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In order to effectively make up for the defect of service life of re-tired power battery echelon used in microgrids (MGs) and improve the reliability of MGs system, an energy management method based on the energy hub of the electricity heat hydrogen multi-energy storage system (EHH-MESS) is proposed the in the paper. Firstly, considering the uncertain factors such as energy output, load fluctuation, retired power battery life defects and multi energy flow impact, MGs supply-demand balance model is built. Secondly, taking the economy of energy supply as the goal, a control method based on energy hub is proposed, which considers the weight of multi-objective optimization to control MGs. Finally, the effectiveness of the proposed energy management method is verified by simulation analysis, which improves the power supply reliability and economy of the system. [ABSTRACT FROM AUTHOR]

This paper deals with the possibility of applying superconducting motors and hydrogen fuel cells to electric aviation propulsion systems (APS) for the development of next-generation APS. Instead of the conventional fossil fuel-based power generation system, the APS using hydrogen fuel cells and superconducting motors was conceptually designed. The proposed APS consists of a superconducting motor, a hydrogen fuel cell, a liquid hydrogen tank, and a battery. For specific power comparison, the proposed APS capacity was the same as that of a commercial APS, and the capacity and weight of the hydrogen fuel cell and battery were calculated. The 5 MW superconducting motor was designed and analyzed focusing on magnetic field distribution, thermal load, mechanical stress, efficiency, weight, and specific power. As a result, the proposed APS is expected to reach the level of performance applicable to aircraft in the near future, given the recent development trend of battery and liquid hydrogen technology. These results are expected help in a future-oriented APS design. [ABSTRACT FROM AUTHOR]

If the batteries are charged by clean renewable energy sources, electric vehicles (EVs) can have zero gas emission, contributing greatly toward the preservation of the green environment. In a smart micro-grid, EVs together with other distributed energy storage units can be used to supply electricity to the loads during the peak hours so as to minimize the effects of the load shedding and improve the quality of electricity. To achieve these goals, an isolated hybrid multi-port converter is required to control the power flows and balance the energy among renewable energy sources, EVs, and the grid. In this paper, a new isolated multi-port converter is proposed, which can control the power flow in multiple directions. The converter is modeled in the matlab/Simulink software environment and this validates the technology with a laboratory prototype test platform. The modeling, implementation, and results are discussed comprehensively. [ABSTRACT FROM AUTHOR]

Recent developments in high temperature superconducting (HTS) materials have made superconducting cables and energy storage systems promising alternatives for use in future power systems. High temperature superconducting coils based superconducting magnetic energy storage (SMES) can be integrated to other commercially available battery systems to form a hybrid energy storage system (HESS) to mitigate the potential issues caused by a large-scale penetration of distributed generation, such as the midday voltage rise, the reverse power flow, and the voltage unbalance in the distribution system. The rapid response of the HTS SMES system in the HESS can be used to mitigate the high ramp rate of the photovoltaic (PV) output fluctuation during passing cloud events. This paper has performed a case study for a future low loss distribution grid with a high penetration of renewable energy (RE), such as solar PV, fitted with superconducting cables or superconducting power lines, where issues associated with the large-scale penetration of the RE can be mitigated. [ABSTRACT FROM AUTHOR]

In order to effectively improve the role of battery energy storage system in power system, this paper studies the optimal scheduling strategy of BESS in power grid. Firstly, taking the minimum power exchange cost between power grid and the penalty cost of node voltage deviation as the objective function, an optimal scheduling model of BESS in distribution grid based on mixed integer programming is proposed. Secondly, when BESS tracks the scheduling instruction, the life attenuation of each BESS is inconsistent due to the difference of operation conditions. A scheduling method considering the state of health (SOH) of BESS is proposed. Finally, the SOC and total charge and discharge capacity of each BESS are analyzed, and the change characteristics of SOC under different SOH conditions (0.8, 0.85, 0.9, 0.95, 1.0) are verified effectively, which indirectly verifies that this scheduling method can effectively reduce the scheduling loss. [ABSTRACT FROM AUTHOR]

