Supercapacitor Model Research Articles

Comparative Analytical Modeling and Performance Investigation of Graphene-Based Super Capacitor with Four Traditional Batteries

Graphene, a magical development of 2004, has revolutionized today's energy storage technologies. It is nothing but a graphite two-dimensional (2D) allotropic pure carbon layer which is derived from a three-dimensional (3D) shape. Since batteries have been the most common storage device from the invention of the first electrical battery by an Italian physicist Alessandro Volta in 1799 A.D but batteries offer many drawbacks, such as length, weight, poor transient response, low power density, and high internal resistance. In this contrast, the impressive and unique properties of graphene supercapacitor such as high peak current, high surface area, high electrical conductivity, low internal resistance, high load current, long life cycle, high power density, low-temperature charging, and discharging make graphene supercapacitor a replacement of traditional energy storage devices and sets trend for the future. This analytical comparative analysis presents an overview between four traditional batteries and graphene-based supercapacitor. For this regard, dynamic models, modeling equations, and an integrated simulation model for batteries and graphene-supercapacitors under MATLAB/Simulink® 2020a environment is developed. In addition, the effect of temperature on battery output and graphene-supercapacitor is also addressed.

Application and prospect of supercapacitors in Internet of Energy (IOE)

Internet of Energy (IOE) is a new ecological energy system focusing on renewable energy, based on electric energy. It is characterized by multiple energy sources, coordination of supply and demand, centralization and decentralization, and extensive public participation. It is particularly worth mentioning that it is combined with energy storage, which represents the trend of intelligent development and rational utilization of urban energy in the future. Supercapacitors have become a research hotspot due to their excellent performance in power systems. In this paper, by introducing the energy storage principle of supercapacitors, we summarized the existing five supercapacitor models, and analyzed the characteristics and applicability of each model. At the same time, by summarizing and analyzing the energy storage principle of supercapacitors and related models, we focus on their role in the development of IOE, and also forecast the development prospect of IOE. Based on the deep integration of the Internet concept and advanced information technology with the energy industry, we aim to achieve green, coordinated and efficient development to drive economic growth and support the energy revolution, through multi-energy collaborative energy network, information and physics integrated energy system and innovative energy operation mode.

Characterization and Modeling of Supercapacitors Used for Hybrid Electric Energy Storage

Characterization and Modeling of Supercapacitors Used for Hybrid Electric Energy Storage

Stable conge red doped poly (3,4-ethylene dioxythiophene)/graphene oxide composite as electrode material for high-performance asymmetric supercapacitors

Congo red doped poly (3,4-ethylene dioxythiophene)/graphene oxide (GO/CR-PEDOT) composite was prepared by simple chemical oxidation method, where Congo red doped poly (3,4-ethylene dioxythiophene) (CR-PEDOT) evenly and stably coated on the surface of graphene oxide (GO) under the guidance and connection of congo red (CR), respectively. Therefore, GO with a large specific surface area could bring into full play its function as a supporting skeleton to decrease the degree of volume expansion and shrinkage of GO/CR-PEDOT composite in charge/discharge process and improve its specific capacitance and cycle stability. The results showed that the maximum specific capacitance of GO/CR-PEDOT composite was up to 227 F/g when the feeding mass ratio of GO to 3,4-ethylene dioxythiophene was 1:1, which was 110% higher than that of poly (3,4-ethylene dioxythiophene) (PEDOT), and the capacitance retention was 92.3 % after 10,000 cycles. Furthermore, a model of asymmetric supercapacitor was fabricated by using GO/CR-PEDOT composite as positive material, activated carbon as negative material and 1 mol/L Na2SO4 as electrolyte, which exhibited that the energy density was as high as 14.4 Wh/kg when the power density was 996 W/kg and still achieved 9.11 Wh/kg at a high power density of 7999 W/kg.

The control of lithium‐ion batteries and supercapacitors in hybrid energy storage systems for electric vehicles: A review

This article discusses control solutions for hybrid energy systems composed of lithium-ion batteries and supercapacitors for electric vehicles. The advantages and disadvantages of the respective systems of lithium-ion batteries and supercapacitors as well as hybrid systems are discussed. This article summarizes the research on behavior modeling, optimal configuration, energy management, and so on from the two levels of energy storage components and energy storage systems, and provides theoretical and methodological support for the application and management of hybrid energy storage systems for electric vehicles. First, it summarizes the research progress of the hybrid energy system of lithium-ion batteries and supercapacitors and its research significance for the development of electric vehicles. Then the circuit models of lithium-ion batteries and supercapacitors are analyzed, and the control results of the respective systems and hybrid systems under different research methods are introduced to optimize resource allocation. Then based on the energy management and control strategy, the deficiencies of the respective research methods are analyzed. Finally, we emphasized and summarized some key issues for future research in this field. Therefore, the control optimization of hybrid systems has become the focus of the long-term development of electric vehicles. An overview of the lithium battery-supercapacitor hybrid system. Analyze the optimization strategy of lithium battery-supercapacitor hybrid system from energy management. Summarize the circuit research of the hybrid system.

