Artykuły w czasopismach: „Pulse Step Modulation (PSM)”

1

Hou, Yanbin, Wanrong Sun, Aifeng Ren i Shuming Liu. "Design of High-Voltage Switch-Mode Power Amplifier Based on Digital-Controlled Hybrid Multilevel Converter". Active and Passive Electronic Components 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/3982594.

Pełny tekst źródła

Streszczenie:

Compared with conventional Class-A, Class-B, and Class-AB amplifiers, Class-D amplifier, also known as switching amplifier, employs pulse width modulation (PWM) technology and solid-state switching devices, capable of achieving much higher efficiency. However, PWM-based switching amplifier is usually designed for low-voltage application, offering a maximum output voltage of several hundred Volts. Therefore, a step-up transformer is indispensably adopted in PWM-based Class-D amplifier to produce high-voltage output. In this paper, a switching amplifier without step-up transformer is developed based on digital pulse step modulation (PSM) and hybrid multilevel converter. Under the control of input signal, cascaded power converters with separate DC sources operate in PSM switch mode to directly generate high-voltage and high-power output. The relevant topological structure, operating principle, and design scheme are introduced. Finally, a prototype system is built, which can provide power up to 1400 Watts and peak voltage up to ±1700 Volts. And the performance, including efficiency, linearity, and distortion, is evaluated by experimental tests.

Style APA, Harvard, Vancouver, ISO itp.

2

Zhang, Jian, Rui Guan, Fei Guo, Yu Zhou, Haozhang Sun, Junjiang Wang i Yiyun Huang. "Study on the soft-start process of PSM high voltage power supply for ECRH". EPJ Web of Conferences 203 (2019): 04019. http://dx.doi.org/10.1051/epjconf/201920304019.

Pełny tekst źródła

Streszczenie:

The soft-start process of high voltage power supply (HVPS) based on pulse step modulation (PSM) for ECRH on EAST is introduced, which is the first procedure of system operation. The response process is detailed by proposing DC equivalent circuit model, process analysis and performance comparison is given under the conditions of different soft-start resistor parameters, and the theoretical analysis is proved by the simulation package ANSYS Simplorer simulations. The soft-start resistor is designed for the HVPS of 140GHz ECRH system for a smooth charging without overshoot of the capacitor[6], and the final experimental results show that it is in agreement with the theoretical analysis and is stable and reliable to the power devices.

Style APA, Harvard, Vancouver, ISO itp.

3

Li, Zhaohan, Yongcheng Ji, Shu Yang i Yuchun Chang. "A Dual-Mode High-Voltage High-Efficiency Peak-Current-Mode Asynchronous Buck Converter". Journal of Circuits, Systems and Computers 25, nr 11 (14.08.2016): 1650136. http://dx.doi.org/10.1142/s021812661650136x.

Pełny tekst źródła

Streszczenie:

This paper proposes a high-voltage high-efficiency peak-current-mode asynchronous DC–DC step-down converter operating with dual operation modes. The asynchronous buck converter achieves higher efficiency in light load condition compared to synchronous buck converters. Furthermore, the proposed buck converter switches operation mode automatically from pulse-width modulation (PWM) mode to pulse-skipping mode (PSM). By reducing power MOS on-state resistance and optimizing rise/fall time of switches, the proposed buck converter also obtains high efficiency under heavy load condition. The maximum efficiency of the proposed buck converter is 92.9%, implemented with 0.35[Formula: see text][Formula: see text]m BCDMOS 2P3M process, and the total size is 1.1[Formula: see text] 1.2[Formula: see text]mm2. The input range and output range of the converter are 6–30 V, and ([Formula: see text]–3) V, respectively, with the maximum output current of 3 A. Moreover, its built-in current loop leads to good transient response characteristics. Therefore, it can be used widely in communication system and 12 V/24 V distributed power system.

Style APA, Harvard, Vancouver, ISO itp.

4

Malavena, Gerardo, Alessandro Sottocornola Spinelli i Christian Monzio Compagnoni. "A Noise-Resilient Neuromorphic Digit Classifier Based on NOR Flash Memories with Pulse–Width Modulation Scheme". Electronics 10, nr 22 (13.11.2021): 2784. http://dx.doi.org/10.3390/electronics10222784.

Pełny tekst źródła

Streszczenie:

In this work, we investigate the implementation of a neuromorphic digit classifier based on NOR Flash memory arrays as artificial synaptic arrays and exploiting a pulse-width modulation (PWM) scheme. Its performance is compared in presence of various noise sources against what achieved when a classical pulse-amplitude modulation (PAM) scheme is employed. First, by modeling the cell threshold voltage (VT) placement affected by program noise during a program-and-verify scheme based on incremental step pulse programming (ISPP), we show that the classifier truthfulness degradation due to the limited program accuracy achieved in the PWM case is considerably lower than that obtained with the PAM approach. Then, a similar analysis is carried out to investigate the classifier behavior after program in presence of cell VT instabilities due to random telegraph noise (RTN) and to temperature variations, leading again to results in favor of the PWM approach. In light of these results, the present work suggests a viable solution to overcome some of the more serious reliability issues of NOR Flash-based artificial neural networks, paving the way to the implementation of highly-reliable, noise-resilient neuromorphic systems.

Style APA, Harvard, Vancouver, ISO itp.

5

Ren, Jiaqi. "A Nonisolated Multiport Converter Based on LLC and Bidirectional Buck/Boost for Low Power EH-Battery Systems". CPSS Transactions on Power Electronics and Applications 7, nr 2 (30.06.2022): 196–205. http://dx.doi.org/10.24295/cpsstpea.2022.00018.

Pełny tekst źródła

Streszczenie:

Concerning about integration and high efficiency of topology, nonisolated multiport converters are widely researched in low power Energy-Harvesting-battery (EH-battery) systems. However, the pulse width modulation (PWM) based nonisolated multiport converters usually have the shortages of larger number of switches, ports’ voltage restrictions, hard switching, time-sharing transmission of energy and poor compatibility of MPPT algorithms. Therefore, in this article, a transformer-less multiport converter based on LLC and bidirectional buck/boost converter is proposed, which has the ability to step up and down voltage and well compatibility of MPPT. Meanwhile, soft switching technology is applied so that the converter can work in higher frequency and has smaller size. In addition, the energy can be transmitted simultaneously with the control of PWM and pulse frequency modulation (PFM). Finally, the experimental results of the proposed topology and its comparison with several topologies are given to prove the characteristics of the proposed converter

Style APA, Harvard, Vancouver, ISO itp.