This paper investigates a new DC voltage sag compensating scheme by using hybrid energy storage (HES) technology involved with one superconducting magnetic energy storage (SMES) unit and one battery energy storage (BES) unit. Two fault simulations of power supply fluctuation and sensitive load fluctuation are carried out to evaluate the dynamic voltage and power smoothing behaviours. The results obtained show that this HES-based DC voltage sag compensator has the ability to suppress the discharging / charging current overshoots for the BES unit and to enlarge the voltage compensating time for the SMES simultaneously. [ABSTRACT FROM AUTHOR]

This paper proposes an application of superconducting flywheel energy storages (SFESs) to compensate the power fluctuation of the large scale wind farm. Based on the global interest against global warming, the power capacity of the renewable generation, especially wind generation, has been increased steeply. However, since wind generations depend on the natural wind speed completely, the power output cannot be controlled. The power fluctuation caused by the non-controllable output characteristic may create voltage problem for local system and frequency problem for whole power system. To solve those problems, the hybrid application of the large-capacity battery energy storage system (BESS) and the high-speed superconducting flywheel energy storage system (SFES) are considered in Heangwon wind farm in Cheju Island in Korea. Through the case studies based on the site-measured output data, the optimal power and energy capacity of the BESSs and SFES are figured out. [ABSTRACT FROM PUBLISHER]

This paper focuses on a review of the state of the art of future power grids, where new and modern technologies will be integrated into the power distribution grid, and will become the future key players for electricity generation, transmission, and distribution. The current power grids are undergoing an unprecedented transformation from the original design, changing the way how energy has been produced, delivered, and consumed over the past century. This new energy era includes the integration of renewable sources such as wind and solar, supported by the distributed or community energy storage, to power distribution grids through innovative high-frequency magnetic links and power-electronic converters. The use of emission free transportation, such as electric vehicles, and energy efficient technologies, such as superconducting generators and storage systems, are also rapidly emerging and will be integrated into the power grids in the foreseeable future. However, it is necessary to reconsider the current paradigms of system analysis and plan with a focus on how to achieve the most flexible, efficient, and reliable power grid for the future––the one that enables operation in a domain which is very different than the current one to deliver the services to consumers at an affordable cost. [ABSTRACT FROM AUTHOR]

This paper proposed a hybrid power supply system for quasi-continuous high magnetic field systems at the Wuhan National High Magnetic Field Center. The hybrid power supply combines a battery power supply and a 12-pulse generator-rectifier power supply together. Based on the power supply, a 60 T dual-coil quasi-continuous magnet is presented. The inner coil and outer coil are powered by the battery power supply and the generator-rectifier power supply separately. Both coils are wound with soft copper wires reinforced by HS4-glass fiber. To verify the proposed design scheme, Matlab/Simulink and COMSOL Multiphysics 3.5a are adopted to build the simulation models of the hybrid power supply system and the 60 T dual-coil magnet. Simulation results show that the proposed system has enough margins to achieve a 60 T/100 ms quasi-continuous field. Higher fields can be achieved without large changes when advanced conductors and fibers are adopted. [ABSTRACT FROM PUBLISHER]

A 40 T long-pulse magnet has been constructed and tested to 32 T with total pulse width of 1.5 s at the Wuhan National High Magnetic Field Center (WHMFC). The magnet is energized by a battery bank power source consisting of 900 12 V/200 Ah lead-acid battery cells. The magnet consists of a polyhelix inner coil and an outer coil wound with copper foil. We made some improvements by adding axial slots on the helices due to the eddy current electromagnetic force, and each layer of helices is reinforced by Zylon-epoxy composite. The copper foil coil is insulated with polyimide film extending over the sides of the foil. The copper bar electrode is silver brazed on the ends of copper foil and has been proved to be quite feasible. In this paper, the calculated results of the electromagnetic force caused by eddy current will be presented. The magnet manufacture techniques will be described and the magnet test results will be listed and analyzed. [ABSTRACT FROM PUBLISHER]

