory of Open Access Journals (Sweden)

Yee-Pien Yang

2015-12-01

Full Text Available This paper proposes an optimal design of a middle motor integrated into a mid-drive unit for pedal electric cycles. This middle motor is an axial-flux permanent magnet brushless DC motor with a stator plate. Facing this plate is a rotor plate that acts as an eccentric component of a cycloidal reducer next to the stator. Both the middle motor and cycloidal reducer are easily installed on the same axle of the bike crankset. In the preliminary design, driving requirements are used to make the middle motor specifications. The numbers of stator slots and magnet poles on the rotor were chosen to achieve the best winding factor, and the winding layout was determined accordingly. A one-dimensional magnetic circuit model of the middle motor was built, and its shape was optimized utilizing a multifunctional optimization system tool. Finally, the resulting design was verified and refined by a finite element analysis. A prototype of the middle motor was fabricated with a stator made of a soft magnetic composite and integrated with a cycloidal reducer. Experimental results show that the motor has a sinusoidal back electromotive force. Additionally, it is easily controlled by sinusoidal currents with acceptable torque and speed curves.

Wake Influence on Dynamic Load Characteristics of Offshore Floating Wind Turbines

DEFF Research Database (Denmark)

Jeon, Minu; Lee, Soogab; Kim, Taeseong

2016-01-01

Because the flow conditions of an offshore floating wind turbine and onshore fixed wind turbine differ, it is debatable whether the aerodynamic load predictions of an offshore floating wind turbine using the conventional blade-element momentum theory, which does not consider the dynamic wake effe...

Preliminary study on a rotating armature type superconducting motor

International Nuclear Information System (INIS)

Hoshino, Tsutomu; Muta, Itsuya; Itoh, Takeshi; Hayashi, K.; Mukai, E.

1994-01-01

A rotating armature type motor with a laboratory made four pole saddle shape superconducting field winding has been constructed. Cool-down tests were carried out successfully several times.By the motor operating as a generator under no load and resistive load conditions, machine constants are obtained. The air gap field with outer magnetic shield yoke is 29% higher than without yoke. The field coil could stand current up to 120 A. The rated terminal voltage should be 200 V for 1,800 rpm (at 90 A field current). The armature coil could stand current up to 50 A, with a rate armature current value of 40 A corresponding to 15 kW at 0.98 power factor. Moreover the experimental and theoretical characteristics of the motor will be presented

The Capacity Value of Wind in the United States: Methods and Implementation

Energy Technology Data Exchange (ETDEWEB)

Milligan, Michael; Porter, Kevin

2006-03-01

As more wind energy capacity is added in the nation, the question of wind's capacity value is raised. This article shows how the capacity value of wind is determined, both in theory and in practice. (author)

Laddermill-sailing. Ship propulsion by wind energy independent from the wind direction

Energy Technology Data Exchange (ETDEWEB)

Ockels, W. J.

2007-12-15

The use of large kites in ship propulsion has been getting a growing attention because of the urgent need to reduce the CO2 production and thus stop the use of fossil fuels. A novel application of ship propulsion by kites is proposed based on a Laddermill apparatus mounted on a ship. Such an apparatus consist of a winch, an electric motor/generator, a kite system (including launch and retrieval) and controlling electronics. Rather than the traditional sailing by wind force the Laddermill propulsion is achieved by a combination of the production and use of electrical power and the direct pulling force from the kite system. The feasibility of this application is investigated. It is shown that when the overall Laddermill to ship thrust efficiency can be made around 50% the resulting speed of the ship becomes practically independent from the wind direction. Such a capability could thus well change the world's seafaring.

A dynamical systems approach to motor development.

Science.gov (United States)

Kamm, K; Thelen, E; Jensen, J L

1990-12-01

The study of motor development has long influenced the clinical practice of physical therapy. We first review the contributions and deficiencies of two traditional maturational and reflex-based models of motor development. Second, we describe basic principles of kinematic and kinetic analyses of movement and show how we have applied these techniques to understand infant stepping and kicking. Third, we propose a theory of motor development based on a dynamical systems perspective that is consistent with our infant studies. Finally, we explore the implications of the model for physical therapists.

Wind Extraction for Natural Ventilation

Science.gov (United States)

Fagundes, Tadeu; Yaghoobian, Neda; Kumar, Rajan; Ordonez, Juan

2017-11-01

Due to the depletion of energy resources and the environmental impact of pollution and unsustainable energy resources, energy consumption has become one of the main concerns in our rapidly growing world. Natural ventilation, a traditional method to remove anthropogenic and solar heat gains, proved to be a cost-effective, alternative method to mechanical ventilation. However, while natural ventilation is simple in theory, its detailed design can be a challenge, particularly for wind-driven ventilation, which its performance highly involves the buildings' form, surrounding topography, turbulent flow characteristics, and climate. One of the main challenges with wind-driven natural ventilation schemes is due to the turbulent and unpredictable nature of the wind around the building that impose complex pressure loads on the structure. In practice, these challenges have resulted in founding the natural ventilation mainly on buoyancy (rather than the wind), as the primary force. This study is the initial step for investigating the physical principals of wind extraction over building walls and investigating strategies to reduce the dependence of the wind extraction on the incoming flow characteristics and the target building form.

Assessment of low-order theories for analysis and design of shrouded wind turbines using CFD

International Nuclear Information System (INIS)

Aranake, Aniket C; Lakshminarayan, Vinod K; Duraisamy, Karthik

2014-01-01

The use of a shroud around the rotor of a wind turbine has been known to augment the airflow through the rotor plane and hence result in improved performance. This work uses Computational Fluid Dynamics (CFD) to assess the validity of several simple theories which attempt to extend Betz theory to shrouded turbines. Two CFD models are employed and compared to predictions of previously published models. The first makes use of a fixed pressure-drop actuator disk, while the second incorporates the twist and chord distribution of the turbine blade as well as an airfoil polar using a technique much like the classical blade element momentum (BEM) method. Calculations are performed for a sweep of turbine loadings using the fixed pressure-drop model and a sweep of tip speed ratios using the BEM model for both an open and shrouded turbine. Power is computed using a control volume approach for the fixed pressure-drop model and by integrating tangential forces for the BEM model. Information including mass flow ratio, power coefficient ratio, axial induction, and shroud force is extracted from the solution fields and compared against the predictions of low-order theories. Finally, the blade element model is used to redesign the turbine twist distribution to achieve greater performance across a range of tip speed ratios

The formation of molecules in protostellar winds

International Nuclear Information System (INIS)

Glassgold, A.E.; Mamon, G.A.; Huggins, P.J.

1991-01-01

The production and destruction processes for molecules in very fast protostellar winds are analyzed and modeled with a one-dimensional chemical kinetics code. Radial density and temperature distributions suggested by protostellar theory are explored as are a range of mass-loss rates. The efficiency of in situ formation of heavy molecules is found to be high if the wind temperature falls sufficiently rapidly, as indicated by theory. The degree of molecular conversion is a strong function of the mass-loss rate and of density gradients associated with the acceleration and collimation of the wind. Even in cases where essentially all of the heavy atoms are processed into molecules, a significant fraction of atomic hydrogen remains so that hghly molecular, protostellar winds are able to emit the 21-cm line. Although CO has a substantial abundance in most models relevant to very young protostars, high abundances of other molecules such as SiO and H2O signify more complete association characteristic of winds containing regions of very high density. Although the models apply only to regions close to the protostar, they are in qualitative accord with recent observations at much larger distances of both atomic and molecular emission from extremely high-velocity flow. 57 refs

THE ROLE OF DYNAMIC SYSTEMS IN MOTOR DEVELOPMENT RESEARCH. JUST A METAPHOR OR A NOTABLE REALITY?