6

Yin, Jingbo, Xing Liu, Xunde Guo i Lianwang Gudsla. "Software Optimization of Welding Machine Motion System Based on Switch Control Algorithm". Mobile Information Systems 2022 (22.06.2022): 1–6. http://dx.doi.org/10.1155/2022/1271190.

Pełny tekst źródła

Streszczenie:

In order to improve the software optimization of welding machine motion system based on switch control algorithm. Based on soft switch arc welding power source current peak control the stability of the BUCK converter, the method by solving peak current control circuit transfer function, and to analyze the formation mechanism of soft switch arc welding power source external characteristic, the frequency of pulse current in the simulation model is set to 200 Hz, the base value of pulse current is 40 A, the peak value of pulse current is 500 A, and the duty cycle is 40%. The welding wire melting speed during the peak value of pulse current is 480 mm/s, while the base value of pulse current is 20 mm/s. The results show that in the 2 s moment of the simulation model, the welding torch suddenly drops from 40 mm height to 30 mm height. Inevitably, the arc length changes from about 16 mm before the step to about 6 mm, which is basically equal to the step change distance. Using pulse frequency modulation (PFM) and adaptive adjustment of pulse current related parameters, effectively eliminate the interference factors in the welding process, quickly adjust arc welding parameters to make the welding wire melting speed equal to the wire feeding speed, maintain the stability of the welding process, and improve the weld forming effect. It is of great significance to the software optimization of the motion system of the pulse welding machine.

Style APA, Harvard, Vancouver, ISO itp.

7

Kanakis, Iliadis, Soenen, Moeneclaey, Argyris, Kalavrouziotis, Spiga, Bakopoulos i Avramopoulos. "High-Speed VCSEL-Based Transceiver for 200 GbE Short-Reach Intra-Datacenter Optical Interconnects". Applied Sciences 9, nr 12 (18.06.2019): 2488. http://dx.doi.org/10.3390/app9122488.

Pełny tekst źródła

Streszczenie:

The soaring demand for higher speeds in datacenters to address the relentless growth of the global IP traffic places optical interconnects in the spotlight. In this manuscript, we present a high-speed optical transceiver for intra-datacenter connectivity. The transceiver is based on single-mode, single-polarization high-speed vertical-cavity surface-emitting lasers (VCSELs), a VCSEL driver chip, and a linear receiver. Following a step-by-step approach, we present the architectures, assembly processes, and experimental results from the different modules. More specifically, we demonstrate (1) a data transmission experiment at 80 Gb/s using PAM-4 (four-level Pulse Amplitude Modulation) modulation for a reach of up to 500 m by employing a single-mode VCSEL module, and (2) a full-link experiment proving up to 64 Gb/s per lane capacity using PAM-4 signaling of the VCSEL-based optical transceiver test vehicles in back-to-back configuration and up to 56 Gb/s for 500 m and 2 km transmission distances. The acquired experimental results verify the suitability of the optical transceiver for intra-datacenter interconnects’ applications.

Style APA, Harvard, Vancouver, ISO itp.

8

Bahri, Hamza, i Adelghani Harrag. "Matlab/Stateflow P&O and ICMPPT Implementation for PEM Fuel Cell Power System". Progress in Solar Energy and Engineering Systems 5, nr 1 (31.12.2021): 1–7. http://dx.doi.org/10.18280/psees.050101.

Pełny tekst źródła

Streszczenie:

This paper outlines an innovative way in the assessment of proton exchange membrane fuel cell maximum power point tracking using Matlab/Stateflow implementation of variable step size version of perturb and observe and incremental conductance maximum power point tracking algorithms. In this study, the perturb and observe as well as the incremental conductance maximum power point tracking controllers have been completely implemented as Matlab/Stateflow models having as inputs: cell voltage, cell current and the variable step size; the model's output is the pulse width modulation ratio to drive the DC-DC boost converter for supplying the maximum power available from the 7kW proton exchange membrane fuel cell to a 50W resistive load. Simulation obtained results under different test scenarios prove the effectiveness of the proposed Matlab/Stateflow maximum power point tracking models that can provide accurate results and giving a strong tool to test and validate maximum power point tracking controllers.

Style APA, Harvard, Vancouver, ISO itp.

9

Kim, Younghee, Hongzhou Jin, Dohoon Kim, Panbong Ha, Min-Kyu Park, Joon Hwang, Jongho Lee i in. "Design of Synaptic Driving Circuit for TFT eFlash-Based Processing-In-Memory Hardware Using Hybrid Bonding". Electronics 12, nr 3 (29.01.2023): 678. http://dx.doi.org/10.3390/electronics12030678.

Pełny tekst źródła

Streszczenie:

This paper presents a synaptic driving circuit design for processing in-memory (PIM) hardware with a thin-film transistor (TFT) embedded flash (eFlash) for a binary/ternary-weight neural network (NN). An eFlash-based synaptic cell capable of programming negative weight values to store binary/ternary weight values (i.e., ±1, 0) and synaptic driving circuits for erase, program, and read operations of synaptic arrays have been proposed. The proposed synaptic driving circuits improve the calculation accuracy of PIM operation by precisely programming the sensing current of the eFlash synaptic cell to the target current (50 nA ± 0.5 nA) using a pulse train. In addition, during PIM operation, the pulse-width modulation (PWM) conversion circuit converts 8-bit input data into one continuous PWM pulse to minimize non-linearity in the synaptic sensing current integration step of the neuron circuit. The prototype chip, including the proposed synaptic driving circuit, PWM conversion circuit, neuron circuit, and digital blocks, is designed and laid out as the accelerator for binary/ternary weighted NN with a size of 324 × 80 × 10 using a 0.35 μm CMOS process. Hybrid bonding technology using bump bonding and wire bonding is used to package the designed CMOS accelerator die and TFT eFlash-based synapse array dies into a single chip package.