Towards accurate calculation of supercapacitor electrical variables in constant power applications using new analytical closed-form expressions

Supercapacitor (SC) is one of the most trending energy storage solutions. The SCs equivalent circuit models have been extensively applied to energy management because of their accuracy and simplicity. However, there is a difficulty in solving the conventional differential equation-based model used to characterize the electrical behavior of SCs operating in constant power applications. Hence, numerical or metaheuristic techniques have been used in the literature to derive SC's internal voltage at any time. In this work, a thorough mathematical analysis that enables a precise calculation of the electrical variables implied in the charge/discharge processes of SCs operated at constant power as a function of time is presented. First, the transcendental discharge voltage expression of SCs operating at constant power is formulated, and then it was solved using the Special Trans Function theory (STFT). The precision of calculation of the method used for solving the transcendental expression is presented and discussed. Second, the transcendental voltage of charging expression of SCs operating at constant power as a function of time is also formulated, and then it was solved using Lambert W equation. Third, a comparison of different methods for solving mentioned equations is presented. Fourth, the electrical variables involved in the charge/discharge processes of SCs – voltage, current, power, energy, state of charge, and power loss are investigated. Furthermore, the results obtained for the variation of parameters and their operating conditions demonstrate the proposed equations’ applicability and accuracy. Finally, the results obtained validate that the closed-form expressions suggested in this paper are accurate and straightforward, which can contribute to proper modeling, investigation, sizing, regulation, and control of constant power SCs in modern energy systems.

A Multi-Model Probability Based Two-Layer Fusion Modeling Approach of Supercapacitor for Electric Vehicles

The improvement of the supercapacitor model redundancy is a significant method to guarantee the reliability of the power system in electric vehicle application. In order to enhance the accuracy of the supercapacitor model, eight conventional supercapacitor models were selected for parameter identification by genetic algorithm, and the model accuracies based on standard diving cycle are further discussed. Then, three fusion modeling approaches including Bayesian fusion, residual normalization fusion, and state of charge (SOC) fragment fusion are presented and compared. In order to further improve the accuracy of these models, a two-layer fusion model based on SOC fragments is proposed in this paper. Compared with other fusion models, the root mean square error (RMSE), maximum error, and mean error of the two-layer fusion model can be reduced by at least 23.04%, 8.70%, and 30.13%, respectively. Moreover, the two-layer fusion model is further verified at 10, 25, and 40 °C, and the RMSE can be correspondingly reduced by 60.41%, 47.26%, 23.04%. The results indicate that the two-layer fusion model proposed in this paper achieves better robustness and accuracy.

The use of supercapacitor in smart metering gateway

Advanced Metering Infrastructure (AMI) consists smart meter, gateway, meter data management software. Smart meter and gateway work together to measure energy on the field. Then, gateway send the measured smart meter data that can be periodic or instant meter reading results, power factor, voltage-current-power information. In addition, gateway sends the information to the meter data management system whether there is energy or not by using a communication method in the field. If there is an integration between AMI and other distribution network systems like Outage Management System (OMS), Customer Relations Management, AMI provides measured data to these systems. Supercapacitor (SC) is a new type small energy storage device and it can easily use power system to provide the energy certain time in case of power failure. The gateway that is part of AMI connects the distribution grid physically on the field and provides own energy so when the power failure occurs in distribution grid at same time gateway energy will be cut. This means last measured data and last field situation can’t be send to the AMI software so all system integration and remote meter operation will halt. This paper handles SC usage as a part of AMI system gateway on the field to provide last measured data to the AMI software. SC benefits are shown using AMI system with measured data in distribution grid. SC model will explain considering gateway design. Gateway with SC and gateway without SC situations will compare in terms of AMI and other system integrations.

