Circuit Solutions Research Articles

Study of Supercapacitors Built in the Start-Up System of the Main Diesel Locomotive

A successful guaranteed launch of a mainline diesel locomotive is one of the most important and urgent problems of the rolling stock operation. Improvement of the start-up system of the main diesel locomotive when using a supercapacitor allows multiple restarts of diesel locomotives, meaning that the operation of the diesel locomotive can be stopped several times without wasting fuel in idle operations. In this study, we simulated the electric starting circuit of a diesel locomotive with a block of supercapacitors using the Matlab Simulink program. The simulation results show that using only a supercapacitor in the start-up system is impossible. Even though the supercapacitor produces the required current and voltage, its operating time is extremely insufficient. Using a storage battery along with a supercapacitor in the diesel locomotive start-up system is most effective. This reduces the peak current load on the standard battery. The article suggests an effective principle for starting a mainline diesel locomotive and provides an effective circuit solution involving a supercapacitor. Based on the booster stabilizer scheme, a new scheme was modeled to study the successful launch of a diesel locomotive that has various start-up systems. Applying a supercapacitor in the start-up system of a main diesel locomotive is proposed and the results of its use are presented. In addition, this study defines the basic requirements for using a system based on a battery in conjunction with a supercapacitor. Characteristics such as the temperature range of the system are shown.

Theory of Doubly-Shielded Coupled Lines for Directional Couplers of Various Directivity Types With Impedance Transformation

Asymmetric coupled lines (CLs) with double shielding in an inhomogeneous dielectric medium are studied. They have specific properties that allow the creation of impedance-transforming directional couplers with a given directivity type. The proposed models and synthesis techniques take into account both electric asymmetry and dielectric inhomogeneity. Numerical simulations and measurements prove the correctness of the general theory, and the possibility of creating co-, contra-, and trans-directional couplers with impedance-transforming and phase-shifting properties. The results will be useful for finding new design solutions for next-generation microwave circuits.

Transmission line characterization and modeling for electronic circuits and systems design

Channel bandwidth-limited high-speed links or interfaces make circuit solutions not efficient. Both recent and subsequent links (SerDes-Serializer/Deserializer) design demand efficient and effective coupling between future circuit design, communication, and optimization. The challenges vary and new solutions are needed. In this article, an analytical wireline model is presented to predict electronic path loss towards adequate designs of electronic circuits and systems. An open loop system analysis is adapted in this paper. Our model was tested against different channels: a legacy channel with via stub discontinuity and FR4 dielectric, and a more recent microwave-engineered channel without stub and NELCO 6,000 dielectric, a very good matching attained. Good agreement was observed between our model and electromagnetic full-wave simulation data, as a result showed high level of applicability to thin-film microstrip line for adequate circuit design. The model is recommended for electronic engineers for adequate and faster interfaces and high-speed links designs.

Assessing the Efficiency of Circuit Solutions for LNG-Fueled GTP-Based Cogeneration Plants

Assessing the Efficiency of Circuit Solutions for LNG-Fueled GTP-Based Cogeneration Plants

Overview about E-Mobility Conducted Immunity Tests on ESA Communication Lines

Due to the complexity of the Automotive Electromagnetic Compatibility legislation in force, this article aims to describe a simplified overview of several technical standards relating to conducted immunity tests on electronic sub-assemblies, where communication lines are involved. The discussed automotive standards reported in this article are: ISO 11452-1 and ISO 11452-4 for continuous narrowband electromagnetic fields immunity test, bulk current injection and tubular wave coupler, IEC 61000-4-5 for immunity against surge events, IEC 61000-4-4 for electrical fast transient/burst events immunity, ISO 10605 for electrostatic discharge events immunity, ISO 7637-2 and ISO 7637-3 for transient disturbances events immunity. For each cited standard, disturbance bandwidth evaluation was performed. Practical examples are reported, with analysis and discussion of some of the adoptable disturbance countermeasures applicable on controlled area network communication lines, and possible design advantages and disadvantages with different types of filtering and suppression circuit solutions.