Directory of Open Access Journals (Sweden)

Ivan Šerbetar

2015-01-01

Full Text Available In the present article an application of a new theory of motor control in the context of motor development theories and research has been discussed. In a brief overview of traditional theories of motor development a neuro-maturational theory is mentioned along with the two prominent proponents - McGraw & Gesell. Bernstein’s fundamental insights in motor control were emphasized, such as the concepts of degrees of freedom and synergies, along with his contribution to the measurement technology and quantification. Basic principles of dynamic systems theory and common concepts such as self-organization, patterns, attractors or non-equilibrium systems are briefly described. In the main part, an example of research in motor development carried out in dynamical perspective was introduced. The chosen example was the body of the research performed by Thelen et al. (1982, 1984, 1990 on a newborn’s stepping. The distinction between the maturational perspective in which all the sequences of motor development are the result of maturation of nervous system, and the dynamic perspective in which development is seen as a mutual interaction between a number of body systems, including neural and muscular systems, which continuously affect the movement although none of them dominate (Kamm et al., 1990 has been made.

Aspects of the determination of winds by means of scatterometry and of the utilization of vector wind data for meteorological forecasts

Science.gov (United States)

Pierson, W. J., Jr.; Sylvester, W. B.; Donelan, M. A.

1986-01-01

The present paper provides a description of four aspects of scatterometer winds and their uses. The theory of wave generation by the wind is considered along with an analysis of the properties of superobservations, and studies of intermittent versus continuous data assimilation methods for numerical weather predictions which use remotely sensed data. A comparison of the sum of squares versus the maximum likelihood method for recovering the vector winds is also conducted. Questions regarding wind speed, friction velocity, or normal stress are discussed and synoptic scale fields from Seasat-SASS data are examined.

Corollary discharge inhibition of wind-sensitive cercal giant interneurons in the singing field cricket

Science.gov (United States)

Hedwig, Berthold

2014-01-01

Crickets carry wind-sensitive mechanoreceptors on their cerci, which, in response to the airflow produced by approaching predators, triggers escape reactions via ascending giant interneurons (GIs). Males also activate their cercal system by air currents generated due to the wing movements underlying sound production. Singing males still respond to external wind stimulation, but are not startled by the self-generated airflow. To investigate how the nervous system discriminates sensory responses to self-generated and external airflow, we intracellularly recorded wind-sensitive afferents and ventral GIs of the cercal escape pathway in fictively singing crickets, a situation lacking any self-stimulation. GI spiking was reduced whenever cercal wind stimulation coincided with singing motor activity. The axonal terminals of cercal afferents showed no indication of presynaptic inhibition during singing. In two ventral GIs, however, a corollary discharge inhibition occurred strictly in phase with the singing motor pattern. Paired intracellular recordings revealed that this inhibition was not mediated by the activity of the previously identified corollary discharge interneuron (CDI) that rhythmically inhibits the auditory pathway during singing. Cercal wind stimulation, however, reduced the spike activity of this CDI by postsynaptic inhibition. Our study reveals how precisely timed corollary discharge inhibition of ventral GIs can prevent self-generated airflow from triggering inadvertent escape responses in singing crickets. The results indicate that the responsiveness of the auditory and wind-sensitive pathway is modulated by distinct CDIs in singing crickets and that the corollary discharge inhibition in the auditory pathway can be attenuated by cercal wind stimulation. PMID:25318763

JacketSE: An Offshore Wind Turbine Jacket Sizing Tool; Theory Manual and Sample Usage with Preliminary Validation

Energy Technology Data Exchange (ETDEWEB)

Damiani, Rick [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-02-08

This manual summarizes the theory and preliminary verifications of the JacketSE module, which is an offshore jacket sizing tool that is part of the Wind-Plant Integrated System Design & Engineering Model toolbox. JacketSE is based on a finite-element formulation and on user-prescribed inputs and design standards' criteria (constraints). The physics are highly simplified, with a primary focus on satisfying ultimate limit states and modal performance requirements. Preliminary validation work included comparing industry data and verification against ANSYS, a commercial finite-element analysis package. The results are encouraging, and future improvements to the code are recommended in this manual.

On the rejection of internal and external disturbances in a wind energy conversion system with direct-driven PMSG.

Science.gov (United States)

Li, Shengquan; Zhang, Kezhao; Li, Juan; Liu, Chao

2016-03-01

This paper deals with the critical issue in a wind energy conversion system (WECS) based on a direct-driven permanent magnet synchronous generator (PMSG): the rejection of lumped disturbance, including the system uncertainties in the internal dynamics and unknown external forces. To simultaneously track the motor speed in real time and capture the maximum power, a maximum power point tracking strategy is proposed based on active disturbance rejection control (ADRC) theory. In real application, system inertia, drive torque and some other parameters change in a wide range with the variations of disturbances and wind speeds, which substantially degrade the performance of WECS. The ADRC design must incorporate the available model information into an extended state observer (ESO) to compensate the lumped disturbance efficiently. Based on this principle, a model-compensation ADRC is proposed in this paper. Simulation study is conducted to evaluate the performance of the proposed control strategy. It is shown that the effect of lumped disturbance is compensated in a more effective way compared with the traditional ADRC approach. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Effects of slotting and unipolar flux on magnetic pull in a two-pole induction motor with an extra four-pole stator winding

Energy Technology Data Exchange (ETDEWEB)

Sinervo, A.

2013-06-01

This thesis is about the radial magnetic forces between the rotor and stator in twopole induction machines. The magnetic forces arise from rotor eccentricity. The asymmetric air-gap makes the flux density on one side of the rotor stronger than on the opposite side. This produces magnetic pull. The magnetic flux density distribution in the air-gap can be expressed with spatial harmonics, i.e. flux densities with different pole-pair numbers. In two-pole machines, the main part of the magnetic force is produced by the interaction of two- and fourpole flux unless the four-pole flux is damped by parallel paths in the stator winding or an extra four-pole stator winding. The rest of the force comes from the interaction of two-pole and unipolar flux and from the higher harmonics of the air-gap flux of which the slot harmonics are a major part. The force caused by the higher harmonics and the unipolar flux is studied in the case where a four-pole stator winding is used to reduce the four-pole flux. The higher harmonics are found to produce, in addition to the traditional unbalanced magnetic pull, a force similar to the effect of the unipolar flux and the two can be distinguished only by measuring the unipolar flux. In measurements at various operation points, the higher harmonics are found to produce much more force than the unipolar flux and two-pole flux but the unipolar flux is still significant. The four-pole winding also is used to actively control the four-pole flux and the magnetic forces. Designing the controller requires a low order model of the system. Such a model is derived and the effect of the slot harmonics and the unipolar flux are included in the model. Different measurements techniques and methods are presented to identify and validate the control model. The operation point dependence of the system dynamics is studied via measurements. All results are obtained from a 30 kW test motor. The rotor of the test machine has a long flexible shaft on external

Porters versus rowers: a unified stochastic model of motor proteins.

Science.gov (United States)

Leibler, S; Huse, D A

1993-06-01

We present a general phenomenological theory for chemical to mechanical energy transduction by motor enzymes which is based on the classical "tight-coupling" mechanism. The associated minimal stochastic model takes explicitly into account both ATP hydrolysis and thermal noise effects. It provides expressions for the hydrolysis rate and the sliding velocity, as functions of the ATP concentration and the number of motor enzymes. It explains in a unified way many results of recent in vitro motility assays. More importantly, the theory provides a natural classification scheme for the motors: it correlates the biochemical and mechanical differences between "porters" such as cellular kinesins or dyneins, and "rowers" such as muscular myosins or flagellar dyneins.