Style APA, Harvard, Vancouver, ISO itp.

10

Gaeid, Khalaf S., Mshari Aead Asker, Nada N. Tawfeeq i Salam Razooky Mahdi. "Computer Simulation of PMSM Motor with Five Phase Inverter Control using Signal Processing Techniques". International Journal of Electrical and Computer Engineering (IJECE) 8, nr 5 (1.10.2018): 3697. http://dx.doi.org/10.11591/ijece.v8i5.pp3697-3710.

Pełny tekst źródła

Streszczenie:

The signal processing techniques and computer simulation play an important role in the fault diagnosis and tolerance of all types of machines in the first step of design. Permanent magnet synchronous motor (PMSM) and five phase inverter with sine wave pulse width modulation (SPWM) strategy is developed. The PMSM speed is controlled by vector control. In this work, a fault tolerant control (FTC) system in the PMSM using wavelet switching is introduced. The feature extraction property of wavelet analysis used the error as obtained by the wavelet de-noised signal as input to the mechanism unit to decide the healthy system. The diagnosis algorithm, which depends on both wavelet and vector control to generate PWM as current based manage any parameter variation. An open-end phase PMSM has a larger range of speed regulation than normal PMSM. Simulation results confirm the validity and effectiveness of the switching strategy.

Style APA, Harvard, Vancouver, ISO itp.

11

Liu, Lianxi, Xufeng Liao, Wenbin Huang, Zhangming Zhu i Yintang Yang. "Adaptive On-Time-Controlled PFM Boost Converter with a Below-Threshold Startup Voltage". Journal of Circuits, Systems and Computers 27, nr 08 (12.04.2018): 1850120. http://dx.doi.org/10.1142/s0218126618501207.

Pełny tekst źródła

Streszczenie:

A high-efficiency pulse-frequency modulation (PFM) boost DC–DC converter with adaptive on-time (AOT) control method is proposed. A novel three-step startup procedure is proposed and applied on the boost converter, which makes the converter start up with a below-threshold voltage. Besides, adaptive on-time control method can reduce the output ripple dramatically. The proposed integrated boost converter is designed in an SMIC 0.18-[Formula: see text]m standard CMOS process and occupied a chip area of [Formula: see text][Formula: see text]mm2 without any low-[Formula: see text] MOSFETs. In the adopted process, the threshold voltages of PMOS and NMOS are [Formula: see text]0.45[Formula: see text]V and 0.48[Formula: see text]V, respectively. The simulation results show that the proposed converter can start up successfully at the input voltage of 0.25[Formula: see text]V, the output voltage is 1.8[Formula: see text]V with the ripple less than 33[Formula: see text]mV, and the peak efficiency can be up to 94.7%.

Style APA, Harvard, Vancouver, ISO itp.

12

Haentjens, B., G. Desruelles, G. Chrétien, A. Leborgne, Y. Haentjens, J. Dupuy, F. Jorge i in. "Packaging Tradeoff for SIP Integration Targeting High Speed PAM-4 Applications". International Symposium on Microelectronics 2015, nr 1 (1.10.2015): 000730–34. http://dx.doi.org/10.4071/isom-poster3.

Pełny tekst źródła

Streszczenie:

High speed transmission systems using optical fiber are now focusing on 4-level PAM (Pulse Amplitude Modulation) format. This is requesting ultra-wideband electronic system in package, with a high phase linearity behavior in order to drive the electro-optical modulators. Moreover, new power DAC (Digital to Analog Converter) dies, are now available to generate up to 56 GBd, 4-level PAM signals, and providing 4Vpp of differential output amplitude swing. High frequency studies have been pursued to provide system integration in a BGA (Ball Grid Array) package. The BGA package transitions optimization and the configuration of multi-lines carriers, becomes a key step in the design flow. In this paper, some steps of the design, manufacturing process of the SIP (System In Package) and its demonstration board are proposed. The choices of the package, the thermal management, the clock management function are studied according to the final environmental constraint of the SIP. The data lines phase skew are analyzed with the support of EM (Electro Magnetic) simulations to better understand the potential impact on the output eye. Finally, the BGA package transition, simulated and measured results are compared, from DC up to 40 GHz and the measured SIP output, 4 levels, 56GBps eye diagram is presented.

Style APA, Harvard, Vancouver, ISO itp.

13

Lu, Zhiqi, Ziwen Fang, Jun Huang i Xiaobin He. "Efficiency Analysis of Phase Shift LLC Resonant Converter". Journal of Physics: Conference Series 2396, nr 1 (1.12.2022): 012001. http://dx.doi.org/10.1088/1742-6596/2396/1/012001.

Pełny tekst źródła

Streszczenie:

Abstract Compared with pulse frequency modulation, a phase-shift modulated LLC resonant converter has a wider voltage modulation range and better EMI characteristics, but the efficiency is relatively lower. In this paper, the working process and power loss characteristics of PSM LLC are analyzed, the efficiency optimization method of PSM LLC is proposed, and the relevant conclusions are verified by simulation.

Style APA, Harvard, Vancouver, ISO itp.

14

Sanderson, Brian Gavin, Charles William Bangley, Louise Patricia McGarry i Daniel James Hasselman. "Measuring Detection Efficiency of High-Residency Acoustic Signals for Estimating Probability of Fish–Turbine Encounter in a Fast-Flowing Tidal Passage". Journal of Marine Science and Engineering 11, nr 6 (2.06.2023): 1172. http://dx.doi.org/10.3390/jmse11061172.

Pełny tekst źródła

Streszczenie:

Semidiurnal tidal currents can exceed 5 ms−1 in Minas Passage, Bay of Fundy, where a tidal energy demonstration area has been designated to generate electricity using marine hydrokinetic turbines. The risk of harmful fish–turbine interaction cannot be dismissed for either migratory or local fish populations. Individuals belonging to several fish populations were acoustically tagged and monitored by using acoustic receivers moored within the Minas Passage. Detection efficiency ρ is required as the first step to estimate the probability of fish–turbine encounter. Moored Innovasea HR2 receivers and high-residency (HR) tags were used to obtain detection efficiency ρ as a function of range and current speed, for near-seafloor signal paths within the tidal energy development area. Strong tidal currents moved moorings, so HR tag signals and their reflections from the sea surface were used to measure ranges from tags to receivers. HR2 self-signals that reflected off the sea surface showed which moorings were displaced to lower and higher levels on the seafloor. Some of the range testing paths had anomalously low ρ, which might be attributed to variable bathymetry blocking the line-of-sight signal path. Clear and blocked signal paths accord with mooring levels. The application of ρ is demonstrated for the calculation of abundance, effective detection range, and detection-positive intervals. High-residency signals were better detected than pulse position modulation (PPM) signals. Providing that the presently obtained ρ applies to tagged fish that swim higher in the water column, there is a reasonable prospect that probability of fish–turbine encounter can be estimated by monitoring fish that carry HR tags.

