Equivalent Series Resistance Research Articles

Bidirectional Converter for Plug-In Hybrid Electric Vehicle On-Board Battery Chargers with Hybrid Technique

Recently, Plug-in Hybrid Electric Vehicles (PHEVs) have gathered a lot of attention by integrating an electric motor with an Internal Combustion Engine (ICE) to minimize fuel consumption and greenhouse gas emissions. The On-Board Chargers (OBCs) are selected in this research because they are limited by dimensions and mass, and also consume low amounts of power. The Equivalent Series Resistance (ESR) of a filter capacitor is minor, so the zero produced by the ESR is positioned at a high frequency. In this state, the system magnitude gradually drops, causing a ripple in the circuit that generates a harmful impact on the battery’s stability. To improve the stability of the system, a Neural Network with an Improved Particle Swarm Optimization (NN–IPSO) control algorithm was developed. This study establishes an isolated converter topology for PHEVs to preserve battery-charging functions through a lesser number of power electronic devices over the existing topology. This isolated converter topology is controlled by NN–IPSO for the PHEV, which interfaces with the battery. The simulation results were validated in MATLAB, indicating that the proposed NN–IPSO-based isolated converter topology minimizes the Total Harmonic Distortion (THD) to 3.69% and the power losses to 0.047 KW, and increases the efficiency to 99.823%, which is much better than that of the existing Switched Reluctance Motor (SRM) power train topology.

Power quality improvement in single-phase transformerless semi-quasi-Z-source inverters for off-grid photovoltaic systems

The transformerless single-phase semi-quasi-Z-source inverter (SqZSI) provides several advantages over classical PWM converters. Reduced or eliminated leakage current, high power density, and low cost are important features making this topology an attractive choice for PV micro-inverter applications. Two drawbacks of this topology are DC and second harmonic injection in the output AC port, which in some cases prevent the fulfillment of standard requirements. To alleviate this power quality issue, four novel harmonic mitigation algorithms based on PI and PR controllers are proposed, analyzed, and experimentally verified with the 90 W SqZSI in this paper. Moreover, a modified modulation reference waveform strategy is introduced. Consequently, the converter performance, in terms of total harmonic distortion (THDV) is achieved at about 1.27% under full power load. Also, in this paper, the non-ideal state-space model of the SqZSI with the effect of the equivalent series resistance of inductors is developed and the generation origin of DC and second harmonic component is analyzed based on the obtained model. The achieved results confirms the significant THD reduction by more than 75%, the DC component suppression, the second harmonic mitigation, and the power quality improvement.

A case study of high-temperature polyetherimide film capacitor fabrication

Capacitors, as the basic building block of power electronics and electrical systems, are the major constraint of the increasingly integrated power systems that require new capable polymer dielectric films operating at higher temperatures >125 °C. Despite tremendous research efforts on the lab scale, there remains a considerable barrier and knowledge basis for converting polymeric films to functioning capacitors desired in actual applications. The authors tackled the polyetherimide (PEI) film scale up issues and developed various engineering processes for film de-wrinkling, optimal metallization, static elimination, and capacitor fabrication improvement. The authors discovered various fabrication challenges such as the electrostatic charge, metallization scheme, winding tension, and end electrode disconnects. To fabricate a high yield of PEI capacitor bobbins, it is necessary to utilize static eliminators (radioactive ionizers), moderately thick aluminum metallization (15–30 Ω/sq), and winding tension (60–100 g). It is also effective to evaluate capacitance, dielectric loss, equivalent series resistance, and thermal cycling stability of capacitors. This work sheds some light on converting PEI films and other polymeric films to capacitors on a scale up fabrication effort. The practical learning from film handling to capacitor fabrication in this work provided the necessary knowledge for manufacturing high-temperature polar film capacitors.