Levitation Performance of Two Opposed Permanent Magnet Pole-Pair Separated Conical Bearingless Motors

Science.gov (United States)

Kascak, Peter; Jansen, Ralph; Dever, Timothy; Nagorny, Aleksandr; Loparo, Kenneth

2013-01-01

In standard motor applications, rotor suspension with traditional mechanical bearings represents the most economical solution. However, in certain high performance applications, rotor suspension without contacting bearings is either required or highly beneficial. Examples include applications requiring very high speed or extreme environment operation, or with limited access for maintenance. This paper expands upon a novel bearingless motor concept, in which two motors with opposing conical air-gaps are used to achieve full five-axis levitation and rotation of the rotor. Force in this motor is created by deliberately leaving the motor s pole-pairs unconnected, which allows the creation of different d-axis flux in each pole pair. This flux imbalance is used to create lateral force. This approach is different than previous bearingless motor designs, which require separate windings for levitation and rotation. This paper examines the predicted and achieved suspension performance of a fully levitated prototype bearingless system.

On the continuum theory of the two-fluid solar wind for small mass ratio

International Nuclear Information System (INIS)

Johnson, R.S.

1976-01-01

The continuum theory for the two-fluid solar wind is considered. The fluid is assumed to be a fully ionized neutral plasma of electrons and protons which is compressible, viscous and heat conducting with a constant Prandtl number and a viscosity proportional to (temperature) sup(ω), ω > 1. The gas is under the influence of a gravitational field centred on the Sun. It is assumed that the bulk velocity (at any point) is the same for both electrons and protons, but that an energy transfer can occur between the two species due to binary (Coulomb) collisions. The equations are non-dimensionalized and it is shown that the natural parameter to use in the construction of an asymptotic solution is the mass ratio. The limit mass ratio → zero corresponds to the small Prandtl number limit for the one-fluid theory developed by Johnson (Proc. R. Soc. (Lond) A; 347:537 (1976)). By using the method of matched asymptotic expansions, a solution is constructed that starts from the base of the corona and extends out to a diffuse shock layer. The results obtained exactly parallel the one-fluid theory and many details are identified and absorbed into this analysis. It is shown how the temperatures in the corona eventually become the well-known behaviours: rsup(-2/7) (electrons), rsup(-6/7) (protons) when ω = 5/2 and r is the radial coordinate. However, the continuum theory will probably have failed in the shock layer region - the more so since this occurs at about 100 light years distance - and further mathematical details are omitted. The numerical estimates given here compare tolerably well with the observed data and very favourably with other work on the same equations. (author)

Design of Linear Control System for Wind Turbine Blade Fatigue Testing

DEFF Research Database (Denmark)

Toft, Anders; Roe-Poulsen, Bjarke Nørskov; Christiansen, Rasmus

2016-01-01

This paper proposes a linear method for wind turbine blade fatigue testing at Siemens Wind Power. The setup consists of a blade, an actuator (motor and load mass) that acts on the blade with a sinusoidal moment, and a distribution of strain gauges to measure the blade flexure. Based...... difficult to control. To make a linear controller, a different approach has been chosen, namely making a controller which is not regulating on the input frequency, but on the input amplitude. A non-linear mechanical model for the blade and the motor has been constructed. This model has been simplified based...... on the desired output, namely the amplitude of the blade. Furthermore, the model has been linearised to make it suitable for linear analysis and control design methods.\\\\ The controller is designed based on a simplified and linearised model, and its gain parameter determined using pole placement. The model...

Wind Turbine design and fabrication to power street lights

Directory of Open Access Journals (Sweden)

Khan Mohammad

2017-01-01

Full Text Available The objective of this work was to design and build a wind turbine which can be used to power small street lights. Considering the typical wind speeds in Abu Dhabi, UAE and ease of construction, the design of the wind turbine was chosen to be Sea Hawk design from vertical axis wind turbine category. A three phase AC generator was used for its availability over the DC motors within the region. A 12V battery was used for storage and a charge controller was used for controlling the charge flow into the battery and for controlling the turbine rotation when the battery is fully charged. The blades used in the turbine were made of foam board according to the NACA 0018 airfoil shape with a chord length of 15cm. The connecting shaft was made of stainless steel. Structural analysis and CFD analysis were performed along with other calculations. Testing was executed to calculate the voltage output from the turbine at different wind speeds. The maximum voltage the turbine produced at 6.4 m/s wind speed was 2.4Vand the rotational speed of the turbine was 60.3 rpm.

Counteracting Rotor Imbalance in a Bearingless Motor System with Feedforward Control

Science.gov (United States)

Kascak, Peter Eugene; Jansen, Ralph H.; Dever, Timothy; Nagorny, Aleksandr; Loparo, Kenneth

2012-01-01

In standard motor applications, traditional mechanical bearings represent the most economical approach to rotor suspension. However, in certain high performance applications, rotor suspension without bearing contact is either required or highly beneficial. Such applications include very high speed, extreme environment, or limited maintenance access applications. This paper extends upon a novel bearingless motor concept, in which full five-axis levitation and rotation of the rotor is achieved using two motors with opposing conical air-gaps. By leaving the motors' pole-pairs unconnected, different d-axis flux in each pole-pair is created, generating a flux imbalance which creates lateral force. Note this is approach is different than that used in previous bearingless motors, which use separate windings for levitation and rotation. This paper will examine the use of feedforward control to counteract synchronous whirl caused by rotor imbalance. Experimental results will be presented showing the performance of a prototype bearingless system, which was sized for a high speed flywheel energy storage application, with and without feedforward control.

Toward an Integrated Optical Data System for Wind Tunnel Testing

National Research Council Canada - National Science Library

Ruyten, Wim

1999-01-01

...) of the test article in a wind tunnel test. The theory for such P&A determinations is developed and applied to data from a recent pressure sensitive paint test in AEDC's 16 ft transonic wind tunnel...

Adaptive State Feedback—Theory and Application for Wind Turbine Control

Directory of Open Access Journals (Sweden)

Kaman Thapa Magar

2017-12-01

Full Text Available A class of adaptive disturbance tracking controllers (ADTCs is augmented with disturbance and state estimation and adaptive state feedback, in which a controller and estimator, which are designed on the basis of a lower-order model, are used to control a higher-order nonlinear plant. The ADTC requires that the plant be almost strict positive real (ASPR to ensure stability. In this paper, we show that the ASPR property of a plant is retained with the addition of disturbance and state estimation and state feedback, thereby ensuring the stability of the augmented system. The proposed adaptive controller with augmentation is presented in the context of maximum power extraction from a wind turbine in a low-wind-speed operation region. A simulation and comparative study on the National Renewable Energy Laboratory’s (NREL’s 5 MW nonlinear wind turbine model with an existing baseline Proportional-Integral-Derivative(PID controller shows that the proposed controller is more effective than the existing baseline PID controller.

DC servo motor positioning with anti-windup implementation using C2000 ARM-Texas Instrument

Science.gov (United States)

Linggarjati, Jimmy

2017-12-01

One of the most important topics in control system is DC Motor. At this research, a positioning control system for a DC motor is investigated. Firstly, the DC Motor will be paramaterized to get the transfer function model, in order to be simulated in Matlab, and then implemented in a C2000-ARM microcontroller from TI (Texas Instrument). With this investigation, students in control system theory will be able to understand the importance of classical control theories, in relation to the real world implementation of the position control for the DC Motor, escpecially the importance of Anti-Windup technique in real-world implementation.