HIL Simulation of a Tram Regenerative Braking System

Regenerative braking systems are an efficient way to increase the energy efficiency of electric rail vehicles. During the development phase, testing of a regenerative braking system in an electric vehicle is costly and potentially dangerous. For this reason, Hardware-In-the-Loop (HIL) simulation is a useful technique to conduct the system’s testing in real time where the physical parts of the system are replaced by simulation models. This paper presents a HIL simulation of a tram regenerative braking system performed on a scaled model. First, offline simulations are performed using a measured speed profile in order to validate the tram, supercapacitor, and power grid model, as well as the energy control algorithm. The results are then verified in the real-time HIL simulation in which the tram and power grid are emulated using a three-phase converter and LiFePO4 batteries. The energy flow control algorithm controls a three-phase converter which enables the control of energy flow within the regenerative braking system. The results validate the simulated regenerative braking system, making it applicable for implementation in a tram vehicle.

Supercapacitor Modeling for Conversion Systems and Power Supply in Electric Vehicles

The main obstacle in an Electric Vehicle (EV) is the large torque requirement at the start. And in this case, it must be overcome with a battery that is bigger and heavier. However, a large battery will become a burden when moving and braking. The use of supercapacitors can make the vehicle move more powerful at the beginning of the movement because of its very fast energy release. This paper presents a supercapacitor modeling to support battery performance in an energy storage system. This research is focused on modeling the supercapacitor connected to the drive converter circuit by looking for a mathematical model in the form of a state-space equation, the results of which are simulated using the C Mex S function in Matlab / Simulink. From the modeling carried out, it is obtained a system that has a system response that is built and shows the system is working properly, the output voltage can follow the reference results.

Revisiting the Time-Domain and Frequency-Domain Definitions of Capacitance

The capacitance is a characteristic function of an electrical energy storage device that relates the applied voltage on the device to the accumulated electric charge. It is inconsistently taken in some studies as a multiplicative function in the time domain [i.e., q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> (t)=c <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> (t) ×v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> (t)], and in others as a multiplicative function in the frequency domain [i.e., Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> (s)=C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> (s) × V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> (s) derived from the definition of admittance I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> (s)/V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> (s) = s C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> (s)], despite the fact that the capacitance is time- and frequency-dependent. However, the convolution theorem states that multiplication of functions in the time domain is equivalent to a convolution operation in the frequency domain, and vice versa. In this work, we revisit and compare the two outlined definitions of capacitance for an ideal capacitor and for a lossy fractional-order capacitor. Although c <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> (t) = C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> (s) = C for an ideal constant capacitor, we show that this is not the case for fractional-order capacitors which exhibit frequency-dispersed impedance, memory effects, and nonexponential relaxation functions. This fact is crucial in the accurate modeling and characterization of supercapacitors and batteries. For these devices, and for being consistent with measurements using conventional impedance analyzers, it is recommended to apply the integral convolution definition in the time domain which reverts to the multiplicative definition in the frequency domain.

Selection of mathematical model of on-board capacity energy storage as element of hybrid traction unit of motor car rolling stock

The authors of the study work out to determinate of the mathematical model of supercapacitors as an object of an electric traction system capable of providing non-encumbering of obtaining research results and correct reproduction of energy exchange processes in conditions of repeated-short-term modes of traction load operation. In paper, authors make a comparative assessment of six models for the possibility of their integration into the model of electric traction systems with on-board placement of the energy storage.

Self-discharge modeling of supercapacitors using an optimal time-domain based approach

This paper deals with the dynamic simulation of a developed equivalent circuit model of supercapacitors, taking into account the self-discharge phenomenon. The self-discharge is modeled with a time-varying resistance in the equivalent circuit. Using the acquired experimental data of the self-discharge experiments, an optimal number of exponential functions are fitted on the data employing the weighted least-square technique. The optimal number of the functions is determined considering a trade-off between the accuracy and complexity of the model. The results confirm a desirable performance of the model compared with the other similar models.

Modelling of Supercapacitors Based on Simplified Equivalent Circuit

The need for energy storage devices especially in renewable energy applications has increased the use of supercapacitors. Accordingly, several supercapacitor models have been proposed in previous researches. Nevertheless, most of them require an intensive test to obtain the model parameters. These may not be suitable for an initial simulation study, where a simple model based on the datasheet is required to evaluate the system performance before building the hardware prototype. A simplified electrical circuit model for a supercapacitor (SC) based on the voltage-current equation is proposed in this paper to address this issue. This model doesn’t need an intensive test for accuracy. The structural simplicity and decent modelling accuracy make the equivalent electrical circuit model very suitable for power electronic applications and real-time energy management simulations. The parameters of the proposed model can be obtained from the datasheets value with a minimum test requirement. The experimental method to provide the parameters of the supercapacitor equivalent circuit is described. Based on the proposed method, the supercapacitor model is built in Matlab/Simulink, and the characteristics of equivalent series resistance (ESR) measurement and cycle life are compared with datasheets. The simulation results have verified that the proposed model can be applied to simulate the behaviour of the supercapacitor in most energy and power applications for a short time of energy storage. A supercapacitor test circuit is given to test the charge and discharge of supercapacitor modules. The experimental results are suitable for simulation results.

