IEEE Transactions on Industrial Electronics 

Volume 59,  Number 5, May 2012           Access to the journal on IEEE XPLORE     IE Transactions Home Page

59.5.1    L. Alberti, N. Bianchi, " Experimental Tests of Dual Three-Phase Induction Motor Under Faulty Operating Condition ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2041-2048, May 2012.   Abstract Link    Full Text

Abstract: This paper describes a set of experimental tests on a dual three-phase induction machine for fault-tolerant applications. Both three-phase and six-phase machine operations are considered. Different winding configurations are investigated and compared in case of both open-circuit and short-circuit faults. Experimental tests for each configuration are reported at no-load and under load operating conditions.

59.5.2    J.W. Bennett, G.J. Atkinson, B.C. Mecrow, D.J. Atkinson, " Fault-Tolerant Design Considerations and Control Strategies for Aerospace Drives ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2049-2058, May 2012.   Abstract Link    Full Text

Abstract: This paper considers existing more electric technologies in commercial aircraft and observes modern reliability data and redundancy techniques to highlight the reasons restricting the application of new components featuring electric drives and electromechanical actuation. Two techniques for maintaining a constant torque when faulted are applied to two very different fault-tolerant drives. Taking into consideration the test results and reliability data, conclusions are drawn as to the suitability of these and other drive configurations with regard to the stringent aerospace reliability and fault tolerance standards.

59.5.3    Xiao-Lin Wang, Qing-Chang Zhong, Zhi-Quan Deng, Shen-Zhou Yue, " Current-Controlled Multiphase Slice Permanent Magnetic Bearingless Motors With Open-Circuited Phases: Fault-Tolerant Controllability and Its Verification ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2059-2072, May 2012.   Abstract Link    Full Text

Abstract: The fault-tolerant control of bearingless motors is vital for their safe and robust operation. In this paper, the operation of current-controlled multiphase slice permanent-magnet bearingless motors (PMBMs) with different open-circuited faulty phases is analyzed, and their fault-tolerant controllability in the general case is investigated. As an example, the feasibility of fault-tolerant control with arbitrary single, double, or triple open-circuited faulty phase(s) for a six-phase slice PMBM is discussed in detail. Simulation results from finite-element analysis are presented to demonstrate the operation of the motor under the proposed fault-tolerant control strategy. Moreover, experimental results are also provided to further verify the theoretical development.

59.5.4    M. Villani, M. Tursini, G. Fabri, L. Castellini, " High Reliability Permanent Magnet Brushless Motor Drive for Aircraft Application ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2073-2081, May 2012.   Abstract Link    Full Text

Abstract: Reliability is a fundamental requirement in aircraft safety-critical equipments. Its pursuing involves the adoption of protective design concepts such as fault-tolerant or redundant approaches, aiming to minimize mission failure probabilities. Multi-phase motor drives are gaining a growing interest to this extent, because they permit a boost in torque and power density, allowing the design of very compact high efficiency drives with intrinsic fault-tolerant capabilities. This paper presents a five-phase permanent magnet brushless motor drive developed for an aircraft flap actuator application. The motor is designed to satisfy the load specifications with one or two phases open or with a phase short circuited, while a failure in the rotor position sensors is remedied through a sensorless strategy. Design studies aiming to predict the faulty mode performance in case of different remedial strategies are presented. Experimental tests on the drive prototype are included, which confirm its capability to satisfy the planned degraded modes of operation.

59.5.5    A. Ceban, R. Pusca, R. Romary, " Study of Rotor Faults in Induction Motors Using External Magnetic Field Analysis ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2082-2093, May 2012.   Abstract Link    Full Text

Abstract: This paper presents a new signature for detection of rotor faults in induction motors, such as eccentricity and broken rotor bars, that uses the external magnetic field analysis. The proposed method is based on the variations of axial flux density in the presence of these faults. The low frequency part of the magnetic field spectrum is particularly analyzed. The analysis is realized through a machine modeling based on permeance circuit under eccentricity fault and also by machine modeling based on coupled magnetic circuit theory under broken rotor bars fault. Analytical relations which describe the machine operation under broken bars fault highlight the influence of speed variation to modify the low frequency components of the external magnetic field. The theoretical results have been validated by experimental measurements. In particular, an inverse stator cage induction machine have been used to measure the bar currents under healthy and faulty cases.

