3D Interconnected Porous Carbon Derived from Spontaneous Merging of the Nano-sized ZIF-8 Polyhedrons for High-Mass-Loading Supercapacitor Electrodes

Interconnected porous carbons show great potential for high-rate capacitive energy storage, especially at high electrode mass loadings, due to their continuous conductive network and ion migration channels. Herein, we show...

Biaxially oriented silica-polypropylene nanocomposites for HVDC film capacitors: Morphology-dielectric property relationships, and critical evaluation of the current progress and limitations

Dielectric polymer nanocomposites are considered as one of the most promising insulation material candidates for future capacitive energy storage applications, providing tailorability of charge trapping and transport properties at the...

MANAGEMENT STRATEGIES FOR ENERGY PROCESSES IN ELECTRIC ROLLING STOCK WITH ON-BOARD ENERGY STORAGE DEVICES

The article deals with the main existing strategies for management strategy of energy exchange processes in the electric rolling stock with onboard capacitive energy storage devices. When considering strategies, it is assumed that the onboard capacitive storage has low power and capacitance. Therefore, this capacitor storage is not able to accept the full amount of regenerative braking energy of the electric rolling stock. The purpose of the paper is to consider and analyze management strategies for energy exchange processes in the electric rolling stock with onboard capacitive energy storages; to define the advantages and disadvantages of each of the existing strategies and propose a concept for the effective management of energy exchange processes in the electric rolling stock. The block diagram of electric rolling stock with the onboard capacitive energy storage which is used for the analysis of management strategies for energy exchange processes is presented. The modes of operation of electric rolling stock with onboard capacitive energy storages are described. Five main strategies for management of energy exchange processes on the electric rolling stock with onboard capacitive energy storages are determined. The advantages and disadvantages of each strategy are set out taking into account the given conditions (characteristics of the electric rolling stock, conditions of the rolling stock motion, oscillograph charts, etc.). The general advantages and shortcomings of each strategy are defined, which allowed to propose the concept of creating an adaptive strategy for managing energy exchange processes in electric rolling stock with onboard capacitive energy storages. The main concept of this management strategy is to implement efficient energy exchange between the traction equipment, the onboard capacitive energy storage, the overhead contact system, both in normal and emergency modes of traction power supply, taking into account the dynamics of energy exchange processes in the overhead contact system, which will generally allow safety and energy efficiency of the transportation process. The obtained research results will contribute to the development and implementation of effective strategies for managing energy exchange processes in the electric rolling stock.

Shape and Measurement Monitoring of Inrush Current Characteristics of a Battery-Capacitive Energy Storage Device with Two-Channel Digital Oscilloscope

The main reason of voltage instability in stand-alone power supply systems is the electric drive motors inrush current, which are usually higher than their nominal value. The most reasonable way to solve this problem is using capacitive energy storage. The purpose of research is shape and measurement monitoring of battery-capacitive energy storage device inrush current characteristics. Parameters comparative analysis for lithium-ion battery (LIB) part and capacitive part of the energy storage device was holding with the twochannel digital oscilloscope.Measuring testing bench included parallel connected LIB part and capacitive part of the storage device and connected to the power source. The LIB part of the storage device is made on the basis of the ATOM 10 multifunctional motor drive device of the new generation, which contains 15 V lithium-ion battery and 9.4 A·h capacity. The capacitive part of the storage device is the INSPECTOR Booster supercapacitor with an 80 F electrostatic capacitance and 15.5 V voltage. A 12 V AC/DC step-down converter was used as a power source. An electric air automobile compressor M-14001 was used as a current drain. The testing bench measuring part consisted of a two-channel digital oscilloscope and two standard measuring shunts with 15000 μOm resistance serial attached to LIB part and capacitive part of the storage device. Shape and measurement monitoring of inrush current characteristics of LIB part and capacitive part of the energy storage device was held synchronously using a two-channel digital oscilloscope with recording data to FAT32 file system USB flash drive. Obtained data was transferred to a personal computer and analyzed.The measurement results showed that 82.3 % of the energy losses compensation of the motor start is taken over by the capacitive part of the energy storage device, what makes longer LIB’s life. By adjusting the oscilloscope sweep trace index you can analyze more detailed time response shape and its duration. The values of the inrush current amplitudes were calculated in proportion to the voltage drop on the shunts and their resistances.The developed method for monitoring shape and measurement inrush current characteristics can be used in various technical applications: smart stand-alone photovoltaic system, uninterruptible power supply devices, electric drive control systems, etc.

Influence of limiting the duration of the armature winding current on the operating indicators of a linear pulse electromechanical induction type converter

Introduction. Linear pulse electromechanical converters of induction type (LPECIT) are used in many branches of science and technology as shock-power devices and electromechanical accelerators. In them, due to the phase shift between the excitation current in the inductor winding and the induced current in the armature winding, in addition to the initial electrodynamic forces (EDF) of repulsion, subsequent EDF of attraction also arise. As a result, the operating indicators of LPECIT are reduced. The purpose of the article is to increase the performance of linear pulse electromechanical induction-type converters when operating as a shock-power device and an electromechanical accelerator by limiting the duration of the induced current in the armature winding until its polarity changes. Methodology. To analyze the electromechanical characteristics and indicators of LPECIT, a mathematical model was used, in which the solutions of equations describing interrelated electrical, magnetic, mechanical and thermal processes are presented in a recurrent form. Results. To eliminate the EDF of attraction between the LPIECIT windings, it is proposed to limit the duration of the induced current in the armature winding before changing its polarity by connecting a rectifier diode to it. It was found that when the converter operates as a shock-power device without limiting the armature winding current, the value of the EDF pulse after reaching the maximum value decreases by the end of the operating cycle. In the presence of a diode in the armature winding, the efficiency criterion, taking into account the EDF pulse, recoil force, current and heating temperature of the inductor winding, increases. When the converter operates as an electromechanical accelerator without limiting the armature winding current, the speed and efficiency decrease, taking into account the kinetic energy and voltage of the capacitive energy storage at the end of the operating cycle. In the presence of a diode in the armature winding, the efficiency criterion increases, the temperature rise of the armature winding decreases, the value of the maximum efficiency increases, reaching 16.16 %. Originality. It has been established that due to the limitation of the duration of the armature winding current, the power indicators of the LPECIT increase when operating as a shock-power device and the speed indicators when the LPECIT operates as an electromechanical accelerator. Practical value. It was found that with the help of a rectifier diode connected to the multi-turn winding of the armature, unipolarity of the current is ensured, which leads to the elimination of the EDF of attraction and an increase in the performance of the LPECIT.

Ferroelectric properties and breakdown strength of layer-by-layer poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) and polyurethane (PU) for energy storage application

Ferroelectric polymers are one of the next- generation pulsed capacitor materials for the potential application in capacitive energy storage. This polymer with higher saturated polarization, smaller remnant polarization, and higher electrical breakdown are the most promising candidates. In this work, the dielectric properties and energy storage capacity of the bilayer polymer films of Poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) and polyurethane (PU) were studied. These bilayer polymers were prepared by layer- by- layer method at the condition of variable layer thickness. The results show that the dielectric constants and the saturated polarization of the bilayer films increased, and bilayer films with P70/PU30 exhibit electrical high breakdown strength up to 379 V/μm. Moreover, enhanced energy storage density and the energy efficiency of the bilayer constrictors will be discussed for the capacitive energy storage polymers.