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The content of flux-density space-harmonics in axial-flux permanent-magnet machines (AFPMMs) is an important concern to the machine designer due to its impact on machine performances. In AFPMMs, the space-harmonics are related to the flux-density and the MMF distributions in the airgap, which are mainly determined by the PM excitation. This paper proposes two different approaches to study the flux density in the airgap. The finite-element and analytical methods are jointly developed in order to model and compare the flux density waveforms. Many optimization methods have been proposed in order to optimize the design of PM machines. In this paper, the authors investigate the optimal PM design in order to minimize the space-harmonics distribution using the sequential quadratic programming (SQP) optimization algorithm. By selecting the appropriate PM shape and size, it is possible to remove the undesirable harmonics. Using the SQP, the PM shape is optimized, and the harmonics content is notably reduced. The optimal solutions given by the FE model are then validated.

This paper aims to evaluate capabilities of axial-flux and radial-flux permanent-magnet machines. The comparison is done exclusively from an electromagnetic point of view. The electromagnetic design comparison of conventional radial- flux and axial-flux topologies is carried out in view of traction drive applications.

This paper proposes a modeling method for axial-flux permanent-magnet machine (AFPMM) based on a finite elements analysis, and achieves a shape optimization of AFPMM poles. To solve the questions regarding the modeling of AFPMM with surface-mounted PMs, an axial 3-D to radial 2-D finite-element transformation is proposed. A special analytical method for back-emf computation is also provided. The results related to 2-D finite-element analysis are presented and compared with the experimental ones, validating the proposed approach. The amount of space-harmonic content in AFPMM is a primary concern to the machine designer due to its impact on the AFPMM performances. These harmonics are directly related to the flux-density and mmf distributions in the airgap, which are mainly determined by the PM excitation. Therefore, the slotless machine is analyzed. The influence of design parameters on the total harmonic distortion (THD) and the methodology to reduce space harmonics by selecting the appropriate PM shape and size are also addressed in this paper. The space-harmonic analysis is carried out according to the variety of design parameters of the finite element models.

Three methods for estimating the equivalent core-loss resistance of vector-controlled interior permanent-magnet synchronous machines (IPMSMs) are comparatively analyzed in the paper. Among them a new identification method based on expressing the IPMSM equivalent core-loss resistance, in steady-state conditions, as a function of direct- and quadrature-axis currents, at fixed values of load torque and rotor speed, is proposed. The effectiveness of the proposed method is experimentally verified.

Hybrid electric vehicles and full electric vehicles are becoming a viable alternative to gasoline or diesel powered vehicles. Four main factors are contributing to this evolution: oil price, pollution, greenhouse effect and advances in electrochemical energy storage. All major car manufacturers are developing projects in this area. Until now, the full electric vehicles available on the market have autonomy of about 100 to 150 km, limited by the energy stored in the electrochemical battery. The battery is the most expensive part of the electric vehicle, and has also a limited lifetime. This paper presents a solution to enhance the battery lifetime, by blocking the short charging energy pulses (usually, submitted to the battery) retrieved from the electric machine, mainly when the vehicle is braking. This is obtained with the help of supercapacitor energy storage device. The solution developed is a fuzzy-logic supervisor that imposes the battery and supercapacitor powers in order to limit the number of charge/discharge cycles of the electrochemical battery. Experimental tests and results validate the proposed supervision technique.

