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Section 1. Power and Industrial Electronics
https://us02web.zoom.us/my/khpiweek2022.1
Access code: KhPIWeek
14:00 | ABSTRACT. Purpose. The aim of this work is to compare the effectiveness of various methods for correcting cell failures in cascade high voltage frequency converters. These methods provide the smallest voltage drop on the motor, the least loads and oscillation of electromagnetic torque in an accident modes, and evaluate the effectiveness of pulse width modulation (PWM) methods with the injection of third harmonic and space-vector PWM in normal and emergency modes. Methodology. We use mathematical and geometrical interpretation of all analysed methods – Sinusoidal PWM (SPWM), Balanced sinusoidal PWM (BSPWM), Balanced PWM with injected 3rd harmonic (THPWM) and Balanced Space Vector PWM (SVPWM). Results. The method of balancing the phase-to-phase voltages by to such a shift of the zero point and rotation of the phase vectors, in which the amplitude of the phase-to-phase voltage decreases to the minimum possible value. Injection of the 3rd harmonic allows you to further increase the utilisation factor of power supplies in terms of voltage. But the violation of the symmetry of the phase voltages leads to the need to reduce the voltage amplitude to exclude saturation of the power supplies, which reduces this coefficient compared to the theoretically possible 15.6%. A distinctive feature of the method of balanced Space Vector PWM is that the amplitude of the 1st harmonic is always greater than the radius of the circle by 15.6%. Comparison of methods of space vector PWM (SVPWM), balancing of phase-to-phase voltage with the injection of the 3rd harmonic (THPWM) with sinusoidal PWM shows that SVPWM is the best method. Despite the more complex mathematical software for the implementation of this method, it provides the best performance in all considered emergency modes of 3…6 cascade converters. The Table of indicators for all methods are presented in the article. The use of a balanced SVPWM in combination with field oriented control makes it possible to obtain an electric drive in which, in the event of an accident, there are practically no shock mechanical and electromagnetic processes. After damage of cells the currents, electromagnetic torque and motor speed change along the required trajectory. |
14:15 | Adequacy and Robustness Analysis of the Capacitive Moisture Meters’ Static Function ABSTRACT. Moisture content takes a special place among food quality factors as a parameter that changes during the processes of storage and processing, and, in many cases, determines consumer properties of different food products. Modern grain moisture meters’ uncertainty is restricted to not more than 3 % of relative full scale error. Main task of the research is to receive robust linear static function for the grain moisture meter with four capacitive sensors. Robustness of new static function had been checked with a help of dispersion analysis. It was possible to conclude that values of repeatability and adequacy dispersions for new linear static function are approximately three times smaller, so as F-test values are seven times smaller in comparison with initial static function of a moisture meter, what proves its’ better robust properties |
14:30 | Research of microprocessor system by methods of statistical analysis ABSTRACT. The paper considers the solution of the scientific and practical problem of assessing the accuracy and stability of the sensors working as part of the microprocessor control system for the parameters of the microclimate of an artificial ecosystem by using statistical methods for analyzing measurement results using the example of a temperature sensor. The importance of this task lies in the fact that the organization of accurate control of the parameters of the microclimate will ensure optimal climatic conditions for the development of plants and fish, and create an environment as similar as possible to the natural one by timely control of parameters and a quick reaction to the output of parameters at critical values. For the analysis, three series of measurement results of the control indicator (water temperature) were used. The analysis confirmed the hypothesis that there are no violations of the stability of the temperature sensor, which makes it possible to recognize the metrological sensor as reliable. It is proved that the problems of increasing the likelihood of controlling objects with stochastic parameters, and controlling their metrological reliability are relevant and are important for the development of the theory and practice of non-dismantling control. |
14:45 | Ensuring the magnetic compatibility of electronic components of small spacecraft ABSTRACT. The technology of limiting the magnitude of the magnetostatic field created by the electronic components of the spacecraft is considered. The incorrectness of the methods based on the multidipole model of the magnetic moment for modeling the magnetic hindrance of the microsatellite components is established. It is proposed to use a limited number of experimentally determined spherical harmonics of the magnetic field created by each electronic unit for modeling and calculating the magnetic induction of hindrance. The practical possibility of controlling the number and location of magnetic sources inside the spacecraft is shown. |
15:00 | The operating conditions of the equipment of the combined compensation rectifier ABSTRACT. Abstract — The results of a study of the operating conditions of the main power equipment of a three-phase combined compensation rectifier are presented. Due to the novelty of the circuit and the complexity of electromagnetic processes, the study was carried out without taking into account the inductance of the AC circuit. The dynamics of changes in the value of currents and voltages of the equipment depending on the value of the turn-on delay of the commutating link transistors is analyzed. Conclusions are drawn about the advantages of the proposed circuit implementation of the converter, implemented according to the three-phase combined compensation circuit, in comparison with the compensation converters of the previous generation. |
15:15 | Commutating processes in a three-phase combined compensation rectifier ABSTRACT. Abstract —The paper presents the results of a study of commutating processes in a three-phase combined compensation rectifier. It is shown that based on the features of the circuit design, in the investigated rectifier, during one the frequency period of the supplying network voltage, there are four switching processes. One is the switching of the power electrical diodes of the non-compensation part of the rectifier. The other three commutating processes take place in the power valves of the compensation part. They are related both to switching between the power valves of different phases and to switching between the power valves of the same phase. The research methodology is based on solving systems of differential equations. |
