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Due to the rapid development of the Intelligent Traffic System (for short, ITS), the shared information among successive vehicles can be acquired accurately and reliably. In this paper, a control scheme utilizing the successive flux difference under honk environment (SFDHE) is investigated in the lattice hydrodynamic model. Based on the Hurwitz criteria and the $H_{\infty }$ -norm, the sufficient condition for the transfer function is derived with the control theory analysis. The Bode-plot of transfer function indicates that the stability of the traffic flow is increased significantly with the novel controller. Moreover, the numerical simulation results of the new model are compared with that of Peng’s model, which demonstrates that traffic jams can be suppressed efficiently when the SFDHE control signal is taken into account.

Interior permanent magnet synchronous machines (IPMSMs) are widely used in electric vehicles due to their high power density, high efficiency, and wide speed range. Compared with surface-mounted PMSMs, the salient effect of IPMSMs causes a significant difference between quadrature-axis and direct-axis flux paths, which can increase the harmonic components of the air-gap field and affect the operation of the machine. Herein, taking a 6-poles 36-slots PMSM as an example, this paper analyzes the influence of salient effect on the air-gap flux density. Based on salient effect function, the analytical model of air-gap flux density considering the salient effect is established, and the influence of the salient effect on the spatial-temporal distribution characteristics of air-gap flux density excited by permanent magnets and armature reaction are derived, which are verified by the finite element method (FEM). Both simulation and experiment results of the prototype show good agreement, and the sources of salient effect are found with finite element model and equivalent magnetic circuit. Further, different current excitations are applied to analyze the influence of the salient effect on different magnetic fields. The results show that the salient effect has a more significant influence on the direct-axis armature reaction magnetic field, which increases the harmonics components with the temporal orders of $3k_{a}$ ( $k_{a}=1,2,3\ldots $ ).

In this paper a novel outer-rotor consequent pole permanent magnet machine (OR-CPPMM) with H-type modular stator core is proposed for higher average torque ( $T_{avg}$ ), flux linkage ( $\Phi$ ) and efficiency ( $\eta$ ) whereas low cogging torque ( $T_{cog}$ ), torque ripple ( $T_{rip}$ ) and harmonics content in flux linkage ( $\Phi _{THD}$ ) and back-EMF ( ${\mathrm {EMF}}_{THD}$ ). The proposed OR-CPPMM is investigated with different stator flux gaps width for static and dynamics electromagnetic performances. Analysis reveals that flux gaps in H-type stator core not only improve electromagnetic performance i.e., $\Phi $ is enhanced by 10.23%, $\Phi _{THD}$ is suppressed by 80.65%, diminished ${\mathrm {EMF}}_{THD}$ by 59.37%, truncate $T_{rip}$ by 44.37% and improve $T_{avg}$ by 15.99% but also exhibits better flux focusing effect to enhance flux linkage and diminish harmonic contents. In addition, H-type modular stator structure provide physical isolation of adjacent phase that de-couple the adjacent phase coupling flux which enhance self-inductance and weaken mutual-inductance and hence improve fault tolerant capability. In addition, to elaborate effectiveness of the proposed design and justification of OR-CPPMM novelty with H-type modular stator, electromagnetic performance is extensively compared with existing state of the art including E-core and C-core structure. Analysis and comparison with state-of-the-art reveals that proposed OR-CPPMM enhanced $\Phi $ by 65.35%, diminish $\Phi _{THD}$ by 67.24%, truncate $T_{cog}$ by 96.72%, suppresses ${EMF}_{THD}$ by 44.40%, diminish $T_{rip}$ by 77.23% whereas $T_{avg}$ is enhanced by 91.69%. Furthermore, the proposed design novelty is justified with comparison of OR-CPPMM with inner rotor and dual rotor permanent magnet flux switching machines. Comparison and analysis unveil that OR-CPPMM exhibits $T_{avg}$ higher up to 35.16%, truncate $T_{rip}$ up to 32.88%, enhanced $\Phi $ up to 22.13% and boost $T_{den}$ to 3.41 times at the cost of 2.58% increase in $T_{rip}$ .

