Internal Circuit Research Articles

Analysis and Recommendations for LED Catastrophic Failure Due to Voltage Stress

Light-emitting diode (LED) lighting has, compared to other types of lighting, a significantly lower energy consumption. However, the perceived service life is also important for customer satisfaction and here there is a discrepancy between customers’ experience and manufacturers’ statements. Many customers experience a significantly shorter service life than claimed by the manufacturers. An experiment was carried out in the Pehr Högström Laboratory at Luleå University of Technology in Skellefteå, Sweden to investigate whether voltage disturbances could explain this discrepancy. Over 1000 LED lamps were exposed to high levels of voltage disturbances for more than 6000 h; the failure rate from this experiment was similar to the one from previous experiments in which lamps were exposed to normal voltage. The discrepancy thus remains, even though some possible explanations have emerged from the project’s results. The lamps were exposed to five different types of voltage disturbances: short interruptions; transients; overvoltage; undervoltage; and harmonics. Only overvoltage resulted in failure of the lamps, and only for a single topology of lamp. A detailed analysis has been made of the topology of lamps that failed. This lamp type contains a different internal electronics circuit than the other lamp types. Failures of the lamps when exposed to overvoltage are due to the heat development in the control circuit increasing sharply when the lamps are exposed to a higher voltage. Hence, it is concluded that there are lamps that are significantly more sensitive to voltage disturbances than other lamp types. Manufactures need to consider the voltage quality that can be expected at the terminal of the lamp to prevent failure of lamps due to voltage disturbances. This paper therefore contains recommendations for manufacturers of lighting; the recommendations describe which voltage disturbances lamps should cope with.

Controlled Production of Natural Gas Hydrates in an Experimental Device with an Internal Circulation Circuit

For countries with limited access to conventional hydrocarbon gases, methane hydrates have emerged as a potential energy source. In view of the European Union’s requirements to reduce the energy intensity of technological processes and increase energy security, it appears promising to accumulate natural gas and biomethane in the form of hydrate structures and release them if necessary. Storing gas in this form in an energy-efficient manner creates interest in developing and innovating technologies in this area. Hydrates that form in gas pipelines are generated by a more or less random process and are an undesirable phenomenon in gas transportation. In our case, the process implemented in the proposed experimental device is a controlled process, which can generate hydrates in orders of magnitude shorter times compared to the classical methods of generating natural gas hydrates in autoclaves by saturating water only. The recirculation of gas-saturated water has been shown to be the most significant factor in reducing the energy consumption of natural gas hydrate generation. Not only is the energy intensity of generation reduced, but also its generation time. In this paper, a circuit diagram for an experimental device for natural gas hydrate generation is shown with complete description, principle of operation, and measurement methodology. The natural gas hydrate formation process is analyzed using a mathematical model that correlates well with the measured hydrate formation times. Hydrates may become a current challenge in the future and, once verified, may find applications in various fields of technology or industry.

Design and analysis of coupled-inductor Cockcroft–Walton-switched-capacitor boost DC–AC inverter

ABSTRACT The objective of this study is to present a novel simple structure of coupled-inductor Cockcroft–Walton-switched-capacitor (CICWSC) inverter for DC–AC conversion/closed-loop regulation. In structure, the power part is contained by three units: coupled–inductor booster, Cockcroft–Walton-switched-capacitor doubler, and half-bridge DC-link, working together for providing the DC–AC gain range as (n: turn ratio, : ratio cycle). In control, for the time sequence (to different topologies) and output regulation/robustness (to various desired output/loading variation), the control part is made of phase generator and sinusoidal pulse-width-modulation (SPWM) block, and its chip internal circuit is designed through pre/post-layout procedure via CADENCE. By the assistance of Chip Design and Implementation Center (CIC) and TSMC, this control part is practically fabricated on a real chip (D35-104B-E0013, TSMC 0.35μm, 2P4M, 3.3V, 3.889mW). In analysis and design, the quantitative mathematical modeling of CICWSC is carefully derived, and the relevant system analysis/ design is also presented (e.g. steady-state response, conversion ratio, power efficiency, parameter selection, stability, and control design). In implementation, it contains several cases of simulation and experiment (via testing on prototype circuit) so as to examine the validity of the analysis/design and check the efficacy of the proposed structure.