59.5.6    N. Hodgins, O. Keysan, A.S. McDonald, M.A. Mueller, " Design and Testing of a Linear Generator for Wave-Energy Applications ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2094-2103, May 2012.   Abstract Link    Full Text

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

59.5.7    R. Vermaak, M.J. Kamper, " Design Aspects of a Novel Topology Air-Cored Permanent Magnet Linear Generator for Direct Drive Wave Energy Converters ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2104-2115, May 2012.   Abstract Link    Full Text

Abstract: Direct drive wave energy converters are attractive due to the elimination of intermediate mechanical power conversion stages. Longitudinal flux (LF) linear generators with iron-cored stators have so far been dominant in experimental direct drive WECs, but suffer from high bearing loads and unwanted end effects. A novel linear air-cored topology is presented in this paper which eliminates most of the end effects associated with LF iron-cored machines as well as the attraction forces between iron-cored stators and magnet translators. The attraction forces between the opposing sides of the translators of double-sided air-cored machines are also ideally eliminated. An analytical model and an exhaustive optimization procedure for finding the minimum active mass subject to certain performance specifications are developed for the novel topology. Finite element analysis is used to verify and further analyze the model. First test results from a 1 kW experimental machine correspond well with designed values and confirm the feasibility of implementing the novel topology on a small scale.

59.5.8    J. Aubry, H. Ben Ahmed, B. Multon, " Sizing Optimization Methodology of a Surface Permanent Magnet Machine-Converter System Over a Torque-Speed Operating Profile: Application to a Wave Energy Converter ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2116-2125, May 2012.   Abstract Link    Full Text

Abstract: This paper sets forth a sizing optimization methodology of a surface permanent magnet machine-converter system over a torque-speed operating profile. The two optimization objectives are to minimize the cost of the machine-converter system and to minimize (or maximize) electrical energy consumption (or generation). The optimization parameters serve to describe both the machine geometry and the electrical ratings of the electronic power converter. Each operating point of the profile is treated independently, and current control is optimized at every operating point to not only minimize machine drive losses but also satisfy several constraints and then implicitly considering flux-weakening possibility. This optimization methodology is generic and is applied to a particular case: a direct-drive conversion chain for a wave energy converter (WEC). We show that taking into account both the sizing parameters of the converter and the flux-weakening control, in addition to the classical sizing parameters of the machine, has a strong impact on the machine-converter system optimal results. Moreover, the strong coupling with the WEC through damping parameters plays also a crucial role on the sizing results.

59.5.9    A. Lidozzi, L. Solero, F. Crescimbini, " Adaptive Direct-Tuning Control for Variable-Speed Diesel-Electric Generating Units ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2126-2134, May 2012.   Abstract Link    Full Text

Abstract: This paper deals with an adaptive control method to be used in the dc-link voltage controller of diesel-electric power supply units being arranged with both permanent-magnet generator and three-phase boost rectifier. The proposed control method is based on the suitable manipulation of the overall system transfer function to achieve an adaptive “closed-form” expression for the parameters of the dc-link voltage controller. Such an approach allows overcoming the inherent nonlinear behavior of the system, so that the overall system dynamic performance is not affected by the system load conditions. Moreover, a current feedforward technique based on the estimation of the load current will be introduced to improve the control stiffness to load unbalances.

59.5.10    A. Di Gerlando, G. Foglia, M.F. Iacchetti, R. Perini, " Analysis and Test of Diode Rectifier Solutions in Grid-Connected Wind Energy Conversion Systems Employing Modular Permanent-Magnet Synchronous Generators ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2135-2146, May 2012.   Abstract Link    Full Text

Abstract: This paper deals with the ac-dc interface conversion in grid-connected wind energy conversion systems based on modular permanent-magnet synchronous generators. In particular, some solutions based on diode rectifiers are extensively analyzed as for the waveforms, the efficiency, and the torque ripple, by considering several connections, which are allowed by the inherent modularity of the considered generators. Rectifier schemes with a high number of pulses can be easily realized without using special shifter transformers so that these solutions can be attractive for low- and medium-power applications.