Air supply system is an important subsystem in a PEMFC engine system. Research on the control strategy of air supply system is of great importance and significance in engineering. In this paper an intelligent controller based on distributed deep reinforcement learning which exerts better control over the air flux of a proton exchange membrane fuel cell (PEMFC) air supply system is proposed. In addition, a collective intelligence exploration distributed multi-delay deep deterministic policy gradient (CIED-MD3) algorithm is presented for the controller. This improved algorithm is developed on the basis of deep deterministic policy gradient (DDPG) and adopted the collective intelligence exploration policy which enables full exploration of the environment. This classification experience replay mechanism is introduced to improve training efficiency. A number of techniques are employed in an effort to address the Q-value overestimation problem of the DDPG, including clipped multiple Q-learning, delayed update of policy and smooth regularization of target policy. Finally, the application of CIED-MD3 (with its better global search ability and optimization speed) is demonstrated to the model-free PEMFC air flux intelligent controller. The simulation results show that the proposed controller exerts greater control of the PEMFC air supply system. Compared with other control methods, the proposed intelligent controller exhibits better control performance and robustness. The control algorithm proposed in this paper is of significance to future PEMFC air flux control research.

This paper proposes a rotary-linear surface-mounted permanent magnet (PM) voice coil motor (RL-SVCM) with PM flux bridges in place of the iron flux bridges in a traditional RL-SVCM for enhancing average torque and force ripple but slight damage of torque ripple and average linear force. The iron flux bridges in a basic RL-SVCM cannot participate in the generation of rotary torque. In contrast, the PM flux bridges in the proposed RL-SVCM can participate in the generation of rotary torque. The magnetic equivalent circuit (MEC) is used to analyze the magnetic circuits of the basic and proposed models. The results explain the reasons for the performance improvements achieved by the proposed motor. The finite element method (FEM) is used to derive the precise output performance of the basic and proposed motors. Additionally, a prototype of the proposed RL-SVCM with PM flux bridges was manufactured for experimental verification. Close agreement between the experimental results and FEM results validates the feasibility of the proposed RL-SVCM.

An improved method for tracing electric flux lines in the vicinity of the overhead high voltage direct current (HVDC) transmission lines is developed by using parametric curves. Based on the geometric relation between the electric field vector and the derivative of the parametric curve function, the electric flux lines can be successfully traced without accumulation of the numerical error caused by the differentiation for calculating the electric potential. Considering the structural characteristics of the transmission line, the control points at both ends of the parametric curve can be easily located, and the remaining control points are modified to minimize an error function defined by the electric field vectors at nodes along the curve. Once the electric flux lines are traced, a series of flux tubes is created by bundling adjacent flux lines, and the nodal electric field vectors and space charge densities are iteratively updated. In order to consider the ionized space charge effect, new flux lines of modified electric field are traced, which in turn affects the existing space charge distribution. The process is repeated until the effect of the space charge is fully considered. The performance of the proposed algorithm is verified by comparing the resulting ground profiles of the ion flow field distribution with the result of the analytical model and the long-term measurement of the full-scale transmission line.

Hybrid excited (HE) machines are a potential solution for wind power generation for their high efficiency from permanent magnet (PM) and good flux regulation ability from flexible field current. However, the principle and machine performance of different structures are diverse, which brings challenges in selection of machine topologies and in the dimensional parameter design. Hence, in this article, two machines with different topologies are presented and analyzed to show their merits and demerits. Both machines have relieving-DC-saturation PMs located in the slot openings, while only one of them has consequent rotor PMs to provide an auxiliary flux and to enhance torque production. In this article, the machine structure and working principle are presented, including the relieving-DC-saturation-relieving effect and air-gap field harmonic analysis. For a fair comparison, under the same outer diameter, rated current density, the dimensional parameters of two machines are optimized with genetic algorithm (GA). Further, the machine performance of the optimal models is compared in terms of torque production, back EMF, voltage regulation ability and speed range. The merits and demerits of both machines are summarized in the conclusion.

A high gear ratio flux switching permanent magnet machine (HFSPM) was proposed to improve the torque performance in flux switching permanent magnet machine (FSPM). Conventional FSPMs address flux bypass issue when designed with a high gear ratio. The HFSPM adopts a dual rotor structure to overcome this flux bypass issue. First, the cause and effect of flux bypass issue was discussed using a magnetic equivalent circuit (MEC). Further, the process of overcoming the flux bypass issue using dual rotor structure was discussed. An alternative HFSPM, consequent pole HFSPM (CP-HFSPM), was proposed to enhance torque performance. The CP-HFSPM was optimized for high torque performance and proper power factor.

