Duty Cycle Values Research Articles

A New High Gain Active Switched Network-Based Boost Converter for DC Microgrid Application

This paper deals with an active switched inductor network-based high gain boost converter. By using less number of components in circuit topology, a higher gain in voltage can be attained at a small duty cycle value by using the proposed converter, which helps in reducing the switch voltage stress and conduction loss. In addition, it draws continuous input current, has lower diode voltage stress, and lower passive component voltage ratings. The operating principles and key waveforms in Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) are presented. Parameter design, power loss calculation, characteristics, and comparative study with other non-isolated converters have been presented. Finally, a 200W hardware prototype is constructed and the viability of the proposed converter is verified through the experimentally obtained results.

Analysis of a Hybrid Variable-Frequency-Duty-Cycle-Modulated Low-$Q$ $LLC$ Resonant Converter for Improving the Light-Load Efficiency for a Wide Input Voltage Range

Light load efficiency and output voltage regulation of alow-Q LLC resonant converter is a critical problem for wide input voltage and load range applications. Parasitic capacitances such as rectifier diode junction capacitance (C3) degrade the soft switching performance. Compact size, high density, and high transformer turns-ratio requirements for microinverter applications add significant distributed capacitance (Cd) of the low-profile transformer, worsening the output regulation and zero-voltage-switching (ZVS) capability at light loads. Wide switching frequency requirement for regulation at light loads, which increases core losses and turnOFF switching losses in power MOSFETs, further degrades the power conversion efficiency. The conventional phase-shift modulation causes a high circulating current and loss of ZVS at light loads. Therefore, a hybrid adjustable switching-frequency-dutycycle modulation technique for improving the light load efficiency is proposed and analyzed for a full-bridge LLC resonant converter. Accurate loss analysis for the proposed modulation scheme, including the effect of parasitic capacitances, is performed using time-domain equations. The proposed methodology precalculates the optimal duty cycle at light load conditions for the required input voltage range such that minimum power losses are incurred. Variation in switching frequency at the preselected duty-cycle value regulates the output voltage. ZVS over a wide range of operating conditions is observed. An experimental prototype for a 20-40 V input, 380-V/300-W output LLC converter is tested for the validation of theoretical analysis.

Extended Analysis of the Asymmetrical Half-Bridge Flyback Converter

Isolated, zero-voltage-switching dc-dc converter topologies represent attractive solutions in the continuous run toward higher switching frequencies, allowing more compact power supplies. Among them, the asymmetrical half-bridge flyback converter represents an interesting option, featuring simple duty-cycle control at constant switching frequency, as opposed to the popular LLC converter. The majority of papers dealing with this topology consider an approximated voltage gain similar to that of an isolated buck converter operating in continuous conduction mode, i.e., proportional to the duty cycle and, practically, load independent. On the contrary, the true voltage gain is nonmonotonic at high duty-cycle values. Anytime the converter is designed for a resonant operation, as is advisable to eliminate any reverse recovery problem of the rectifier diode, the voltage gain not only increases, but also becomes a function of the switching frequency. This article investigates the converter's voltage gain in detail, deriving a theoretical framework capable of capturing its real behavior and dependencies. The proposed analytical model has been verified through simulations as well as experimental measurements taken on a 160-W prototype working at 400 kHz.

BURNING MODES OF A BIPOLAR PULSED DISCHARGE IN CO2

We have studied the burning modes of the bipolar pulsed discharge in CO2 within the frequency range between 20 and 300 kHz and the duty cycle of 11...97 %. The current and voltage waveforms within the pressure range between 0.1 to 1 Torr were registered. We have established that the duty cycle values may affect the axial structure of the discharge considerably causing the voltage drop redistribution across the electrodes. The bipolar pulsed discharge may burn in a high-current mode (with cathode sheaths near every electrode) as well as in a low-current one (with a low discharge current and weak glow). The transition between these modes may be observed at high duty cycle values. We have found that one may make a shift of the complete oscilloscope voltage pattern higher or lower along the voltage axis and produce a self-bias constant voltage the value and sign of which depend on the duty cycle, amplitude and frequency of the applied voltage.