Modeling and AI-Based Control of Regenerative Fuel Cell, Battery and Supercapacitor Based Hybrid Electric Vehicle

Modeling and AI-Based Control of Regenerative Fuel Cell, Battery and Supercapacitor Based Hybrid Electric Vehicle

Modeling and Control of Fuel Cell/Supercapacitor Hybrid Source Based on Energetic Macroscopic Representation

In this paper, we present a dynamic simulator that uses a proton exchange membrane fuel cell (PEMFC). This source, is used as a primary source with a supercapacitor (SC) considered as a secondary source. This simulator integrates a PEMFC’s dynamic model, validated on the Bahia bench and a semi-empirical model of SC. The developed model is implemented using the macroscopic energetic representation tool (EMR). The energy management system (EMS) is based on rule-based power management, where a low-pass filter splits the power among sources (PEMFC and SCs) using a cut-off frequency of 0.2Hz, and a controller block that regulates the bus voltage deduced by the EMR’s inversion-based control approach.

基于红薯基活性炭的超级电容器充放电模型

基于红薯基活性炭的超级电容器充放电模型

State of Charge Estimation of Composite Energy Storage Systems with Supercapacitors and Lithium Batteries

This paper studies the state of charge (SOC) estimation of supercapacitors and lithium batteries in the hybrid energy storage system of electric vehicles. According to the energy storage principle of the electric vehicle composite energy storage system, the circuit models of supercapacitors and lithium batteries were established, respectively, and the model parameters were identified online using the recursive least square (RLS) method and Kalman filtering (KF) algorithm. Then, the online estimation of SOC was completed based on the Kalman filtering algorithm and unscented Kalman filtering algorithm. Finally, the experimental platform for SOC estimation was built and Matlab was used for calculation and analysis. The experimental results showed that the SOC estimation results reached a high accuracy, and the variation range of estimation error was [−0.94%, 0.34%]. For lithium batteries, the recursive least square method is combined with the 2RC model to obtain the optimal result, and the estimation error is within the range of [−1.16%, 0.85%] in the case of comprehensive weighing accuracy and calculation amount. Moreover, the system has excellent robustness and high reliability.

Differential flatness-based strategy of Photovoltaic/Battery/supercapacitor hybrid source for stand-alone system

This work presents the differential flatness-based energy management strategy for stand-alone Photovoltaic (PV) system with high energy density - battery and high-power density- supercapacitor with DC load. The fluctuation in DC bus voltage is due to the variation in generation of PV power and load Power requirement. This causes the frequent charging /discharging profile of the battery which ultimately reduces the life cycle and increase the internal temperature of the battery. This drawback can be overcome by adopting the flatness-based control technique. In this technique, the supercapacitor converter maintains the DC link voltage constant and the battery converter provides the constant current with the distribution of solar power. Due to constant charging/discharging of battery the thermal run-away problem like leak, smoke, gas venting, rapid disassembly, flames etc., can be eliminated. Decoupling of load power and battery power significantly increase the battery life cycle and maintain the internal temperature of battery within the optimum of 20 °C to 40 °C. In order to achieve efficient charging/discharging of Supercapacitor (SC), Dynamic Temperature Dependent SC Model (DTDSCM) is considered. To verify the performance of the control technique, simulation is carried out in the Mat lab Simulink and it is tested for daily load profile.

Design and experimental verification of a fuel cell/supercapacitor passive configuration for a light vehicle

The fuel cell/supercapacitor passive configuration without using any DC/DC converters is promising in automotive applications as it can downsize the fuel cell stack, maintain the peak power capability, improve the system efficiency, and remove the need of additional control. This paper presents the design and characterization of a fuel cell/supercapacitor passive hybrid system for a 60 V light vehicle. A detailed design procedure for the passive hybrid test platform is presented with each component modelled and experimentally verified. The voltage error of the fuel cell and the supercapacitor model in the steady state is within 2% and 3%, respectively. Experimental results also validate the function of the passive configuration under conditions of a step load and a drive cycle. The simulation model of the passive hybrid system matches the measurements when a step load current is applied. The supercapacitor provides the transient current due to its smaller resistance while the fuel cell handles the steady state current, which makes it possible to downsize the fuel cell stack. For the drive cycle examined in this paper, the fuel cell stack can be downsized to one third of the load peak power.