scholarly journals DEPENDENCIES OF THE DISTORTION FACTOR OF THE SINUSOIDALITY OF THE RECOVERY CURRENT ON THE PARAMETERS OF THE PROCESS WHEN CONTROLLING THE FORCED DISCHARGE OF ACCUMULATOR BATTERIES INTO THE NETWORK BY SIGNAL WITH SINGLE-CYCLE ONE-WAY PULSE-WIDTH MODULATION

2021 ◽  
pp. 146-153
Author(s):  
Sergey S. Frolov ◽  
Dmitry A. Shatilov
Keyword(s):  
Discharge Current ◽  
Pulse Width ◽  
Energy Savings ◽  
Relevant Information ◽  
Distortion Factor ◽  
Universal System ◽  
Active Rectifier ◽  
Distortion Coefficient ◽  
Maximum Current ◽  
Uninterruptible Power

For modern remote and closed systems of uninterruptible power supply, a operation of forced discharge of accumulator batteries is in demand. It is advisable to carry out the specified process of forced discharge with recuperation into the network. This way of leads: firstly, to a decrease in the mass of charging and discharging devices due to the exclusion of powerful resistive loads from the latter; secondly, to noticeable energy savings for closed autonomous objects. At the same time, for the regenerative current, increased requirements are imposed on its sinusoidality, the distortion coefficient of which is significantly influenced by the relationship between the EMF of the battery and the amplitude of the mains voltage, the discharge current and the maximum current of the coil of the active rectifier. The influence the frequency of the PWM control signal and the frequency of the regeneration current (mains frequency) is also possible. In uninterruptible systems, storage batteries are used with different total EMF and capacity that determines the discharge current. In addition, the mentioned values change during operation, and at forced discharge, various technique can be used that differ in the ratio of the discharge current to the capacity of the battery and the law of its change. Therefore, in the development of a universal system for forced discharge of a battery into a network with pulse-width control of the regenerative current shape, is relevant information on the dependences of the distortion factor of the sinusoidality on the above ratios of the battery voltage and the amplitude of the mains voltage, the discharge current and the maximum current of the coil of the active rectifier coil, as well as from the number of pulses for the regeneration current period. The article presents the results of work on obtaining diagrams of these dependencies. To obtain the latter, the function of the output current of the active rectifier is formed – of the regeneration current, then its spectral function. Using the latter, the current waveform distortions are estimated based on the spectral approach. The results obtained are in demand in the development of program modules for microcontrollers of the pulse-width regulators of the regeneration current, which implement algorithms for the formation of a current curve with acceptable values of the distortion coefficient of the sinusoidality when changing the parameters of the battery, network and discharge current.

scholarly journals Recovery Current Sinusoidality Distortion in the Control System of Forced Discharge of Batteries into the Mains

2020 ◽  
Vol 26 (4) ◽  
pp. 540-554
Author(s):  
S. S. Frolov ◽  
◽  
D. A. Shatilov ◽  
Keyword(s):  
Control System ◽  
Electromotive Force ◽  
Pulse Width ◽  
Single Phase ◽  
Pulse Width Modulation ◽  
Universal System ◽  
Current Function ◽  
Active Rectifier ◽  
Storage Batteries ◽  
The Relationship

The requirements for the reverse recovery current sinusoidality are high. Therefore, when developing programs for microcontrollers for a universal system of pulse-width modulation of the recovery current, it is important to have information on the dependences of the sinusoidality distortion degree on the relationship between the total electromotive force of the battery and the mains voltage, the amplitude of the recovery current, the inductance of the active rectifier coil, through which it flows, as well as between the frequencies of the network and the control PWM signal. The results of research into the development of a microcontroller modulation system for a routine forced (training or diagnostic) discharge of storage batteries into a single-phase network are presented. The sought expressions for the dependences of the sinusoidality distortion degree are obtained on the basis of the results of the spectral transformation of the regenerative current function obtained in MathCAD when the latter is formed by the control signal with single-stroke double-sided PWM-2.