Измерение эквивалентного последовательного сопротивления химических источников тока методом прерывания тока на заданное время

It is proposed to measure the equivalent series resistance of various chemical current sources by the method of periodic interruption of the charge current or of the discharge current for a given time period. The current interruption frequency and duration could be selected from a wide range of values. By changing the current interruption duration, it becomes possible to significantly vary conditions in measuring the equivalent series resistance. Thus, when the current is interrupted for 0.5 ms, the proposed method approaches the resistance measurement by the alternating current method with a frequency of 1000 Hz. With current interruption durations of 0.5 s or more, the method under consideration becomes equivalent to the direct current method. The proposed method allows measuring the resistance both once and periodically with a given repetition period. Based on the results obtained, dependences of the equivalent series resistance on the charge level of the chemical current source, its residual resource, temperature, and other parameters were plotted. The method obtains several advantages, is easy to implement, misses errors inherent in other methods of measuring resistance and makes it possible to measure the equivalent series resistance directly in the process of charging and discharging the chemical current source under testing

A Self-Tuning Adaptive Control Scheme for a Grid-Connected Three-Phase PV System

This article presents a new self-tuning sinusoidal recursive controller (STSRC) for handling the uncertainties and disturbances in a three-phase grid-connected photovoltaic system (GCPVS). The performance of a GCPVS is greatly influenced by the uncertainties, such as intermittency in solar irradiation, change in capacitance and equivalent series resistance (ESR) of dc-link capacitor, and variation of impedance between the inverter and the grid. This STSRC comprises improved linear sinusoidal tracer-based recursive least-square estimation (IRLS) to achieve robust performances, despite the parametric uncertainties through real-time estimation of its parameters, and updation of its gains. The efficacy of the proposed STSRC is verified through simulation using MATLAB/Simulink and experimental studies pursued on a 2.5-kW prototype. It is observed that STSRC exhibits superior tracking of PV voltage with reduced ripple and improved grid current with reduced total harmonic distortion (THD) of 1.66%. The estimation accuracy is found above 92%.

Measurement of Extreme Impedances with the S Parameters

High frequency measurement of extreme impedances, such as the Equivalent-Series-Resistance (ESR) of an ultra high-Q capacitor, can be performed with specific and costly instrumentation whose principle is generally based upon a coaxial resonant line or a resonant cavity [1]. A cost-effective solution for measuring impedances at high frequencies is the classical One-Port reflection technique that can be performed with a Vector Network Analyzer (VNA). In [2], only this technique was considered, and the analysis was limited to a relative error of 10%; nevertheless, this work showed that the reflection technique is unsuited for measuring extreme impedances. In [3], all of the impedance measurement techniques that can be performed with a VNA are presented and compared. This analysis confirmed the limitations of the reflection technique and showed the abilities of the transmission technique for measuring extreme impedances. Unfortunately, these comparisons were based on absolute errors of the measured impedance (ΔZ) that are not significant for an engineer who needs to select the best method. Moreover, in [2], [3], the analyses are not extended to the negative resistances, and the resistance's sign inversion error is not considered.

Direct laser-assisted fabrication of turbostratic graphene electrodes: Comparing symmetric and zinc-ion hybrid supercapacitors

Lasers offer a versatile means towards the single-step, binder-free synthesis of three-dimensional graphene-like porous networks, providing an enticing alternative over energy intensive, multi-step traditional synthesis protocols creating unwanted waste streams. Here, we report on a novel laser-assisted method for the one-step preparation of the electrode component, not solely the active material, based on the simultaneous synthesis of turbostratic graphene-like structures on a carbon precursor and its transfer/deposition on the selected current collector. The performance of the graphene-based electrodes was electrochemically evaluated for both electric double layer capacitor (EDLC) and zinc-ion hybrid capacitor (ZIC) configurations. The performance of the EDLC devices was found to be superior to that of the current state-of-the-art devices prepared by laser-grown graphene. The ZIC exhibited higher areal energy density than the symmetric devices by one order of magnitude. The devices showed very low equivalent series resistance, good rate performance and high long-term cycling stability. Notably, the EDLC with the KOH electrolyte demonstrated an unexpected ∼20% increase in capacitance during the stability test of 10,000 cycles. This result was attributed to the substantial increase of oxygen content of the graphene electrodes, which act as sites for redox activity.