USE OF ORDINARY DIFFERENTIAL EQUATIONS APPLIED TO MECHANICAL AND ELECTRICAL PROBLEMS WITH FIRST ORDER LINEAR SYSTEMS

In recent years there has been an increased interest in the study of mathematics applied to engineering to study aspects of its teaching. In the present research work, a compilation of analytical concepts of differential equations applied to the solution of problems of electrical circuits, a branch of electrical engineering and mechanical engineering problems, specifical problems of spring-mass mechanical systems, through the description of the analytical solutions of direct current electrical circuits and spring-mass mechanical systems, applying differential equations. This method stands out among the diverse mathematical treatments used to solve this type of engineering problem, both for its demonstrative elegance and capacity to offer a total answer. Likewise, practical engineering examples related to the studied subject were presented and the results were obtained and analyzed by using the mathematical software, Wolfram Mathematica.

Selective Light Measurement in the Control of Reference LED Sources.

This paper describes an original adaptive multispectral LED light source that utilizes miniature spectrometer to control its flux in real time. Current measurement of the flux spectrum is necessary in high-stability LED sources. In such cases, it is important the spectrometer work effectively with the system that controls the source and the whole system. Therefore, as important as flux stabilization is the integration of the integrating sphere-based design with the electronic module and power subsystem. Since the problem is interdisciplinary, the paper mainly focuses on presenting the solution of the flux measurement circuit. In particular, the proprietary way of operating the MEMS optical sensor as a real-time spectrometer was proposed. Then, the implementation of the sensor handling circuit, which determines the spectral measurements accuracy and thus the output flux quality, is described. Also presented is the custom method of coupling the analog part of the flux measurement path with the analog-to-digital conversion system and the control system based on the FPGA. The description of the conceptual solutions was supported by the results of simulation and laboratory tests at selected points of the measurement path. The presented concept allows to build adaptive LED light sources in the spectral range from 340 nm to 780 nm with adjustable spectrum and flux value, with electrical power up to 100 W, with adjustable flux value in the range of 100 dB, operating in constant current or pulsed mode.

A universal model of three-phase asynchronous motors for electrical power system analysis

<p><span lang="EN-US">The high incidence of three-phase asynchronous motors (TAM) in global energy consumption and its influence on the operation of electrical systems makes it necessary to develop models that allow their analysis effectively. Based on this, this paper presents a universal model of TAM based on the relationship between the active and reactive power of the TAM and the deviation of voltage and frequency. It can be applied to any general-purpose TAM and is very useful when representing these motors in electrical power system studies. The model parameters were obtained from a statistical analysis performed on 70 TAM of different classifications. The results are validated by comparing them with those obtained from the solution of the equivalent circuit, demonstrating its validity by less than 6% errors.</span></p>

Increasing the energy efficiency of modes of distribution networks with photovoltaic stations

Purpose. Establishing the regularities of changes in influence of power quality indicators caused by the operating modes of photovoltaic (PV) station inverters on the operating modes of distribution networks’ equipment to improve their energy efficiency by reducing power losses. Methodology. To solve the scientific problems, the following methods are used such as: the method of harmonic analysis (Fourier integral); decomposition of the current spectrum by amplitude-frequency component using Mdaq-14 hardware and software platforms and LabVIEW software; the method of data correlation analysis to determine the higher harmonic current dependence on the load of an on-grid inverter; mathematical and physical modeling in the development of a way to improve the energy efficiency of on-grid inverters of PV stations. Findings. The conducted studies on electromagnetic compatibility indicators of grid photovoltaic station inverters in stationary and dynamic operation modes made it possible to establish the characteristic regularities of changes in the spectrum and amplitudes of higher harmonic components depending on the level of inverter loading. Hyperbolic dependences of the change in the sinusoidal signal distortion coefficients of the harmonic component on the level of inverter loading were experimentally established. A method has been developed for reducing the electromagnetic interference levels caused by photovoltaic station converters by implementing a circuit solution and algorithm for loading on-grid inverters in non-stationary modes in order to improve their electromagnetic compatibility and increase the energy efficiency of distribution networks with appropriate decentralized sources. Originality. The regularities are established of influence of the operating mode’s parameters of photovoltaic station inverters on the indicators of electromagnetic compatibility in their power supply system, including taking into account special circuit solutions, which allows increasing the energy efficiency of distribution network modes. Practical value. The method for reducing the electromagnetic interference levels generated by photovoltaic station inverters by implementing the proposed circuit solution and algorithm for loading the on-grid inverters in non-stationary modes is universal and can be applied to any photovoltaic station. This will help to reduce the power losses and electromagnetic damage to equipment from the action of higher harmonic components. Granting the established regularities of higher harmonics influence will allow one to take into account the impact of the relevant indicators on the additional insulation heating of power supply system elements and to assess the corresponding electromagnetic damage, to provide recommendations for consideration of the modes in calculating methods and PV equipment selection.