Design and simulation of permanent magnet synchronous motor control system

Science.gov (United States)

Li, Li; Liu, Yongqiu

2018-06-01

In recent years, with the development of power electronics, microelectronics, new motor control theory and rare earth permanent magnet materials, permanent magnet synchronous motors have been rapidly applied. Permanent magnet synchronous motors have the advantages of small size, low loss and high efficiency. Today, energy conservation and environmental protection are increasingly valued. It is very necessary to study them. Permanent magnet synchronous motor control system has a wide range of application prospects in the fields of electric vehicles, ships and other transportation. Using the simulation function of MATLAB/SIMULINK, a modular design structure was used to simulate the whole system model of speed loop adjustment, current PI modulation, SVPWM (Space Vector Pulse Width Module) wave generation and double closed loop. The results show that this control method has good robustness, and this method can improve the design efficiency and shorten the system design time. In this article, the analysis of the control principle of modern permanent magnet synchronous motor and the various processes of MATLAB simulation application will be analyzed in detail. The basic theory, basic method and application technology of the permanent magnet synchronous motor control system are systematically introduced.

Four quadrant control circuit for a brushless three-phase dc motor

Science.gov (United States)

Nola, Frank J. (Inventor)

1987-01-01

A control circuit is provided for a brushless three-phase dc motor which affords four quadrant control from a single command. The control circuit probes acceleration of the motor in both clockwise and counterclockwise directions and braking and generation in both clockwise and counterclockwise directions. In addition to turning on individual transistors of the transistor pairs connected to the phase windings of the motor for 120 deg periods while the other transistor of that pair is off, the control circuit also provides, in a future mode of operation, turning the two transistors of each pair on and off alternately at a phase modulation frequency during such a 120 deg period. A feedback signal is derived which is proportional to the motor current and which has a polarity consistent with the command signal, such that negative feedback results.

Turbulent wind field characterization and re-generation based on pitot tube measurements mounted on a wind turbine

DEFF Research Database (Denmark)

Pedersen, Mads Mølgaard; Larsen, Torben J.; Aagaard Madsen, Helge

2015-01-01

models that compensate for axial and tangential induction, approximated by blade element momentum theory, radial expansion of the inflow, rotor tilt, dynamic and skew inflow, tip loss, as well as braking and circulation of the flow local to the airfoil. The wind speeds measured on the rotating blades...... the measured wind speeds at the recording position. In the theoretical part of this study a quite good agreement is seen between load sensors on a turbine model exposed to the reference and the re-generated turbulence field. Finally the method is applied to full scale measurements and reasonable wind shear...

Wind scatterometry with improved ambiguity selection and rain modeling

Science.gov (United States)

Draper, David Willis

Although generally accurate, the quality of SeaWinds on QuikSCAT scatterometer ocean vector winds is compromised by certain natural phenomena and retrieval algorithm limitations. This dissertation addresses three main contributors to scatterometer estimate error: poor ambiguity selection, estimate uncertainty at low wind speeds, and rain corruption. A quality assurance (QA) analysis performed on SeaWinds data suggests that about 5% of SeaWinds data contain ambiguity selection errors and that scatterometer estimation error is correlated with low wind speeds and rain events. Ambiguity selection errors are partly due to the "nudging" step (initialization from outside data). A sophisticated new non-nudging ambiguity selection approach produces generally more consistent wind than the nudging method in moderate wind conditions. The non-nudging method selects 93% of the same ambiguities as the nudged data, validating both techniques, and indicating that ambiguity selection can be accomplished without nudging. Variability at low wind speeds is analyzed using tower-mounted scatterometer data. According to theory, below a threshold wind speed, the wind fails to generate the surface roughness necessary for wind measurement. A simple analysis suggests the existence of the threshold in much of the tower-mounted scatterometer data. However, the backscatter does not "go to zero" beneath the threshold in an uncontrolled environment as theory suggests, but rather has a mean drop and higher variability below the threshold. Rain is the largest weather-related contributor to scatterometer error, affecting approximately 4% to 10% of SeaWinds data. A simple model formed via comparison of co-located TRMM PR and SeaWinds measurements characterizes the average effect of rain on SeaWinds backscatter. The model is generally accurate to within 3 dB over the tropics. The rain/wind backscatter model is used to simultaneously retrieve wind and rain from SeaWinds measurements. The simultaneous

Double-winding Wilson loops in SU(N) Yang-Mills theory - A criterion for testing the confinement models -

Science.gov (United States)

Matsudo, Ryutaro; Kondo, Kei-Ichi; Shibata, Akihiro

2018-03-01

We examine how the average of double-winding Wilson loops depends on the number of color N in the SU(N) Yang-Mills theory. In the case where the two loops C1 and C2 are identical, we derive the exact operator relation which relates the doublewinding Wilson loop operator in the fundamental representation to that in the higher dimensional representations depending on N. By taking the average of the relation, we find that the difference-of-areas law for the area law falloff recently claimed for N = 2 is excluded for N ⩾ 3, provided that the string tension obeys the Casimir scaling for the higher representations. In the case where the two loops are distinct, we argue that the area law follows a novel law (N - 3)A1/(N - 1) + A2 with A1 and A2(A1 law when (N ⩾ 3). Indeed, this behavior can be confirmed in the two-dimensional SU(N) Yang-Mills theory exactly.

Motivation in pediatric motor rehabilitation: A systematic search of the literature using the self-determination theory as a conceptual framework.

Science.gov (United States)

Meyns, Pieter; Roman de Mettelinge, Tine; van der Spank, Judith; Coussens, Marieke; Van Waelvelde, Hilde

2017-03-09

Motivation is suggested as an important factor in pediatric motor rehabilitation. Therefore, we reviewed the existing evidence of (motivational) motor rehabilitation paradigms, and how motivation influences rehabilitation outcome using self-determination theory as conceptual framework. PubMed and Web-of-Science databases were systematically searched until June 2015. Data were independently extracted and critiqued for quality by three authors. Studies reporting motivational aspects were included. Most studies examined new technology (e.g., virtual reality [VR]). Out of 479 records, three RCT, six case-control, and six non-comparative studies were included with mixed quality. Motivation was rarely reported. Training individualization to the child's capabilities with more variety seemed promising to increase motivation. Motivation increased when the exercises seemed helpful for daily activities. Motivation in pediatric rehabilitation should be comprehensively assessed within a theoretical framework as there are indications that motivated children have better rehabilitation outcomes, depending on the aspect of motivation.

Dynamic Response Analysis of Linear Pulse Motor with Closed Loop Control

OpenAIRE

山本, 行雄; 山田, 一

1989-01-01

A linear pulse motor can translate digital signals into linear positions without a gear system. It is important to predict a dynamic response in order to the motor that has the good performance. In this report the maximum pulse rate and the maximum speed on the linear pulse motor are obtained by using the sampling theory.

Measurement of starting characteristics of a remote area Darrieus wind turbine

Energy Technology Data Exchange (ETDEWEB)

Freere, P. [Monash University, Clayton (Australia). Dept. of Electrical Engineering; Moller, C.; Jespersen, R. [Danish Technical University, Copenhagen (Denmark). Dept. of Electrical Engineering

1999-07-01

A 17 kW Darrieus was constructed as a remote area power supply for an independent community outside Melbourne, Australia. After languishing for several years it was reconditioned, but found not to start at wind speeds up to 12 m/s. Therefore, the turbine was modelled by driving it with an electric motor at various rotational speeds over a range of wind speeds. Thus it was possible to measure the turbine starting characteristics, thereby indicating reasons for the turbine's lack of performance. (author)

Comparative FEM-based Analysis of Multiphase Induction Motor

Directory of Open Access Journals (Sweden)

Leonard Livadaru

2014-09-01

Full Text Available This paper presents a comparative study of multiphase induction motor, which has alternately three-, five- and six-phase stator winding. The machine has been designed particularly for this purpose and has individual ring coils placed in each stator slot. The study consists in FEM analyses and mainly looks for the particularities of magnetic quantities such as air-gap flux density and electromagnetic torque.