Preparation and Characterization of Reduced Graphene Oxide-Incorporated ZnO Nanorods for Supercapacitor Application

This study’s objective is to prepare and characterize a ZnO-rGO composite for use in supercapacitors. The hydrothermal method was used to successfully prepare ZnO and ZnO-rGO. Characterization of the prepared materials was carried out using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and ultraviolet-visible (UV–Vis) spectrometers. The electrochemical properties of the ZnO and ZnO-rGO electrodes were examined using cyclic voltammetry (CV) and impedance spectroscopy. The specific capacitance of the ZnO-rGO composite electrode in 1[Formula: see text]M NaOH as an electrolyte was 293.37[Formula: see text]F/g at the scan rate of 5[Formula: see text]mV/s. As a result of the low equivalent series resistance and improved ion diffusion produced by ZnO and rGO working together, the ZnO-rGO nanoparticles electrode has a higher super capacitance. The result achieved a higher energy density of 39.93[Formula: see text]Wh/kg and a power density of 54.45[Formula: see text]kW/kg. These findings demonstrated the significance of rGO-based composites in the development of high-performance energy storage systems as well as their enormous potential for improvement.

An Online Monitoring Method for Single Aluminum Electrolytic Capacitor in the DC Bank of Single-Phase Inverter Based on the Rogowski Coil

State-of-the-art capacitor online monitoring methods are designed for the whole dc bank. The capacitance or equivalent series resistance of the dc bank, as an aging indicator, is obtained by the sensors installed at the dc terminal, or derived from the state equation of the system. The difference of capacitor parameters from manufacturing and the arrangement of the dc bank will result in uneven thermal stress for the capacitors. Due to the restriction of the low stray inductance specification and high power density requirement, the traditional online monitoring circuits are hard to be designed for the single capacitor in the dc bank. In this article, a Rogowski coil based online monitoring circuit has been designed for the single capacitor in the dc bank. A new aging criterion has been established for aluminum electrolytic capacitors based on the accelerated aging test. To achieve a compact integration design, a six-layer printed-circuit-board-type Rogowski coil is designed under an optimized frequency. A 2-kW single-phase inverter is built to verify the theoretical analysis and practical performance of the monitoring circuit.

Electrospun Benzimidazole-Based Polyimide Membrane for Supercapacitor Applications.

A benzimidazole-containing diamine monomer was prepared via a simple one-step synthesis process. A two-step procedure involving polycondensation in the presence of aromatic dianhydrides (4,4′-oxydiphthalic anhydride, ODPA) followed by thermal imidization was then performed to prepare a benzimidazole-based polyimide (BI-PI). BI-PI membranes were fabricated using an electrospinning technique and were hot pressed for 30 min at 200 °C under a pressure of 50 kgf /cm2. Finally, the hot-pressed membranes were assembled into supercapacitors, utilizing high-porosity-activated water chestnut shell biochar as the active material. The TGA results showed that the BI-PI polymer produced in the two-step synthesis process had a high thermal stability (Td5% = 527 °C). Moreover, the hot-press process reduced the pore size in the BI-PI membrane and improved the pore-size uniformity. The hot-press procedure additionally improved the mechanical properties of the BI-PI membrane, resulting in a high tensile modulus of 783 MPa and a tensile strength of 34.8 MPa. The cyclic voltammetry test results showed that the membrane had a specific capacitance of 121 F/g and a capacitance retention of 77%. By contrast, a commercial cellulose separator showed a specific capacitance value of 107 F/g and a capacitance retention of 49% under the same scanning conditions. Finally, the membrane showed both a small equivalent series resistance (Rs) and a small interfacial resistance (Rct). Overall, the results showed that the BI-PI membrane has significant potential as a separator for high-performance supercapacitor applications.

A data-driven method for anomaly detection and aging model parameter estimation of capacitors based on condition monitoring

The reliability of capacitor is a crucial problem affecting power electronics system. However, the sudden failure caused by parameter mutation cannot be identified from normal aging and the aging model parameters obtained from prior knowledge cannot accurately describe the aging process of the capacitor under practical operating conditions. Therefore, a data-driven method for anomaly detection and aging model parameter estimation of capacitors is proposed. Firstly, Mahalanobis distance is introduced to analyse the correlation between capacitance loss and equivalent series resistance (ESR) and eliminate the dimensional effect. The anomaly is detected when there is a sudden change of the distance between the current monitoring value and the historical data. Then, parameter estimation method of aging model based on Bayesian linear regression is proposed to modify model parameters in real time, combining the prior knowledge and posterior data. The Markov chain Monte Carlo (MCMC) algorithm according to Gibbs sampling is introduced to obtain parameter posterior distribution. Finally, the superiority of the method is verified by accelerated aging test.