A novel 6/13-pole hybrid excitation axial field flux-switching permanent magnet machine (HEAFFSPMM) exhibits strong fault tolerance capability, high efficiency, and large torque density. However, merely few research on speed sensorless control in HEAFFSPMM exists. The speed sensorless control methods based on model reference adaptive system (MRAS) are studied and compared for the machine to improve the stability and reliability of the system and consequently improve the application of machine in control system. Based on the field-oriented control strategy, the MRAS observer of speed is designed and built by applying stator currents, stator flux linkages, and simplified stator currents. The three speed sensorless control algorithms of MRAS are compared and analyzed by using MATLAB/Simulink simulation and dSPACE1104 experimental platform. Results show that the speed sensorless control algorithm based on simplified stator currents has good control performance and high control accuracy.

This paper proposes two novel hybrid rotors permanent magnet (PM) machines for the high torque density in short duration condition operation. In order to enhance the torque performance, the flux concentrated structure of spoke-type PM is employed to increase the air-gap flux density. Meanwhile, the non-magnetic connector of the rotor is employed to eliminate the magnetic flux leakage. The rotors of the conventional machines and the proposed machines are optimized by the finite element analysis (FEA). Furthermore, based on the comparisons of electromagnetic performances for the optimized machines, including the open-circuit flux density, torque, PM eddy current loss, overload capability, the characteristics of the proposed machines are analyzed. The results indicate that the proposed machine can improve the torque at rated and overload operation with growth rate 14.3% and 13.1%, respectively. Finally, a 12-slots/10-pole PM machine is prototyped and FEA is to be validated.

In this study, a novel natural frame control method without AC voltage sensors is proposed for single-phase cascaded H-bridge (CHB) multilevel converter and implemented in the three-cell CHB converter platform. An improved virtual flux observer (VFO) is introduced to convert the estimated AC voltage signal into the virtual flux (VF) signal and then to vectorize it. The relationship between the instantaneous power and flux linkage is used to achieve independent control of the active and reactive currents. Compared with the conventional single-phase dq control, phase-locked loop (PLL) and coordinate transformation are unnecessary for natural frame control. Furthermore, only orthogonal voltages are required in the proposed control scheme, thus eliminating the time delay caused by constructing orthogonal current signals to improve dynamic performance. The simplification of the entire system is achieved by the omission of AC voltage sensors, the PLL, and coordinate transformations without deteriorating the steady-state and dynamic performances of the entire system. Simulation and experimental results verify the effectiveness of proposed control method.

Oceanic wave energy extraction through electrical generator is one of the most interesting topics in the field of power engineering. Almost all the existing relevant review paper focus on electrical generator with the working principle of electromagnetic induction or piezoelectric or triboelectric effect. In this paper, all the existing types (based on principle of operation) of electrical generator used for wave power harvesting are discussed. This paper not only covers recent progress in electrical power generation by electro-magnetic induction, piezoelectric generator, and electrostatic induction, but also presents critical comparative review as well where suitable use and weakness of each type of generators are discussed. Moreover, the application of advanced magnetic core, winding, and permanent magnets are discussed with extensive explanation which are not focused in the existing reviews. Various new constructional features of the electrical generators such as split translator flux switching, two-point absorber, triangular coil, dual port linear generator, piezoelectric, triboelectric nanogenerator, etc. are highlighted with principles of operation. It also includes emerging human intervened optimization method for determining optimum shape of generator and cooling system which is necessary to prevent demagnetization of the permanent magnet. Finally, the way of supply the generated electrical power form the generator to load/grid is thoroughly described in a separate section that would be obvious for successful operation. The comparison among all types of generators in terms of output voltage, current, scale of power production, power-frequency characteristics, power density, cascading, and approaches are tabulated in this paper.

In this paper, a virtual-flux finite control set model predictive control (MPC) strategy for dual three-phase interior permanent magnet synchronous motors (DTP-IPMSM) is proposed. The technique is based on the conventional predictive current control, but it maps the measured variables into a virtual- flux domain, thus simplifying the prediction stage. The technique uses a flux-based cost function to track the estimated reference flux. The flux tracking cancels out to guarantee an improved current tracking, and thus, a better torque ripple. The proposed technique is validated through simulation of a 100 kW DTP- IPMSM in Matlab/Simulink. Results evidenced a reduced current control error, thus improving the torque tracking up to 38.9 % when compared to the conventional inductance based model predictive control.

This paper presents the current controller-based parameter measurement of a variable flux permanent magnet synchronous machine (VFM) for different magnetization states (MS). A series of pulse currents are supplied to the VFM in a closed-loop system. The machine voltage and current response are measured and are processed in real-time to calculate the flux linkage, inductance and resistance. Thus, automated machine parameters are generated in real-time by the real-time processor. Since the same closed-loop system is used to change the machine MS to the desired level, the machine parameters for different MS can be automatically calculated. Experimental validation is performed on a 5 hp VFM. The experimental results are compared with the finite-element analysis results and show a good correlation.

