Online supercapacitor health monitoring using a balancing circuit (original) (raw)
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Online diagnosis of supercapacitors using extended Kalman filter combined with PID corrector
International Journal of Power Electronics and Drive Systems (IJPEDS), 2021
Supercapacitors are electrical energy storage devices with a high specific power density, a long cycle life and a good efficiency, which make them attractive alternative storage devices for various applications. However, supercapacitors are subject to a progressive degradation of their performance because of aging phenomenon. Therefore, it is very important to be able to estimate their State-of-Health during operation. Electrochemical Impedance Spectroscopy (EIS) is a very recognized technique to determine supercapacitors' state-of-health. However, it requires the interruption of system operation and thus cannot be performed in real time (online). In this paper, a new online identification method is proposed based on extended Kalman observer combined with a complementary PID corrector. The proposed method allows to accurately estimating supercapacitor resistance and capacitance, which are the main indicators of supercapacitor state-ofhealth. The new online identification method was applied for two voltage/current profiles using two different supercapacitors. The resistance/capacitance estimated by the new method and the conventional EKF were compared with those obtained by an experimental offline method. In comparison with conventional EKF, the capacitance obtained by the new method is significantly more accurate.
Interconnected Observers for online supercapacitor ageing monitoring
To observe the state of health of supercapacitors, offline laboratory techniques such as Electrochemical Impedance Spectroscopy (EIS) are regularly used. But this requires the supercapacitors to be removed from their application. This paper proposes an online in situ monitoring method based on the estimation of the supercapacitor parameters by means of real-time observers. Two kinds of observers, an Extended Kalman Observer (EKO) and Interconnected Observers (IOs), are designed and compared. Identification results are presented for real 1F Nichicon supercapacitors enduring an accelerated ageing process, and compared with the offline characterization.
Diagnostics, measurement and control of electrical parameters supercapacitors
MATEC web of conferences, 2021
This article considers possible approaches to diagnostics and measurement electrical parameters of supercapacitors. The analysis the results of diagnostics and measurement the parameters of supercapacitors has determined a significant frequency dependence of theirs. The discrepancy between the two-element equivalent circuit of supercapacitors has been established. Diagnostics and control electrical parameters of supercapacitors in the infralow frequency range can be performed by direct conversion methods. In this case, high-precision low-resistance resistors can be used as an exemplary measure. For the diagnostics and design of meters for the electrical parameters of supercapacitors of capacitors, the authors propose an iterative-recursive method for determining the numerical values of the electrical parameters of the equivalent circuit of such objects. The essence of the proposed iterative-recursive method is that at the first stage, the iterative approximation determines the number of n-absorption links, which it is enough to know when developing, manufacturing and operating supercapacitors. Theoretical and experimental studies of the equivalent circuit of supercapacitors show that the equivalent resistance of such capacitors and their capacitance increase with decreasing frequency of the measuring signal, and the nature of these dependences is determined by the number of n-absorption links and the numerical values of the elements of each link.
Balancing Circuit New Control for Supercapacitor Storage System Lifetime Maximization
IEEE Transactions on Power Electronics, 2017
Energy storage elements such as supercapacitors are widely used in high power applications. However, due to single cell voltage limitation, an energy storage system with large number of supercapacitors is often employed. Energy management systems are associated to energy storage systems in order to assure user and equipment safety. Balancing circuits, which enable the equalization of the voltage of each element in series, are a part of energy management system device. The work presented in this paper aims to enhance the lifetime of energy storage systems. It relies on better controlling balancing circuits on the terminals of the storage system elements. With the conventional function of balancing circuit, the energy storage system is limited by its weakest element which may fail prematurely. Thus, a new balancing approach is presented, discussed and analyzed. It is based on the elements degradation level prediction. The model predictive control used with the new approach, aims to equalize aging speed between elements of a module and ensures a maximum lifetime to the energy storage system. A comparison with the conventional control, shows that adopting this new approach, with the same equipment, can enhance the storage system's lifetime by dozens percent.
