Traction electric drive based on fuel cell batteries and on-board inertial energy storage for multi unit train

The aim of the work is to study the possibility and features of the use of inertial storage devices in the traction electric drive of multi unit train with a power plant based on fuel cells. Methodology. The principle of power flow control in traction electric drives in the modes of acceleration and braking of rolling stock is proposed. The mathematical model of the traction electric drive in the form of the combination of three components: the train, the traction unit and the battery of fuel cells is developed. It was used to study the operation of a traction electric drive when solving a test traction task for rolling stock. Results. It is established that the use of inertial energy storage reduces hydrogen consumption by at least 25 %, which increases the mileage of rolling stock between equipment by more than 30 %. Originality. The traction electric drive on the basis of fuel elements and the inertial energy storage for the multi unit train is offered. The work of the proposed traction electric drive in solving the test traction problem for rolling stock is investigated. Practical significance. A mathematical model of the traction electric drive has been developed. The test traction problem for rolling stock is solved.

High-Frequency Motions in the Southeastern South China Sea During Winter–Spring 2018/2019

High-frequency motions in the southeastern South China Sea (SCS) have rarely been investigated due to sparse field observations. The vertical distribution and temporal variation of internal tides (ITs) and near-inertial waves (NIWs) near the Nansha area in the southeastern SCS were studied using a mooring current dataset from December 2018 to June 2019 in this study. Results showed that ITs were mainly dominated by O1, K1, and M2. Tidal energy analysis indicates that the diurnal ITs were the most energetic components, followed by the semidiurnal ITs. Modal decomposition reveals that diurnal ITs were dominated by mode-3, rather than mode-1, as reported by previous studies. The horizontal kinetic energy (HKE) of diurnal ITs fluctuated within a limited range, almost unaffected by the background field. However, the HKE of semidiurnal ITs was dominated by mode-1 and more affected by the background field, especially at the end of March. Most observations showed the phase of the NIWs propagating upward and the energy propagating downward. During the northeast monsoon period, the near-inertial energy had a large magnitude due to strong wind forcing. In addition, the near-inertial energy peaked from the middle of March to the beginning of April because of the input of NIWs from afar. Overall, near-inertial energy was found concentrated above a 500–600 m depth in the southeastern SCS.

Near-inertial wave modulated turbulence in a Kuroshio anticyclonic eddy

<p>Storm-generated near-inertial waves are a significant source for deep-ocean mixing. However, their energy pathways beyond wind generation and equatorward propagation as low modes are still elusive. Previous studies suggest that the bulk of inertial wind power is lost in the nearfield of storm forcing, but there is little observational evidence to confirm this.</p><p>Finescale horizontal velocity, temperature, salinity and microscale temperature profiles to 500-m depth were collected in the Kuroshio-Oyashio Confluence east of Japan during the storm-seasons of 2016 and 2017 with chi-augmented EM-APEX floats. Temporal sampling was at 1-h resolution during storms, sufficient to resolve near-inertial motions. Turbulent dissipation rates  and diapycnal diffusivities K were inferred from microscale temperature-gradient spectra.  Several floats were trapped near the velocity maximum of anticyclonic eddies.  Mesoscale eddies are known to trap and amplify near-inertial waves and to modulate near-inertial wave distribution and dissipation.</p><p>Near-inertial energy-fluxes within the eddy are mostly inward and downward. Signatures of a critical layer, e.g., increasing vertical wavenumbers, shear, and turbulence are present at the depth where the eddy vorticity approaches the surface value, and strong vertical mean shears and vorticity-gradients occur. Turbulence is reduced by a factor of 10 above 180-m depth, despite elevated near-inertial energy, and enhanced between 200 and 255 m. Three mechanisms for the generation of enhanced turbulence are hypothesized: i) local and remotely forced near-inertial waves superimposing to create shear-unstable layers, ii) kinematic superposition of eddy and near-inertial shear that generates patches of turbulence at inertial periods, iii) a near-inertial critical layer due to dynamic wave/mean interaction. Ray tracing simulations will be performed to examine whether vertical vorticity gradients and/or Doppler shifting are responsible for the presence of a critical layer.</p>

The temporal variability of near-inertial internal waves in an internal tide beam

<p>Low mode internal waves in the stratified ocean are generated by the interaction between barotropic tides and seafloor topography and by the wind field in the near-inertial range. They are crucial for interior mixing and for the oceanic energy pathways, since they carry a large portion of the energy of the entire internal wave field. Long-term observations of energy fluxes of internal waves are sparse. The aim of this work is to study the temporal variability of wind generated low mode near-inertial internal waves inside an internal tide beam emanating from seamounts south of the Azores. For this, 20 months of consecutive mooring observations are used to calculate the mode 1 and mode 2 near-inertial energy fluxes as well as kinetic and potential energies. The gathered time series of near-inertial internal wave energy flux is not steady due to its intermittent forcing and is neither dominated by either mode 1 or mode 2. It shows a peak induced by a distinct strong wind event which is directly linked to wind-power input into the mixed layer north-east of the mooring location, and allows a comparison between the wind event and a background state. Furthermore, indications of non-linear interactions of the near-inertial waves with the internal tides in the form of resonant triad interaction and non-linear self-interaction have been found. This study provides new insights on the relative importance of single wind events and reinforces the assumption of a global non-uniform distribution of near-inertial energy with emphasis in regions where these events occur often and regularly. It furthermore displays its importance to be adequately incorporated into ocean general circulation models and in generating ocean mixing estimates by near-inertial waves as a similarly important component next to the internal tides.</p>

Experimental Analysis of Power Flows in the Regenerative Vibration Reduction System with a Magnetorheological Damper

The aim of the work is to investigate power flows in the vibration reduction system equipped with a magnetorheological (MR) damper and energy regeneration. For this purpose, experiments were conducted in the test rig compound of the shaker and the vibration reduction system (electromagnetic harvester, MR damper, spring) which are attached to the sprung mass. The experimental data acquired under sine excitations enabled us to analyze instantaneous power fluxes, as well as a rate of inertial energy changes in the system.

The Inertial Energy Control Strategy of the Cascade H-Bridge Module applied in Photovoltaic System

This paper put forward the inertial control strategy based on the control of charge and discharge of supercapacitor and the trigger angle of H-bridge which integrates photovoltaic (PV) system. The whole cascade H-bridge structure is composed of traditional photovoltaic module, Boost/Buck circuit, supercapacitor (SC), and H-bridge circuit. First, the charging state and the inertial energy power support of the SC are analysed. Then the control strategy of the cascade H-bridge is proposed. To verify the efficiency of the control strategy, a cascade chain consists of 12 H-bridge unit was built in EMTP simulation software. Finally the simulation results prove that the newly developed SC-integrated cascade module can do inertial energy support well, which is important to the coordination between the power system and solar energy.

Application of an Innovate Energy Balance to Investigate Viscoelastic Problems

Modeling and investigating of energy distribution especially the wasted one is very important in viscoelastic problems. In this article, an applied energy model based on separation of energy components of the system is extracted and expanded to apply in linear viscoelastic problems, although this method is applicable in nonlinear problems as well. It is assumed that the whole energy of the system can be divided into two parts: Residual and non-inertial energies. The non-inertial energy is the sum of the energies that do not depend on the inertia of the system, while residual energy is the remaining of total energy. When an amount of energy is applied to the system, by determining the non-inertial energy from a novel energy conservation equation, the residual energy can be calculated. Some basic viscoelastic examples are investigated and obtained results will be compared with the expected ones.