The Evidence Against Learnability of Early Motor Skills Reconsidered.

Science.gov (United States)

Razel, Micha

This paper attempts to refute the assumption that early motor development is determined genetically and is not influenced by environmental factors. The paper re-examines three studies which are consistently cited as providing evidence for a maturational theory of motor development: the "early training study" by Gesell and Thompson, the "swaddling…

Analysis of the linear induction motor in transient operation

Energy Technology Data Exchange (ETDEWEB)

Gentile, G; Rotondale, N; Scarano, M

1987-05-01

The paper deals with the analysis of a bilateral linear induction motor in transient operation. We have considered an impressed voltage one-dimensional model which takes into account end effects. The real winding distribution of the armature has been represented as a lumped parameters system. By using the space vectors methodology, the partial differential equation of the sheet is solved bythe variable separation method. Therefore it's possible to arrange a system of ordinary differential equations where the unknown quantities are the space vectors of the air-gap flux density and sheet currents. Finally, we have analyzed the characteristic quantities for a no-load starting of small power motors.

Performance of a 10 kilowatt wind-electric water pumping system for irrigating crops

Energy Technology Data Exchange (ETDEWEB)

Vick, B.D.; Clark, R.N. [Conservation and Production Research Lab., Bushland, TX (United States); Molla, S. [Texas A& M Univ., College Station, TX (United States)

1997-12-31

A 10 kW wind-electric water pumping system was tested for field crop irrigation at pumping depths from 50 to 120 m. The wind turbine for this system used a permanent magnet alternator that powered off-the-shelf submersible motors and pumps without the use of an inverter. Pumping performance was determined at the USDA-Agricultural Research Service (ARS), Wind Energy Laboratory in Bushland, TX for the 10 kW wind turbine using a pressure valve and a pressure tank to simulate different pumping depths. Pumping performance was measured for two 10 kW wind turbines of the same type at farms near the cities of Garden City, TX and Stiles, TX. The pumping performance data collected at these actual wells compared favorably with the data collected at the USDA-ARS, Wind Energy Laboratory. If utility generated electricity was accessible, payback on the wind turbine depended on the cost of utility generated electricity and the transmission line extension cost.

Online Business Strategy: Mazda Motor Europe GmbH

OpenAIRE

Peltokangas, Merja

2009-01-01

Mazda Motors is a japanese car manufacturer, founded in 1920. The headquarter is located in Hiroshima, Japan and the European headquarter is located in Leverkusen, Germany. The aim of this thesis is to investigate how Mazda Motor Europe GmbH could improve its accessory sales in the future and reach more young customers. Based on the research results Mazda Motor Europe GmbH can see how the main competitors are positioned in the market and consider its own strategy. In the theory part o...

O?shore ?oating wind turbine and its dynamic problems?

Institute of Scientific and Technical Information of China (English)

Renchuan ZHU; Guoping MIAO; Ju FAN; Hua LIU

2016-01-01

Green energy sources and ocean wind power are plentiful in deep sea. More and more o?shore wind power plants are constructed in the deep water over hundred meters below the surface. While o?shore ?oating wind turbine system is working, wind turbine, ?oating foundation, and mooring system a?ect each other with wind, waves, and currents acting on them. Various o?shore ?oating wind turbine systems and the encoun-tered environmental loads are brie?y reviewed and discussed. It is di?cult and crucial to comprehensively analyze the aerodynamic-hydrodynamic-service system-structure un-der the coupling e?ect of o?shore ?oating wind turbine system. The environmental ?ow ?eld, structure scale, and rational applications of theories and approaches should be well considered in advance.

Technical analysis of utilization suitability of various wind rotor’s types for compressor’s power driving

Directory of Open Access Journals (Sweden)

Radim Rybár

2005-03-01

Full Text Available Conception is from the converting of wind energy, which flows across the wind turbine in mechanic work needed for compressor working. The wind motor one part of energy transform into mechanical work, part of energy is unused and part of energy of stead flow is transformed into eddy after wind rotor.The aim was rendering of technical analysis for equipment, which would use the wind with parameters for chosen area and whole unit would supply power in peak demand. Unit consists of wind turbine, which pushes compressor. Compressor pumps air into the compressed air storage. The air is used for power producing in time of peak demand.

Survey of variable speed operation of wind turbines

Energy Technology Data Exchange (ETDEWEB)

Carlson, Ola; Hylander, J.; Thorborg, K. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electric Power Engineering

1996-12-01

During the last five years the production and operation of variable-speed wind turbines have advanced from a few experimental machines to a serial production of at least 10 MW of installed capacity of variable speed machines per week. The rated power of serial wind turbines is today around 600 kW and for the prototypes up to 3000 kW. Variable speed operation of wind turbines can be obtained with several different types of electrical generating systems, such as synchronous generators with diode rectifiers and thyristor inverters or induction generators with IGBT-converters, for the wide speed range. For the narrow speed range the wound motor induction generator with a rotor cascade or a controlled rotor resistance is preferable. The development of permanent magnetic material and the reduction of costs of the power electronic components have opened a possibility of designing cost-effective wind turbines with a directly driven generator. Pitch control together with variable speed will make it possible to limit the power variation within a few percent, 2 to 5 %, of the rated power. 7 refs, 4 figs, 2 tabs

Electric vehicle battery charging algorithm using PMSM windings and an inverter as an active rectifier

DEFF Research Database (Denmark)

Zaja, Mario; Oprea, Matei-lon; Suárez, Carlos Gómez

2014-01-01

for battery charging. Alternatively, charging could be done using the motor windings as grid side inductors and controlling the inverter to operate as an active boost rectifier. The challenge in this approach is the unequal phase inductances which depend on the rotor position. Another problem appears when...... an integrated charger control algorithm to charge the battery through a permanent magnet synchronous machine (PMSM) windings....

Flow widening through a Darrieus wind turbine - Theory and experiment

Science.gov (United States)

Comolet, R.; Harajli, I.; Mercier Des Rochettes, P.; Yeznasni, A.

1982-11-01

A two-dimensional multiple stream tube model is developed for the air flow through a Darrieus wind turbine. The model is configured to account for the widening of the flux tubes as they cross the interior of the actuator disk. Note is made of the lateral broadening of the flow as it moves through the area, leaving a turbulent wake. A relation is defined between the variation in the kinetic energy of the flow and the aerodynamic forces acting on the blades. The global efficiency and the power output of the machine are calculated. Experimental results are reported for a machine equipped with two NACA 0015 blades, each 110 cm long and with a 10 cm chord. The Darrieus had a 1 m diam and was tested in a wind tunnel at wind speeds of 0-18 m/sec. Soap bubbles inflated with He were used for visualization. Power output was found to match prediction. The model is recommended for use in calculating the forces acting on the machine and studying vibration and fatigue causative mechanisms.