Style APA, Harvard, Vancouver, ISO itp.

15

Ebrahimpour-Malekshah, Roohollah, Abdollah Amini, Fatemeh Zare, Atarodsadat Mostafavinia, Samin Davoody, Niloofar Deravi, Mohammad Rahmanian i in. "Combined therapy of photobiomodulation and adipose-derived stem cells synergistically improve healing in an ischemic, infected and delayed healing wound model in rats with type 1 diabetes mellitus". BMJ Open Diabetes Research & Care 8, nr 1 (luty 2020): e001033. http://dx.doi.org/10.1136/bmjdrc-2019-001033.

Pełny tekst źródła

Streszczenie:

ObjectiveWe assessed the therapeutic effects of photobiomodulation (PBM) and adipose-derived stem cell (ADS) treatments individually and together on the maturation step of repairing of a delayed healing wound model in rats with type 1 diabetes mellitus (DM1).Research design and methodsWe randomly assigned 24 rats with DM1 to four groups (n=6 per group). Group 1 was the control (placebo) group. In group 2, allograft human ADSs were transplanted. Group 3 was subjected to PBM (wavelength: 890 nm, peak power output: 80 W, pulse frequency: 80 Hz, pulsed duration: 180 ns, duration of exposure for each point: 200 s, power density: 0.001 W/cm2, energy density: 0.2 J/cm2) immediately after surgery, which continued for 6 days per week for 16 days. Group 4 received both the human ADS and PBM. In addition, we inflicted an ischemic, delayed healing, and infected wound simulation in all of the rats. The wounds were infected with methicillin-resistant Staphylococcus aureus (MRSA).ResultsAll three treatment regimens significantly decreased the amount of microbial flora, significantly increased wound strength and significantly modulated inflammatory response and significantly increased angiogenesis on day 16. Microbiological analysis showed that PBM+ADS was significantly better than PBM and ADS alone. In terms of wound closure rate and angiogenesis, PBM+ADS was significantly better than the PBM, ADS and control groups.ConclusionsCombination therapy of PBM+ADS is more effective that either PBM or ADS in stimulating skin injury repair, and modulating inflammatory response in an MRSA-infected wound model of rats with DM1.

Style APA, Harvard, Vancouver, ISO itp.

16

Kilani, Dima, Baker Mohammad i Mohammad Alhawari. "Switched Inductor DC–DC Boost Regulator Using Voltage-to-Time Controller for TEG Applications". Energies 15, nr 9 (3.05.2022): 3330. http://dx.doi.org/10.3390/en15093330.

Pełny tekst źródła

Streszczenie:

This paper presents a switched inductor (SI) DC–DC boost regulator designed for thermoelectric generator (TEG) applications. To boost and regulate the output voltage, two feedback loops are implemented which control the duty cycle of the SI clock. The first loop consists of a pulse skip modulation (PSM) controller that compares the load voltage and reference voltage. Based on the comparison output, the PSM will either pass or bypass the modulated pulse width signal generated from the second loop. The second loop replaces the conventional circuit design of the pulse width modulation (PWM) with a voltage-to-time converter (VTC). The VTC converts the difference between load and supply voltage to time delay resulting in a modulated pulse width. This work is the first to report on utilizing VTC circuit in the SI boost regulator. The proposed SI boost regulator is designed using 65 nm CMOS technology which converts the TEG voltage of 50 mV to support dynamic voltage scaling in the range of 0.6 V to 0.8 V. The PSM and PWM controller loops can tune the duty cycle of the clock in the range of 0 to 70%. It achieves a peak efficiency of 60.9% at 30 μW load power. Comparing the proposed single-stage SI boost regulator with the conventional two cascaded stages of switched-inductor boost converter followed by switched capacitor regulator, the area is reduced by 9.6× and power efficiency is increased by 1.35×.

Style APA, Harvard, Vancouver, ISO itp.

17

KAPAT, SANTANU, SOUMITRO BANERJEE i AMIT PATRA. "ONE-DIMENSIONAL DISCONTINUOUS MAP ANALYSIS OF DC–DC CONVERTERS UNDER VOLTAGE CONTROLLED PULSE SKIPPING MODULATION". International Journal of Bifurcation and Chaos 22, nr 03 (marzec 2012): 1250049. http://dx.doi.org/10.1142/s0218127412500496.

Pełny tekst źródła

Streszczenie:

A pulse skipping modulation (PSM) technique is useful for improving the efficiency of a dc–dc converter under light load conditions. Under such condition, the discrete-time model of the converter could be modeled as a discontinuous map, comprising either 1D functions only or a combination of 1D and 2D functions. Using the PSM mechanism, efficiency and spectral composition could be further improved by incorporating a voltage feedback loop. In this paper we show that, in a converter under voltage controlled PSM, the entire map can be restricted to one dimension for a wide range of parameters, by properly designing the controller. As a parameter is varied, the periodicity of the output waveform may change either monotonically or non-monotonically depending on the character of the voltage mode control loop. Technically it is desirable to operate the converter in such a way that a variation of a parameter can cause only incremental change in the periodicity and hence in the spectral composition. In the nonlinear dynamics literature, such a bifurcation scenario is known as pure period incrementing cascade. Using the theory for 1D discontinuous maps, we obtain the conditions on the converter's parameters such that such a cascade is obtained, and the variation of a parameter does not cause large variation of the periodicity. The results have been experimentally validated.

Style APA, Harvard, Vancouver, ISO itp.