59.5.11    J.H.J. Potgieter, M.J. Kamper, " Torque and Voltage Quality in Design Optimization of Low-Cost Non-Overlap Single Layer Winding Permanent Magnet Wind Generator ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2147-2156, May 2012.   Abstract Link    Full Text

Abstract: The main focus of this paper is cost-effective techniques to reduce the cogging torque in permanent magnet (PM) wind generators. However, there are also certain limits with which other machine design aspects need to comply. These aspects include ease of manufacturing, mass, load torque ripple, and voltage quality. In this paper, a low-cost single layer PM wind generator with an irregular, parallel slotted stator is analyzed. The sensitivity of average torque and cogging torque to machine dimension variations is investigated, as well as the effects imposed upon the load torque ripple and the voltage quality. Methods are proposed whereby regions of low cogging torque can be identified more quickly in the design optimization. Furthermore, an interesting observation is made regarding the effects imposed upon the cogging torque by varying the yoke heights. Finite element calculated results are validated by practical measurements on a 15-kW PM wind generator.

59.5.12    J.M.M. Rovers, J.W. Jansen, J.C. Compter, E.A. Lomonova, " Analysis Method of the Dynamic Force and Torque Distribution in the Magnet Array of a Commutated Magnetically Levitated Planar Actuator ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2157-2166, May 2012.   Abstract Link    Full Text

Abstract: This paper concerns the analysis of the dynamic forces and torques acting on the magnets in a Halbach permanent magnet array of a magnetically levitated moving-magnet planar actuator. A new analysis tool is presented which predicts the dynamic force and torque distribution on the magnet array. This design tool uses lookup table data, which are generated by numerically solving the Lorentz force and torque integral, to describe the force and torque between each magnet and coil in the topology. It offers a fast and accurate solution for the analysis of magnetically levitated planar actuators. The results for two different commutation methods are presented.

59.5.13    F. Marignetti, S. Carbone, V. Delli Colli, C. Attaianese, " Cryogenic Characterization of Copper-Wound Linear Tubular Actuators ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2167-2177, May 2012.   Abstract Link    Full Text

Abstract: Electrical machine power density can be increased by liquid nitrogen (LN) cooling, since these machines operate at low resistivity and have a high heat transfer coefficient. This paper describes the experiments carried out on a short stroke tubular linear permanent magnet machine with copper windings and LN cooling. A cryogenic test rig for linear actuators was designed and built, and tests were carried out aimed at highlighting inherent current limiting capability, electric parameter variation in the fall from room to cryogenic temperatures, and actuator high thrust density. Shear stress reaches 17.8 kN/m2, and thrust-to-copper-loss ratio is 4 N W-1/2, which are significantly better compared to conventional actuators.

59.5.14    M. Carpita, T. Beltrami, C. Besson, S. Gavin, " Multiphase Active Way Linear Motor: Proof-of-Concept Prototype ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2178-2188, May 2012.   Abstract Link    Full Text

Abstract: In this paper, an active way linear synchronous motor with multiphase independent supply is presented. A proof-of-concept prototype of the proposed linear motor has been built, including power electronics and control. The control is based on a multi digital signal processor (multi DSP) master-slave structure. The controller design and the power and control boards have been described. The analytical model of the motor is presented. The analytical results are compared with a finite-element simulation, showing a good agreement. The analytical model has been also used to implement a dynamic model of the whole system in the Matlab/Simulink/Plecs simulation environment. The proof-of-concept prototype has been fully tested with one and two independent gliders. The obtained experimental results show that the chosen multi DSP master-slave structure allows the control of the proposed linear motor with good performances and reasonable costs.

59.5.15    N. Niguchi, K. Hirata, " Cogging Torque Analysis of Magnetic Gear ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2189-2197, May 2012.   Abstract Link    Full Text

Abstract: This paper describes the harmonic spectra of the cogging torque of a magnetic gear. The operating principle of this gear is described, and the transmission torque under operation in accordance with the gear ratio is mathematically formulated. In particular, the harmonic order of the cogging torque is described in detail. Moreover, the orders of the cogging torque of both rotors are verified by employing 3-D finite element method. The computed results are also then further verified by carrying out measurements on a prototype. Other harmonic components are observed in the computed and measured results, but it is discussed why they are contained in the cogging torque.