Optimized chord and twist angle distributions of wind turbine blade considering Reynolds number effects

Energy Technology Data Exchange (ETDEWEB)

Wang, L.; Tang, X. [Univ. of Central Lancashire. Engineering and Physical Sciences, Preston (United Kingdom); Liu, X. [Univ. of Cumbria. Sustainable Engineering, Workington (United Kingdom)

2012-07-01

The aerodynamic performance of a wind turbine depends very much on its blade geometric design, typically based on the blade element momentum (BEM) theory, which divides the blade into several blade elements. In current blade design practices based on Schmitz rotor design theory, the blade geometric parameters including chord and twist angle distributions are determined based on airfoil aerodynamic data at a specific Reynolds number. However, rotating wind turbine blade elements operate at different Reynolds numbers due to variable wind speed and different blade span locations. Therefore, the blade design through Schmitz rotor theory at a specific Reynolds number does not necessarily provide the best power performance under operational conditions. This paper aims to provide an optimal blade design strategy for horizontal-axis wind turbines operating at different Reynolds numbers. A fixed-pitch variable-speed (FPVS) wind turbine with S809 airfoil is chosen as a case study and a Matlab program which considers Reynolds number effects is developed to determine the optimized chord and twist angle distributions of the blade. The performance of the optimized blade is compared with that of the preliminary blade which is designed based on Schmitz rotor design theory at a specific Reynolds number. The results demonstrate that the proposed blade design optimization strategy can improve the power performance of the wind turbine. This approach can be further developed for any practice of horizontal axis wind turbine blade design. (Author)

High speed subfractional HP-motor with permanent magnets

International Nuclear Information System (INIS)

Hanitsch, R.; Frenzel, B.

1998-01-01

During the last years an increasing demand for small permanent magnet motors can be detected, especially in the fields of medical applications. For heart assist devices there is the request to have small high speed devices operating at low voltage supply with almost no overtemperature. The design of a special hollow shaft motor for the speed range of 15000..25000 rpm and a torque of 4 to 8 mNm will be outlined. The low noise requirements and the high efficiency request lead to a design with an airgap winding. A thermal analysis is also done in order to meet the conditions given by the medical specialists. The features of the prototype will be presented and also the sensorless control strategy will be outlined. Measured and calculated data show good agreement. Focus will be on the magnetic circuit and the thermal behaviour and not on the control aspects of the motor. Specific parameters demonstrate the good quality of the drive system. (orig.)

Muscle activation described with a differential equation model for large ensembles of locally coupled molecular motors.

Science.gov (United States)

Walcott, Sam

2014-10-01

Molecular motors, by turning chemical energy into mechanical work, are responsible for active cellular processes. Often groups of these motors work together to perform their biological role. Motors in an ensemble are coupled and exhibit complex emergent behavior. Although large motor ensembles can be modeled with partial differential equations (PDEs) by assuming that molecules function independently of their neighbors, this assumption is violated when motors are coupled locally. It is therefore unclear how to describe the ensemble behavior of the locally coupled motors responsible for biological processes such as calcium-dependent skeletal muscle activation. Here we develop a theory to describe locally coupled motor ensembles and apply the theory to skeletal muscle activation. The central idea is that a muscle filament can be divided into two phases: an active and an inactive phase. Dynamic changes in the relative size of these phases are described by a set of linear ordinary differential equations (ODEs). As the dynamics of the active phase are described by PDEs, muscle activation is governed by a set of coupled ODEs and PDEs, building on previous PDE models. With comparison to Monte Carlo simulations, we demonstrate that the theory captures the behavior of locally coupled ensembles. The theory also plausibly describes and predicts muscle experiments from molecular to whole muscle scales, suggesting that a micro- to macroscale muscle model is within reach.

Wind Energy and Transport Synergy: Electric Vehicle or Hydrogen Vehicle?; Sinergia Energia Eolica Transporte: vehiculo electrico o vehiculo de hidrogeno?

Energy Technology Data Exchange (ETDEWEB)

Cruz, I.

2009-07-01

This article briefly analyzes the potential uses of hydrogen as a form of energy from wind power. It also briefly describes the different experiences gained in wind energy-based hydrogen production by water hydrolysis, and finally it concludes with a brief analysis of the competition between hydrogen and the new ion-lithium batteries used in motor vehicles as potential solutions to support wind energy management. (Author)

Sensing the wind profile

Energy Technology Data Exchange (ETDEWEB)

Pena, A.

2009-03-15

This thesis consists of two parts. The first is a synopsis of the theoretical progress of the study that is based on a number of journal papers. The papers, which constitute the second part of the report, aim to analyze, measure, and model the wind prole in and beyond the surface layer by combining observations from cup anemometers with lidars. The lidar is necessary to extend the measurements on masts at the Horns Rev offshore wind farm and over at land at Hoevsoere, Denmark. Both sensing techniques show a high degree of agreement for wind speed measurements performed at either sites. The wind speed measurements are averaged for several stability conditions and compare well with the surface-layer wind profile. At Hoevsoere, it is sufficient to scale the wind speed with the surface friction velocity, whereas at Horns Rev a new scaling is added, due to the variant roughness length. This new scaling is coupled to wind prole models derived for flow over the sea and tested against the wind proles up to 160 m at Horns Rev. The models, which account for the boundary-layer height in stable conditions, show better agreement with the measurements than compared to the traditional theory. Mixing-length parameterizations for the neutral wind prole compare well with length-scale measurements up to 300 m at Hoevsoere and 950 m at Leipzig. The mixing-length-derived wind proles strongly deviate from the logarithmic wind prole, but agree better with the wind speed measurements. The length-scale measurements are compared to the length scale derived from a spectral analysis performed up to 160 m at Hoevsoere showing high agreement. Mixing-length parameterizations are corrected to account for stability and used to derive wind prole models. These compared better to wind speed measurements up to 300 m at Hoevsoere than the surface-layer wind prole. The boundary-layer height is derived in nearneutral and stable conditions based on turbulent momentum uxes only and in unstable conditions

Sensorless AC electric motor control robust advanced design techniques and applications

CERN Document Server

Glumineau, Alain

2015-01-01

This monograph shows the reader how to avoid the burdens of sensor cost, reduced internal physical space, and system complexity in the control of AC motors. Many applications fields—electric vehicles, wind- and wave-energy converters and robotics, among them—will benefit. Sensorless AC Electric Motor Control describes the elimination of physical sensors and their replacement with observers, i.e., software sensors. Robustness is introduced to overcome problems associated with the unavoidable imperfection of knowledge of machine parameters—resistance, inertia, and so on—encountered in real systems. The details of a large number of speed- and/or position-sensorless ideas for different types of permanent-magnet synchronous motors and induction motors are presented along with several novel observer designs for electrical machines. Control strategies are developed using high-order, sliding-mode and quasi-continuous-sliding-mode techniques and two types of observer–controller schemes based on backstepping ...

Dynamics and mechanics of motor-filament systems

Science.gov (United States)

Kruse, K.; Jülicher, F.

2006-08-01

Motivated by the cytoskeleton of eukaryotic cells, we develop a general framework for describing the large-scale dynamics of an active filament network. In the cytoskeleton, active cross-links are formed by motor proteins that are able to induce relative motion between filaments. Starting from pair-wise interactions of filaments via such active processes, our framework is based on momentum conservation and an analysis of the momentum flux. This allows us to calculate the stresses in the filament network generated by the action of motor proteins. We derive effective theories for the filament dynamics which can be related to continuum theories of active polar gels. As an example, we discuss the stability of homogenous isotropic filament distributions in two spatial dimensions.