18

Li, Bin, Changyan Sun, Yun Ling, Heng Zhou i Kun Qiu. "Step-Pulse Modulation of Gain-Switched Semiconductor Pulsed Laser". Applied Sciences 9, nr 3 (12.02.2019): 602. http://dx.doi.org/10.3390/app9030602.

Pełny tekst źródła

Streszczenie:

To improve the peak power and extinction ratio and produce ultra-short pulses, a novel approach is presented in this paper offers a highly effective modulated method for a gain-switched semiconductor laser by using step-pulse signal modulation. For the purpose of single pulse output, then the effects on the output from the gain-switched semiconductor laser are studied by simulating single mode rate equation when changing the amplitude and width of the modulated signal. The results show that the proposed method can effectively accelerate the accumulation speed of the population inversion and we can acquire the output pulse with higher peak power and shorter width. Compared with the traditional rectangular wave modulation, this method is advantageous to obtain a high gain switching effect by increasing the second modulation current and reduce the pulse width to saturation at the best working point. It can be incorporated as a practical and cost-effective approach for many fields which need high extinction ratio short pulse, such as the optical time domain reflectometry.

Style APA, Harvard, Vancouver, ISO itp.

19

Gujjula, Ramana Reddy, Chitra Perumal, Prakash Kodali i Bodapati Venkata Rajanna. "Design and analysis of dual-mode numerically controlled oscillators based controlled oscillator frequency modulation". International Journal of Electrical and Computer Engineering (IJECE) 12, nr 5 (1.10.2022): 4935. http://dx.doi.org/10.11591/ijece.v12i5.pp4935-4943.

Pełny tekst źródła

Streszczenie:

In this paper, the design and analysis of dual-mode numerically controlled oscillators (NCO) based controlled oscillator frequency Modulation is implemented. Initially, input is given to the analog to digital (ADC) converter. This will change the input from analog to digital converter. After that, the pulse skipping mode (PSM) logic and proportional integral (PI) are applied to the converted data. After applying PSM logic, data is directly transferred to the connection block. The proportional and integral block will transfer the data will be decoded using the decoder. After decoding the values, it is saved using a modulo accumulator. After that, it is converted from one hot residue (OHR) to binary converter. The converted data is saved in the register. Now both data will pass through the gate driver circuit and output will be obtained finally. From simulation results, it can observe that the usage of metal oxide semiconductor field effect transistors (MOSFETs) and total nodes are very less in dual-mode NCO-based controlled oscillator frequency modulation.

Style APA, Harvard, Vancouver, ISO itp.

20

Ke, Xinran. "Analysis on improving channel capacity of MPPM". Highlights in Science, Engineering and Technology 53 (30.06.2023): 133–43. http://dx.doi.org/10.54097/hset.v53i.9698.

Pełny tekst źródła

Streszczenie:

Nowadays, optical wireless communication has been widely applied and various techniques are used to achieve signals with higher quality and higher efficiency. Pulse position modulation (PPM) is a commonly used modulation scheme. However, PPM suffers from its low bandwidth efficiency and Multiple pulse position modulation (MPPM) is generated to improve the performance of signals. Further research can be carried out to figure out ways to further improve channel capacity of communication systems by combining modulation techniques together. In this paper, three different schemes are introduced, including LDPC-coded MPPM UWOC system, MIMO-MPPM WOC system, and PSM-MPPM system. Fundamental principles of these three techniques are mentioned before going through the methods used to carrying out experiments. Both simulations derived from numerical analysis and experiment results are obtained to support the results. In LDPC-coded and MIMO research, turbulence effects are considered by adopting different statistical distributions. The aim of the paper is to compare properties of three recent research and discuss how they can be applied in different scenarios to improve the communication systems.

Style APA, Harvard, Vancouver, ISO itp.

21

Arimoto, Hideki, Hisakazu Umeda, Yukiji Yamauchi i Shukichi Kaku. "Two-step pulse width modulation sinusoidal inverter with modulation switching and frequency spectra". Electronics and Communications in Japan (Part III: Fundamental Electronic Science) 78, nr 11 (listopad 1995): 80–88. http://dx.doi.org/10.1002/ecjc.4430781108.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

22

Al Attar, Houssein, Mohamed Assaad Hamida, Malek Ghanes i Miassa Taleb. "Review on Modeling and Control Strategies of DC–DC LLC Converters for Bidirectional Electric Vehicle Charger Applications". Energies 16, nr 9 (8.05.2023): 3946. http://dx.doi.org/10.3390/en16093946.

Pełny tekst źródła

Streszczenie:

Bidirectional DC–DC converters are frequently chosen for applications requiring high power density such as in bidirectional electric vehicle (EV) chargers. Vehicle to Everything (V2X) technology makes the EV battery an electrical energy source. In this article, the use of a DC–DC LLC converter used in a bidirectional EV charger is reviewed. Different modeling approaches of the DC–DC LLC converter, such as small and large signal modeling, are discussed. Common modulation strategies applied to the DC–DC LLC converter in V2X mode, such as Pulse Frequency Modulation (PFM), Pulse Width Modulation (PWM) and Phase-Shift Modulation (PSM), are presented. The new challenge is to present the main characteristics and limitations of each modulation strategy in order to cover the whole operating zone of the EV charger in V2X mode. Furthermore, different control strategies based on a small or large signal model combined with different modulation strategies are highlighted. Linear and nonlinear controllers applied to the DC–DC LLC converter are discussed. Robust controllers are mainly highlighted regarding their advantage in ensuring the control robustness with respect to unexpected disturbances. A comparative study among modulation strategies as well as different control algorithms is conducted in terms of control performance and converter efficiency in V2X mode.

Style APA, Harvard, Vancouver, ISO itp.

23

Valizade, Arash, Pejman Rezaei i Ali Asghar Orouji. "A compact reconfigurable sub-nanosecond pulse generator with pulse-shape modulation". International Journal of Microwave and Wireless Technologies 9, nr 4 (15.08.2016): 741–45. http://dx.doi.org/10.1017/s1759078716000921.

