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Дисертації з теми "621.314.22"
Говоров, Владлен Пилипович. "Підвищення ефективності розподільчих мереж міст в умовах слабкої кореляції графіків навантажень та нелінійності характеристик електроприймачів". Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21845.
Повний текст джерелаThe thesis for the degree of candidate of technical sciences, specialty 05.14.02 - "Electric stations, networks and systems." National Technical University “Kharkiv Politechnical Institute”, Kharkiv 2016. The thesis is devoted to increased efficiency of electrical distribution networks of cities in terms of nonlinearity characteristics at the project level. The paper based on the study of modes of electrical distribution networks by the methods of physical and mathematical modeling peculiarities modes of electrical distribution networks of cities that are in large size reactive power and low correlation graph of change to the schedule of active power and large size of noise and distortion in networks. According to the research of energy processes in electrical distribution networks of cities proved that with the huge level of noise and distortion reactive power distortion is the dominant influence on modes of electrical networks and the necessity of separate accounting shift reactive power and reactive power distortion. Based on the study parameters and modes voltododavalnyh transformers installed the opportunity to integrated solutions and solved on the basis of voltage control and reactive power compensation in networks.
Говоров, Владлен Пилипович. "Підвищення ефективності розподільчих мереж міст в умовах слабкої кореляції графіків навантажень та нелінійності характеристик електроприймачів". Thesis, Харківський національний університет міського господарства ім. О. М. Бекетова, 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21852.
Повний текст джерелаThe thesis for the degree of candidate of technical sciences, specialty 05.14.02 - "Electric stations, networks and systems." National Technical University “Kharkiv Politechnical Institute”, Kharkiv 2016. The thesis is devoted to increased efficiency of electrical distribution networks of cities in terms of nonlinearity characteristics at the project level. The paper based on the study of modes of electrical distribution networks by the methods of physical and mathematical modeling peculiarities modes of electrical distribution networks of cities that are in large size reactive power and low correlation graph of change to the schedule of active power and large size of noise and distortion in networks. According to the research of energy processes in electrical distribution networks of cities proved that with the huge level of noise and distortion reactive power distortion is the dominant influence on modes of electrical networks and the necessity of separate accounting shift reactive power and reactive power distortion. Based on the study parameters and modes voltododavalnyh transformers installed the opportunity to integrated solutions and solved on the basis of voltage control and reactive power compensation in networks.
Василевський, Володимир Валентинович. "Прогнозування строку служби силового трансформатора за допомогою комплексної моделі технічного стану целюлозної ізоляції". Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/39553.
Повний текст джерелаThesis for granting the Degree of Candidate of Technical sciences in speciality 05.09.01 – Electric machines and apparatus. – National Technical University "Kharkiv Politechnical Institute", 2019. The thesis is dedicated to the improvement of mathematical models for forecasting the residual lifetime of a power transformer and the feasibility study of its maintenance strategy by developing a complex model of cellulose insulation technical condition. The complex model of the cellulose insulation technical condition, which consists of a mathematical model of the transformer's real resource formation at the stage of its production and a model of the resource consumption of the power transformer's cellulose insulation during the exploitation phase, is proposed. The mathematical model of water exchange in the system of cellulose insulation - transformer oil in the interrelation with other mathematical models, describing the condition of the transformer in exploitation is developed. The analysis of the effect of maintenance of power transformer (in particular, drying of the active part) on the characteristics of cellulose insulation is carried out. The transformer resource consumption modeling for different maintenance strategies is executed. The simulation justified the need to take into account the maintenance in the calculations of the residual resource and the modeling of the insulation resource consumption in operation. The calculation method for determining the reduction of insulation's lifetime was further developed by adjusting the known formula of the integral of aging by more accurate interpolation of the original data used to construct the dependence of the rate of aging on the moisture content of the insulation. For the first time, mathematical models for assessing the influence of the production stage on the assigned resource, which differ by the imperfection of control and stochasticity of the process of resource change during the technological process, are proposed.
Краснов, Олексій Олександрович. "Активний тяговий перетворювач для електровозів змінного струму з колекторними тяговими двигунами". Thesis, Національний технічний університет "Харківський політехнічний інститут", 2020. http://repository.kpi.kharkov.ua/handle/KhPI-Press/48911.