Hardware Update through Digital TV Signals

This paper presents a new hardware reconfiguration approach named hardware reconfiguration through digital television (HARD), which can update FPGA hardware modules based on digital TV (DTV) signals. Such a scheme allows several synthesized hardware cores (bitstreams) signaled and broadcast through open DTV signals via data streaming to be identified, acquired, decoded, and then used for system updates. Reconfiguration data are partitioned, encapsulated into private sections, and then sent in a carrousel fashion in order to be recovered by modified receivers. Service information content, specially designed for identifying and describing the characteristics of multiplexed hardware bitstreams, was added to the transmitted signal and provided all necessary information in the traditional DTV style. The receiver framework, in turn, checked whether those characteristics corresponded to its embedded reconfigurable devices and, if a match was found, it reassembled the related bitstreams and reconfigured the respective internal circuits. Experiments performed with an implementation of the proposed methodology confirmed its feasibility and showed that remounting and reconfiguration times were satisfactory and presented no blocking aspect. Finally, HARD can be used in several designs regarding intelligent reconfigurable devices, minimize device costs in the long term, and provide better hardware reuse.

Preparation of Dr\xe4ger Atlan A350 and General Electric Healthcare Carestation 650 anesthesia workstations for malignant hyperthermia susceptible patients

BackgroundPatients at risk of malignant hyperthermia need trigger-free anesthesia. Therefore, anesthesia machines prepared for safe use in predisposed patients should be free of volatile anesthetics. The washout time depends on the composition of rubber and plastic in the anesthesia machine. Therefore, new anesthesia machines should be evaluated regarding the safe preparation for trigger-free anesthesia. This study investigates wash out procedures of volatile anesthetics for two new anesthetic workstations: Dräger Atlan A350 and General Electric Healthcare (GE) Carestation 650 and compare it with preparation using activated charcoal filters (ACF).MethodsA Dräger Atlan and a Carestation 650 were contaminated with 4% sevoflurane for 90 min. The machines were decontaminated with method (M1): using ACF, method 2 (M2): a wash out method that included exchange of internal parts, breathing circuits and soda lime canister followed by ventilating a test lung using a preliminary protocol provided by Dräger or method 3 (M3): a universal wash out instruction of GE, method 4 (M4): M3 plus exchange of breathing system and bellows. Decontamination was followed by a simulated trigger-free ventilation. All experiments were repeated with 8% desflurane contaminated machines. Volatile anesthetics were detected with a closed gas loop high-resolution ion mobility spectrometer with gas chromatographic pre-separation attached to the bacterial filter of the breathing circuits. Primary outcome was time until < 5 ppm of volatile anesthetics and total preparation time.ResultsTime to < 5 ppm for the Atlan was 17 min (desflurane) and 50 min (sevoflurane), wash out continued for a total of 60 min according to protocol resulting in a total preparation time of 96-122 min. The Carestation needed 66 min (desflurane) and 24 min (sevoflurane) which could be abbreviated to 24 min (desflurane) if breathing system and bellows were changed. Total preparation time was 30-73 min. When using active charcoal filters time to < 5 ppm was 0 min for both machines, and total preparation time < 5 min.ConclusionBoth wash out protocols resulted in a significant reduction of trace gas concentrations. However, due to the complexity of the protocols and prolonged total preparation time, feasibility in clinical practice remains questionable. Especially when time is limited preparation of the anesthetic machines using ACF remain superior.

Memristive Circuit Design of Brain-Inspired Emotional Evolution Based on Theories of Internal Regulation and External Stimulation.

In this work, a bionic memristive circuit with functions of emotional evolution is proposed by mimicking the emotional circuit in limbic system, which can perform unconscious and conscious emotional evolutions by using theories of internal regulation and external stimulation respectively. Two kinds of memristive models, volatile and non-volatile, play key roles in the process of emotional evolution. That is, the internal regulation is mainly responsible for simulating the unconscious evolution process over time by using the forgetting effect of the volatile memristor. The external stimulation is mainly responsible for using the memristance plasticity of the non-volatile memristor to simulate the evolutionary learning behavior under the action of multi-modal inputs (such as visual, speech and text signals), so as to realize the conscious emotional evolution. A two-dimensional (2D) emotional state space consisted of valence and arousal signals is adopted, the evolution behaviors are performed on the basis of valence and arousal signals in the space, in order to achieve continuous emotional evolution and express the evolved emotions intuitively. Due to the use of memristors, the proposed circuit can realize in-memory computing, which fundamentally avoids the problem of storage wall and constructs a brain-inspired information processing architecture. The simulation results in PSPICE show that a nonlinear mapping relationship between inputs and outputs is constructed through the proposed circuit, which can carry out diversified emotional evolution based on the designed internal regulation and external stimulation evolution circuits.