Pełny tekst źródła

Streszczenie:

A new design of reconfigurable sub-nanosecond pulse generator (PG) with pulse shape selection ability is presented in this paper. Step recovery diode is used as the pulse sharpening device and the pulse shaping circuit consists of a controllable RC differentiator in which a single PIN diode is embedded, which provides two different switchable pulse shaping performances. The realized PG has a compact (10 × 12 mm2) simple structure and is easy to implement while generating Gaussian and monocycle pulses with 510 and 660 ps pulse width, respectively. The proposed pulse shaping method is versatile and can be effectively modified and reconfigured to generate more complicated pulse shapes such as polycycle signals. The measured results reveal that the proposed reconfigurable PG is suitable to be used in systems with pulse shape modulation that require sub-nanosecond pulses at low pulse repetition rates.

Style APA, Harvard, Vancouver, ISO itp.

24

Rohit, Shinde, Ramachandiran Gunabalan i Mehtra Pavan Kumar. "Pulse Density Modulation Flyback Converter for LED Automotive Lighting". Indonesian Journal of Electrical Engineering and Computer Science 8, nr 1 (1.10.2017): 85. http://dx.doi.org/10.11591/ijeecs.v8.i1.pp85-91.

Pełny tekst źródła

Streszczenie:

Switched mode power supply (SMPS) converter is a dc-dc power electronic converter which is used to step up or step down the dc output voltage. A dimmable driver circuit for Light Emitting Diode (LED) lamp for automotive lighting with dimming feature is used in this paper. A flyback converter is used as a driver circuit operated in discontinuous conduction mode to perform dimming control of LEDs. High overall circuit efficiency is achieved by regulating the current through the LED lamps using pulse density modulation scheme. The LED driver circuit design and operating principle is discussed in detail. A gentle current control feature is achieved by pulse density modulation technique. The high performance driver circuit is designed for 25 W LED lamps.

Style APA, Harvard, Vancouver, ISO itp.

25

CIUCUR, VIOLETA-VALI. "ELECTRICAL DRIVE AND CONTROL OF AN ELECTRIC MOTOR STEP BY STEP BY STEP BIPOLAR". Journal of marine Technology and Environment 2021, nr 2 (1.10.2021): 11–14. http://dx.doi.org/10.53464/jmte.02.2021.02.

Pełny tekst źródła

Streszczenie:

"PWM, (Pulse Width Modulation) is the most effective way to control analog circuits using numerical outputs by changing the duration and frequency of the signal. The duration of each state t1 and t2, so the filling factor, where T = t1 + t2 = constant. If only one of the times (t1 or t2) varies, then the Tt period of a cycle varies, so the f = 1 / T frequency varies. The PWM signal is actually a modulated rectangular signal over the duration by modifying the duration of each period t1, t2 of the cycle as well as the change in frequency. The maximum benefit of a stepper motor can only be obtained if it is ordered correctly, this requiring a direct current source, an electronic switch and a controlled pulse generator (numerical information). The frequency of the CLOCK cycle is measured in Hz and the filling factor is measured in percentage (%). The amplitude of the output signal is constant even if the amplitude of signals producing the fill factor varies. "

Style APA, Harvard, Vancouver, ISO itp.

26

Ma, Shaoxiang, Bangyou Zhu, Shengyuan Guan, Aoxiang Wang, Ming Zhang, Hongqi Zhang, Kexun Yu i Yuan Pan. "Development of a novel power module based on pulse step modulation". Fusion Engineering and Design 169 (sierpień 2021): 112491. http://dx.doi.org/10.1016/j.fusengdes.2021.112491.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

27

Zhao, Shuaipeng, Xin Liu, Yingxi Wang i Yong An. "A 125 KHz, Single-Stage, Dual-Output Wireless Power Receiver with PSM Modulation". Electronics 11, nr 8 (8.04.2022): 1184. http://dx.doi.org/10.3390/electronics11081184.

Pełny tekst źródła

Streszczenie:

This paper presents a 125 KHz, single-stage, dual-output wireless power receiver with pulse skip modulation (PSM). Multi-output receivers are proposed to supply different modules in one system. Conventional multi-output receivers contain a rectifier and a multi-output regulator, which degrade the power conversion efficiency (PCE) due to interstage loss of the rectifier and the regulator. Additionally, existing single-inductor multi-output (SIMO) receivers exhibit a cross-regulation phenomenon because of the sharing inductor, which decreases the stability of the output voltages, and the use of an inductor in SIMO receivers increases the cost of the circuit. The proposed receiver in this article realizes rectification and regulation in only one stage, which eliminates interstage loss; this improves the power conversion efficiency of the system and realizes dual-output voltages with only four power transistors without an inductor, which reduces the chip area and minimizes cost. There is no cross-regulation in this dual-output architecture because the dual-output voltages are charged by different phases of the input signal. PSM modulation was adopted to regulate output voltages for higher efficiency. The proposed single-stage, dual-output regulating rectifier delivers a maximum power of 47 mW, and the dual-output voltages are 1.8 V and 2 V. This receiver is designed by a 0.18 μm complementary metal-oxide-semiconductor (CMOS) process and realizes a peak efficiency of 86% when the output power ranges from 15 mW to 47 mW.

Style APA, Harvard, Vancouver, ISO itp.

28

Cheng, Hung Liang, Chun An Cheng, Chao Shun Chen i Kuan Lung Huang. "Design and Implementation of a Dimmable LED Driver with Low-Frequency PWM Control". Applied Mechanics and Materials 284-287 (styczeń 2013): 2538–42. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.2538.

Pełny tekst źródła

Streszczenie:

This paper proposes a high-efficiency dimmable LED driver for light emitting diodes (LED). The developed LED driver consists of a full-bridge resonant converter and six buck converters. The function of the full-bridge resonant converter is to obtain a smooth dc-link voltage for the buck converters by phase-shift modulation (PSM) while that of the six buck converters is to drive six LED modules, respectively. The gate voltage of the active switch of each buck converter is a combination of high-frequency and low-frequency pulses. The duty ratio of the high-frequency pulse controls the LED voltage and thereby, controls the amplitude of LED current. LEDs are dimmed by low-frequency pulse-width modulation (PWM) to vary the average current flowing through LED. Circuit equations are derived and circuit parameters are designed. High circuit efficiency is ensured by operating the active switches at zero-voltage switching-on to reduce the switching loss. Finally, a prototype circuit was built to verify the accuracy and feasibility of the proposed LED driver.