59.5.16    Jibin Zou, Mei Zhao, Qian Wang, Jiming Zou, Guangkun Wu, " Development and Analysis of Tubular Transverse Flux Machine With Permanent-Magnet Excitation ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2198-2207, May 2012.   Abstract Link    Full Text

Abstract: The magnetic field computation and performance characteristics analysis for a tubular transverse flux machine (TFM) with permanent-magnet excitation have been discussed. The following issues have been emphasized: construction of the tubular TFM, magnetic flux distribution, winding back electromotive force, winding inductance, and thrust force. The topology of such a machine requires a 3-D finite-element method to accurately predict the machine performance. The simplified computation model is proposed in order to save the computing time. The experimental setup has been developed. The calculated results and the measured results are in good agreement. Thus, the validity of the simplified computation model is indirectly proved. The thrust-force capabilities of the tubular TFM are compared with other topologies of linear machines. The technology of the tubular machine could be enriched.

59.5.17    I.A. Smadi, H. Omori, Y. Fujimoto, " Development, Analysis, and Experimental Realization of a Direct-Drive Helical Motor ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2208-2216, May 2012.   Abstract Link    Full Text

Abstract: Safety issue is a great concern for rehabilitation robots that are expected to contribute to future aging society. Appropriate compliance is required for their joints. However, combination of servomotors and high-ratio gears, such as harmonic gears, makes the joint of robots nonbackdrivable. The nonbackdrivability causes lack of adaptability and safety. On the other hand, conventional direct-drive systems, including linear motors, are relatively big for such application. This paper presents the development and analysis of compact high-backdrivable direct-drive linear actuator. The motor consists of a helical structure stator and mover. The mover does not contact the stator and moves helically in the stator under a proper magnetic levitation control. Thus, the motor realizes direct-drive motion without mechanical gears. Decoupling control is proposed and integrated with disturbance observer to achieve robustness against model uncertainties and input disturbance. The main contribution of this paper is to experimentally realize the direct-drive feature of the helical motor.

59.5.18    B.B. Jensen, A.G. Jack, G.J. Atkinson, B.C. Mecrow, " Performance of a Folded-Strip Toroidally Wound Induction Machine ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2217-2226, May 2012.   Abstract Link    Full Text

Abstract: This paper presents the measured experimental results from a four-pole toroidally wound induction machine, where the stator is constructed as a prewound foldable strip. It shows that if the machine is axially restricted in length, the toroidally wound induction machine can have substantially shorter stator end windings than conventionally wound induction machines, and hence, it shows that a toroidally wound induction machine can have lower losses and a higher efficiency. This paper also presents the employed construction method, which emphasizes manufacturability, and highlights the advantages and disadvantages of this method.

59.5.19    K. Suzuki, Yong-Jae Kim, H. Dohmeki, " Driving Method of Permanent-Magnet Linear Synchronous Motor With the Stationary Discontinuous Armature for Long-Distance Transportation System ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2227-2235, May 2012.   Abstract Link    Full Text

Abstract: In recent years, long-distance transportation systems have been increasingly used in the factory. The high cost of the linear synchronous motor (LSM) at the initial stage, however, is a problem. This paper proposes that a discontinuous stator permanent-magnet LSM can decrease this initial cost. The motor composed of a stator block (accelerator, reaccelerator, and decelerator) and a free-running section has problems with restarting, however, when the mover stops in the free-running section. As for discontinuous arrangement of the stator block proposed newly, to resolve this problem, one or two stators always overlap the mover. This arrangement can always supply a thrust force to the mover. However, the problem with this system is that, because one inverter is connected to each stator, the number of inverters increases. Moreover, the structure of the control system becomes complicated. Therefore, the number of inverters is decreased by changing the output point of the inverter using a solid-state relay linked to the stator block (the section). This paper describes the section change method of the stator block. This drive method is verified by carrying out experiments and simulation of various drive patterns.