Colorectal cancer (CRC) develops by accumulation of multiple genetic damages leading to genetic instability that can be evaluated by cytogenetic methods. In the current study we used Cytokinesis-Blocked Micronucleus Assay (CBMN) technique to assess the behavior of Nuclear Division Index(NDI) in peripheral lymphocytes of patients with CRC and polyps versus patients with normal colonoscopy.Blood samples were collected from patients after informed consent. By CBMN technique we assessed the proportion of mono-nucleated, bi-nucleated, tri-nucleated and tetra-nucleated cells/500 cells, to calculate NDI. Data were statistically analyzed using the SPSS 11.0 package.45 patients were available for analysis, 23 men and 22 women, with a mean age of 58.7±13.5. 17 had normal colonoscopy, 17 colonic polyps and 11 CRC. The mean NDI values were significantly smaller for patients with CRC or polyps than in patients with normal colonoscopy (1.57 vs 1.73, p=0.013). The difference persisted for patients with neoplastic lesions (adenomas and carcinomas) when compared with patients with normal colonoscopy or non neoplastic (hyperplastic) polyps (1.56 vs.1.71, p=0.018). The NDI cut-off value to predict the presence of adenomas or carcinomas was equal to 1.55 with a 54.2% sensitivity and 81% specificity of lower values (p=0.019). The NDI cut off value to predict the presence of advanced adenomas or cancer was 1.525 for a sensitivity of 56.3% and a specificity of 82.8% (p=0.048).NDI may be useful in screening strategies for colorectal cancer as simple, noninvasive, inexpensive cytogenetic biomarker.

A comparison between two current control methods of grid side inverter, PI current control and Robust Forward control is made. PI control is implemented in d-q synchronous frame while Forward is implemented in abc stationary frames.The report contains both simulations and experimental test wich were made at a reduced scale ( 2.2 kW). The constant power test showed that both method havegood results which can respect existing grid codes. The constant power test showed that both method have good results which can respect existing grid codes.

A comparison between two predictive control methods of grid side inverter, Robust Dead Beat control and Robust Forward control is made. The report contains both simulations and experimental test wich were made at a reduced scale (2.2 kW). The harmonic monitoring has shown that Dead Beat control presents less harmonic contents, while Forward control recovery time looks better due to any reference changes.

A Permeance Network Analysis (PNA) of the dynamic behavior of a three phase Switched Reluctance Motor fed from a full-bridge inverter is presented. The non-linear effects due to global and local saturation are taken into consideration as well as the mutual coupling between phases. All permeances in the magnetic circuit are analytically computed in order to reduce the overall computation time in view of a future integration with an optimization process. The switching technique is also integrated within the PNA model. A validation of the obtained results is provided using finite element analysis and experimental measurements.

Starting form an existing induction motor, which was tested according to an international standard, an optimized model is developed in order to reach higher energy efficiency. The optimization procedure is based on the analytical model of the machine. Hence, the first step is to develop the model and to compare the results with the data provided by the international standard for validity purpose. The next step is to introduce the analytical model equation into the optimization process. Then, the results of the optimization are checked against the finite element method.

Interior permanent-magnet synchronous motors (IPMSMs) are suitable for small-size light traction drives due to their rugged and compact construction, high torque and power densities, good efficiency as well as operability over a wide speed range at constant power. This paper presents a bi-objective particle-swarm- optimized (PSO) design of a small three-phase concentrated-winding IPMSM for light traction applications. The PSO design is thus formulated as a constrained optimization problem of maximizing the IPMSM energy efficiency, while minimizing the weight of its active parts.

This paper proposes a solution for the optimization of a full-bridge three-phase inverter-fed switched reluctance motor (SRM) simultaneously accounting for the geometry of the motor as well as for its switching strategy. The optimization method proposed for this is Particle Swarm Optimization (PSO), allowing a multi-objective optimization. By means of the Permeance Network Analysis (PNA), magnetic phenomena and control scheme are both accurately modeled. The Pareto-front provides the compromise between the two objective functions imposed by the application, i.e. the average torque and torque ripple.

This paper proposes a direct power control technique applied to a variable-speed doubly-fed induction generator (DFIG) of a micro-hydro energy conversion system. This assembly consists of a permanent-magnet synchronous machine (PMSM) linked mechanically and electrically (through back-to-back power electronic converters) to the DFIG (on the rotor side). The PMSM has the role to recover or supply the slip power of the DFIG. The main advantages related to this system are that the energy conversion system is completely autonomous (can supply isolated load or can be connected to power grid) and also, the PMSM and the power converters are designed for only about 25 % of the hydro-plant rated power.

This paper reports on experimental results for a grid-connected hybrid wind/micro-hydro power system associated with a supercapacitor energy storage device (SCESD). It comprises a doubly-fed induction generator linked mechanically and electrically (through back-to-back power electronic converters in the rotor circuit) to a permanent magnet synchronous machine, which may recover or supply the slip power. The SCESD is connected via a DC/DC converter between the two back-to-back power electronic converters. A fixed-speed wind generator driven by a squirrel-cage induction generator is also connected to the power grid.

