Development and Experimental Validation of a Supercapacitor Frequency Domain Model for Industrial Energy Applications Considering Dynamic Behaviour at High Frequencies

Abstract

Supercapacitors, one of the most promising energy storage technologies for high power density industrial applications, exchange the energy mostly through power electronic converters, operating under high frequency components due to the commutation. The high frequency produces important effects on the performance of the supercapacitors in relation to their capacitance, inductance and internal resistance (ESR). These parameters are fundamental to evaluate the efficiency of this energy storage system. The aim of the paper is to obtain an accurate model of two supercapacitors connected in series (functional and extrapolated unit) to represent the frequency effects for a wide range of frequencies. The methodology is based on the definition of an appropriate equivalent electric circuit with voltage dependance, obtaining their parameters from experimental tests, carried out by means of electrochemical impedance spectroscopy (EIS) and the use of specific software tools such as EC-Lab ® and Statgraphics Centurion ® . The paper concludes with a model which reproduces with accuracy both the frequency response of the model BCAP3000 supercapacitors, provided by the manufacturer, and the experimental results obtained by the authors.Energies 2020, 13, 1156 2 of 18 reducing the battery stress and extending the lifespan of the system. Moreover, in applications where long-time backups are not required, SCs can totally replace the battery storage system [8][9][10]. Thirdly, SCs are used in the energy harvesting industry for their integration with non-dispatchable renewable energy sources, i.e., wind and solar energies. The intermittent nature and uncertain prediction of these energy resources results in voltage and frequency fluctuations, which can destabilise the electric grid. Hence, energy storage systems, particularly SCs, play an important role in frequency regulation and peak shaving [11][12][13].SCs modelling has become of maximum importance when designing and dimensioning SC installations since it is the way to know in advance about the behaviour and performance of the energy storage system when applied to particular operation profiles or conditions. Control strategies or operational parameters and limits can also be obtained from a model, enlarging the lifetime of the storage technology and therefore achieving a higher level of reliability and competitiveness. Numerous SC models have been published in the literature for different purposes, including capturing electrical dynamic behaviour, which is of utmost importance for the aforementioned industrial applications. The models that capture electrical behaviour of SCs can be classified in three main categories: electrochemical models, intelligent models and equivalent circuit models [2].Commonly, electrochemical models account for high accuracy and low calculation efficiency, since they capture the reactions inside the SCs by employing coupled partial differential equations (PDEs). Among the electrochemical models, the three-domain model based on the uniform formulation of e...

Dimensioning Methodology of an Energy Storage System Based on Supercapacitors for Grid Code Compliance of a Wave Power Plant

“…This analysis is based on experimental tests and on the design of a simulation model whose frequency response is adjusted to the results obtained experimentally. A complete analysis of the frequency response of the cell model (BCAP3000) on which the present study is based is presented in [44]. In this way, using Equation (6) the efficiency (η ESR ) of the SCESS cabinet can be calculated including the losses in the ESR for a given duty cycle (frequency) as per:…”

“…sponse of the cell model (BCAP3000) on which the present study is based is presented in [44]. In this way, using Equation (6) the efficiency (ηESR) of the SCESS cabinet can be calculated including the losses in the ESR for a given duty cycle (frequency) as per:…”

Self-Discharge of a Proton Exchange Membrane Electrolyzer: Investigation for Modeling Purposes

“…On the other hand, for supercapacitors, besides being determinant for the duration of energy storage (i.e., rest phases), self-discharge voltage is an important indicator to quantify performance [ 26 , 27 ]. As a result, by decreasing the effects of supercapacitors’ self-discharge voltage, the lifespans of devices that depend on the power supply of supercapacitors are improved [ 28 , 29 ]. Like batteries, different materials for the construction of supercapacitors have been used, and the development of models has been implemented as a strategy to decrease the self-discharge voltage [ 30 , 31 ].…”

Studies on Dynamic Properties of Ultracapacitors Using Infinite r–C Chain Equivalent Circuit and Reverse Fourier Transform

“…In a previous article, we proposed that the infinite r-C chains-based equivalent circuit model could describe the behavior of double layer UCs [13]. The multibranch r-C circuit modeling approach was also studied by other researchers [27][28][29][30][31][32][33]. The frequency-domain models comprise the best overall performance in terms of complexity, correctness, and robustness [31][32][33].…”

“…The multibranch r-C circuit modeling approach was also studied by other researchers [27][28][29][30][31][32][33]. The frequency-domain models comprise the best overall performance in terms of complexity, correctness, and robustness [31][32][33]. Logerais et al proposed the multibranch r-C circuit model for the analysis of UC [28], but the proposed model did not provide rigorous closed-form analytical solutions and did not consider the inductance of connecting cables and electrodes.…”