Numerical Evaluation and Experimental Test on a New Giant Magnetostrictive Transducer with Low Heat Loss Design.

Giant magnetostrictive transducer with micro and nano precision has a wide application prospect in the field of remote sensing. However, excessive heat loss of components could generate during the energy conversion and transfer from electric energy to magnetic energy, and magnetic energy to mechanical energy, thereby affecting its long-term service and also reducing energy utilization. In this paper, a new magnetostrictive transducer is proposed and its excitation coil, internal and external magnetic circuit are optimized from the perspective of reducing heat loss. With the help of theoretical and finite element analysis, the response law between key parameters and heat loss of key components are summarized, which provides a basis for reducing heat loss. Finally, according to the optimization scheme, the prototype is processed, and the temperature rise and dynamic output performance of the transducer are tested by constructing an experimental setup. The results show that the transducer has a low temperature rise and good frequency response characteristics, which can provide support for long-time precise actuation on-orbit.

Analysis of Electromagnetic Reflection Loss for Mesh Structure with A16061 MMC for Aerospace Applications

One of the major problems facing by the aircraft was a lightning strike. To overcome this problem, fiber-reinforced materials have been used. The fiber-reinforced materials have less conductivity. These fiber-reinforced materials can’t eliminate the lightning strike effect. For that purpose, the metal matrix composite materials significantly impacted the aircraft’s internal circuits and physical components from the lightning strike effect. To meet industries dynamic and ever-increasing demands, Al6061 metal matrix composite reinforced with fly ash must be utilized to build the aircraft to offer HIRF. The material thickness should be kept low as possible then it can be used to cover the plane’s surface. To prevent lightning strikes, it might be used to protect electronic components from a concentrated high-intensity radiated field, primarily in Aeroplan configuration. The electromagnetic characteristics of composites are measured using the X-band for normal incidence. The electromagnetic reflection properties of AL6061 reinforced with fly ash are studied in this study for mesh structure. Mat lab Software was used to calculate the maximum reflection loss of 33.88dB for 15% fly ash and 85 percent AL6061 at X-band.

Universal equivalent circuit model and verification of current source for triboelectric nanogenerator

In the field of energy harvesting and self-powered sensing, the universal equivalent circuit model of triboelectric nanogenerators (TENGs) is an important development tool for research and applications. Such a universal model of the current source is established to first order for the basic operating modes of a TENG, which provide the related theoretical models and electrical models used in simulation. The universal first-order equivalent circuit model demonstrates that the carrying capacity of a TENG separates into three regions of distinct output characteristics, namely, constant current, maximum power, and constant voltage. Moreover, employing electrometers, an electrometer and multimeters, and TENGs in series and parallel in successive experiments, we verify that the TENG can be considered a current source with a resistance of mega-ohms and a capacitance of nano-farads. Overall, our first-order model sets electrical standards for the internal circuit of the TENG and therefore provides theoretical guidance that lays the foundation for applications in high-performance supply and grid-connected power generation. • The first-order equivalent circuit model (FO-ECM) of the current source is established for TENG. • The universal FO-ECM presents three different output characteristic regions both in theory and experiment. • The FO-ECM is verified by employing electrometers, an electrometer and multimeters, and TENGs in series and parallel.

Иерархия механизмов гомеостаза человеко-машинных комплексов: проблемы их анализа и реализации

