A Driving Method for Reducing Oil Film Splitting in Electrowetting Displays

Electrowetting displays (EWDs) are one of the most potential electronic papers. However, they have the problem of oil film splitting, which could lead to a low aperture ratio of EWDs. In this paper, a driving waveform was proposed to reduce oil film splitting. The driving waveform was composed of a rising stage and a driving stage. First, the rupture voltage of oil film was analyzed by testing the voltage characteristic curve of EWDs. Then, a quadratic function waveform with an initial voltage was applied at the rising stage to suppress oil film splitting. Finally, a square wave was applied at the driving stage to maintain the aperture ratio of EWDs. The experimental results show that the luminance was increased by 8.78% and the aperture ratio was increased by 4.47% compared with an exponential function driving waveform.

Implementasi Kontrol Proportional - Integral Pada Bidirectional Converter Untuk Sistem Pengisian Baterai Turbin Angin

The level of demand for electrical energy in Indonesia is currently getting higher and will continue with the increase in population so that it is required to conduct research in the field of renewable energy. To be able to support renewable energy research, a switching circuit is needed for the battery charging system. The switching circuit used is a converter bidirectional circuit controlled by an Arduino Uno microcontroller based on PI (Proportional-Integral) control. PI control functions to regulate the voltage so that it has a stable output voltage value. From the research results of the Konverter bidirectional circuit, using trial and error control constants Kp: 2,6 and Ki: 5,6, it was found that the battery charging time was obtained with an initial voltage of 22.9 Volt to 24 Volt battery without using PI control, which was 6 hours 57 minutes, whereas if using the PI control with Kp: 2,6 and Ki: 5,6 with the initial battery voltage of 22.9 Volt to 24 Volt, the battery charging becomes faster, which is 2 hours 45 minutes.

Features of excitation of a linear electromechanical converter of induction type from an AC source

Purpose. The purpose of the article is to establish the basic laws of operation of induction-type linear electromechanical converter (LEMС) during operation in high-speed and shock-power modes and excitation from an AC source of increased frequency. Methodology. With the help of a mathematical model, the regularities of the course of processes in a LEMС, excited from an AC source, were established when working with shock-power and high-speed modes. The solutions of the equations of the mathematical model, which describe interrelated electrical, magnetic, mechanical and thermal processes, are presented in a recurrent form. Results. It was found that when the LEMC operates in the shock-power mode, the maximum value of the current in the inductor winding occurs in the first half-period, and in the inhibited armature winding in the second half-period. The electrodynamic force changes at twice the frequency, taking on both positive and negative values. Since the positive values exceed the negative ones, the magnitude of the impulse of the electrodynamic force increases with each period of the force. Depending on the initial voltage phase, the relative change in the magnitude of the force impulse is 1.5 %. It was found that when the LEMC operates in high-speed mode, the current in the inductor winding in the first half-period has the greatest value, but after several periods it takes on a steady state. The temperature rise of the inductor winding increases with the time of connection to the AC source, and the temperature rise of the armature winding has the nature of saturation. The electrodynamic force has an oscillatory character with strong damping and a significant predominance of the positive component. Depending on the initial phase of the voltage, the relative change in the maximum speed of the armature winding is 2.5 %. Originality. For the first time, a mathematical model of the LEMC, excited from an AC source, was developed, the solutions of the equations of which describe the interrelated electrical, magnetic, mechanical and thermal processes. For the first time, the regularities of the course of processes in LEMC were established when working with shock-power and high-speed modes. Practical value. The characteristics of LEMC are obtained, which determine the efficiency of work in shock-power and high-speed modes. It is shown that the initial voltage phase has no significant effect on the power, high-speed thermal performance of the converter excited from an alternating current source.

Исследование динамики формирования плазмоидов в гатчинском разряде

The results of studies of the Gatchina discharge carried out at the Harbin Technological University (China) are presented. The Gatchina discharge is mainly used to create an analogue of ball lightning in the ordinary atmosphere of a laboratory. Most of the research on this discharge by various groups of scientists is devoted to the study of the first phase of the discharge, when an electric discharge is galvanically coupled to an electrode. This is due to the fact that many researchers consider this phase of the discharge to be decisive for the subsequent long-term existence of an autonomous luminous formation - the second phase of the discharge. In this paper, in comparison with similar works, the leader-streamer process on the water surface was demonstrated more fully and with a better resolution. The use of the filter made it possible to better show the role of leaders, streamers, and the ionization region in the immediate vicinity of the water surface and to clarify some of the processes occurring in the autonomous phase of the discharge. In the wavelength range of 400-500 nm, the autonomous luminous formation showed a longer lifetime in the form of a spherical shape than when observed in "white" light. With a sharp increase in the amount of substance introduced to the cathode, a new physical effect was recorded, which consists in the fact that in the medium of an ordinary atmosphere, a complex formation of a white color is formed without losing contact with the electrode (cathode). By varying the electrical conductivity and initial voltage, an unexpectedly small luminous formation with a diameter of 15-17 mm was obtained for the first time, which was not previously observed in a Gatchina discharge. Key words: Gatchina discharge, plasmoid, long-lived luminous formations, plasma sheet, space charge, virtual cathode, ball lightning. By varying the electrical conductivity and the initial voltage, an unexpectedly small luminous formation with a diameter of 15-17 mm was obtained for the first time, which was not previously observed in the Gatchina discharge.