The high-field quasi-continuous magnets (QCM) are of great interest for scientific experiments that require long pulse duration and in particular a field pulse with a flat-top. For the QCM, the power supply is a real challenge. At the Wuhan National High Magnetic Field Center (WHMFC), it is planned to realize a 45 T/500 ms flat-top field by the series combination of a 0.6 kV/35 kA battery bank and a 12-pulse rectifier that is powered by a 100 MVA/100 MJ flywheel pulse generator (FPG). In order to reduce the dc current ripple, a dc passive filter is connected in parallel with the rectifier. The simulation of the pulse shape with respect to the voltage profile supplied by the power supply takes the resistance of the magnet into account; this increases with temperature as a function of coil current. The configuration and the associated control strategy are presented in this paper. A simulation model of the combined power supply system is developed and compared with the model of a single rectifier supply system. Results are provided to validate the proposed method. [ABSTRACT FROM PUBLISHER]

In order to improve the screening accuracy of decommissioned power batteries and reduce the regulation errors of batteries in the process of echelon utilization, a cascade batteries selection method based on confidence interval probability prediction is proposed. Firstly, according to the internal and external characteristic parameters, residual capacity, state of health (SOH) and other historical parameters, K-means clustering is used to divide static clusters of retired power batteries with similar parameters. Secondly, the bootstrap probability method is used to analyze the deviation subset of SOH estimation in echelon utilization process, and the probability interval density function of SOH subset is established. Finally, further optimization grouping is carried out according to the predicted SOH characteristics. By comparative analysis, the influence of confidence interval estimation on the screening accuracy is determined, and the effectiveness of the proposed screening method is determined. The consistency of dynamic characteristics is improved while the static parameters are similar in the screening process, which lays a foundation for accurate regulation of retired power battery echelon utilization. [ABSTRACT FROM AUTHOR]

The pulsed high magnetic field facility funded by the Chinese National Development and Reformation Committee has been developed at the Wuhan National High Magnetic Field Center (WHMFC). Magnets of short pulse, long pulse and the combination of both with bore sizes from 12 to 34 mm have been developed and are operational for electric transport, magnetization, magneto-optics and electron spin resonance at temperatures in the range from 100 mK to 350 K. The power supplies for these magnets consist of a capacitor bank with 12 modules of 1 MJ/25 kV each and 2 modules of 0.8 MJ/25 kV each, a 100 MVA/100 MJ flywheel pulse generator and a 771 V/180 kAh battery bank. A dual-coil magnet driven by the capacitor banks has successfully generated 86.3 T field with a total pulse duration over 350 ms in a 12-mm bore. A dual-coil long pulse magnet wound from soft copper wire energized by the flywheel generator produces 50 T peak field with a 100 ms flat-top and a total 1.1 s pulse duration in a 22 mm bore. A battery bank driven long pulse magnet composed by the series connection of two nested coils generates 32 T peak field with the pulse duration of 1.5 s in a 21-mm bore. [ABSTRACT FROM PUBLISHER]

In 2008, the Wuhan National High Magnetic Field Center (WHMFC) was set up at the Huazhong University of Science and Technology, Wuhan, China. The objective of the pulsed magnet program is to produce pulsed magnetic fields in the range of 50 to 80 T. The following pulsed magnets were initially conceived: 1) 50–80 T monolithic magnets energized by one or a few modules of the 1 MJ capacitor bank, 2) a 50 T/100 ms flattop long pulse magnet energized by the 100 MJ/100 MVA pulse generator, 3) a 60 T/200 ms long pulse magnet energized by the 12 MJ capacitor bank, and 4) an 80 T dual coil system energized by two capacitor bank modules. In addition, a 16 T PPMS and a 7 T SQUID-VSM systems were acquired. Currently, work on a 40 T long pulse magnet energized by lead acid battery units and the acquisition of a 400 MHz NMR spectrometer are in progress. [ABSTRACT FROM PUBLISHER]

A 35 kA thyristor DC switch which consists of 8 paralleled high power thyristors installed in a disc-shaped aluminum bus to get a symmetrical structure is developed in order to meet the requirement of the DC power supply using lead-acid batteries in pulsed magnetic field with maximum flat-top current 35 kA, pulse width 1 s. This thyristor DC switch will be turned on at the beginning of experiment, and turned off by forced commutation technology which uses charged capacitors to output inverse current to extinguish the current of thyristor switch at the end. Every branch of 8 thyristors is in series with a stainless steel resistor 1.4 m\Omega and a fast-fuse to achieve parallel current sharing and overload protection of the thyristors. [ABSTRACT FROM PUBLISHER]