15:30 | Estimation of the characteristics of a bridge inverter with complementary forms of non-sinusoidal half-bridge voltages ABSTRACT. A study was made of the performance of a bridge inverter with complementary forms of non-sinusoidal half-bridge voltages with a combined form of modulation. The bridge inverter is characterized by a wide range of regulation of the output sinusoidal voltage, compliance with the requirements for power quality in terms of spectral composition, ease of formation of the modulation law and the functionality of changing the type of modulation. The influence of the ratio of the components of the combined type of modulation on the level of common-mode interference is studied and the conditions for achieving the smallest value are determined. Comparative estimates of the power of dynamic losses in the switching elements of the inverter and the power of circulation are obtained for combined and traditional types of modulation. |
15:45 | Calculation of DC-DC SEPIC converter by averaging method ABSTRACT. This paper illustrates the application of averaging method based on Lagrange theorems for analysis and calculation of SEPIC converter operating in continuous conduction mode of reactive storage elements. It is shown that this method simplifies the calculation of converter by reducing the number of calculations and avoiding cumbersome intermediate transformations. A mathematical model has been developed that reflects the relationship between the parameters of SEPIC converter and the convenient analytical relationships for calculating the constant and pulsating components of converter processes are obtained. Based on them, expressions for calculating the boundaries of continuous conduction modes of reactive storage elements, as well as the maximum currents and voltages in the switching elements and other parameters of SEPIC converter are developed. The obtained analytical relations allow to apply the methods of mathematical analysis of quantitative and qualitative characteristics of processes, which helps to increase the efficiency of converter calculation at the stage of its design. |
16:00 | Programmable instrumentation amplifier with digital potentiometer based gain control ABSTRACT. The subject matter of study in the article is schematic solutions of instrumentation amplifiers with a programmable gain applied for the digital processing systems, biomedical equipment, measuring instruments, data analysis systems, etc. The goal is the creation of the circuitry that implements a programmable instrumentation amplifier that combines the advantages of already-known solutions with the possibility of setting the necessary gain through a digital I2C / SPI interface. During the research, a new solution was proposed for a small-sized programmable instrumentation amplifier based on a differential amplifier with a fixed gain and programmable digital potentiometer. |
16:15 | State feedback controller synthesis of T-S fuzzy nonlinear systems with interval time-varying delay ABSTRACT. In this paper, we developed a new synthesis of state feedback controllers for nonlinear discrete-time systems where time-varying delays are bounded. Using T-S fuzzy models, these controllers are applied based on a new design methodology to overcome the obstacle of bilinearity. The results of this methodology yields to a quite simple LMI condition that is numerically tractable employing many convex optimization algorithms. The effectiveness of our LMI-based design method is illustrated using some numerical examples. Namely, the proposed design approach is very useful comparing with those obtained in the literature. |
16:30 | Analysis of a DC Converter Working on a Plasma Arc ABSTRACT. The analysis of a stabilized DC converter operating on a plasma arc is carried out. The frequency characteristics of the input and output resistances and the transfer functions of the L-shaped LC filter loaded on the active resistance of the load are obtained. |
16:45 | Study of the Effect of Transformer Windings Coupling Coefficient of Flyback Resonant Converter for Wireless Energy Transfer on its Output Characteristics ABSTRACT. The article analyzes the influence of the coupling coefficient of the transformer windings on the output characteristics of the resonant flyback converter intended for use in applications for the implementation of contactless power transmission. Expressions for the theoretical calculation of the dependences of the output characteristics of the converter on the coupling coefficient have been obtained. The coupling coefficient has been calculated for the L-shaped transformer replacement circuit of the flyback resonant converter. A simulation experiment of the wireless capacitor charging using the flyback resonant converter has been carried out. Its results coincide with the theoretical ones. It has been established that during the flyback converter design, it is most appropriate to use an L-shaped transformer replacement circuit, which causes the difference between theoretical and experimental results within 2%. |
17:00 | Pulse-forming Network Computer Simulation Model with Implicit Euler Algorithm ABSTRACT. The paper is devoted to application of implicit Euler algorithm for computer simulation of pulse-forming networks. In the previous paper, the authors proposed to use a computer model based on explicit Euler algorithm to optimise performance of a modified pulse-forming network with the damping resistor connected in parallel to the first inductance of the network. Although the research showed very good characteristics of the proposed pulse-forming network, it is well-known from the literature that computer models based on explicit Euler algorithms can accumulate errors, what can undermine the validity of the obtained results. To verify and confirm performance of the computer simulation model used previously, authors designed a computer simulation model based on implicit Euler algorithm, which is free from this accumulation of errors. Developed computer simulation model with implicit Euler algorithm has confirmed the previous results obtained with explicit Euler algorithm and, although it requires more calculations, it gives a range of options for the researchers. These possibilities include testing other models in the absence of the analytical solutions or using this model when an added accuracy of the simulation is necessary. Designed computer simulation model with implicit Euler algorithm can be used in pulse-forming networks design and improvements. |
17:15 | Synchronous Adjustment of Three Modulated Inverters of Grid-Tied Photovoltaic Installation PRESENTER: Valentin Oleschuk ABSTRACT. This paper presents analysis and comparison of three variants of the modified scheme and techniques of spacevector-based synchronous pulsewidth modulation (PWM), applied for control of three diode clamped inverters of transformerbased photovoltaic (PV) installation, and focused on assuring of the symmetry of winding voltage of power transformer during the whole control diapason. Power supply of inverters is insuring by the corresponding three solar strings consisting of a set of PV panels, and the outputs of three inverters are connected specifically with inverter-side windings of multi-winding grid-tired transformer. Results of simulation prove the fact of advanced spectral composition of the winding voltage of PV installation with triple inverters regulated by algorithms of synchronous space-vector PWM, assuring potential reduction of losses in these systems. |
Section 2. Electrical Drives and Industrial Applications
https://us02web.zoom.us/my/khpiweek2022.2
Access code: KhPIWeek