SISTEM PENGEPAKAN DENGAN METODE SORTASI PENGATURAN KECEPATAN KONVEYOR BERDASARKAN UKURAN KEMASAN MENGGUNAKAN OUTSEAL PLC NANO V.4 DAN HAIWELL SCADA

The production process which is designed is a packaging system for the initial storage of products to be filled in the packaging, in this study a conveyor is designed that can sort objects using a proximity sensor and adjust the speed based on the size of the packaging using pulse width modulation (PWM), and can fill the packaging based on the size of the packaging. The product. Automatic control of packing using Outseal PLC Nano.V.4, the system can be controlled and monitored using Haiwell SCADA software on a PC. Outseal PLC nano V.4 test results can operate based on program commands that have been designed. The use of PWM Outseal PLC Nano V.4 on a 12 volt DC motor as a speed controller works in accordance with the duty cycle and PWM scale values given with an efficiency value of 86,56 % at at a PWM value of 900 and 86,23 % at a PWM value of 1023. HMI system made using Haiwell SCADA to control and monitor a successful packing system. Outseal PLC Nano V.4 can operate optimally with the SCADA system. The overall system test results of all sensor components, product packaging and HMI variables are 100 % successful, with an average processing time of packing size M for 11.62 seconds and size L for 14.58 seconds.

A topology of coupled inductor DC–DC converter with large conversion ratio and reduced voltage stress on semiconductors

This study presents a high boost DC–DC converter, integrates voltage multiplier cell, voltage lift capacitor, and coupled-inductor techniques to achieve a high-voltage gain. The proposed topology has the capability of extension without utilising any additional winding for a very large voltage conversion ratio. With utilising a passive clamp circuit and without requiring higher duty cycle values, the suggested converter obtains a large conversion ratio, low conduction losses, and reduced voltage stress of semiconductors with a steady value for the whole range of duty cycle. The converter operation principle is discussed and its steady-state operation is analysed in detail. Also, theoretic efficiency calculation and design guidelines of the topology are explained. Then, the proposed DC–DC converter is compared with similar configurations to indicate its advantages. Eventually, the validity of theoretic analysis is verified using experimental measurement results of the implemented prototype with a power rating of 226 W.

V C Digital Controlled DC DC Converter

In this paper, the switching of dc-dc converter using voltage/current digital control is proposed. It is the combination of existed digital average voltage and digital average current controls. The stability analysis of V/C digital controlled dc-dc converter is derived by using sampled data model. The transient analysis of V/C digital controlled dc-dc converter is also derived by using z-domain small signal model. The proposed V/C digital controlled dc-dc converter has over current protection, fast load transient response, no sub-harmonic oscillations at any value of duty cycle, and wider stability range. The proposed system is analysed with a simple buck converter. The output voltage and inductor current weighting factors influence the stability boundary and transient performances of V/C digital controlled dc-dc converter. The stability analysis and transient analysis is investigated and verified by circuit simulations.

Extendable topology of step‐up DC–DC converter with continuous input current for renewable energy applications

A single-switch high boost DC–DC converter is introduced in this work. In the suggested topology, a voltage multiplier cell and three-winding coupled inductor (CL) are integrated to obtain an ultra-large conversion ratio. Using a passive clamp circuit and also, no requirement of larger duty cycle values enable the converter to have a very high voltage gain, low conduction loss, and reduced voltage stress of semiconductors. Moreover, the leakage inductance of the CL alleviated diodes reverse recovery problem. Some important merits include ultra-high voltage gain, operating in low duty cycles, reduced voltage stress of semiconductors, continuous input current, high efficiency, and low turn ratio of the CL makes the introduced converter very suitable for renewable energy applications. Steady-state analysis and operation principles of the presented topology are expressed completely in the study. Moreover, the theoretical efficiency analysis and design guidelines of the suggested configuration are presented. Also, the superiority of the presented topology over the state-of-the-art similar DC–DC converters is demonstrated in the comparison study. Eventually, the validity of theoretical analysis is verified using experimental measurement results of the implemented prototype with a power rating of 240 W and an output voltage of 440 V.