A comparative LCA study on aluminum electrolytic capacitors: From liquid-state electrolyte, solid-state polymer to their hybrid

Polymer hybrid aluminum electrolytic capacitors (PHAECs) are a new generation of aluminum electrolytic capacitors (AECs) following traditional liquid AECs (LAECs) and polymer AECs (PAECs). The differences in the potential environmental impact among the three types of AECs have not been well investigated. A cradle-to-grave comparative LCA study was conducted to evaluate whether PHAECs have ecologically environmental advantages over PAECs and LAECs throughout their entire life cycle. In this study, the functional unit was taken to be 1,000,000 pieces of the AECs with 25 V rated working voltage and 150 μF rated capacitance, each operating for 2000 h. Furthermore, a capacitor manufacturer (located in Jiangsu, China) with its suppliers was investigated to obtain the life cycle inventory data of the AECs. According to the ReCiPe2016 method, climate change, fossil depletion, and photochemical ozone formation were identified as the main categories of AECs' environmental problems. Electricity consumption and aluminum ingot use were identified as the main contributors to AECs' environmental impact based on the ReCiPe2016 normalization factors (mid-point, World). The application of conductive polymer increases the environmental impact of the AECs from cradle to gate but effectively reduces their equivalent series resistance (ESR). In addition, the liquid electrolyte in PHAEC will solve the problem of large leakage currents in PAECs. The environmental impact of PHAECs from cradle to grave, thus, is no more than 30.5% of LAECs and 50.5% of PAECs, respectively. Difference analysis, sensitivity analysis, scenario analysis, and sustainability opportunities of PHAECs were also discussed. This work would provide a quantitative benchmark and calculation framework to assess the environmental burden of the PHAECs and guide environmentally conscious design, manufacturing, marketing, operation, and recycling of future PHAEC products.

Influence of fuel to oxidizer ratio on the supercapacitive properties of NiO synthesized by solution combustion method

Porous Nickel oxide nanocrystallites were successfully synthesized by a facile single-step glycine assisted solution combustion method without a post calcination treatment. Effect of fuel to oxidizer (F/O) ratio on the combustion behaviour, crystallite size, surface characteristics, morphology, and agglomeration were thoroughly investigated. A systematic variation of crystallite size with F/O ratio was revealed from PXRD studies. BET studies showed a decrease of surface area with increase of F/O ratio. Highly porous morphology of NiO nanocrystallites synthesized at low F/O ratio (0.5) was evident from scanning electron micrograph (SEM). Transmission electron microscopy (TEM) studies showed polycrystalline nature of the material. NiO nanocrystallites exhibit high thermal stability, which was revealed from thermal analysis. The maximum specific capacitance obtained for NiO synthesized at different F/O ratios ranged from 215.6 to 99.2 C/g at 5 mV/s scan rate and 174.7 to 73.0 C/g at 10 A/g current density. Highest value of specific capacitance and lowest values of equivalent series resistance and charge transfer resistance were exhibited by NiO synthesized at low F/O ratio of 0.5. The enhanced electrochemical performance of the sample synthesized at low F/O ratio was benefited mainly from its high surface area and optimal pore size for the diffusion of ions and electrons within the electrode. An asymmetric device fabricated using NiO as the positive electrode and activated carbon derived from phyllanthus emblica as the negative electrode and 3 M KOH as the electrolyte delivered an energy density of 12 Wh/kg at a power density of 427 W/kg.

A review on characterization of supercapacitors and its efficiency analysis for different charging methods and applications

AbstractThe dependence on renewable energy to solve the major energy issues related to global warming and shortage of energy resources is increasing drastically. This has led to high level awareness of proper energy storage and management. In this regard, supercapacitors have evolved as an efficient energy storage solution and hence successfully employed in several applications. This is attributed to its high‐power density, superior performance, and extended maintenance‐free lifetime. Also, it is known for low equivalent series resistance, that means, only a small amount of energy is lost while its charging/discharging even at high current. As a result, it has developed a lot of inquisitiveness among the research community of recent past for further exploration of different aspects of supercapacitors, ranging from material science, modeling and characterizations, engineering applications, and so forth. This review article aims at putting forth an exclusive study of their characterization of supercapacitor for different charging methods and applications. Further, the prime focus is given to the efficiency estimation of supercapacitors which is very essential as it denotes the amount of energy loss or the utilizable state of charge. The analysis has been carried out based on different charging methods and applications, which is essential for improving overall system reliability and performance. The purpose is to organize all important research carried out in this domain till date and to stimulate further insights for effective energy storage and management.