Повний текст джерелаThesis for candidate degree of technical sciences of speсialty 05.22.09 — Electric transport. Joint-Stock Company “Ukrainian zaliznytsia”, Branch “Design and survey institute of railway transport”, Ministry of Infrastructure of Ukraine, National Technical University “Kharkiv Polytechnic Institute”, MES of Ukraine. Kharkiv, 2020. The dissertation is devoted to the actual scientific and technical problem of increasing the energy efficiency of the AC electric locomotives with DC traction motors due to the improvement of traction converters. The basis of the park of freight and passenger AC electric locomotives of “Ukrzaliznytsya” are electric locomotives with DC traction motors. Such electric locomotives have a relatively low power factor. For electric locomotives with diode rectifiers (VL80K, VL80T) its value is 0.65...0.85, and for electric locomotives with thyristor converters (2ES5K, 2EL5) — 0.3...0.84. The aggregate of the energy defects of the electromotive force and traction power causes a relatively low power factor of the AC electrified railways — about 0.7, while according to modern world standards the power factor is not lower than 0.95. Therefore, increasing the energy efficiency of the traction load is an urgent task. Today, Ukrainian, Russian and foreign specialists have developed a number of technical solutions that provide an increase in the power characteristics of electric locomotives. These solutions can be conventionally grouped into three groups: 1) improved schemes of traction converters and control algorithms; 2) passive and active reactive power compensators installed on the electric locomotives; 3) converters on fully controlled semiconductor devices (active converters). Despite the high energy characteristics of the active converters, investigations of the operation modes of such converters with DC traction motors, today is not enough. Consequently, further development of this research direction can be considered relevant. The base element of the converter for DC motor is a single-phase active current source rectifier. In the paper a mathematical description of the active current source rectifier in the rectifier and inverter modes is obtained. On the basis of the mathematical apparatus of logic algebra, a unified description of pulse-width modulation algorithms with sinusoidal, trapezoidal, and rectangular-step modulation signals is obtained. Investigation of electromagnetic processes and the comparison of the energy characteristics of the active current source rectifier with selected PWM algorithms and modulation frequencies of 900 Hz, 1,200 Hz and 1,800 Hz is carried out by simulation in MATLAB. Studies have shown that for all three algorithms, at a modulation index of 0.2...1.0, the input power factor of the active current source rectifier is 0.6...0.99 regardless of the modulation frequency. The power circuit with two-zone regulation of DC voltage and the control algorithm of the active traction converter of the electric locomotive are proposed. The use of rectangular-stepped PWM with a modulation frequency of 1,200 Hz has been substantiated. The regulation of the DC voltage with a modulation index of less than 0.5 is used only in short-term operating modes. A mathematical model of the AC electric traction system (25 kV, 50 Hz) was developed, taking into account two variants of the traction converter — a thyristor and active converter with pulse-width modulation. From the point of view of modeling of converters control systems, the developed model is universal because on the basis of logic functions of pulse formation and distribution a unified mathematical description of algorithms of thyristor control and active traction converter is developed. This model is implemented in MATLAB. Computer simulation of electromagnetic processes in the “traction network — electric locomotive” system has allowed to investigate the energy efficiency of an electric locomotive with an active traction converter. So, the power factor is 0.839...0.991, and its value is more than 0.9 provided with a modulation index of more than 0.5. In nominal mode, the power factor of an electric locomotive with an active traction converter is 19.4 % higher than that of an electric locomotive with a thyristor converter. The THD of the contact wire voltage of the electric locomotive with the active traction converter in the whole range of regulation varies within the range of 3...11 %, and the THD of the contact wire current is within the range of 9...17 %. When changing the distance from the electric locomotive to the traction substation in the range 0...10 km, the THD of contact wire voltage in nominal mode is 5...9 %. The virtual experiments showed that the active traction converter is the source of a wide spectrum of voltage and current harmonics. The least advantageous is the mode with a modulation index of 0.5...0.6. The results of harmonic analysis allowed to establish characteristic groups of harmonics, which basically determine the nonsinusoidal form of the of voltage and current waveforms. Therefore, in further research works of the active traction converter we must focus on correction of the voltage and current waveforms. In general, the results of the research showed that the active traction converter have higher energy characteristics than traditional rectifiers based on diode and thyristor schemes.