This paper proposes a new framework for the deadbeat predictive direct torque control for interior permanent magnet synchronous machine (IPMSM) utilizing active flux. Unlike the existing deadbeat predictive direct torque and stator flux control, it is relatively simple and does not require to neglect any physical quantities such as stator resistance votlage drop and cross-coupling. In addition, a sliding-mode-disturbance-observer (SMDO) is combined to track the system disturbances caused by parameter mismatch in real time. The effectiveness of the proposed composite control is verified by simulation and experiment results.

High frequency multiresonant electronic ballasts have been widely used into fluorescent lamps because it can obviously prolong the life of fluorescent lamps. In this paper, a passive integrated passive unit with the flexible multi-layer foil (FMLF) integration technique is proposed to improve the power density of the high frequency multiresonant electronic ballast. Furthermore, the construction, flux analysis and parameter design of the integrated unit are demonstrated in detail. Finally, a simulation model based on Maxwell/Ansoft and a prototype for a 68W-23.5kHz multiresonant converter electronic ballast are established to verify the feasibility of the proposed idea.

The power losses in high power-density motors due to high rotational speed and/or high pole counts may be reduced adopting metal amorphous nanocomposites (MANCs) featuring low power loss and a relatively high flux density ($\sim$1.3 T). We recently proposed a flux switching permanent magnet (FSPM) motor with a rating of 2.5 kW at 1400 Hz electrical speed that incorporates low loss (

An eddy current of a permanent magnet (PM) used to be calculated by a 3-dimensional transient finite element analysis (3D FEA) in a conventional method. Although the 3D transient FEA brings out accurate results, it is hard to be used in the motor design because of its long computational time. Therefore, this paper proposes a cost-efficient 2D analysis to calculate the PM eddy current loss with high accuracy and low computational resource. Assuming that the flux generated by the eddy current of the PM is ignored, the flus distribution is calculated by a 2D static $\mathrm{A}-\Phi$ method on $x y$-plane. The harmonics of the flux density in the PM region are calculated. Since the time-variant of the flux density is the source of the eddy current, the flus density harmonics are reflected in a time harmonic $T-\Omega$ method to calculate the eddy current of the PM on $x z$ - and $y z$-plane. Through the proposed method, the conventional 3D FEA is replaced by multiple 2D FEAs. In addition, the static and time harmonic analyses allow the advantage in the computational time. Thus, the proposed method has advantages of high reliability and short computation. Results, such as average value of the PM eddy current loss and computational time, which is obtained on the proposed and conventional method were compared for validation.

This work is evaluating the typically applied iron loss modeling for radial flux machines. The particular focus is on a comparison with true loss characteristics derived by utilizing a measurement setup with a disc shaped specimen. The 2D flux density trajectories along the machine’s cross section, obtained through the finite element analysis (FEA), feature significant differences in shape depending on which part of the machine is analyzed, e.g., a stator tooth or the stator yoke. In order to facilitate a detailed evaluation and comparison, the flux density trajectories obtained for each finite element in FEA will be automatically measured using the presented setup. This further allows for studying the loss density over the soft magnetic material’s cross section and to identify local errors made when using typically applied loss modeling approaches. The obtained results thus provide interesting insights that can stimulate future modeling improvements by focusing on flux density trajectories where most significant discrepancies are discovered.

This paper evaluates the parameter sensitivity of deadbeat flux vector control for six-step operation of permanent magnet synchronous machines. The flux-based torque control law is speed-dependent, causing an increased parameter sensitivity at the lower-speed range of the field-weakening region. This paper uses a linear operating point model to analyze and compare different torque control laws for six-step operation. However, while insightful, these linear modeling techniques break down for torque components near the fundamental electrical frequency when the six-step operation’s nonlinearities start to dominate. The paper explains the different effects that can be seen in a six-step frequency response function. With this understanding, machines can be selected and build to have a more robust performance in six-step operation.

This paper presents a Direct Quadrate (D-Q) model of a Direct Torque Control (DTC) for a 3-Phase Induction Motor (IM) using MATLAB Simulink. The impact of various loads on the 3-Phase IM were also studied and simulations were carried out using MATLAB Simulink. The simulation results show that the estimated stator flux angle varies from 0 rad (00) to 2n rad 3600) with an approximate frequency of 50Hz. The steady state estimated stator flux module fluctuates from the reference value with an error of 0.525% maximum ripple. Results obtained from the simulations using the proposed model indicate that the model gives a better performance in comparison with conventional Direct Torque Control models.