A Two-Step Approach for the Analysis of Bulk Current Injection Setups Involving Multiwire Bundles

In this work, a two-step procedure to predict maximum (worst-case scenario) and minimum (best-case scenario) noise levels induced by bulk current injection (BCI) at the terminal sections of a wiring harness is presented. To this end, common mode (CM) and differential mode (DM) quantities are introduced by a suitable modal transformation, and equivalent modal circuits are derived, where CM (dominant mode) into DM (secondary mode) conversion is modelled by induced sources included into the DM circuit. The procedure initially foresees the solution of the CM circuit to provide input data for subsequent solution of the DM circuit. Such a two-step approach is then used to develop a probabilistic–possibilistic framework for computationally-efficient estimation of lower and upper boundaries to the variability of the noise voltages induced at the bundle terminations. To this end, random uncertainty affecting certain setup parameters is addressed through probability theory, whereas epistemic uncertainty is represented via possibility theory. Accuracy and computational efficiency of the proposed two-step method are assessed by examples involving seven and nineteen wire harnesses.

Analysis of the Energy Efficiency of the Air Conditioning System Based on Absorption Refrigeration Machine with Connection of Heat Pump and Solar Collectors

This article proposes and analyzes a circuit solution for providing heat supply to the generator of an absorption refrigeration machine (AHM) in centralized air conditioning systems using a heat pump unit (HPU) and solar collectors (SOL). Previously, such schemes have already been considered in the scientific works of Russian and foreign authors. The aim of the work is to propose new circuit solutions aimed at improving such systems, as well as confirming higher energy efficiency. This goal is achieved by solving the following problems: additional supply of the circuit with a common storage tank, operation of the absorption refrigeration machine generator and the condenser of the heat pump unit based on a common heat exchanger. Such a solution for the air conditioning complex based on an absorption refrigeration unit has been proposed for the first time. The most important results are the possibility of obtaining high values of the coefficient of performance, the possibility of achieving a number of technological advantages, increasing reliability and efficiency, as well as reducing the metal consumption of an absorption-type plant operating from solar collectors and a heat pump plant compared to similar systems. The significance of the obtained results lies in the fact that the use of a common storage tank and a combined heat exchanger (AHM generator / HPU heater) provides a significant increase in the coefficient of performance, a decrease in the metal consumption (reduction in costs) of the main equipment.

ОПРЕДЕЛЕНИЕ ТЕПЛОПОСТУПЛЕНИЙ ОТ ЧЕЛОВЕКА С УЧЕТОМ ЭНЕРГОТРАТ И ФИЗИЧЕСКОЙ АКТИВНОСТИ

The analysis of the current regulatory documents and reference and methodological literature used in carrying out calculations related to the determination of heat emissions from people engaged in various types of work is carried out. The incomplete correspondence of the values of heat emissions to the characteristics of the severity of the work performed for various types of activities, taking into account the age of people with their physique corresponding to normal body weight, was revealed. The calculated values of the coefficient of physical activity for a conditional person, as well as the values of heat emissions of men with their division by age categories, are determined. The graphs of energy expenditure for men of different ages performing the following types of work are presented: light (Ia, Ib), moderate (IIa, IIb), heavy. The obtained values of energy consumption are compared with the data of regulatory documents and reference literature for various categories of work. The relevance and necessity of taking into account data on heat emissions from people, taking into account their age, anthropometric parameters and other conditions when designing microclimate systems, including personal and adaptive ventilation systems, is shown. The results of the study will be useful to design engineers implementing circuit solutions of microclimate systems that provide comfortable parameters of the air environment in rooms for various purposes.