Impact of Electrical Process Parameter in Electrochemical Micromachining of Nimonic 75 Alloy

Electrochemical micromachining is one among the widely known method for machining micro holes in electrically conductive, hard to cut materials. As nimonic 75 alloy can withstand alternate cooling and heating conditions, it finds application in aero combustor liner. In this study, solid tungsten carbide (500µm) was selected as the tool to produce micro holes in the work-piece (nimonic 75 alloy). As pulsed current, results in more confined dissolution, trials were performed by changing electrical process parameter such as duty cycle, pulse on period and pulse off period and their effect on MRR and dimensional deviation were studied. Employing TOPSIS, lower values of duty cycle and pulse on period was desirable for the production of holes with better geometrical features and the similar was found to be in concurrent with SEM images.

DESAIN KONVERTER BOOST DENGAN METODE KECERDASAN BUATAN BERBASIS MIKROKONTROLER STM32F103C8

Energy conversion is needed to serve load characteristics according to consumer needs. Some of the human energy conversion techniques to date include: AC to DC (Rectifier), AC to AC (AC Controller), DC to AC (Inverter), DC to DC (Chopper).The use of electromechanical switching has begun to be reduced or even abandoned and replaced by electrical switching which has very high switching speeds.The energy conversion technique also includes the regulation of the output voltage produced by a converter so that current research is leading to the design of a reliable converter.Boost Converter is a converter that functions to regulate and increase the output voltage of the source voltage by setting its duty cycle.The optimal duty cycle value to produce the output voltage that is in accordance with the target, can be determined using the Flower Pollination (FPA) algorithm, together with the current sensor as feedback, and then controlled by the STM32F103C8 Microcontroller.

Analisis Variasi Nilai Duty Cycle pada PWM Terhadap Durasi Pengisian Baterai Lithium-Ion dan Lithium-Polymer

Lithium batteries are currently widely used as energy storage devices in electric vehicles. However, it takes quite a long time to charge the battery. One solution to the problem of battery charging is to increase the charging voltage and current. The purpose of this study was to determine the effect of variation in the value of the duty cycle with pulse-width modulation on the duration of the battery charge. The battery charging test method uses various duty cycle values ranging from 50% to 100%. Data extraction uses a method of changing the output voltage and current with different duty cycle values on a pulse width modulation signal, which is controlled by the Arduino Uno microcontroller. The results of this study show that changes in the duty cycle value can affect the charging time of Lithium Ion and Lithium Polymer batteries. Fastest charging results on Lithium Ion battery 15,183 minutes with 100% duty cycle at 14V output voltage and 5.83A Lithium polymer battery 15,083 minutes with 100% duty cycle at 14V output voltage and current 6 ,14A.

Micro-Electro-Mechanical System Fourier Transform Infrared (MEMS FT-IR) Spectrometer Under Modulated-Pulsed Light Source Excitation.

Miniaturized Fourier transform infrared (FT-IR) spectrometers suffer from limited optical throughput due to their tiny aperture size. Therefore, coherent wideband sources with high brightness can provide an advantage over the wideband thermal radiation sources. However, the former ones are available based on pulsed operation. In this work, we present and study a miniaturized FT-IR spectrometer with pulsed light sources including chopped thermal source, semiconductor optical amplifier, Q-switched and femtosecond mode-locked laser sources. A system model for the FT-IR spectrometer system under a modulated input light source is presented. The model accounts for the relatively high scanning speed of the micro-electro-mechanical system (MEMS) interferometer. The signal-to-noise ratio of the spectrometer, due to the light source modulation, is calculated at different values of modulation repetition rate ranging from 20 Hz to 2 MHz, and duty cycle values ranging from 1% to 50%. An analytical expression for the worst-case repetition rate for the spectrometer system is derived. The model results are verified by experimental measurements showing good agreement with the theoretical expectations. Spectroscopic measurements for CO2 gas with pressure ranging from 300 mbar to 700 mbar are also performed using a high-repetition rate source, and the measured spectra agree with the simulation results demonstrating the utility of the spectrometer.