In this paper, a novel doubly salient linear hybrid excited machine (DSLHEM) is proposed. The armature and field windings of the proposed design are non-overlapped. The iron bridge is designed next to PM to offer a second magnetic flux path for DC excitation. This will increase the magnetic flux and hence the thrust force. The proposed machine has all excitation sources housed on the mover, and the stator is completely passive, which makes it suitable for long stroke applications. Field windings are used, which improves the flux linkage, and hence the proposed machine has better flux regulation capacity at different field currents. The design parameters are optimized using parametric optimization. Finally, the proposed machine is compared with a conventional machine, 8.89% higher average thrust force (TF avg ) was achieved with a 53% reduction in the volume of PM while keeping the volume of the whole machine constant.

This paper presents a comparative electromagnetic performance analysis of different topologies of Brushless DC (BLDC) Permanent Magnet (PM) machines. In particular, five distinct motor configurations with different rotor structures (i.e., axial flux machine with disk rotor, radial flux machine with inner rotor, and radial flux machine with outer rotor), stator structure (i.e., slotted and slot-less) and winding arrangements (i.e., concentrated winding and distributed winding) are presented, their steady-state electromagnetic performances are compared and conclusions are made on their key differences. The analysis is carried out using field and circuit models. In addition, the impact of the magnets remanence on the motor performance is highlighted.

Plasma sheaths control particle and energy transport between the plasma and surface [1] . They can be further complicated when the surface is electron emitting (i.e., thermionic emission). These emissive sheaths are seen in various engineering applications such as RF devices, dusty plasmas, divertors/scrape-off layers, and plasma probes. Recently, emissive sheaths have been hypothesized to promote surface cooling on hypersonic vehicles via thermionically emitted electrons in Hanquist et al. [2] , where a space-charge limiting (SCL) sheath assumption was used to predict the electron current exiting the sheath. However, excessive emission from a surface may lead to the formation of an inverse sheath [3] , which may further reduce the number of electrons escaping the surface. In recent experimental works by Kraus et al. [3] , thermionically emitting filaments (thoriated tungsten) were submersed in Xe plasma flow that produced a space-charge limited (SCL) sheath. We will present a 1D study on sheath formation for an emissive surface that may prevent the emitted electrons from reaching the bulk plasma using the Particle-in-Cell (PIC) method. Prediction of these sheaths is important as they may affect the heat loss and charge flux from the surface [1] .

Studies on the generation of electromagnetic radiation during beam-plasma interaction are of considerable scientific interest from the standpoint of analyzing the results of astrophysical observations [1] . Such studies look no less important from the standpoint of solving a wide range of practical problems using high-powerful submillimeter radiation. Experimental and theoretical studies on multimegawatt power submillimeter wave generation due to intense interaction of a relativistic electron beam (REB) with a magnetized plasma column are carried out in BINP SB RAS [2] . In the experiments performed at the GOL-PET facility, the beam with parameters 0.5 MeV/15 kA/6 μs was propagated in a magnetized (induction up to 4.7 T) plasma column with the diameter 6 cm, length 2 m and density (1÷2)x10 15 cm -3 . A radiation flux generated due to beam-plasma interaction was extracted in atmosphere through an output fluoroplastic window of 18 cm diameter. We measured the power and the spectral power density of this flux in the frequency band 0.1÷0.8 THz for various plasma density distributions. The radiation angular distribution of the output flux propagated in the hall atmosphere was also measured. The experiments have shown that the maximal spectral power density of the flux power is located in the frequency range 0.2÷0.35 THz that is the area of the upper-hybrid frequency of plasma oscillations. The value of the spectral power density in this frequency interval depends on the plasma density distribution over the plasma column diameter and on the law of density decrease along the axis at the beam output from the column. The experimental results are discussed in comparison with analytical and computer modeling.