59.5.20    B. Warberger, R. Kaelin, T. Nussbaumer, J.W. Kolar, " 50- \hbox {N}\cdot\hbox {m} /2500-W Bearingless Motor for High-Purity Pharmaceutical Mixing ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2236-2247, May 2012.   Abstract Link    Full Text

Abstract: In this paper, a novel bearingless motor (50 N·m /2.5 kW) for high-purity mixing applications is presented. The motor consists of a stator with concentrated windings and an exterior rotor with permanent magnets. The rotor is propelled and spatially suspended only by means of magnetic fields. This paper deals with the functionality and the mechanical setup of the new motor. Thereby, the optimization of the motor design is presented in detail. In order to evaluate the load of the bearingless motor in mixing operation, a fluid simulation is set up. Moreover, after the identification of the losses, a thermal simulation is established in order to predict the temperature distribution within the motor. Finally, a functional model is built up to verify the results.

59.5.21    B. Weilharter, O. Biro, H. Lang, G. Ofner, S. Rainer, " Validation of a Comprehensive Analytic Noise Computation Method for Induction Machines ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2248-2257, May 2012.   Abstract Link    Full Text

Abstract: The validation of an analytical approach to determine the noise behavior of induction machines is presented. Analytical electromagnetic, structural, and acoustical computations are performed. Data obtained by numerical computations as well as by vibration and noise measurements are compared with the analytical results.

59.5.22    G. Traxler-Samek, T. Lugand, M. Uemori, " Vibrational Forces in Salient Pole Synchronous Machines Considering Tooth Ripple Effects ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2258-2266, May 2012.   Abstract Link    Full Text

Abstract: In rotating electrical machines, the air-gap magnetic field causes radial forces on the stator core physically based on the Maxwell stress. These radial force waves do not contribute to the torque generation of the machine but may lead to dangerous vibrations. This problem must be especially researched when designing salient pole synchronous machines with a high number of poles and fractional slot windings. At full load operation, the stator winding magnetomotive force (MMF), the stator tooth ripple effects, the saliency of the rotor poles, the induced currents in the damper winding, and the field winding MMF generate a set of harmonic field waves circulating around the air gap. The waves interact by modulation effects and therefore create different magnetic force wave modes. This paper presents an analytical computation model for force waves and compares results with finite-element calculations as well as measurements. Attention is paid to tooth ripple phenomena and reduction of parasitic forces with nonstandard stator winding phase belt distributions.

59.5.23    J. Krotsch, B. Piepenbreier, " Radial Forces in External Rotor Permanent Magnet Synchronous Motors With Non-Overlapping Windings ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2267-2276, May 2012.   Abstract Link    Full Text

Abstract: In external rotor permanent magnet synchronous motors with non-overlapping windings, the higher frequency harmonics of the radial forces generate considerable resonant vibrations and acoustic noise. Therefore, diversity of spatial and specifically frequency harmonic ordinal numbers of representative slot and pole number combinations are derived analytically with open circuit and under load. Amplitudes of radial force waves are calculated by means of the finite element method and 2-D Fourier analysis. The obtained results confirm the analytical investigation. Determining factors on amplitudes are studied on machines having different slot and pole numbers and double-layer windings. Higher frequency harmonics significantly depend on the pole and tooth shape as well as the current profile. With open circuit, the calculations are validated by experiments. The findings are applied to reduce the noise of a centrifugal fan.

59.5.24    L. Aarniovuori, L.I.E. Laurila, M. Niemela, J.J. Pyrhonen, " Measurements and Simulations of DTC Voltage Source Converter and Induction Motor Losses ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2277-2287, May 2012.   Abstract Link    Full Text

Abstract: Energy efficient pulse-width modulation inverters are widely used to control electrical machines accurately for process needs. The pulse-width modulation, however, has also adverse effects and produces additional losses in the motor. These losses increase the motor temperature and result in derating of the machine power in converter use. A reliable and reasonably accurate loss model of an induction motor drive system is important for the performance prediction of a variable-speed drive. A two-level frequency converter main circuit model is coupled to a finite-element method motor model. The drive model is controlled by closed-loop direct torque control. The frequency converter losses are calculated analytically, and the finite-element method motor model provides an analysis of the motor losses. The simulation results are compared with measurement results.