Developing control systems for regional socio-economic and large technical systems is inevitably associated with the concept of human-machine complexes (HMC). They are considered as a set of a large number of hierarchically dependent complex subsystems, including staffs and machines, possessing a certain degree of organization and autonomy, interconnected by mechanisms and means of organization (i.e. material and informational links) to ensure the purposeful functioning of the entire system as a single whole in conditions of tense internal resource close to the limiting ones.&#x0D; The article discusses the hierarchy of interrelated homeostasis mechanisms of the HMC, ensuring both its parameter constancy and the performance of systemic functions at all hierarchy levels. In particular, the following types of homeostasis are considered: a parametric type (the internal circuit of homeostasis), designed to maintain the parameter constancy of HMC active elements and a functional type (the external circuit of homeostasis), ensuring the constancy of its functioning. At the same time, the functional integrity of the system is ensured by the work of the interrelated static-dynamic and entropy-organizational homeostasis mechanisms, which, in turn, in practical activity are implemented through coordination-motivational (CMR), organizational-motivational (OMP) and functional (FMR) mechanisms of regulation. The need for an integrated application of all entropy-organizational regulation mechanisms (CMR, OMR, FMR) in the operators’ activities determines the necessity to use multivariate methods to determine their composition and application. &#x0D; To solve this problem, the article examines the supersystem elements of the activity regulation, which are formed as a result of the operators’ psychological interaction in the process of their activity, as a kind of an abstract system of a higher order, which has its own supersystem properties, its own autonomous metric and conservation laws, and most importantly, its situation reflection which is different from the system one. In this case, homeostatic hierarchical networks, the elements of which are homeostatic mechanisms of HMC operators at various levels, become the basis of HMC structural-hierarchical homeostasis.&#x0D; Thus, being complex systems, HMC synergistically change (adapt) their internal characteristics, thereby ensure the integrity of the entire system functioning, which allows speaking, on the one hand, of their homeostaticity as the HMC most important characteristic, and on the other hand, determining the need to search for new approaches to their methodological description, and, consequently, to organizing their management and design.

Basic principles of construction of high-quality analytical adaptable control systems for thermal energy processes

The modeling results and industrial tests of a typical automatic control system (ACS) and the proposed invariant cascade ACS are presented. The advantages of structural-parametric optimization methods for creating high-quality control systems for heat-and-power processes have been substantiated. The following algorithm for forming a block diagram of a high-quality invariant cascade SAR is proposed. At the beginning, the structure of the optimal transfer function of the stabilizing regulator is determined as the product of the inverse transfer function of the leading section of the object by a given transfer function of the open system of the internal circuit in the form of an ideal integrating link with one calculated parameter of dynamic tuning, which allows optimally working out both internal disturbances and the task of the stabilizing regulator. Then, the parameters of the dynamic adjustment of the corrective regulator are calculated for optimal processing of the extreme external disturbance. Next, an equivalent external perturbation is isolated without its direct measurement using a complete model of the inertial section of the object. At the same time, the obtained difference between the main adjustable value and the model output is fed to the input of an equivalent external perturbation compensation device implemented in the form of a differentiator, which makes it possible to increase the accuracy and speed of the invariant SAR compared to the standard one. To ensure high quality control over the entire range of load changes, the parameters of the dynamic adjustment of the invariant SAR and the model of the inertial section are adjusted in the load function.

A comprehensive review of distributed power system architecture for telecom and datacenter applications

With the dominating utility of the internet, it becomes critical to manage the efficiency and reliability of telecom and datacenter, as the power consumption of the involved equipment also increases. Much power being wasted through the power conversion stages by converting AC voltage to DC voltage and then stepping down to lower voltages to connect to information and communication technology (ICT) equipment. 48/12 VDC is the standard DC bus architecture to serve the end utility equipment. This voltage level is further processed to multiple lower voltages to power up the internal auxiliary circuits. Power losses are involved when it is converted from higher voltage to lower voltages. Therefore, the efficiency of power conversion is lower. There is a need to increase the efficiency by minimizing the power losses which occur due to the conversion stages. Different methods are available to increase the efficiency of a system by optimizing the converter topologies, semiconductor materials and control methods. There is another possibility of increasing the efficiency by changing the architecture of a system by increasing the DC bus voltage to higher voltages to optimize the losses. This paper presents a review of available high voltage options for telecom power distribution and developments, implementations and challenges across the world.

Effect of mechanical extrusion force on thermal runaway of lithium-ion batteries caused by flat heating

The thermal runaway (TR) of lithium-ion batteries (LIBs) hinders the development of new energy vehicles (NEVs) because its extrusion-state characteristics remain unclear. Here, 100% state of charge (SOC) pouch LIBs are heated under extrusion, for triggering TR. The battery temperature, voltage, and deformation during the TR are recorded, and a high-speed infrared camera is used along with a high-definition camera for capturing the TR's flame evolution process. The battery thickness gradually decreases with increasing the temperature of a squeezed-state battery, until dropping abruptly at the TR onset. In the squeezed state, smoke is produced for a shorter time, the TR jet intensity significantly increases, and the wreckage exhibits a tight block structure. The TR onset occurs faster for higher squeezing pressures, the jet fire duration is shorter, while the flame temperature and area increase. The maximal temperature of the battery surface increases first and then drops, and the mechanism of the TR gradually changes from heating to internal circuit shorting. For squeezing pressures under 5000 N, the TR onset temperature increases slightly compare with the non-squeezed state, and then decreases to approximately 100 °C as the pressure approaches 5000 N.