Краснов, Олексій Олександрович. "Активний тяговий перетворювач для електровозів змінного струму з колекторними тяговими двигунами". Thesis, Національний технічний університет "Харківський політехнічний інститут", 2020. http://repository.kpi.kharkov.ua/handle/KhPI-Press/48908.
Повний текст джерелаThesis for candidate degree of technical sciences of specialty 05.22.09 — electric transport. — Joint-Stock Company “Ukrainian zaliznytsia”, Branch “Design and survey institute of railway transport”, Ministry of Infrastructure of Ukraine, National Technical University “Kharkiv Polytechnic Institute”, MES of Ukraine. Kharkiv, 2020. Active rectifiers are one of the effective ways to increase the power factor on AC electric locomotives with DC traction motors. In this thesis, the mathematical description of the active current source rectifier with DC motor is improved. The analysis of the active rectifier energy efficiency with a sinusoidal, trapezoidal and rectangular-stepped pulsewidth modulation (modulation frequency 900 Hz, 1,200 Hz and 1,800 Hz) is performed. The power circuit of the active traction converter with two-zone DC voltage regulation and the algorithm for controlling transistors in traction and recuperation modes has been developed. The results of computer simulation showed that the active traction converter can provide a high power factor of electric locomotive (0.83...0.99). The trolley wire current THD is 9...17%, which is less than with a thyristor converter. This reduces the consumption of electricity for traction.
Лобко, Андрій Валерійович. "Енергозберігаючі напівпровідникові перетворювачі для перспективних систем електропостачання". Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/22721.
Повний текст джерелаDissertation on competition degree of candidate of technical sciences of speсiality 05.09.12 – Semiconductor converters of electric energy. – National Technical University "Kharkov Politechnical Institute", Kharkov, 2016. Dissertation is devoted to development of high-performance and energy-saving semiconductor converters for applications in new and perspective power systems. Developed semiconductor converter with phase control method for forwardlooking FREEDM electrical system is presented. It is shown that that converter performs the same functions available in the converter of this system and allows to obtain the best energy performance by reducing switching loss using soft switching at the fundamental frequency 50 Hz. It is demonstrated that the proposed phase control method is based on the symmetric detuning of the resonance and the introduction of a controlled phase shift between the voltages at the input of the power semiconductor switch and the AC mains. In the dissertation a method of calculating the basic converter settings is proposed. The quality of his work is analyzed. With the help of computer simulations single and three phase converter circuit in different operating modes are studied. The methods of protection from emergency modes are proposed. Experimental studies on the physical model confirmed the accuracy of the theoretical results.
Лобко, Андрій Валерійович. "Енергозберігаючі напівпровідникові перетворювачі для перспективних систем електропостачання". Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/22720.
Повний текст джерелаDissertation on competition degree of candidate of technical sciences of speсiality 05.09.12 – Semiconductor converters of electric energy. – National Technical University "Kharkov Politechnical Institute", Kharkov, 2016. Dissertation is devoted to development of high-performance and energy-saving semiconductor converters for applications in new and perspective power systems. Developed semiconductor converter with phase control method for forwardlooking FREEDM electrical system is presented. It is shown that that converter performs the same functions available in the converter of this system and allows to obtain the best energy performance by reducing switching loss using soft switching at the fundamental frequency 50 Hz. It is demonstrated that the proposed phase control method is based on the symmetric detuning of the resonance and the introduction of a controlled phase shift between the voltages at the input of the power semiconductor switch and the AC mains. In the dissertation a method of calculating the basic converter settings is proposed. The quality of his work is analyzed. With the help of computer simulations single and three phase converter circuit in different operating modes are studied. The methods of protection from emergency modes are proposed. Experimental studies on the physical model confirmed the accuracy of the theoretical results.
Стисло, Богдан Олександрович. "Напівпровідникові перетворювачі для систем з накопичувачами електричної енергії". Thesis, НТУ "ХПІ", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37176.