FPGA-based variable modulation-indexed-SPWM generator architecture for constant-output-voltage inverter applications

Modulation Index (MI) variant sinusoidal-pulse-width-modulation (SPWM) is desirable for converter applications in maintaining output voltage under variable input and load environments. Enabling a high-speed switching and resolution, field-programmable gate-arrays (FPGAs) have been dominating in digital control of power electronics. This paper proposes an FPGA-based high-frequency high-resolution digital variable-modulation-indexed sinusoidal-pulse-width-modulation (DVMI-SPWM) generator architecture which can support the requirements of modern high-frequency switching and the MI adjustment ability in voltage-source-inverter (VSI) applications. A mathematically formulated optimized finite-state-machine (FSM) architecture is introduced, which adopts MI of SPWM by adjusting the duty-cycle values of SPWM pulses based on the measured feedback signal. The design employs a minor segment of medium-sized FPGA and, thereby, provides a good trade-off for multi-functional and larger schemes. The post-design simulation and experimental results validate that compared to the earlier-reported architectures, the proposed DVMI-SPWM architecture is the most appropriate one for variable MI applications with improved performance such as lower power consumption, lower harmonic distortion, and higher resolution.

Mechanically-Induced Long-Period Fiber Gratings Using Laminated Plates.

This work presents a formation method of mechanically-induced long-period fiber gratings using laminated plates. The mechanically-induced long-period fiber grating is temporarily inscribed by compressing the optical fiber between a flat plate and the proposed laminated plate. In turn, the new laminated plate consists of a parallel assembling of single-edged utility blades. We present the experimental characterization of mechanically-induced long-period fiber gratings while employing three laminated plates with a period of 480 ± 20 µm and low duty cycles. These mechanically-induced long-period fiber gratings display a leading rejection band (>15 dB) with a couple of shallow rejection bands (<2 dB) in the range of 1100–1700 nm. This spectral behavior is due to the new mechanical fabrication process that is based on laminated plates that we have proposed, which consists of piling multiple blades with trapezoidal edges that are polished with different levels to obtain different duty-cycles. With the proposed method, we can obtain values of duty-cycles around 10%, much lower than those obtained using traditional methods. Additionally, with this new method, the required mechanical pressure to form the grating is remarkably reduced, which minimizes the probability of the optical fiber failure in the mechanically-induced long-period fiber gratings (MI-LPFGs). Moreover, the proposed mechanically-induced long-period fiber gratings with a single rejection band open the feasibility to implement coarse wavelength division multiplexing systems that are based on long-period fiber gratings.

Multiport DC–DC Converter With Step-Up Capability and Reduced Voltage Stress on Switches/Diodes

This article aims to propose a new nonisolated step-up multiport dc–dc converter. The proposed topology is a dual-input dual-output dc–dc converter with different output voltages levels. This makes it possible to be used in hybrid energy systems with different input sources as well as in electric vehicles to supply the traction motor and auxiliary loads. The proposed converter is capable of providing high voltage gains with small values of duty cycles and low normalized peak voltage stress across the semiconductor devices. Therefore, the switches with small turn- on resistance and the diodes with a reduced nominal voltage can be used, which in turn reduces the switching and conduction losses. The operation principles of the proposed converter are explained and steady-state analysis is carried out. Then, the circuit performance is compared with other related step-up multiport dc–dc converters in the literature. Eventually, the performance of the proposed converter is validated with experimental results.

Simplified Hysteresis Sliding-Mode Control for Superbuck Converter

A simplified hysteresis sliding-mode control (SMC) is proposed to improve the dynamic response of the superbuck converter operating in continuous condition mode with high duty cycle values. The controller based on the sliding surface composed of output voltage error and input current error is derived and further simplified in structure. The simplified process decreases the number of control parameters and reduces system cost. The relationship between control parameters and the performance of the proposed controller is studied and verified by simulation. An experimental prototype using the proposed controller is designed with analog devices. Moreover, a dynamical performance comparison involving the proposed sliding-mode controller and existing controller is provided.