The influence of dense and strongly coupled ions on the ion current to a particle is modeled in this work. Langevin Dynamics is used to simulate the motion of multiple ions around a negatively charged grain in a periodic domain. The ion flux coefficient is calculated using the grain-ion collision time distribution. In addition to the ion-ion electrostatic coupling strength Γ=e 2 /(4πe 0 k B T i n i -1/3 ), the ion flux coefficient is also influenced by the diffusive Knudsen number Kn D =(m i k B T i ) 1/2 /f i a p that characterizes the ion-neutral gas interactions (through the scalar friction factor f i =k B T i /D i , D i is the ion diffusion coefficient), a concentration parameter χ=a p /n i -1/3 that compares the size of the grain a p to the mean inter-ion spacing n i -1/3 , where n i is the ion number concentration and Ψ E =-z p Γ/χ that denotes the strength of particle-ion interaction. The influence of Kn D on the structure of the ions and their self-organization is demonstrated by analyzing the ion-ion pair correlation function g 2 (r) and ion velocity distribution function. It is seen that depending on the regime defined by Γ, Kn D , χ, Ψ E the ion velocity distribution function is Maxwellian for Γ

Self-generated magnetic fields are expected to be generated in excess of 10,000T in ICF hot-spots [1] . A model for magnetic flux generation is presented, showing that more flux is expected around large amplitude and high mode perturbations. The model compares favorably with Gorgon extended-MHD simulations, allowing for greater understanding of which target designs will be susceptible to MHD effects. For example, the model can be used to ascertain when most magnetic flux is expected to be generated. If generation is weighted more towards early times, then more high-mode magnetic field loops will be generated; even if the high-mode perturbations are ablatively stabilized at later times, the high mode magnetic field will still be present.

In this paper, two encoderless control systems are comparatively presented working at ultra-low speeds. A novel referencing position encoderless control of PM-RSM drives is proposed, based on active flux observer, without using signal injection. To improve the drive dynamics, for the position and speed estimator a phase-locked loop mechanical tracking observer was developed. The referencing speed encoderless control, used for comparison, is also based on an active flux observer. Extensive comparative simulation results with good performances at ultra-low speed validate the proposed position encoderless control system. Therefore, the effectiveness of the proposed referencing position encoderless control is confirmed.

Several studies on long-term trend using the ion temperature in ionospheric F-region are made in high-latitude stations using Incoherent Scatter Radar (ISR) measurements. Those observed trends indicate the upper atmospheric cooling. Those studies reported that those have strong dependency on magnetic latitude for the altitudes above −275 km. Given the advantage of high sensitivity of Arecibo Observatory's ISR and its location at geomagnetic latitude (29°N), it is very much interesting to examine the long-term trends of the ion temperatures (T i ) for the altitudes above −275 km. We have analyzed T i data sets of ISR from 1985 to 2015, to examine the long-term trends of the ion temperature as function of altitude from ~122 km to ~700 km over Arecibo (18.3°N). These long-term trends are examined in relation to solar flux of F 10.7 (flux at 10.7 cm) and A p index for the understanding of influence of solar flux and geomagnetic activity on temperature trends of the F-region. These results will be discussed to understand the effects of solar activity and geomagnetic activity.

The impulse-induced super substorm of 21st January 2005 has been reported by Hajra and Tsurutani (2018) and they have discussed the abnormal morphology of the auroral dynamics mainly examining the auroral images and currents. This event is revisited here with additional datasets of global Cosmic Noise Absorption (CNA) by Riometers, auroral images by a space-based Imager, plasma flux data from geostationary satellites and magnetic field measurements of ground stations covering almost all latitudinal and local time sectors. We have observed some peculiar characteristics of this event: (1) No southward component of IMF Bz prior to the substorm onset. (2) Westward electrojet current peaks in the dawn sector, and not in the midnight sector, during the substorm interval. (3) Presence of dayside shock-auroras: The electron & proton auroras are stronger in the pre and post-midnight sectors and strongest on the dayside. (4) The time of CNA onset and substorm onset coincide in the narrow belt of magnetic latitude near 65°. The time delay between these two increases away from this belt on both-poleward and equatorward latitudes. The delay is small (~ 2 minutes) on the dayside and significant (~11 minutes) on the night side. (5) The percentage of CNA is found to vary with MLT as well as with latitudes. CNA absorption is lowest on the dayside (~20%) whereas near dawn and dusk the percentage of CNA is nearly equal (~40-50%). (6) Considering the model proposed by Sorathia et al. (2019) we can say that the dawn-dusk symmetry observed in the CNA indicates the entry of particles from the flanks facilitated by Kelvin-Helmholtz instability.