ОПРЕДЕЛЕНИЕ ТЕПЛОПОСТУПЛЕНИЙ ОТ ЧЕЛОВЕКА С УЧЕТОМ ЭНЕРГОТРАТ И ФИЗИЧЕСКОЙ АКТИВНОСТИ

The analysis of the current regulatory documents and reference and methodological literature used in carrying out calculations related to the determination of heat emissions from people engaged in various types of work is carried out. The incomplete correspondence of the values of heat emissions to the characteristics of the severity of the work performed for various types of activities, taking into account the age of people with their physique corresponding to normal body weight, was revealed. The calculated values of the coefficient of physical activity for a conditional person, as well as the values of heat emissions of men with their division by age categories, are determined. The graphs of energy expenditure for men of different ages performing the following types of work are presented: light (Ia, Ib), moderate (IIa, IIb), heavy. The obtained values of energy consumption are compared with the data of regulatory documents and reference literature for various categories of work. The relevance and necessity of taking into account data on heat emissions from people, taking into account their age, anthropometric parameters and other conditions when designing microclimate systems, including personal and adaptive ventilation systems, is shown. The results of the study will be useful to design engineers implementing circuit solutions of microclimate systems that provide comfortable parameters of the air environment in rooms for various purposes.

Overview on Latch-Up Prevention in CMOS Integrated Circuits by Circuit Solutions

In CMOS chips, the wider layout rules were traditionally applied to overcome latch-up issues. However, the chip area with wider layout rules was often enlarged, and in turn the chip cost was also increased. To effectively improve latch-up immunity without enlarging the chip area, circuit methods were therefore invented. An overview on circuit methodology used to prevent latch-up issues in CMOS integrated circuits (ICs) is presented in this article. The circuit solutions, including reducing the I/O pad trigger current, sensing the trigger current to control the power supply, and restarting the power supply through an MOS switch to shut off the latch-up current, are overviewed.

N-кратное расщепление явной разностной схемы для уравнения вихря в вязкой несжимаемой жидкости

This work is the first to consider the possibility of N-fold (n=100,200) splitting of an explicit difference scheme for the vortex equation in the system of equations of a hydrodynamic problem in a rectangular cavity with a viscous incompressible fluid and with the Reynolds number Re=1000. The algorithm proposed in the work allows us to significantly increase the maximum time step per iteration of the general problem and reduce the total calculation time by tens to hundreds of times. The splitting algorithm for the vortex equation explicit difference scheme is effective if the time spent by the program on the splitting cycle is many times less than the general problem on one iterationsolving time. It is shown numerically that the solution without splitting qualitatively coincides with the solution of the split circuit (match to five significant figures). In this case, the solution to the problem without splitting is not completely steady (the first five significant digits are constant in time after 400000 iterations). It is shown numerically that two-layer and three-layer explicit difference schemes have steady-state solutions with fields matching in 11-12 significant signs at each node of the computational grid (velocity, vortex, stream function) after 21000 iterations.

Analysis and optimization of acceleration model in coaxial plasma gun in pre-fill mode

Snowplow model is the main method to describe the acceleration process of coaxial plasma gun in the pre-fill mode, which can directly give the analytical expression of plasma velocity versus time. So it has become an important reference in designing the device structures satisfying the requirements for different applications. Through measuring the current, magnetic and optical signals, the characteristics of current during the discharge and the motion of plasmoid are investigated. The variation of discharge current with time is close to the damping sine curve, which is an underdamping solution of RLC equivalent discharge circuit. The measured current in lieu of the sine one is used to calculate the theoretical velocity so as to eliminate the error of magnetic pressure. The variation of plasma velocity with discharge voltage and chamber pressure are consistent with those obtained by solving the equation of plasma motion under snow plough model, but the acceleration process is another story. At the initial stage of the discharge, owing to the low sweep efficiency, the plasma is accelerated to a higher velocity than the predicted one, the increase of voltage and the decrease of pressure further enhance the effect. With the extension of the acceleration distance, owing to the friction resistance between plasma and electrodes, the acceleration slows down and the velocity starts to fall below the predicated value, the saturation of plasma velocity at the nozzle is found. The friction resistance term is added to the equation of plasma motion. Compared with the deviation range of 26.8%–53.6% of the existing model, the differences between the theoretical speed and the measured speed under different voltages and pressures are in a range of 3.1%–8.4% after adding the friction resistance term into the equation of plasma motion. The optimization of snow plow model greatly improves the accuracy of velocity prediction, which can provide an effective reference for designing device structure and calculating energy efficiency.

