Fast Energy Storage Systems Research Articles

Improving power output wind turbine in micro-grids assisted virtual wind speed prediction

Wind energy is an alternative form of energy easily obtainable in the landscape. However, the main challenge is to extract electrical power from varying wind speeds. Wind energy can be a significant production resource for power electronics technologies, converters, and electrical generators. Due to their dependence on wind speed, the output power from wind turbines experiences severe fluctuations with the change in wind speed, and ripples increase the output power from the wind turbine. Therefore, the engineers’ critical research prediction will smooth these extraction fluctuations. Several speed prediction methods have been used to reduce the changes in the output power of wind turbines. One of these wind speed prediction methods is a fast energy storage system that can be charged and discharged in seconds. Applying wind speed prediction to overcome the slowness of the wind source will be the primary approach considered in this article. Also, a wind turbine with a nominal power of 50 kW and an ultra-capacitor storage system are determined, and these sources are made in MATLAB/SIMULINK softwareIn this study, the control signal for adjusting the turbine pitch angle is derived from both actual and predicted data. The signal from actual data undergoes a multiplication by 0.8, while the signal from predicted data is multiplied by 0.2. This approach serves two purposes: firstly, it helps prevent overshooting of turbine power at the initial stages, ensuring a smoother transition. Secondly, it aids in maintaining a consistent power output of 50 kW during subsequent moments. By combining actual and predicted data in this weighted manner, the control system achieves a balanced response, effectively managing turbine power dynamics. Finally, the results show that utilizing wind speed prediction to improve output wind turbine in Micro-grids (MGs) will reduce fluctuations in the wind source's output power and the ultra-capacitor storage.

Fast Energy Storage Systems Comparison in Terms of Energy Efficiency for a Specific Application

One of the key parameters to properly and accurately assess an energy storage system is the energy efficiency, which has a direct impact on the system performance and an indirect impact in its cost. In this paper, a methodology for comparing double-layer capacitors (EDLC) and kinetic energy storage systems (KESS) in terms of energy efficiency is proposed. This methodology, based on accurate loss models, takes real operating cycles into account, so a realistic result is obtained for each particular case. An accurate study of the losses of both technologies is accomplished during the paper, getting a complete model for EDLCs and KESSs, and obtaining efficiency maps for the whole range of operation points. Some conclusions about the convenience to use one or the other alternative and the best way to operate them are presented. In addition, a specific study case related to a wave energy power generation plant has been carried out in this paper, defining a methodology to select the energy storage requirements, calculating the round-trip efficiency and getting some recommendations related to the most appropriate operation strategy to take the most advantage of the energy storage system.

Effect of Packaging on Supercapacitors Strings Modeling: Proposal of Functional Unit Defined Around Balancing Circuit

Supercapacitors (SCs), also called electric double-layer capacitors or ultracapacitors, nowadays have a considerable applicability as fast energy storage systems. Mostly, because of its low rated voltage, they are connected in series to reach the required voltage. The most usual approach for SC strings modeling is either the simplification of the whole string to an equivalent RC network, or the concatenation of individual models. However, these approaches lose accuracy because of electrical unbalances between cells. This paper proposes a new modeling approach that defines a new grouping strategy to improve the modeling of an SC string. It implies defining the string modeling around the combination of SCs and voltage balancing circuits. The resulting model is capable of reproducing the dynamic performance of an SC string with better accuracy. Experimental validation corroborates the improved dynamic response of the proposed modeling unit.

Fast discharge energy storage development for advanced X-ray simulators

Design studies have been completed to investigate the impact of improvements in fast energy storage systems on the designs of: larger future simulators (such as a 15-MA plasma radiation source (PRS) simulator), simulator upgrades of operational machines (such as Double-EAGLE), and for very compact, smaller simulators. The fast energy storage system that has been investigated and is presently under development is a fast Marx generator (FMG) with inductance capacitance (LC) 1/2=200 ns and LC 1/2=300 ns, depending on the capacitance per stage. This new fast Marx energy storage system uses newly developed, low-inductance rail switches and low-inductance capacitors. These components are configured in a low-inductance FMG stage and then stacked in series to form a unit for the voltage required and a number of units in parallel for the required system inductance and stored energy. A four-stage fast Marx prototype has been demonstrated with a total of 60-kJ energy stored and an output voltage of 680 kV. This new FMG technology will provide the capability to build X-ray machines in a significantly more compact configuration. The new FMG technology minimizes or eliminates the need for storing the energy in a large water transfer capacitor. A design sketch of a 15-MA PRS machine driven by a fast Marx will be presented. This generator would consist of 48 eight-stage FMG units and would drive the PRS directly without further pulse compression. We will also present the concept of a high voltage (2-3 MV), compact X-ray machine that uses a nine-stage fast Marx module to directly charge a vacuum inductive store. A plasma opening switch (POS) is used to switch the inductive store and deliver the electron beam to the load.

Breakdown of a coaxial diode transverse to the magnetic field

It is noted that the modern development of pulsed power generators with fast energy storage systems in the range of several megajoules makes it necessary to find conditions for charge particle beam formation with the same energy characteristics. Presently, the highest parameters of electron beams (E/sub 0/=140 kJ) are obtained in coaxial diodes, with magnetic insulation. However, even in these experiments the energy transport efficiency from a storage system into the beam was only approximately 20%. One of the main reasons for low efficiency is the breakdown in the diode transverse to the magnetic field. A breakdown centrifugal instability model is described and compared with experiments. It is shown that, in order to raise the electron-beam energy in coaxial diodes it is necessary to suppress the centrifugal instability in the plasma created on the inner diode electrode. For inner cathode diodes it is advisable to use a nonuniform magnetic field configuration with the field strength increasing rapidly enough in the direction from cathode to anode. The large radius diode with uniform magnetic field also seems to be promising for this purpose. >