Повний текст джерелаDissertation for the degree of candidate of technical sciences (doctor of philosophy) in specialty 05.09.12 "Semiconductor power converters" (17 – Electronics and telecommunications). – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2018. The dissertation is devoted to solving an important scientific and technical problem – the study of operation of semiconductor converters with electric energy storage systems. It is determined that one of the perspective directions of scientific work in this branch is the research and development of the operating modes of energy efficient converters working in conjunction with the battery energy storage systems (BESS). It is shown that the use of BESS in power supply systems requires the use of specialized energy-efficient converters. These converters are divided into matching converters, to provide connection BESS with the mains, and service converters that ensure safe operation mode of BESS. For service converters the analysis of the existing systems of balancing of series-connected batteries is made. The advisability of using the active balancing of storage batteries is justified. The energy efficiency of the use of capacitive and inductive buffer elements in active balancing converters is determined. The expediency of using transformer circuits of active balancing is proved. The principle of addressable transfer of the energy be-tween the series connected batteries was proved. It is proved that this system allows in-creasing the efficiency of the balancing process due to the redistribution of missing and surplus energy between the batteries. The implementation of the control system of the addressable balancing system of the prediction type is proposed. It allows to obtain the main parameters of each of the series-connected electrical energy storage devices using a single voltage sensor. It is proved that optimization of the process of balancing by the criterion of energy efficiency allows to further improve the energy performance of the system, reducing static losses in power switches at each stage of balancing up to 70%. Synthesis of the structural scheme of a two-channel additional power source is performed. The possibility of using one low-frequency filter in the control system of two-channel BESS is proved. It generates control signals for matching converters, for servicing both low-frequency and high-frequency channels of BESS. Based on the analysis of switching processes in power switches of matching converters, the expediency of using separated-commutation converters that provide soft switching modes in semiconductor switches is proved. Four variants of realization of the matching converter are developed. On the basis of the techno-economic justification, the optimal converter circuit was chosen. A control system which implements the separated commutation algorithm for a matching converter is proposed. The realization of the fixed and variable time intervals between the control pulses of the power switches is assigned to the digital control system hardware. The algorithm of the control system operation, using the minimum number of sensors is proposed. Proposed algorithm allows to take into account the parameters of the load.
Стисло, Богдан Олександрович. "Напівпровідникові перетворювачі для систем з накопичувачами електричної енергії". Thesis, НТУ "ХПІ", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37175.
Повний текст джерелаDissertation for the degree of candidate of technical sciences (doctor of philosophy) in specialty 05.09.12 "Semiconductor power converters" (17 – Electronics and telecommunications). – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2018. The dissertation is devoted to solving an important scientific and technical problem – the study of operation of semiconductor converters with electric energy storage systems. It is determined that one of the perspective directions of scientific work in this branch is the research and development of the operating modes of energy efficient converters working in conjunction with the battery energy storage systems (BESS). It is shown that the use of BESS in power supply systems requires the use of specialized energy-efficient converters. These converters are divided into matching converters, to provide connection BESS with the mains, and service converters that ensure safe operation mode of BESS. For service converters the analysis of the existing systems of balancing of series-connected batteries is made. The advisability of using the active balancing of storage batteries is justified. The energy efficiency of the use of capacitive and inductive buffer elements in active balancing converters is determined. The expediency of using transformer circuits of active balancing is proved. The principle of addressable transfer of the energy be-tween the series connected batteries was proved. It is proved that this system allows in-creasing the efficiency of the balancing process due to the redistribution of missing and surplus energy between the batteries. The implementation of the control system of the addressable balancing system of the prediction type is proposed. It allows to obtain the main parameters of each of the series-connected electrical energy storage devices using a single voltage sensor. It is proved that optimization of the process of balancing by the criterion of energy efficiency allows to further improve the energy performance of the system, reducing static losses in power switches at each stage of balancing up to 70%. Synthesis of the structural scheme of a two-channel additional power source is performed. The possibility of using one low-frequency filter in the control system of two-channel BESS is proved. It generates control signals for matching converters, for servicing both low-frequency and high-frequency channels of BESS. Based on the analysis of switching processes in power switches of matching converters, the expediency of using separated-commutation converters that provide soft switching modes in semiconductor switches is proved. Four variants of realization of the matching converter are developed. On the basis of the techno-economic justification, the optimal converter circuit was chosen. A control system which implements the separated commutation algorithm for a matching converter is proposed. The realization of the fixed and variable time intervals between the control pulses of the power switches is assigned to the digital control system hardware. The algorithm of the control system operation, using the minimum number of sensors is proposed. Proposed algorithm allows to take into account the parameters of the load.
Миколаєць, Дмитро Анатолійович. "Фільтро-компенсуючий перетворювач в системі гарантованого електроживлення". Doctoral thesis, Київ, 2015. https://ela.kpi.ua/handle/123456789/17617.
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