Reconsidering the Capacity Credit of Wind Power: Application of Cumulative Prospect Theory

NARCIS (Netherlands)

Wilton, E.; Delarue, E.; D'haeseleer, W.; Sark, W.G.J.H.M. van

2014-01-01

The capacity credit is often erroneously considered to be a time-invariant quantity. A multi-year analysis of the incident wind profile of various potential wind sites uncovered that there exist large differences between annual capacity credit figures. The uniformity of these capacity credit

Reconsidering the capacity credit of wind power : Application of cumulative prospect theory

NARCIS (Netherlands)

Wilton, Edgar; Delarue, Erik; D'haeseleer, William; van Sark, Wilfried

The capacity credit is often erroneously considered to be a time-invariant quantity. A multi-year analysis of the incident wind profile of various potential wind sites uncovered that there exist large differences between annual capacity credit figures. The uniformity of these capacity credit figures

Design and analysis of new fault-tolerant permanent magnet motors for four-wheel-driving electric vehicles

Science.gov (United States)

Liu, Guohai; Gong, Wensheng; Chen, Qian; Jian, Linni; Shen, Yue; Zhao, Wenxiang

2012-04-01

In this paper, a novel in-wheel permanent-magnet (PM) motor for four-wheel-driving electrical vehicles is proposed. It adopts an outer-rotor topology, which can help generate a large drive torque, in order to achieve prominent dynamic performance of the vehicle. Moreover, by adopting single-layer concentrated-windings, fault-tolerant teeth, and the optimal combination of slot and pole numbers, the proposed motor inherently offers negligible electromagnetic coupling between different phase windings, hence, it possesses a fault-tolerant characteristic. Meanwhile, the phase back electromotive force waveforms can be designed to be sinusoidal by employing PMs with a trapezoidal shape, eccentric armature teeth, and unequal tooth widths. The electromagnetic performance is comprehensively investigated and the optimal design is conducted by using the finite-element method.

Minimisation of Generation Variability of a Group of Wind Plants

Directory of Open Access Journals (Sweden)

Dubravko Sabolić

2017-09-01

Full Text Available Minimisation of variability of energy delivered from a group of wind plants into the power system using portfolio theory approach was studied. One of the assumptions of that theory is Gaussian distribution of the sample, which is not satisfied in case of wind generation. Therefore, optimisation of a “portfolio” of plants with different goal functions was studied. It was supposed that a decision on distribution of a fixed amount of generation capacity to be installed among a set of geographical locations with known wind statistics is to be made with minimised variability of generation as a goal. In that way the statistical cancellation of variability would be used in the best possible manner. This article is a brief report on results of such an investigation. An example of nine locations in Croatia was used. These locations’ wind statistics are known from historic generation data.

A New Class of Resonant Discharge Drive Topology for Switched Reluctance Motor

Directory of Open Access Journals (Sweden)

M. Asgar

2009-12-01

Full Text Available Switched reluctance motor (SRM drive has a remarkable characteristic, high efficiency, and good controllability, which makes it attractive for high-speed applications. In this paper, the basic control strategy for a switched reluctance motor drive circuit is explained and then three different resonant discharge topologies for SRM drive circuit are proposed. Due to resonantly discharging of excess energy, these topologies provide faster rate of fall for the phase current, which permits the motor to operate at higher speeds. In the new circuits a capacitor is charged resonantly by the use of motor phase windings during the phase turn off periods and then discharged via an inductor and a diode during the next working strokes. Three different drive circuits utilizing this process are proposed. A detailed explanation and demonstration of the converter circuits have been presented.

Pain and motor control: From the laboratory to rehabilitation.

Science.gov (United States)

Hodges, Paul W

2011-04-01

Movement is changed in pain and is the target of clinical interventions. Yet the understanding of the physiological basis for movement adaptation in pain remains limited. Contemporary theories are relatively simplistic and fall short of providing an explanation for the variety of permutations of changes in movement control identified in clinical and experimental contexts. The link between current theories and rehabilitation is weak at best. New theories are required that both account for the breadth of changes in motor control in pain and provide direction for development and refinement of clinical interventions. This paper describes an expanded theory of the motor adaptation to pain to address these two issues. The new theory, based on clinical and experimental data argues that: activity is redistributed within and between muscles rather than stereotypical inhibition or excitation of muscles; modifies the mechanical behaviour in a variable manner with the objective to "protect" the tissues from further pain or injury, or threatened pain or injury; involves changes at multiple levels of the motor system that may be complementary, additive or competitive; and has short-term benefit, but with potential long-term consequences due to factors such as increased load, decreased movement, and decreased variability. This expanded theory provides guidance for rehabilitation directed at alleviating a mechanical contribution to the recurrence and persistence of pain that must be balanced with other aspects of a multifaceted intervention that includes management of psychosocial aspects of the pain experience. Copyright © 2011 Elsevier Ltd. All rights reserved.

Thermal loss of life and load-carrying capacity of marine induction motors

International Nuclear Information System (INIS)

Gnacinski, P.

2014-01-01

Highlights: • The effect of voltage quality on induction motors is investigated. • Power quality significantly affects machine lifetime and load-carrying capacity. • Permissible load levels for induction motors are proposed. - Abstract: This work deals with the effect of a lowered voltage quality on the thermal loss of life and load-carrying capacity of marine induction cage machines. Results of experimental investigations and computer calculations are presented for two low power induction motors with different properties. One of them has a comparatively strongly-saturated magnetic circuit and is especially exposed to the risk of overheating under overvoltage. The other machine has a comparatively weakly-saturated magnetic circuit, and is especially sensitive to undervoltage. The induction motor lifetime expectancy is also estimated on the basis of the temperature coefficient of power quality, whose value is proportional to the windings temperature rise in induction motors especially sensitive to various power quality disturbances. The dependence of the temperature coefficient of power quality and permissible loads for induction motors supplied with voltages of lowered quality is proposed

FUZZY LOGIC BASED OPTIMIZATION OF CAPACITOR VALUE FOR SINGLE PHASE OPEN WELL SUBMERSIBLE INDUCTION MOTOR

Directory of Open Access Journals (Sweden)

R. Subramanian

2011-01-01

Full Text Available Purpose – The aim of this paper is to optimize the capacitor value of a single phase open well submersible motor operating under extreme voltage conditions using fuzzy logic optimization technique and compared with no-load volt-ampere method. This is done by keeping the displacement angle (a between main winding and auxiliary winding near 90o, phase angle (f between the supply voltage and line current near 0o. The optimization work is carried out by using Fuzzy Logic Toolbox software built on the MATLAB technical computing environment with Simulink software. Findings – The optimum capacitor value obtained is used with a motor and tested for different supply voltage conditions. The vector diagrams obtained from the experimental test results indicates that the performance is improved from the existing value. Originality/value – This method will be highly useful for the practicing design engineers in selecting the optimum capacitance value for single phase induction motors to achieve the best performance for operating at extreme supply voltage conditions.

Short-term wind power prediction

DEFF Research Database (Denmark)

Joensen, Alfred K.

2003-01-01

, and to implement these models and methods in an on-line software application. The economical value of having predictions available is also briefly considered. The summary report outlines the background and motivation for developing wind power prediction models. The meteorological theory which is relevant......The present thesis consists of 10 research papers published during the period 1997-2002 together with a summary report. The objective of the work described in the thesis is to develop models and methods for calculation of high accuracy predictions of wind power generated electricity...