High-energy electron populations within the Van Allen radiation belts are highly dynamic, and seen to increase and decrease on timescales as short as hours. One of the lingering questions about radiation belt dynamics overall is which types of plasma waves are responsible for the various changes we observe. Here, we present two studies that illuminate how ULF waves shape the boundaries and enhancements of relativistic electrons. One result, using seven years of Van Allen Probes satellite data, shows that ULF waves can create multi-MeV flux enhancements following geomagnetically active periods. Thus, ULF-driven radial diffusion can often be the dominant mechanism behind ultrarelativistic electron enhancements; although high populations of lower energies, likely produced by VLF interactions, are a necessary precondition. A second analysis, looking at decades of POES data, shows that relativistic breaches of the lower boundary of the outer belt happen in concert with elevated ULF wave power yet are not associated with particular type of solar driving. How relativistic electrons can cross this barrier and enter into the slot region and inner zone is crucial for understanding the radiation environment in this regime closest to Earth.

In this paper, the response of the fluxgate core is analyzed against different design parameters using finite element method simulations. Furthermore, the nonlinear characteristic of the core magnetic material is included during simulations to have reliable evaluation about the fluxgate core behavior under the investigated operating conditions. Results of the conducted numerical simulations reveal that at 100 KHz excitation frequency, a desired flux response was achieved for 20 μm radius' core with 100 mA ac current. Moreover, in addition to the 100 mA ac current, a dc bias of 100 mA was needed to achieve a desired flux response for 20 μm radius' core at 1 MHz excitation frequency. Furthermore, for a core radius of 40 μm, a desired flux response was achieved at 100 KHz, with the excitation ac and dc currents to be 60 mA, and 100 mA respectively.

The main goal of this study was the determination of carbon flux model for the area of the Biebrza Wetlands, to evaluate their potential as carbon sinks, based on meteorological, soil and vegetation parameters. Based on ground data and satellite data (images from the Sentinel -1, -2, -3 and MODIS) acquired in 2017–2019, a statistical model was used that combines the carbon dioxide stream, latent heat and soil moisture. The flux of carbon dioxide and latent heat were recorded using the eddy covariance tower, which allows for very high sensitivity measurements at a frequency of 20 Hz. Soil moisture was measured at various points in the Biebrza National Park at a depth of 5 cm with a time resolution of 15 minutes. Later, the field parameters were replaced with their satellite equivalents (e.g. soil moisture - [1]), which made it possible to obtain carbon dioxide flux values for any point within the park. The assessment of carbon fluxes is performed at 1-km spatial scale. Carbon measurements done by the chamber method were used to verify the model. All data were extracted using a R programming language script. Further analyses were carried out in R and Statistica program, the satellite image processing was performed using a ERDAS and program R.

Surface carbon fluxes associated with terrestrial vegetation play a key role in the global carbon cycle. Remote sensing (RS) and land surface models (LSM) have demonstrated to be valuable tools in assessing the gross primary production (GPP). Yet, the seasonal variability of this flux, and timing of the seasonal cycle remain challenging to observe and simulate accurately. Here, the ability of four RS products and two LSM to simulate GPP and its variability was assessed. It was found that the mean seasonal GPP was simulated accurately with RS-based models, but that it failed to capture the seasonal variability and timing of the seasonal cycle. In contrast, the LSMs demonstrated their ability to simulate seasonal anomalies in GPP, but had trouble to simulate the associated phenology.

Remote sensing-based models are an adequate tool to estimate carbon dioxide (CO 2 ) uptake by terrestrial ecosystems, and to upscale the results from ecosystem to regional or global scales. In this study we compare three models driven by Sentinel-2 derived vegetation indices together with eddy covariance (EC) measured CO 2 flux and radiation data in order to estimate gross primary production (GPP) in northern Europe forest ecosystems. By integrating high spatial resolution satellite data with cutting-edge footprint analysis and an accurate GPP model, we aim at more precise estimation of GPP at regional level.

In recent years, there has been a push to increase agricultural productivity together with water efficiency. The most viable means to achieve this goal is by employing remote sensing technologies. Currently, multiple satellite platforms can provide the spatial information to crop water use models, each of them having diverse spatial resolutions and radiometric characteristics. Here we analyze the spatial scale effects on crop water use (via evaporation) from three satellite platforms (Landsat 8, Sentinel 2, and CubeSats) finding that each estimate shows different spatial variability and that flux aggregation can result in relative mean absolute error up to 120%.