Prospects and tasks of sound vision application for diagnostics and visualization of cavitation and turbulent flows in medium and large diameter fittings

The possibility of using sound vision to solve the problems of visualization and diagnostics of caviation and turbulent flows arising during the operation of pipeline valves is considered. The available methods of realization of sound vision are analyzed. A block diagram with the reconstruction of a holographic image is proposed. The diagram could visualize the picture of the cavitation flow. It is shown that it is most promising to develop such circuit and technical solutions that could form a complete picture of the flow in dynamics with the ability to digitize it for further analysis.

Схемотехнические решения помехоустойчивого регулятора оборотов бесщеточного электродвигателя беспилотного воздушного судна

The article is devoted to the features of the circuit solutions development for noise-resistant electronic speed controllers of brushless electric motors for unmanned aircraft. It analyzes the operating features, that allowed to formulate the technical requirements for a whole class of devices. When analyzing the state-of-the-art, it was concluded that the development of a solution with full program control is highly relevant. The basic principles for controlling a brushless electric motor, recommended for constructing a regulator, are presented. As a practical solution, a structural and circuit diagram has been developed describing the operation of the main elements. In the conclusion, the practical results of testing this regulator are considered. The assessment at the current stage is provided, as well as the ways to improve and develop the regulator in the near future.

ИССЛЕДОВАНИЕ ПОВЫШАЮЩЕГО ПРЕОБРАЗОВАТЕЛЯ ПОСТОЯННОГО НАПРЯЖЕНИЯ НА БАЗЕ МНОГОФУНКЦИОНАЛЬНОГО ИНТЕГРИРОВАННОГО ЭЛЕКТРОМАГНИТНОГО КОМПОНЕНТА

The relevance The methods of functional integration of discrete electrical and electromagnetic components allow increasing the reliability and efficiency of electrical energy conversion systems, reducing their weight and dimensions. The authors proposed a circuit solution based on the replacement of some individual discrete components of a DC boost converter with a multifunctional integrated electromagnetic component (MIEС). The component performs the functions of an inductor and a filter capacitor. Aim of research This article discusses the investigation of a DC voltage booster converter based on a multifunctional integrated electromagnetic component. The main task is to investigate a DC voltage booster converter based on a multifunctional integrated electromagnetic component. Research methods In this study, the following methods were used: the study of scientific literature and computer simulation in the Matlab environment. Results A computer model of a step-up DC voltage converter based on MIEС in the Circuit Simulator software package has been developed. Graphs of the output voltage are obtained. The circuits of step-up DC voltage converters are analyzed. A circuit of a DC voltage boost converter based on MIEС has been assembled. Output voltage waveforms were taken. An analysis of the computer model and laboratory test sample was carried out. A set of works has been completed to improve the output characteristics of a step-up converter based on MIEС. The optimal scheme has been chosen to implement the replacement of the inductor and filter capacitor with a multifunctional integrated electromagnetic component. Conducted laboratory studies confirmed the operability of MIEС as a replacement for individual discrete components of the DC voltage boost converter circuit. The optimal mode of operation of the boost converter based on MIEС is determined, which makes it possible to expand the output voltage range and reduce ripples. Expansion of the output voltage range is feasible due to the near-resonant or resonant mode of operation of the converter, which is feasible due to the MIEС structure, which is a resonant LC circuit.

OPTICAL-ELECTRONIC SYSTEM OF HIGH SPATIAL RESOLUTION WHEN OBSERVING REMOTE OBJECTS

Schematic solutions of an optoelectronic system for obtaining high spatial resolution when observing remote objects are studied, which allow obtaining high resolution of objects in the volume of the observed space, providing high accuracy in determining the coordinates and geometric features of objects in three-dimensional space. A hybrid system is considered for simultaneous registration of the entire set of rays from observed objects in a full solid angle by a high-resolution optical system together with a system for registering sets of different sets of ray directions from objects in the same observed space, which makes it possible to form a set of narrow layers of the observed space in range. To further improve the accuracy of obtaining coordinate and non-coordinate information of the observed objects, the images of narrow layers of space are expanded to the resolution of the first optical registration system by weighted substitution of the detail filters of the discrete wavelet transform. Integration in different digital information ranges is achieved by decomposing the image of the first digital source and each of the set of images of the second digital source into low-frequency and high-frequency components, separate processing of image components based on the principle of weighted summation for each pixel, and the formation of the resulting image. Computational experiments have been carried out showing the effectiveness of the proposed circuit solutions in determining the parameters of objects of interest.