Research on electric thermal aging resistance new energy material transformer oil based on steady quality engineering technology

The aim of this study was to investigate the electrical resistance of polycarbonate film and polyester film materials in new energy materials during electrothermal aging in transformer oil. Insulating paper was used as a comparative material to compare the breakdown voltage and initial voltage of insulating paper, polycarbonate film, and polyester film in electrothermal aging at 90 °C, 110 °C, and 130 °C. The best performance in the test was achieved by polycarbonate film, followed by polyester film, while the worst performance was that of insulating paper. Polycarbonate film can be used as an insulating material in transformers, and it has great application value and commercial prospects.

Measuring Setup for Investigation and Visualization of the Percolation Phenomenon in Non-Оrdered Models of Metal-Dielectric Nanocomposites

The study uses the phenomenon of high voltage partial discharge to investigate the phenomenon of percolation and visualisation of the percolation channel. The phenomenon of partial discharges is very similar to the quantum tunneling phenomenon observed in metal-dielectric nanocomposites. In both cases the flow of alternating current occurs in the absence of direct contact between the metallic phase particles.A measuring stand was developed and constructed to test models of metal dielectric nanocomposites using high voltage partial discharge. The stand consists of a 110 kV high voltage transformer, a voltage regulator protecting the constant rate of high voltage rise, a measuring system consisting of a measuring probe, voltmeters and a computer. The communication between the measuring probe and the voltmeter was made in digital technology with the use of fiber optic technology, which allowed the meter to communicate with the computer without any errors and eliminated the interference caused by a strong electromagnetic field resulting from the use of high voltage.Systems modelling metal-dielectric composites were built, consisting of metallic elements in the form of disks, randomly distributed on the surface of the dielectric matrix. The number of disks was increased in series of 40 in each. The maximum number of disks was 1520. The dependence was determined of one of the important parameters characterising an partial discharge, i. e. the initial voltage, at which an electric current starts to flow between electrodes, on the concentration of the metallic phase. On the basis of these results, a percolation threshold was established for a matrix with a random distribution of metallic phase elements, the value of which is about 50 %. Films and pictures of partial discharges with visible percolation channels were taken with the camera with which the stand was equipped.

Investigation of Reverse Recovery Current of High-Power Thyristor in Pulsed Power Supply

The instantaneous overvoltages from the load side can cause damages of high-power thyristors in conventional pulsed power supply topologies, especially in cases of numerous pulse-forming units that operate together with discharge time intervals. The instantaneous overvoltages from the load side, which leads to high reverse recovery currents in high-power thyristors, can be induced by load mutations in the electromagnetic launching field. This paper establishes circuit models of PPS topologies, and investigates effects of the initial voltage of the energy-storage capacitor, the discharge time intervals, and the load resistance on the reverse recovery currents in high-power thyristors. To overcome the shortcomings of conventional PPS topologies, an improved PPS topology is developed. The improved PPS topology applies coupling inductor and resistance-capacitance snubber techniques, which can absorb the surge energy from the load side and reduce the reverse recovery currents in high-power thyristors. The simulation technique has been applied to validate theoretical analysis and the proposed model.

Influence of the Intensity of the Solar Radiation and the Surface Area of Photovoltaic Module Towards the Electricity Generated by Photovoltaic Module

The intensity of the solar radiation and the surface area of the photovoltaic module directly influence the amounts of electricity produced by the photovoltaic module. This needs to be known to determine the design of an effective solar power system for the use of electricity from solar energy sources. This research aims to determine the influence of the intensity of solar radiation and the area of the photovoltaic module on the performance of the photovoltaic module in producing current and voltage to be distributed to charge the battery. The method used in this research is an experimental method that measures the current and voltage of the photovoltaic module, the intensity of the solar radiation, the temperature, and the surface area of the photovoltaic module the equipment used is 600 Wp photovoltaic module, ammeter, voltmeter, luxmeter, solar charge controller, batteries and temperature gauges. Results of the research show the intensity of the solar radiation is directly proportional to the battery charging current. The intensity of the solar radiation up to 10000 lux produces a charging current on a 100 Ah 12 volt battery that is 0 to 1.55 Amperes, for 10000 lux to 60000 lux produces 1.6 to 8.35 A, for 60000 lux to 90000 lux produces 9 to 14 A and for above 90000 lux produces 14 to 19 A. The ratio of the surface area of the photovoltaic module is proportional to the ratio of the battery charging current and the increase in battery voltage. Photovoltaic modules with a surface area ratio of 1:2:3, produce a battery charging current and voltage that is 1:2:2.7 and 1:2.1:3.1. Comparison of the amount of electricity produced by a photovoltaic module is proportional to the ratio of the surface area of a photovoltaic module if the measurements are made at the same place and time, at the same scc (solar charge controller) and at the same initial voltage of the battery.

Analysis of the Possibility of Using Drill-Type Electrodes for Air Ionization

In this article, the authors present the results of the analysis of the ionization efficiency of drill-type needle electrodes in air. The analysis was carried out on the basis of experimental laboratory measurements, examined at alternating voltages. Drill-type electrode systems of different diameters were adopted for the tests. The ionization efficiency for this type of electrode has been characterized by values of characteristic voltages, such as the initial voltage of the corona voltage and the sparking voltage. The obtained results were compared with the results of classical conical needle electrodes. The ionization efficiency of drill-type electrodes has been shown to be higher than that of classical conical needle electrodes.