Linear machine has been verified to be suitable for some direct-drive applications with linear motion requirement. As a family member of linear machine, the transverse flux linear machine (TFLM) has attached widely interest for the advantage of high force density. However, in the traditional TFLM, the useless permanent magnet flux leakage occupies a large ratio of the total magnetic flux excited by permanent magnet, which leads to the limit of thrust density improvement. In this paper, a tubular transverse flux linear machine with dual-consequent-pole configuration (DCP-TTFLM) is introduced, which improves the force density and space utilization than traditional transverse flux machines. The topology and principle of DCP-TTFLM are introduced. Then, the electromagnetic characteristics of this machine is investigated by a finite element model, and the results shows the excellent performance of the DCP-TTFLM.

This paper proposes a novel linear partitioned hybrid-excited consequent-pole flux-reversal machine featuring a wide flux adjusting range with less PM consumption. Due to the space confliction between armature and field windings in conventional hybrid-excited machine, the consequent-pole partitioned primary structure is employed to improve the PM utilization ratio and further enhance the flux regulation capability. Firstly, the topology, operation principle and flux regulation principle are introduced. Then, using finite element method (FEM), the dimensional parameters of the proposed machine and a conventional machine for comparison are globally optimized for higher thrust force and wider flux adjusting range. The electrical performance of optimized structures including open-circuit phase back-electromotive force (back-EMF), flux adjusting capability and force characteristics are investigated. The proposed machine is observed to have better flux regulation capability than conventional machine with improved PM utilization ratio, which means it is suitable for wide speed range system applications.

In this paper, an MTPA based model predictive thrust control is proposed to eliminate the weighting factor and improve steady-state performance for the linear induction machine (LIM) drive system. The concept of field oriented control is used to derive the condition of MTPA in $d-q$ reference frame. Based on the principle of MTPA and the inherent relationship between thrust and flux, a reference primary flux is introduced as the only criterion in cost function to achieve the control goal without using any weighting factor. Furthermore, to reduce the high flux and thrust ripples caused by single vector, arbitrary double vectors are selected and applied in the control period. Simulation results have demonstrated that the proposed method has smaller flux and thrust ripples and less weighting factor tuning workload than those of the conventional methods.

This work deals with the assessment of an experimental setup for the CO 2 measurement inside the cabin of an electric crane. Different operating and ventilation conditions are compared and the optimal positioning of the CO 2 sensors are discussed. In particular, the results obtained by some sensors placed around the cabin occupant are compared with three sensors positioned in the breathing zone. In all the ventilation modes, a flux of 66 g/h of pure CO 2 is introduced inside the cabin, to simulate the breathing of a driver. We studied three different operating conditions: heating mode, ventilation mode and cooling mode. In each condition the CO 2 distribution is obtained for the cases of internal ventilation in fresh air mode and on/off control of the recirculation mode. Two different ventilation distributions were considered: one for the heating mode and one for ventilation and cooling modes. A stratification of the CO 2 along the vertical axis is shown in both the cases. While in heating mode the CO 2 concentration decreased going from the bottom to the top of the cabin, in the other two modes the CO 2 level was maximum at medium height and minimum at the extremities. The optimal positioning of the CO 2 sensors is obtained for the three operating modes.

To overcome the difficult control problem of the braking force in the linear permanent magnet brakes, a novel double sided flux adjustable linear permanent magnet eddy current brake is presented. The structure and operation principle are addressed. To avoid the excessive computation time and cost of adopting the numerical method, a practical analytical model based on the magnetic equivalent circuit method is established, and verified using 3D finite element analysis. Finally, further analysis employing the developed analytical model is carried out to explore the influence of key parameters on the braking force characteristic.

To reduce the thrust fluctuation of long primary double-sided linear induction motor (LP-DSLIM) segmented in parallel fed by a single inverter, a secondary field-oriented control strategy is proposed. First, the voltage and flux equations of a DSLIM module are presented. Then, the LP-DSLIM system segmented in parallel is analyzed, and the secondary flux linkage and thrust state equations of the system are developed. The control expressions of secondary flux linkage and thrust in the total secondary flux reference frame are derived. A total secondary field-oriented control strategy is proposed. Finally, the simulation results show that the proposed control strategy reduces the thrust fluctuation effectively.

The model predictive thrust control (MPTC) is recognized as an effective approach for a linear induction machine (LIM). The flexibility of MPTC can achieve more control targets. However, the weighting factors in the multiple control objectives need to be tuned. It can greatly increase the complexity of controller design. Based on the robust primary flux constraint and fuzzy probability, a novel predictive thrust control without optimal weighting factor is proposed in this paper. As a result, weighting factor selection is avoided, which can reduce computation time, and increase dynamic response. At last, the performance of the proposed method has been verified by comprehensive simulation results.