Periodic thermodynamics of laser-driven molecular motor

International Nuclear Information System (INIS)

Li Dan; Zheng Wenwei; Wang Zhisong

2008-01-01

Operation of a laser-driven nano-motor inevitably generates a non-trivial amount of heat, which can possibly lead to instability or even hinder the motor's continual running. This work quantitatively examines the overheating problem for a recently proposed laser-operated molecular locomotive. We present a single-molecule cooling theory, in which molecular details of the locomotive system are explicitly treated. This theory is able to quantitatively predict cooling efficiency for various candidates of molecular systems for the locomotive, and also suggests concrete strategies for improving the locomotive's cooling. It is found that water environment is able to cool the hot locomotive down to room temperature within 100 picoseconds after photon absorption. This cooling time is a few orders of magnitude shorter than the typical time for laser operation, effectively preventing any overheating for the nano-locomotive. However, when the cooling is less effective in non-aqueous environment, residual heat may build up. A continuous running of the motor will then lead to a periodic thermodynamics, which is a common character of many laser-operated nano-devices

Comparing mixing-length models of the diabatic wind profile over homogeneous terrain

DEFF Research Database (Denmark)

Pena Diaz, Alfredo; Gryning, Sven-Erik; Hasager, Charlotte Bay

2010-01-01

Models of the diabatic wind profile over homogeneous terrain for the entire atmospheric boundary layer are developed using mixing-length theory and are compared to wind speed observations up to 300 m at the National Test Station for Wind Turbines at Høvsøre, Denmark. The measurements are performe...

High Voltage Power Transmission for Wind Energy

Science.gov (United States)

Kim, Young il

The high wind speeds and wide available area at sea have recently increased the interests on offshore wind farms in the U.S.A. As offshore wind farms become larger and are placed further from the shore, the power transmission to the onshore grid becomes a key feature. Power transmission of the offshore wind farm, in which good wind conditions and a larger installation area than an onshore site are available, requires the use of submarine cable systems. Therefore, an underground power cable system requires unique design and installation challenges not found in the overhead power cable environment. This paper presents analysis about the benefit and drawbacks of three different transmission solutions: HVAC, LCC/VSC HVDC in the grid connecting offshore wind farms and also analyzed the electrical characteristics of underground cables. In particular, loss of HV (High Voltage) subsea power of the transmission cables was evaluated by the Brakelmann's theory, taking into account the distributions of current and temperature.

Development policy for non-grid-connected wind power in China: An analysis based on institutional change

International Nuclear Information System (INIS)

Fang Yong; Li Jing; Wang Mingming

2012-01-01

Government policy continues to play a crucial role in the development of wind power industry in China. The 2005 “Renewable Energy Law” and related policies have driven the rapid increase in wind power installed capacity in China over the past half-decade, with capacity doubling annually since 2005. However, a large number of wind farms generate electricity well below their installed capacity, resulting in considerable wastage of resources. Non-grid-connected wind power theory proposes that large-scale wind power output does not necessarily have to be fed into the grid, but can be used directly in industrial production. Thus, the use of the theory can promote the sustainable development of the wind power industry by obviating the need for power grid. In this paper we analyze the influence of government policy on wind power industry from the perspective of institutional change, by employing the basic theories of new institutional economics. A development model for non-grid-connected wind power is proposed in order to implement institutional change in accordance with the specific characteristics of wind power industry in China. This model requires the government to play an active role in institutional development by increasing economic efficiency in order to promote the sustainable development of wind power. - Highlights: ► New institutional economics-based analysis paradigm for wind power policy proposed. ► Policies for China's wind power industry analyzed according to the paradigm. ► Hybrid development mode of institutional change is the best pathway for wind power. ► Potential development policy for China's wind power industry recommended.

Method and apparatus for sensorless operation of brushless permanent magnet motors

Science.gov (United States)

Sriram, Tillasthanam V.

1998-01-01

A sensorless method and apparatus for providing commutation timing signals for a brushless permanent magnet motor extracts the third harmonic back-emf of a three-phase stator winding and independently cyclically integrates the positive and negative half-cycles thereof and compares the results to a reference level associated with a desired commutation angle.

On-Line Detection of Coil Inter-Turn Short Circuit Faults in Dual-Redundancy Permanent Magnet Synchronous Motors

Directory of Open Access Journals (Sweden)

Yiguang Chen

2018-03-01

Full Text Available In the aerospace and military fields, with high reliability requirements, the dual-redundancy permanent magnet synchronous motor (DRPMSM with weak thermal coupling and no electromagnetic coupling is needed. A common fault in the DRPMSM is the inter-turn short circuit fault (ISCF. However, research on how to diagnose ISCF and the set of faulty windings in the DRPMSM is lacking. In this paper, the structure of the DRPMSM is analyzed and mathematical models of the motor under normal and faulty conditions are established. Then an on-line ISCF detection scheme, which depends on the running modes of the DRPMSM and the average values for the difference of the d-axis voltages between two sets of windings in the latest 20 sampling periods, is proposed. The main contributions of this paper are to analyze the calculation for the inductance of each part of the stator windings and propose the on-line diagnosis method of the ISCF under various operating conditions. The simulation and experimental results show that the proposed method can quickly and effectively diagnose ISCF and determine the set of faulty windings of the DRPMSM.

Advanced axial field D.C. motor development for electric passenger vehicle

Science.gov (United States)

Jones, W. J.

1982-01-01

A wound-field axial-flux dc motor was developed for an electric vehicle drive system. The motor is essentially an axial-flux version of the classical Gramme-ring winding motor, but the active conductors are recessed into slots cut into the two opposite faces of the laminated tape-wound core ring. Three motors were built and tested in the program. The second (functional) model was a six-pole machine which weighed 88.5 kg. It developed 16.9 km (33.0 hp), and a max speed of 4800 rpm. Full load efficiency was 92% and predicted SAE D-cycle efficiency was 88%. The last engineering) model was a 4-pole machine with compoles, allowing a weight reduction to 45 kg (100 lbs.) while addressing some manufacturability problems. The engineering model was rated at 13.2 kw (17.6 hp) at 3000 rpm, with a peak power of 19.8 km (26.4 hp) and a max speed of 7200 rpm. Initial test results on this motor showed poor commutation and efficiency; the program was terminated without resolution of these problems.

Control Systems Lab Using a LEGO Mindstorms NXT Motor System

Science.gov (United States)

Kim, Y.

2011-01-01

This paper introduces a low-cost LEGO Mindstorms NXT motor system for teaching classical and modern control theories in standard third-year undergraduate courses. The LEGO motor system can be used in conjunction with MATLAB, Simulink, and several necessary toolboxes to demonstrate: 1) a modeling technique; 2) proportional-integral-differential…

Design and aero-acoustic analysis of a counter-rotating wind turbine

Science.gov (United States)

Agrawal, Vineesh V.

Wind turbines have become an integral part of the energy business because they are one of the most economical and reliable sources of renewable energy. Conventional wind turbines are capable of capturing less than half of the energy present in the wind. Hence, to make the wind turbines more efficient, it is important to increase their performance. A horizontal axis wind turbine with multiple rotors is one concept that can achieve a higher power conversion rate. Also, a concern for wind energy is the noise generated by wind turbines. Hence, an investigation into the acoustic behavior of a multi-rotor horizontal axis wind turbine is required. In response to the need of a wind turbine design with higher power coefficient, a unique design of a counter-rotating horizontal axis wind turbine (CR-HAWT) is proposed. The Blade Element Momentum (BEM) theory is used to aerodynamically design the blades of the two rotors. Modifications are made to the BEM theory to accommodate the interaction of the two rotors. The tower effect on the noise generation of the downwind rotor is investigated. Predictions are made for the total noise generated by the wind turbine at its design operating conditions. A total power coefficient of 65.2% is predicted for the proposed CR-HAWT design. A low tip speed ratio is chosen to minimize the noise generation. The aeroacoustic analysis of the CR-HAWT shows that the noise generated at its design operating conditions is within an acceptable range. Thus, the CR-HAWT is predicted to be a quiet wind turbine with a high power coefficient, making it highly desirable for small wind turbine applications.