Single and Double Layer of Monoclinic VO2 Ink‐Based Printed and Interdigitated Supercapacitors

Screen printing has received significant attention for manufacturing energy storage devices. However, preparing high‐quality inks is still one of the main challenges. Herein, a homogenous and stable ink based on the monoclinic phase of VO2(M) microparticles has been synthesized by a simple hydrothermal process in only 6 h and through nontoxic solutions. The VO2 ink is printed on Kapton substrate in a single‐layer as well as in a double‐layer arrangement (1‐LP and 2‐LP). The printed 1‐LP VO2 electrode delivers a maximum areal capacitance of 20 mF cm−2 with a small equivalent series resistance of 4 Ω without conducting additives. The interdigitated full‐cell VO2 supercapacitor adequately employs the electric double‐layer and Faradic redox mechanisms in 1.4 V, which is the highest operating voltage reported for symmetric supercapacitors based on pure vanadium oxide electrodes in aqueous inorganic electrolytes. Moreover, the maximum areal energy of the 2‐LP supercapacitor is 0.8 μWh cm−2 at an areal power of 21.0 μW cm−2, which is larger than the 1‐LP (0.2 μWh cm−2 at 17.5 μW cm−2). This improvement is attributed to the homogenously printed double layer of the porous VO2 microparticles. Integrating such supercapacitors into thin‐film electronics could develop portable devices.

Calibration Method of Equivalent Series Resistance Parameter for Nonintrusive Current Sensors Used in DC–DC Power Electronic Converters

Nonintrusive current sensors process indirect measurements (e.g., voltage) in order to estimate the current flow through an electrical element. Within dc–dc power electronic converters, instead of using an additional current sensor(s), high-frequency inductor currents within the topology can be estimated by measuring inductor terminal voltages using simple low-cost comparators used with digital postprocessing circuits. The figure of merit for such sensors depends upon the accurate identification of sensor transfer function. This transfer function relates inductor terminal voltage to estimated current, and consists of two major parameters, i.e., inductance ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i> ) and equivalent series resistance (ESR), of the element. Both the parameters vary with changes in operating conditions, e.g., temperature, and additional trace resistances. Variation of ESR parameter introduces dc offset within the estimated current measurement, and hence an accurate knowledge of ESR is essential for closed-loop stability of dc–dc converters. This letter presents a calibration method of ESR parameter for nonintrusive current sensors used in dc–dc power electronic converter applications. The theory behind the proposed approach, its implementation aspects, and verification are presented in this letter.

A Novel Single-Stage Common-Ground Zeta-Based Inverter With Nonelectrolytic Capacitor

Aiming at the key problems of the existing nonisolated photovoltaic (PV) inverter, such as the common mode (CM) leakage current, the voltage up and down ability, and the service life restricted by the electrolytic capacitor, a novel single-stage common-ground zeta-based inverter with nonelectrolytic capacitor is proposed in this article. The proposed inverter is based on zeta dc converter and has the inherent voltage conversion characteristics of zeta converter, which makes it more suitable for PV system with wide input voltage fluctuation range. In addition, common-ground structure is adopted in this inverter, which can shorten the parasitic capacitor of the PV array to the ground. Therefore, it can effectively suppress the CM leakage current, reduce the shutdown frequency of the PV system, and improve the utilization rate of solar energy. Moreover, the proposed inverter does not contain electrolytic capacitors, which avoids the problem of high maintenance cost due to the short service life and high equivalent series resistance of electrolytic capacitors. First, the topology of the proposed inverter is given, and the modulation and operating principle are analyzed. Second, the passive components are analyzed. Finally, a 1 kW prototype is built for experimental verification. The experimental results verify the correctness of the theoretical analysis and simulation.