P‐13.8: Evaluation of the Structure‐Capacitance Relationship in OLED Device and the Influence of Capacitance Variation on Pixel Circuit

Over the past years, active‐matrix organic light‐emitting diode (AMOLED) has established a commanding position in displays for smart phones, smart watches and TVs. However, AMOLED display still faces challenges in pursuing high‐level performance as TFT and/or OLED suffer device‐level variation and dynamic shifting resulting from the aging effect. Thus, a variety of internal compensation circuits, which are designed to partially compensate these harmful variation and dynamic shifting, have been implemented into pixel circuits of AMOLED products. Previous studies have mainly focused on the instability of TFT device, however the capacitance of OLED device could also affect the overall compensation effect. In this study, the structure‐capacitance relationship of OLED device is systematically presented and the influence of capacitance variation on the pixel circuits at compensation stage is also discussed.

Design a new thermoelectric module with high practicability based on experimental measurement

In practical applications, the thermoelectric module (TEM) conducts continuous heat exchange with the external environment. This causes uneven temperature distribution inside the module and some PN legs do not work effectively. The internal heat transfer direction of the TEM changes under the influence of the environment, resulting in energy loss and an inability to transfer heat in a consistent direction. In this study, the actual working environment of the TEM was simulated by a constant temperature heating platform, and we analyzed the heat transfer characteristics of the module using numerical calculation methods. Then, according to the results of this analysis, a sealed thermoelectric module (STEM) filled with high-temperature vulcanized silicone rubber (HTV) was designed. Besides, to improve the practicality of the STEM, we designed an integrated thermoelectric (TE) plate. The TE plate was equipped with a controllable water-cooling device, which allowed adjustments of the TEM cold end temperature according to the heat source to ensure maximum output power. Results indicated that the STEM can reduce heat exchange behavior at the edges and ensure uniform temperature distribution throughout the module. The maximum temperature gradient at the cold end of the STEM is 4.39 °C, which is 5.27 °C lower than the equivalent value of the TEM. Therefore, the temperature gradient in each of the PN legs in the STEM is similar, which can reduce the electrical loss generated by itself. We implemented a closed structure on the TE plate, and the internal circuit was installed on the contact surface of the water-cooling device to ensure that the circuit was not damaged due to the influence of the thermal environment. When the heat source temperature was 200 °C, the TE plate adopted a two-stage water-cooling mode to deliver a maximum output power of 78.64 W, which equates to a power generation per unit area of 0.86 kW·h/m2. The TEM structure optimization and TE plate design scheme proposed in this study provides an efficient solution for the practical application of TE technology.

A Case Study: Simulation Traffic Model as a Tool to Assess One-Way vs. Two-Way Traffic on Urban Roads around the City Center

This article evaluates changes in the organization of transport on urban roads through the transport model in the OmniTRANS program. The selected location for the case study in this article is the internal traffic circuit of Kosice, which borders the historic core of the city. Currently, the proposal is being prepared to change the organization of transport in the town’s monument reserve and its protection zone. The transition to a one-way road around the historic center is being considered. Before introducing the new proposed change in traffic, it is necessary to test this proposed change and determine how it will affect the traffic situation. The aim of this article is to compare the current transport organization with the proposed change in transport organization in terms of traffic intensity. The use of transport models in the world is not a new concept, but it is often not used in the conditions of the Slovak Republic. However, traffic and simulation models can save money and time and avoid possible unexpected problems before putting the proposed changes into practice. Solving the given problem is an excellent benefit for transport planning and traffic engineering for Kosice and other places with a similar arrangement of the historical center and a similar number of inhabitants. The proposed changes can be tested by modelling traffic and then to adjust them when the cons are identified. Thanks to the traffic simulation model, it is possible to compare the capacity load of the inner traffic circuit of the city before and after the introduction of the one-way circuit.