Methods of Assessing Degradation of Supercapacitors by Using Various Measurement Techniques
Applied Sciences
This article presents the qualitative analyses of the construction of supercapacitor samples. The analyses are based on the suggested thermographic measurements as well as the technique of testing the inherent noise of the investigated element. The indicated assessment methods have been referred to the currently used parameters for the qualitative evaluation of supercapacitors. The approach described in this paper, which introduces additional parameters assessing worn out of supercapacitors, can be included in the so-called non-invasive measurement methods, which allow the assessment of the condition of the sample under test. This article presents the applied measurement stands and verifies of the applicability of measurement methods in relation to the currently used parameters allowing for the qualitative assessment of supercapacitors. The measurement method presented in this article was used to study prototypes of supercapacitors. The measurement results allow for more accurate ch...
The main disadvantage of using supercapacitors in the field of energy storage systems is their limited voltage due to technology limits. To resolve this problem, these components are usually applied in series to reach the suitable voltage. However the tolerance in these components' characteristics leads to imbalanced voltage during the chargedischarge cycle. This may influence adversely the supercapacitors lifetime. To avoid this phenomenon, balancing circuits have to be employed. This turned out to be very useful in improving the performance and extending the lifetime of supercapacitors and the reliability of energy storage system as a whole.
Evaluation of Active Balancing Circuits for Supercapacitors
2019
Supercapacitors are strongly emerged as a promising technology to complement the batteries. Due to their low rated voltages it is usual to build supercapacitor banks, with series connection, in order to obtain higher voltage levels. Because of manufacturing dispersion parameters, during operation in multiple charge-discharge cycles it is very probable to result an uneven state of charge (SOC). During charging at constant current the capacitor that reaches first the rated voltage level could be damaged in a further charging process. In order to prevent this, additional circuitry, named briefly, balancing circuit is provided. The balancing circuit with resistors and diodes are a simple solution, but with high power losses and modest performances. An improved solution is to use transistors to bypass the charging current, when an overvoltage is detected at each capacitor terminals. An even better solution is to use smart control using microcontroller or dedicated circuits for monitoring...
State-of-charge estimation and remaining useful life prediction of supercapacitors
Renewable and Sustainable Energy Reviews, 2021
As a new type of energy storage device, supercapacitors are widely applied in various fields owing to their irreplaceable extraordinary characteristics. The remaining useful life represents the safe service range of a supercapacitor. Precise monitoring of its value can ensure timely replacement before reaching the service limit. An accurate state-of-charge estimation can ensure that the supercapacitor works in a safe area. Superior precision ensures that the safe area is more explicit. Thus, the supercapacitor can exercise maximum effectiveness without damaging the device. Hence, this paper reviews the above sections. The remaining useful life prediction and state-of-charge estimation of supercapacitors are reviewed based on the model and data. The methods of different innovation points are enumerated, the disparate evaluation frameworks are compared, and their merits and demerits are generalized and reviewed. In the research field, while studying the remaining useful life of supercapacitors based on data, the application of artificial neural networks is emphasized. Hence, this study focuses on reviewing the relevant content for this approach. Finally, the challenges and prospects for the prediction of the above studies are briefly described.
MetSuperCap: Metrology for static and dynamic characterisation of supercapacitors
2024
Unlike Li-ion batteries, supercapacitors (SCs) do not use rare or polluting metals, have a life cycle even two orders of magnitude higher than that of batteries, and do not suffer from either runaway effects or extreme temperatures. They, therefore, represent an eco-friendly and reliable technology, which can replace batteries or accompany them in high power density applications. To support the growing use of SCs in real and real-time applications, accurate characterization even under operating conditions is required. Furthermore, validated circuital and software models are needed to identify the SCs behaviour in dynamic applications. Along slower but highly accurate methods, novel quick, traceable, and effective measurement techniques are required to evaluate SCs’ State of Charge (SoC) and State of Health (SoH) and to promote the uptake of SC and banks in consumer, energy, transport, aerospace and in many other applications. The MetSuperCap project aims to improve the characterisation of SCs and SC banks by providing accurate and reliable identification of their parameters in the laboratory and in operation.