59.5.25    S. Stipetic, M. Kovacic, Z. Hanic, M. Vrazic, " Measurement of Excitation Winding Temperature on Synchronous Generator in Rotation Using Infrared Thermography ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2288-2298, May 2012.   Abstract Link    Full Text

Abstract: A new measurement method for infrared (IR) surface temperature measurement of excitation winding in rotation is presented. The method is experimentally verified on a 400-kVA salient pole synchronous generator. This method uses an industrial IR thermometer which represents an alternative to expensive fast IR thermometers or cameras. The target application of this method is the determination of the dynamic limit in the P-Q diagram of a synchronous generator due to excitation winding overheating. The measurement error model which shows the way how to minimize measurement error has also been derived. The effect of the interpolar surface can be cancelled if the IR thermometer is positioned at a certain angle with respect to the machine's main axis. Digital temperature sensors have been mounted on the rotor to measure the excitation winding surface temperature for comparison.

59.5.26    M. Hettegger, B. Streibl, O. Biro, H. Neudorfer, " Measurements and Simulations of the Convective Heat Transfer Coefficients on the End Windings of an Electrical Machine ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2299-2308, May 2012.   Abstract Link    Full Text

Abstract: The prediction of the thermal behavior of an electrical machine in the design process basically depends on the used boundary conditions such as the convective heat transfer coefficient. Due to the complicated shape of the end windings, the heat transfer coefficient has to be identified empirically by using thermopiles as heat flux sensors placed at certain positions on the end windings, because an analytical derivation is not feasible. This paper presents the results of the measured values of the heat transfer on the end windings of an electrical machine. The gained coefficients are compared to the results obtained by numerical simulations using commercial software for computational fluid dynamics. The simulation results are discussed according to the validity of the gained heat transfer coefficient. The configuration of the simulation has been tested on a cylindrical shape in a cross-flow.

59.5.27    L. Ferraris, P. Ferraris, E. Poskovic, A. Tenconi, " Theoretic and Experimental Approach to the Adoption of Bonded Magnets in Fractional Machines for Automotive Applications ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2309-2318, May 2012.   Abstract Link    Full Text

Abstract: This paper aims to tackle the general problem of increasing the performances of small permanent-magnet (PM) machines, through the use of bonded magnets instead of the more diffused ferrite magnets. In particular, the study is developed for a fractional-slot concentrated winding PM machines for automotive applications. Neodymium bonded magnets with different and unconventional resins are realized in the internal laboratories. The rotors with the different magnet technologies are experimentally characterized, and the experimental values are compared with the simulation ones. The obtained results allow to define the possible performance increment. Finally, this paper analyzes the possible improvement of the rotor magnetic circuit for a better exploitation of the bonded magnets, without altering the stator structure and the motor housing.

59.5.28    O. Scaglione, M. Markovic, Y. Perriard, " First-Pulse Technique for Brushless DC Motor Standstill Position Detection Based on Iron B-H Hysteresis ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2319-2328, May 2012.   Abstract Link    Full Text

Abstract: This paper introduces a promising technique, called the first-pulse technique, for detecting the rotor position of a brushless DC motor at standstill. The technique is based on the B-H hysteresis characteristics of the stator iron. Depending on the rotor position, a very particular phenomenon related to B-H hysteresis appears. Voltage pulses are injected into the motor phases, without the need of saturating the stator teeth. In the first-pulse technique, the rotor position is estimated not by an absolute measurement, but by the comparison between the measurated effects created by the first injected pulse and the following ones. This technique permits to detect the electrical position of a non-salient rotor.

59.5.29    E.I. Amoiralis, M.A. Tsili, A.G. Kladas, " Power Transformer Economic Evaluation in Decentralized Electricity Markets ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2329-2341, May 2012.   Abstract Link    Full Text

Abstract: Owing to deregulation, privatization, and competition, estimating financial benefits of electrical power system projects is becoming increasingly important. In other words, it is necessary to assess the project profitability under the light of new developments in the electricity market. In this paper, a detailed methodology for the least cost choice of a distribution transformer is proposed, showing how the higher price of a facility can be traded against its operational cost over its life span. The proposed method involves the incorporation of the discounted cost of transformer losses to their economic evaluation, providing the ability to take into account variable energy cost during the transformer operating lifetime. In addition, the influence of the variability in the energy loss cost is investigated, taking into account a potential policy intended to be adopted by distribution network operators. The method is combined with statistical and probabilistic assessment of electricity price volatility in order to derive its impact on the transformer purchasing policy.