Decrease of oncological patients’ hospital visits during Covid-19 pandemic: The experience of a tertiary Romanian center.

e13607 Background: The outbreak of COVID-19 pandemic has changed the provision of medical services worldwide. Oncological patients continued receiving specialty treatments. We assess the impact of the pandemic on the oncological patients' visits to a tertiary cancer center. Methods: We analyzed registrations from the administrative data system of in and outpatients in all departments of the Cluj-Napoca Oncology Institute, during March-October 2020, compared to the same 7-month period of the previous year. Results: The decrease during March-October 2020 was of 40.2% for new referrals overall (with the most significant drop in April, of 80%), of 52.5% for medical oncology inpatients, 39% for pediatric oncology department inpatients, 69% for radiotherapy inpatients, 34.9% for surgical interventions and 31% decrease of issued pathology reports. The decrease was less important for outpatients: only 10% for medical oncology outpatient department, 33% for radiotherapy, and 27% for breast cancer unit outpatients. Imaging investigations were only slightly influenced by the pandemic (reduction of 5% for MRI scans, 19% for mammograms, whereas performed CT scans were even more after the outbreak of COVID-19). Conclusions: Our results show a decrease in the number of patients during the period after the outbreak of the COVID-19 pandemic, more for inpatients and less significant for outpatient departments, probably because of the internal circuits reorganization but also because of healthcare measures taken nationally and locally to limit the spread of the pandemic. Keywords: COVID-19, pandemic, oncology referrals, disruption.

Catalytic DNA Origami-based Chiral Plasmonic Biosensor

Plasmonic circular dichroism(CD) has been emerged as a promising signal for building biosensors due to its high sensitivity and specificity. In the past years, DNA nanotechnology enabled diverse chiral plasmonic devices, which can response biomolecules and then generate dynamic plasmonic CD signals at the visible range. Although some of them have been successfully employed as biosensors, the detection sensitivity is still relatively low. Herein we report a chiral plasmonic sensor with an improved detection sensitivity by integrating catalytic hairpin assembly circuits into DNA origami structures. We tested two kinds of tumor marker RNA sequences as detection targets and it turns out that the detection limit is below 10 pmol/L, improving one order of magnitude compared to previous work. The chiral plasmonic sensor with internal signal amplification circuits can stimulate a variety of smart nano-sensors for biological detection and offer a promising strategy for pathogenic RNA detection with plasmonic CD output.

Transient Analysis of ESD Protection Circuits for High-Speed ICs

Electrostatic discharge (ESD) failures in high-speed integrated circuits (ICs) cause critical reliability problems in electronic devices. Transient voltage suppressor (TVS) diodes are installed on high-speed I/O traces to improve system-level ESD protection. To protect the circuit, the majority of ESD current must flow into the external TVS diode rather than into the IC, but due to turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> behavior, the TVS diode may not snap back when needed and the IC's internal protection may take most of the current. These race conditions between the internal and external ESD protection circuits were investigated for a universal serial bus(USB) interface board. The transient turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> behavior of the on-chip and off-chip protection circuitry was characterized by measurements and by system efficient ESD design (SEED) simulations. The effect of transmission line pulses (TLP pulses) and power supply voltages of different sizes on the response of the protection circuitry were monitored and compared with SEED simulations. SEED models showed good agreement with measurements and were used to study the impact of passive components added to a high-speed trace or within the IC package on the ESD protection response. Results show the importance of properly accounting for the parasitic resistance and inductance between the on-chip diode and off-chip TVS diode, as well as the length of the transmission line when choosing the external TVS device. Results also show that testing must be performed using mid-level events to account for possible problems due to race conditions.

A Novel Adaptive Function—Dual Kalman Filtering Strategy for Online Battery Model Parameters and State of Charge Co-Estimation

This paper aims to improve the stability and robustness of the state-of-charge estimation algorithm for lithium-ion batteries. A new internal resistance-polarization circuit model is constructed on the basis of the Thevenin equivalent circuit to characterize the difference in internal resistance between charge and discharge. The extended Kalman filter is improved through adding an adaptive noise tracking algorithm and the Kalman gain in the unscented Kalman filter algorithm is improved by introducing a dynamic equation. In addition, for benignization of outliers of the two above-mentioned algorithms, a new dual Kalman algorithm is proposed in this paper by adding a transfer function and through weighted mutation. The model and algorithm accuracy is verified through working condition experiments. The result shows that: the errors of the three algorithms are all maintained within 0.8% during the initial period and middle stages of the discharge; the maximum error of the improved extension of Kalman algorithm is over 1.5%, that of improved unscented Kalman increases to 5%, and the error of the new dual Kalman algorithm is still within 0.4% during the latter period of the discharge. This indicates that the accuracy and robustness of the new dual Kalman algorithm is better than those of traditional algorithm.