Design and implementation of an improved sinusoidal controller for a two-phase enhanced impedance source boost inverter

This study presents a novel Sinusoidal Pulse Width Modulation (SPWM) model for a two-phase Impedance Source-based Inverter (ZSI) with a hardware prototype implementation. The high-gain feature is investigated based on an innovative mathematical model that involves fewer components and presents efficient performances. The presented topology can be applied broadly in Photo Voltaic systems, Wind Power, Fuel Cell, and Uninterrupted Power Supply topologies due to the ability of wide-range load regulation with higher duty cycles. Through Shoot (TS) and higher Total Harmonic Distortion (THD) problems can be solved by a carefully designed gate-drive circuit and proper switching frequency for the appropriate resistance against the Electromagnetic Interfaces (EMIs). One of the essential specifications of the proposed controller is working with intermediate values of duty cycles for power MOSFETs that can decrease the losses for the inverter. A set of numerical simulation and hardware results are presented for ensuring the proposed claims.

Correlation Functions of Navigational cosGBOC Signals as the Inverse Fourier Transform of the Energy Spectra

Abstract—The modulating functions (MFs) of cosGBOC signals (cosine generalized BOC signals) for new-generation satellite radio navigation systems, such as Galileo (EU), GPS (USA), GLONASS (Russia), and BeiDou (China), are considered. Based on inverse Fourier transform (FT) of the energy spectra, analytical expressions are obtained and graphs are constructed for the correlation functions (CFs) of single elements of MFs of cosGBOC signals with a pulse ratio of $${{N}_{{\text{p}}}}$$ = 2 and 4 for different duty cycle values $$\rho $$, where $$\rho $$$$ \in $$ [0, 1]. When calculating the CF, the methodology is based on representing the energy spectrum as the weighted algebraic sum of the cosines of angles determined from the characteristic points of the cosine symbol of the MFs (CF kinks) of cosGBOC signals. In some cases, calculating the CFs of cosGBOC signals by inverse FT of the energy spectra is more preferable (in particular, in terms of labor intensiveness) compared to the method of obtaining the CF based on its general definition.

Direct Modulation for Conventional Matrix Converters Using Analytical Signals and Barycentric Coordinates

This paper proposes the generalized direct modulation for Conventional Matrix Converters (CMC) using the concept of analytical signals and barycentric coordinates. The paper proposes a novel approach to the Pulse Width Modulation (PWM) duty cycle computing, which allows faster prototyping of direct control algorithms. The explanation of the new idea using analytical considerations demonstrating the principles of direct voltage synthesis has been presented in the article. The study concerns mainly the CMC $3\times 3$ but solutions for $3\times {n}$ , $5\times {5}$ , and $5\times {3}$ topologies have also been discussed. The transformation of instantaneous input voltages to analytic signals great permits for simple presenting of real input voltage conditions such as waveform type, asymmetry or other deformation like higher–order harmonics. The proposed interpolation methods allow for determining the values of PWM duty cycles using simple formulas based on the determinants of the 2nd–degree matrices. Therefore, the proposed method, which based on the barycentric coordinates, frees an algorithm from trigonometry and angles.

Neural network design for energy-autonomous artificial intelligence applications using temporal encoding.

Neural networks (NNs) are steering a new generation of artificial intelligence (AI) applications at the micro-edge. Examples include wireless sensors, wearables and cybernetic systems that collect data and process them to support real-world decisions and controls. For energy autonomy, these applications are typically powered by energy harvesters. As harvesters and other power sources which provide energy autonomy inevitably have power variations, the circuits need to robustly operate over a dynamic power envelope. In other words, the NN hardware needs to be able to function correctly under unpredictable and variable supply voltages. In this paper, we propose a novel NN design approach using the principle of pulse width modulation (PWM). PWM signals represent information with their duty cycle values which may be made independent of the voltages and frequencies of the carrier signals. We design a PWM-based perceptron which can serve as the fundamental building block for NNs, by using an entirely new method of realizing arithmetic in the PWM domain. We analyse the proposed approach building from a 3 × 3 perceptron circuit to a complex multi-layer NN. Using handwritten character recognition as an exemplar of AI applications, we demonstrate the power elasticity, resilience and efficiency of the proposed NN design in the presence of functional and parametric variations including large voltage variations in the power supply. This article is part of the theme issue 'Harmonizing energy-autonomous computing and intelligence'.