Synthesis and electrochemical characterization of polyaniline doped cadmium oxide (PANI-CdO) nanocomposites for supercapacitor applications

High-performance nanoscale supercapacitor (SC) electrode materials of polyaniline (PANI) and polyaniline cadmium oxide (PANI-CdO) composites are fabricated using In-situ chemical polymerization route. The structural parameters, crystallite size, and lattice strain of the prepared samples are estimated by X-ray diffraction analysis. The CdO stretching peak in PANI-CdO nanocomposite's FTIR spectra confirms the interaction of CdO with PANI. SEM analysis exposing a random dispersion of CdO nanoparticles in PANI matrix and showing the cluster of indefinitely shaped fibrous flaky architectures. The cyclic voltammetry (CV) results show a higher specific capacitance of 866 F g−1 for PANI-5%CdO composite as compared to Pure PANI 222 F g−1 and Pristine CdO 35.2 F g−1 at 5 mV s−1 scan rate. Galvanostatic charge-discharge (GCD) results also show a higher specific capacitance value of 906.8 F g−1 for PANI-5%CdO composite at 9.26 A g−1 current density revealing a maximum energy density and power density of 9.04 Wh kg−1 and 1510 W kg−1 respectively. The frequency response behavior of PANI-CdO nanocomposites (EIS spectra) reveals (Warburg) diffusive resistance of the electrolyte into the interior of the electrode and ion diffusion into the electrode surface. The higher capacitance and lower ESR (equivalent series resistance) value of PANI-CdO nanocomposite refer to the formation of a more ordered structure and rapid ion diffusion that can develop enhanced surface-dependent electrochemical properties and recommend this material to be a promising potential candidate for practical supercapacitor electrode preparation.

Silver-substituted cobalt zeolite imidazole framework on reduced graphene oxide nanosheets as a novel electrode for supercapacitors

Although metal-organic frameworks demonstrate enhanced surface area, incredible porosity, and a well-controlled structure, they exhibit low conductivity, limiting their use in energy storage devices. In this work, we incorporated different mass loadings of silver, the metal with the highest conductivity in the zeolitic imidazolate framework-67 (ZIF-67) to enhance the electrochemical performance of their composites. The synthesized composites were extensively characterized using various techniques, and the electrochemical characterization of the constructed electrodes in 6 M KOH was performed using a two-electrode Swagelok cell. The results showed that the composite (ZIF-67.Agx=10/RGO) formed an efficient bimetallic structure and performs optimally with a specific capacitance (Cs) of 375 F/g at 5 mV s−1 and the smallest equivalent series resistance. The electrode material exhibited promising cycling stability over 2000 cycles reaching 97 % at 2 A g−1. Moreover, its energy density reached 46.388 Wh/kg along with a power density of 199.7 W/kg. Furthermore, it possessed the maximum specific surface area with all fabricated active material composite electrodes, reaching 1105 m2/g. The proposed composite can be used in energy storage applications and the conductivity will be further enhanced by co-doping.

Activated carbon from olive tree pruning residue for symmetric solid-state supercapacitor

The scientific community is focusing on developing supercapacitors with high capacitance, power and energy from waste-derived electrode materials and low-toxic aqueous electrolytes that can provide an advance in energy storage as well as the care for the environment. This work presents the development of a symmetric solid-state supercapacitor with activated carbon from olive pruning. Activated carbons were synthesized by chemical and physical methods varying their conditions. The physicochemical characterization determined that chemically activated carbons provided the highest surface areas, greater than 2000 m2 g−1. The electrochemical performance of chemically activated carbons was superior to physically activated carbons due to the high surface area and the developed pore structure that promote capacitances of up to 410 F g−1. Three symmetric solid-state supercapacitors with chemically activated carbon as electrode material and PVA-KOH hydrogel as electrolyte were assembled, and windows potential and drying time of the membrane were evaluated. An excellent performance supercapacitor was developed with electrode materials from olive pruning waste, which presented a capacitance of 1.15 F at 5 mA, a voltage of 1.2 V and equivalent series resistance of 1.42 Ω. These results present a promising way to develop competitive energy storage devices using agro-industrial waste to produce electrode materials.