Distributed generation is becoming more and more a reality for the electric power system. One of the main problems encountered with this kind of generation is the potential formation of islands which could be feed by distributed generators even if the utility grid has failed. Many methods have been developed to detect this situation and they have been classified in three groups: passive methods, active methods and methods based on communication systems. This paper presents a micro-hydro power station, which is submitted to a power grid failure. Two active methods are tested in simulations and experiments in order to detect the islanding created.

In order to achieve a better understanding of the modifications of the physical and chemical properties of marine aerosol particles during transport from offshore to the coast, size distribution and chemical composition were measured concurrently in clean air masses over the open North Atlantic Ocean and at an Irish coastal site. Open ocean sampling was performed on board the oceanographic vessel Celtic Explorer sailing 100–300 km off the Irish west coast, while coastal measurements were performed at the Mace Head GAW station. The experiment took place between 11 June and 6 July 2006, during the period of phytoplankton bloom. The number size distribution and size-resolved chemical composition of coastal and open ocean samples were very similar, indicating homogeneous physical and chemical aerosol properties over a wide region in the marine boundary layer. The results also show that submicron chemical and physical aerosol properties measured at the coastal Mace Head Atmospheric Research Station were not unduly influenced by coastal artefacts and are thus representative of open water properties. Greater differences between the coastal site and the open ocean were observed for the aerosol supermicron sea spray components; this could be due to a variety of reasons, ranging from higher local wind speeds at the coastal site over the comparison period, to differences in sampling heights and increased local surf-zone production. Evidence of ageing processes was observed: at the costal site the ratio between non-sea-salt sulphate and methanesulphonic acid was higher, and the aerosol water soluble organic compounds were more oxidized than in the open ocean.

Association of wind power producing units, microhydro power plants and energy storage systems can ensure the stability of an islanded week power grid or can increase the penetration of these renewable energy sources into the large power networks. Experimental results presented in the paper demonstrate the effectiveness of this association. The microhydro power plant consists of a doubly-fed induction generator (DFIG) linked mechanically and electrically (through back-to-back power electronic converters in the rotor circuit) to a permanent-magnet synchronous machine (PMSM). The energy storage device considered is a supercapacitor connected through a bidirectional DC-DC converter to the DC-link of the hydropower station. This system is associated to a fixed-speed wind generator driven by a squirrel-cage induction machine.

Variable speed hydro power plants allow to compensate and to smooth the fluctuating wind power when feeding isolated loads. This is shown experimentally in this paper with the help of a 3 kW laboratory test bench able to emulate a hybrid wind/hydro power system. The test bench is equipped of a doubly fed induction generator based small hydro power plant emulator associated with a fixed-speed wind generator emulator. This kind of wind generator is often used in small or medium power isolated networks. Tests show that the frequency and voltage are well controlled in spite of load variations.

International audience; Aerosol number distribution measurements are reported at San Pietro Capofiume (SPC) station (44°39' N, 11°37' E) for the time period 2002?2005. The station is located in Po Valley, the largest industrial, trading and agricultural area in Italy with a high population density. New particle formation was studied based on observations of the particle size distribution, meteorological and gas phase parameters. The nucleation events were classified according to the event clarity based on the particle number concentrations, and the particle formation and growth rates. Out of a total of 769 operational days from 2002 to 2005 clear events were detected on 36% of the days whilst 33% are clearly non-event days. The event frequency was high during spring and summer months with maximum values in May and July, whereas lower frequency was observed in winter and autumn months. The average particle formation and growth rates were estimated as ~6 cm?3 s?1 and ~7 nm h?1, respectively. Such high growth and formation rates are typical for polluted areas. Temperature, wind speed, solar radiation, SO2 and O3 concentrations were on average higher on nucleation days than on non-event days, whereas relative and absolute humidity and NO2 concentration were lower; however, seasonal differences were observed. Backtrajectory analysis suggests that during majority of nucleation event days, the air masses originate from northern to eastern directions. We also study previously developed nucleation event correlations with environmental variables and show that they predict Po Valley nucleation events with variable success.