Psychophysics Study on LED Flicker Artefacts for Automotive Digital Mirror Replacement Systems

2020 ◽  
Vol 2020 (11) ◽  
pp. 234-1-234-6
Author(s):  
Nicolai Behmann ◽  
Holger Blume
Keyword(s):  
Light Source ◽  
Pulse Width ◽  
Digital Camera ◽  
Relevant Information ◽  
Human Vision ◽  
Light Sources ◽  
Traffic Light ◽  
Pulse Width Modulated ◽  
Novel Approach ◽  
Flicker Light

LED flicker artefacts, caused by unsynchronized irradiation from a pulse-width modulated LED light source captured by a digital camera sensor with discrete exposure times, place new requirements for both visual and machine vision systems. While latter need to capture relevant information from the light source only in a limited number of frames (e.g. a flickering traffic light), human vision is sensitive to illumination modulation in viewing applications, e.g. digital mirror replacement systems. In order to quantify flicker in viewing applications with KPIs related to human vision, we present a novel approach and results of a psychophysics study on the effect of LED flicker artefacts. Diverse real-world driving sequences have been captured with both mirror replacement cameras and a front viewing camera and potential flicker light sources have been masked manually. Synthetic flicker with adjustable parameters is then overlaid on these areas and the flickering sequences are presented to test persons in a driving environment. Feedback from the testers on flicker perception in different viewing areas, sizes and frequencies are collected and evaluated.

scholarly journals INVERTER FULL BRIDGE SATU FASA BERBASIS IC SG3524

TRANSIENT ◽  
2017 ◽  
Vol 6 (3) ◽  
pp. 467
Author(s):  
Kusumo Tri Atmojo ◽  
Mochammad Facta ◽  
Tejo Sukmadi
Keyword(s):  
Duty Cycle ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Power Supplies ◽  
Uninterruptible Power Supplies ◽  
Uninterruptible Power

Inverter merupakan sebuah konverter yang mengubah sebuah masukan arus searah menjadi arus bolak-balik. Dalam beberapa bentuk inverter tegangan keluaran arus bolak balik tersebut dapat dikendalikan besar magnitud dan frekuensinya. Penggunaan inverter dapat berupa catu daya untuk pengaturan kecepatan motor ac, uninterruptible power supplies (UPS) dan alat konversi tenaga listrik dari baterai. Pada penelitian ini, inverter yang dirancang menggunakan topologi full bridge. Topologi ini memiliki keunggulan berupa magnitud tegangan keluaran maksimum yang sama dengan tegangan magnitud tegangan arus searah yang menjadi tegangan masukannya. Dengan tegangan masukan yang sama, topologi full bridge memiliki daya yang lebih besar dibandingkan inverter topologi lainnya. IC SG3524 digunakan sebagai pembangkit sinyal PWM (Pulse Width Modulation). Inverter full bridge dalam penelitian ini dirancang untuk dapat divariasikan besar frekuensi dan duty cyclenya. Frekuensi dari inverter dirancang untuk beroperasi dalam rentang 19 Hz – 65 Hz dan duty cycle 11 % - 44 %. Berdasarkan hasil pengujian Inverter full bridge menghasilkan gelombang kotak keluaran arus bolak balik. Efisiensi inverter full bridge mencapai nilai terendah sebesar 81,56% dan nilai tertinggi sebesar 99,53%  ketika dibebani lampu pijar dengan daya 40, 60, dan 100 W. Efisiensi inverter ketika dibebani motor induksi mencapai nilai 86,55 % sebagai nilai efisiensi terendah dan 98,35% sebagai nilai efisiensi tertinggi.

scholarly journals Improving Electrical Power Quality in Distribution Networks using a Unified Power Quality Conditioner (UPQC) Controlled by an Adaptive Hysteresis Band

2021 ◽  
Vol 23 (2) ◽  
pp. 91-109
Author(s):  
Marah Mariam ◽  
◽  
Hassan Kenjrawy
Keyword(s):  
Power Systems ◽  
Power Quality ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Electrical Power ◽  
Distribution Networks ◽  
Electrical Power Systems ◽  
Distortion Factor ◽  
Unified Power Quality Conditioner ◽  
Power Quality Conditioner