59.5.30    T.D. Kefalas, A.G. Kladas, " Analysis of Transformers Working Under Heavily Saturated Conditions in Grid-Connected Renewable-Energy Systems ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2342-2350, May 2012.   Abstract Link    Full Text

Abstract: In recent years, researchers have proposed transformerless solutions for connecting renewable-energy power plants to the grid. Apart from lack of efficiency and increased cost and weight of the transformer, one of the reasons is the dc input current that causes transformer saturation. The purpose of this paper is the development of a finite-element computational tool that is going to aid transformer manufacturers in designing distribution transformers specifically for the renewable-energy market. It is based on a generalized macroscopic representation of electrical steels used in the transformer manufacturing industry that enables the accurate evaluation of electromagnetic field distribution of transformer cores under heavily saturated conditions. Its advantages over conventional formulations include numerical stability, numerical accuracy, and reduction of iterations of the Newton-Raphson method. An experimental verification of the proposed method is carried out.

59.5.31    G. Zhabelova, V. Vyatkin, " Multiagent Smart Grid Automation Architecture Based on IEC 61850/61499 Intelligent Logical Nodes ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2351-2362, May 2012.   Abstract Link    Full Text

Abstract: Universal, intelligent, and multifunctional devices controlling power distribution and measurement will become the enabling technology of the Smart Grid ICT. In this paper, we report on a novel automation architecture which supports distributed multiagent intelligence, interoperability, and configurability and enables efficient simulation of distributed automation systems. The solution is based on the combination of IEC 61850 object-based modeling and interoperable communication with IEC 61499 function block executable specification. Using the developed simulation environment, we demonstrate the possibility of multiagent control to achieve self-healing grid through collaborative fault location and power restoration.

59.5.32    Jianbo Yu, " Local and Nonlocal Preserving Projection for Bearing Defect Classification and Performance Assessment ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2363-2376, May 2012.   Abstract Link    Full Text

Abstract: The sensitivity of various physical features that are characteristics of bearing performance may vary significantly under different working conditions. Thus, it is critical to extract the most effective information from the original physical features generated from vibration signals for bearing defect classification and performance degradation assessment. This paper proposes a local and nonlocal preserving projection (LNPP)-based feature extraction algorithm, which is different from principal component analysis that aims to discover the global structure of Euclidean space and regular manifold learning algorithms that attempt to preserve local structure in data. LNPP is capable of discovering both local and nonlocal structures of data manifold. This may enable LNPP to find the meaningful low-dimensional information hidden in the high-dimensional feature set and then to serve as a preprocessor for defect classification. Furthermore, an LNPP-based quantification index is proposed for the assessment of bearing performance degradation. An LNPP-based contribution plot for feature selection is developed to improve the degradation detection sensitiveness and to reduce false alarms. A dynamic LNPP for bearing performance assessment is further developed to consider inherent autocorrelation existing in vibration data. Detailed results are very promising and are reported in this paper. This paper will provide guidance for the applications of manifold learning algorithms (e.g., LNPP) in machine fault diagnosis and performance prognostics.

59.5.33    R.C. Luo, O. Chen, " Mobile Sensor Node Deployment and Asynchronous Power Management for Wireless Sensor Networks ," IEEE Trans. on Industrial Electronics, vol. 59, no. 5, pp. 2377-2385, May 2012.   Abstract Link    Full Text

Abstract: Mobile sensor node deployment and power management are important issues in the wireless sensor network system. This study designs a mobile sensor node platform to achieve a highly accurate localization mechanism by using ultrasonic, dead reckoning, and radio frequency information which is processed through a particle filter algorithm. Mobile sensor node with accurate localization ability is of great interest to basic research works and applications, such as sensor deployment, coverage management, dynamic power management, etc. In this paper, we propose an efficient mobile sensor node deployment method, grid deployment, where the map is divided into multiple individual grids and the weight of each grid is determined by environmental factors such as predeployed nodes, boundaries, and obstacles. The grid with minimum values is the goal of the mobile node. We also design an asynchronous power management strategy in our sensor node to reduce power consumption of the sensor network. Several factors such as probability of event generation, battery status, coverage issues, and communication situations have also been taken into consideration. In network communication, we propose an asynchronous awakening scheme so that each node is free to switch on or off its components according to observed event statistics and make a tradeoff between communication and power consumption. The deepest sleep state period is determined by the residual power. By combining these methods, the power consumption of the sensor node can be reduced.