A general overview of high resolution Retinal Scanning Display system and the requirements for driving electronics are presented. Intra-beam pixel positioning mechanisms that provide integral adjustment capability are detailed. Horizontal raster correction is achieved with high accuracy direct digital synthesis.

The paper will outline Retinal Scanning Display (RSD) technology fundamentals and detail some of the potential advantages this technology offers to military HMD applications. We will also present current performance level achieved and the roadmap ahead.

This paper describes the effect of the presence of water soluble organic compounds (WSOC) in aerosol particles on the aerosol critical supersaturation as defined by the Köhler theory and on cloud condensation nuclei (CCN) number concentration. Taking into account both the soluble mass increase and the surface tension depression due to WSOC, we calculated a substantial decrease of the aerosol critical supersaturation, which results in a large increase in CCN number concentration. CCN supersaturation spectra were computed for three different aerosol types: marine, rural and urban. The increase of CCN number concentration in the presence of WSOC (with respect to the case when only the inorganic aerosol compounds are considered) varies with aerosol type, with an increase up to 13% in the marine case, up to 97% in the rural case, and up to 110% in the urban case, for the supersaturation range typical of atmospheric conditions.

We have recently set up a new procedure for characterising the water soluble organic compounds (WSOC) in fog water, for which information is still rather limited. Fog samples collected during the 1998-99 fall-winter season in the Po Valley (Italy) were analysed following this procedure, which allows a quantitative determination of three main classes of organic compounds (neutral species, mono- and di-carboxylic acids, polycarboxylic acids), together accounting for ca. 85% of the total WSOC. This procedure also provides information on the main chemical characteristics of these three classes of compounds (functional groups, aliphatic vs. aromatic character etc.). The enhanced chemical knowledge on fog/cloud chemical composition opens new scenarios as far as chemical and microphysical processes in clouds and fogs are concerned.

The water soluble organic compounds (WSOC) in soot samples as a function of the extent of ozone oxidation have been measured by a new methodology which utilises ion exchange chromatography, total carbon analysis and proton nuclear magnetic resonance. These results have been compared with the same analyses of various atmospheric aerosol samples. The WSOC produced from oxidation of soot particles increase rapidly with ozone exposure and consist primarily of aromatic polyacids which are found widely in atmospheric aerosols and which are frequently referred to as macromolecular humic-like substances (HULIS). This work demonstrates that the atmospheric oxidation of soot can produce HULIS in aerosols. The CCN effectiveness of soot aerosol likely has its origin in these oxidation processes.

High-resolution (i.e., large pixel-count) and high frame rate dynamic microdisplays can be implemented by scanning a photon beam in a raster format across the viewer's retina. A resonant horizontal scanner and a linearly driven vertical scanner can create a 2-D raster for video display. The combined motion of the two scanners form a sinusoidal raster in the vertical direction and cause non-uniform line spacing for the case of bidirectional scanning as if the forward and return half-period raster lines are pinched near the edge of the display screen. Raster pinch effect degrades the image quality, especially for multi-beam scanning systems. What is needed is a vertical scanner that creates a stairstep motion instead of linear motion. A third scanner can be added to the system to create an approximation to a staircase motion in the vertical axis and correct for the non-uniform raster spacing. The raster pinch scanner requirements, mechanical and magnetic designs with FEA analysis, and preliminary test results are discussed in this paper.

A Retinal Scanning Display (RSD) utilizes scanning mirrors and optics to produce a flying spot that forms a raster image directly on the retina of the eye. A high-frequency resonant horizontal scanner and a linear ramp vertical scanner function together to produce video typically at a 60Hz frame rate. Although the raster can be formed by Unidirectional Writing (using only the forward half-period of the horizontal scan function) and one flying spot, it is desirable to achieve Bidirectional Writing (utilizing the full period of the Horizontal scan function) with multiple scanned spots for the purpose of increased efficiency of the display with a limited horizontal scanner frequency. This paper will look at the limitations and requirements for the scanning functions to make this possible.