Recently the use of sensitive electronic devices has increased, and the quality of energy has become an important factor in electrical power systems, where disturbances occurring in the network (harmonics, swell, voltage sag, etc.) affect consumers and lead to technical-economic damages. One of the most prominent solutions to address energy quality problems is the UPQC (Unified Power Quality Conditioner). In this paper, the unified power quality conditioner used to improve the electrical power quality in the distribution networks was discussed, where the Park transformations are used to obtain the required reference signals, and also the use of adaptive hysteresis band to generate the electronic switch pulses in both serial and shunt switches, where the pulse width is determined by dependence on fuzzy logic. The studied system was validated by simulating different distortion cases and comparing the results when using the Sinusoidal Pulse Width Modulation (SPWM) to control the two switches. The results showed improvement in the electrical power quality through the use of an adaptive hysteresis band controller, and that appeared by reducing the total distortion factor (THD%), which resulted in improving the shape of both the voltage and current waveforms.

scholarly journals Reconfiguration of a Multilevel Inverter with Trapezoidal Pulse Width Modulation

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2148 ◽  
Author(s):  
Nataraj Prabaharan ◽  
V. Arun ◽  
Padmanaban Sanjeevikumar ◽  
Lucian Mihet-Popa ◽  
Frede Blaabjerg
Keyword(s):  
Root Mean Square ◽  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Harmonic Distortion ◽  
Multilevel Inverter ◽  
Mean Square ◽  
Distortion Factor ◽  
Field Programmable ◽  
Trapezoidal Pulse

This paper presents different multi-carrier unipolar trapezoidal pulse width modulation strategies for a reduced switch asymmetrical multilevel inverter. The different strategies are phase disposition, alternative phase opposition and disposition, and carrier overlapping and variable frequency that involve triangular waves as carriers with a unipolar trapezoidal wave as a reference. The reduced switch, asymmetrical multilevel inverter operation was examined for generating the seven-level output voltage using Matlab/Simulink 2009b and the results were verified with a real-time laboratory-based experimental setup using a field-programmable gate array. Different parameter analyses, such as total harmonic distortion, fundamental root mean square voltage, and distortion factor, were analyzed with different modulation indices to investigate the performance of the selected topology. Unipolar trapezoidal pulse width modulation provides a higher root mean square voltage value.

scholarly journals A time-correlated study of the Z-pinch discharge in helium

1970 ◽  
Vol 48 (7) ◽  
pp. 884-900 ◽  
Author(s):  
K. Dimoff ◽  
S. Y. K. Tam
Keyword(s):  
Shock Wave ◽  
Shock Front ◽  
Strong Evidence ◽  
Discharge Current ◽  
Time Resolved ◽  
Maximum Current ◽  
Almost All ◽  
Z Pinch ◽  
Insight Into

The development of a miniature "gradient probe" and the successful superposition of multiple photographic recordings have produced useful insight into the action of the Z-pinch discharge in helium.A correlation of luminosity and current fronts yields strong evidence for the occurrence of a nonionizing shock wave at high initial pressures in helium discharges. The relatively nonluminous shock front is followed by overlapping regions of He I and He II radiation within the collapsing current shell. At low filling pressures these two regions coincide and radiation is emitted from almost all the gas trapped within the current shell. In all cases the zone of maximum He II emission is observed to coincide with the position of maximum current density.Synchronization of the discharge current with time-resolved spectroscopic results indicates the presence of successive pinches. They are caused by the interaction of thermal and magnetic pressures after the first collapse of the discharge.

scholarly journals Resonant LCL Converter with Frequency-Pulse-Width Control

2021 ◽  
Vol 24 (2) ◽  
pp. 77-83
Author(s):  
A. V. Osipov ◽  
◽  
V. M. Rulevskiy ◽  
Keyword(s):  
Frequency Characteristic ◽  
Pulse Width ◽  
Resonant Circuit ◽  
Output Current ◽  
Reactive Component ◽  
Load Range ◽  
Frequency Adjustment ◽  
Active Rectifier ◽  
Zero Phase ◽  
Frequency Pulse

The paper considers the features of frequency-pulse-width control in a resonant LCL converter with an active rectifier in the mode of parametric stabilization of the output current. The analysis of the properties of the LCL converter during regulation by the rectifier is carried out, the phase frequency characteristic and the coefficient of parametric stabilization are obtained. It is shown that the rectifier introduces a reactive component into the impedance of the resonant circuit. It is illustrated that the introduction of the control angle leads to the loss of roots by the equation on a part of the load range. The estimation of the frequency adjustment in the converter is carried out, the control characteristic is obtained, the energy advantages of frequency-pulse-width control are demonstrated, which consists in the zero phase of the inverter current and minimization of the recuperation interval

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