Style APA, Harvard, Vancouver, ISO itp.

29

Okhotkin, Grigory P., i Ivan I. Ivanchin. "SPACE VECTOR PWM IN A MULTILEVEL VOLTAGE CONVERTER". Vestnik Chuvashskogo universiteta, nr 1 (30.03.2022): 107–14. http://dx.doi.org/10.47026/1810-1909-2022-1-107-114.

Pełny tekst źródła

Streszczenie:

The present article considers the voltage forming by multilevel converters. Multilevel converters are widely used in industry applications with medium voltages up to 20 kV. An example is the oil industry, where multilevel converters are installed in electric drives of pumping units on pipeline systems. The location of the pipelines in isolated areas implies weak net connections for power system and expects increased requirements for the efficiency of the use of electricity. In this regard, for a multilevel voltage converter, an energy-efficient vector method of pulse-width modulation is proposed. With vector pulse-width modulation, the optimal number of voltage level switching occurs in the phases of the converter, which leads to the lowest harmonic distortion of the voltage, compared with other modulation methods. The features of vector pulse-width modulation in multilevel voltage converters caused by the increased number of basic voltage vectors of a static multilevel converter are analyzed. A step-by-step method of vector pulse-width modulation in a multilevel converter is proposed, including determining the base vectors of the converter closest to a reference voltage vector, calculating the time for each of the base vectors, maintaining the switching order between the base vectors. The method is considered in detail for a multilevel converter with five voltage levels in a phase. In conclusion, the results of modeling control system of this converter with the proposed method of vector pulse-width modulation are presented. According to the obtained time diagrams of voltage formation, a hodograph of the resulting vector of the output voltage of a multilevel static converter was constructed.

Style APA, Harvard, Vancouver, ISO itp.

30

Ravi Kumar, K., i Prof P. Rajesh Kumar. "Implementation of Multi-Objective Grey Wolf Optimizer to Minimize The Sidelobes And Reduce Mainlobe Width". International Journal of Engineering & Technology 7, nr 2.20 (18.04.2018): 219. http://dx.doi.org/10.14419/ijet.v7i2.20.13299.

Pełny tekst źródła

Streszczenie:

Range resolution in radar can be achieved by splitting the long pulse of high energy into the high bandwidth of short pulses using pulse compression technique. Frequency modulation (Linear frequency modulation (LFM)) signal is used to improve range resolution. To get better range resolution, frequency step is introduced between a train of LFM pulses known as stepped frequency pulse train (the SFPT). The SFPT suffers from grating lobes when the product of sub-pulse duration and frequency step becomes more than one. The grating lobes and sidelobes present in the vicinity of the mainlobe. It can cause the false alarm detection and hide the small targets. In this work, Multi-Objective Grey Wolf Algorithm (MOGWO) is used to set the parameters of SFPT to mitigate the grating lobes and minimize the sidelobes at the matched filter output. Trade-off solutions between sidelobes versus grating lobes and mainlobe width versus sidelobes are obtained using the Pareto front for different ranges of SFPT parameters.

Style APA, Harvard, Vancouver, ISO itp.

31

HUANG, YUNXIA, SHUWU XU i XIAOHUA YANG. "HIGH-RESOLUTION PHOTOELECTRON SPECTROSCOPY BY SPECTRAL PHASE STEP MODULATION". Journal of Nonlinear Optical Physics & Materials 22, nr 04 (grudzień 2013): 1350045. http://dx.doi.org/10.1142/s0218863513500458.

Pełny tekst źródła

Streszczenie:

Femtosecond-induced resonance-enhanced multi-photon ionization photoelectron spectroscopy (REMPI-PES) has the drawback of low spectral resolution due to broadband spectrum of the laser. In this paper, we theoretically demonstrate that high-resolution REMPI-PES can be achieved by shaping the femtosecond laser pulse with spectral phase step modulation. Our results show that, by manipulating the phase step position and the modulation depth, a narrowband peak or hole in the photoelectron spectrum can be observed, and the position of the narrowband peak or hole is correlated with the eigenenergy of the excite state. Therefore, both high-resolution REMPI-PES and the excited state structure can be obtained by observing the narrowband peaks or holes.

Style APA, Harvard, Vancouver, ISO itp.

32

Yang, Min, Song Bai Li i Kai Xia. "Study on the Influence of Nonlinear Effect on Pulse Trapping in Photonic Crystal Fiber". Applied Mechanics and Materials 416-417 (wrzesień 2013): 1685–88. http://dx.doi.org/10.4028/www.scientific.net/amm.416-417.1685.

Pełny tekst źródła

Streszczenie:

Based on the nonlinear Schrödinger equations which can satisfy the optical pulses transmission in photonic crystal fiber, it is numerically simulated the pulse t rapping courses between the pump pulse in negative dispersion region and the signal pulse in positive dispersion region using step by step Fourier method, and the effect the nonlinear coefficient to the trapping course. The result shows if the nonlinear coefficient is small, the pulse trapping cant realize. Conversely, if the nonlinear coefficient increases, the cross phase modulation between the two pulses is enhanced and the frequency shifts are intensified too. When the group velocity is matched, the pulse trapping is realized. And the degree of trapping is strength accompany with the nonlinear coefficient increasing.

Style APA, Harvard, Vancouver, ISO itp.

33

XU, SHUWU, YUNXIA HUANG i XIANMING JI. "SELECTIVE EXCITATION OF COHERENT ANTI-STOKES RAMAN SCATTERING VIA PHASE STEP MODULATION". Journal of Nonlinear Optical Physics & Materials 22, nr 01 (marzec 2013): 1350002. http://dx.doi.org/10.1142/s0218863513500021.

Pełny tekst źródła

Streszczenie:

It is known that femtosecond coherent anti-Stokes Raman scattering (CARS) method suffers from the drawback of poor selectivity between neighboring Raman energy levels due to the large bandwidth of the pulses. Quantum coherent control based on the ultrashort pulse shaping technique is a promising solution. In this paper, we propose a simple approach to realize the selective excitation of CARS spectra by shaping both the probe and pump pulses with the π phase step. By phase step modulation of the probe pulse, we show that the CARS signals between neighboring Raman energy levels can be greatly narrowed and differentiated, and then selective excitation can be realized by modulating both the probe and pump pulses. Finally, the mechanism of the selective excitation by population transfer is briefly discussed.

Style APA, Harvard, Vancouver, ISO itp.

34

Gao, Qiang, Matti Linjama, Miika Paloniitty i Yuchuan Zhu. "Investigation on positioning control strategy and switching optimization of an equal coded digital valve system". Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 234, nr 8 (7.11.2019): 959–72. http://dx.doi.org/10.1177/0959651819884749.

Pełny tekst źródła

Streszczenie:

This article concerns high accuracy positioning control with switching optimization for an equal coded digital valve system. Typically, pulse number modulation control cannot realize micro-positioning due to the characteristics of step-wise flow variation, therefore, a new position controller consisting of a model-based pulse number modulation and a differential pulse width modulation strategy is proposed to control the position of a hydraulic cylinder at high and low velocity cases, respectively. In addition, in order to solve several problems caused by the pulse number modulation and differential pulse width modulation, such as increased number of switchings and large difference among number of switchings of valves, a switching optimization consisting of a switching cost function, a circular buffer and a circular switching method is proposed. An adaptive weight of the switching cost function is proposed for the first time to reduce the total number of switchings under different pressure differences and its design criterion is presented. A circular buffer and a new circular switching method are used to improve the degree of equal distribution of switchings when the pulse number modulation and differential pulse width modulation are used, respectively. Comparative experimental results indicated that the average and the minimum positioning error for the proposed controller are only 10 and 1 μm, respectively. The number of switchings and the degree of equal distribution of switchings are significantly optimized. Moreover, the pressure fluctuations caused by the proposed controller remain acceptable.

Style APA, Harvard, Vancouver, ISO itp.

35

Lin, Jing-Yuan, Kuan-Hung Chen, Pin-Hsian Liu, Hsuan-Yu Yueh i Yi-Feng Lin. "Current Sharing Control of an Interleaved Three-Phase Series-Resonant Converter with Phase Shift Modulation". Energies 14, nr 9 (26.04.2021): 2470. http://dx.doi.org/10.3390/en14092470.

Pełny tekst źródła

Streszczenie:

Recently, three-phase series-resonant converters (SRCs) have been proposed for high power applications. Three-phase SRCs can achieve zero-voltage-switching (ZVS) of the primary power switches and regulate the output voltage by pulse-frequency modulation. The interleaving technique is also a conventional method for DC-DC converters to achieve a high power level, reducing the output voltage ripples due to operating out of phase at the same frequency between the two converters. However, an interleaved three-phase SRC cannot easily synchronize switching instants between the two modules due to the component tolerances of circuits. In the proposed control method, phase shift modulation (PSM) is used to solve the output current imbalance caused by component tolerances. The power switches of the converter can also maintain synchronizing switching instants between the two modules. Therefore, the lower output voltage ripple can be achieved. A detailed analysis and design of this new control method for interleaved three-phase SRCs are described. Finally, prototype converters with a 2.4 kW total output were built and successfully tested to verify the feasibility of the current sharing modulation.

Style APA, Harvard, Vancouver, ISO itp.

36

Budevska, Boiana O., i Christopher J. Manning. "Time-Resolved Impulse Photoacoustic Measurements by Step-Scan FT-IR Spectrometry". Applied Spectroscopy 50, nr 7 (lipiec 1996): 939–47. http://dx.doi.org/10.1366/0003702963905457.

Pełny tekst źródła

Streszczenie:

An impulse/response approach for measuring photoacoustic spectra is described. Instead of the usual modulation from either a chopper or an interferometric phase modulation, a radiation pulse is used to generate the photoacoustic (PA) signal at each step of a step-scan FT-IR spectrometer. The signal from the PA cell is recorded as a time-resolved sequence. The time-dependent photoacoustic signal reveals depth-profiling information for solid samples. Examples of time-resolved impulse photoacoustic spectra (TRIPAS) of gas and solid samples are presented.

Style APA, Harvard, Vancouver, ISO itp.

37

Wang, Yunshi, Changming Zhao, Liwei Zhang, Chun Liu i Jian Li. "High-Efficiency Pulse Width Modulation-Based Wireless Laser Power Transmission Step-Down System". IEEE Photonics Journal 12, nr 2 (kwiecień 2020): 1–14. http://dx.doi.org/10.1109/jphot.2020.2973727.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

38

Lv, Xiang-Yun, Quan-Zhi Zhang, Ke Jiang, Fei Gao i You-Nian Wang. "Optimization of overshoot in the pulsed radio frequency inductively coupled argon plasma by step waveform modulation". Journal of Applied Physics 133, nr 4 (28.01.2023): 043301. http://dx.doi.org/10.1063/5.0130054.

Pełny tekst źródła

Streszczenie:

The pulsed inductively coupled plasma (ICP) has considerable potential to satisfy multiple stringent scaling requirements for use in the semiconductor industry. However, overshoot of plasma parameters during the rising period of the pulse affects the stability and uniformity of the plasma and can lead to a breakdown of the wafer and over-sputtering of the film. In this study, a step waveform modulation method is used to reduce the overshoot at the initial stage of the pulse. The behavior of the discharge is monitored by measuring (i) the modulated step waveform signal on the function generator, (ii) the input power (by a time-resolved VI-probe), and (iii) the amplitudes of the coil voltage and current (by voltage and current probes, respectively), as well as (iv) the plasma parameters including the electron density, the effective electron temperature, and the electron energy probability distribution function (by a time-resolved Langmuir probe). It was found that the state of the plasma can be controlled by changing the waveform, such as varying the time of the rising edge, varying the initial amplitude, and varying the duration of the low-high amplitude. The results indicated that the overshoot value of the electron density can be reduced by using a low-high step waveform. When the amplitude of the waveform was 500/550 mV and the duration was 200/300 μs, the overshoot value observed was 1/4 of that of the conventional ICP pulse discharge. In addition, increasing the duty cycle of the pulse could also reduce the overshoot value due to the high electron density that occurs during the afterglow period. Moreover, the plasma can reach a steady state more quickly at high pressure by using a step waveform of high amplitude.

Style APA, Harvard, Vancouver, ISO itp.

39

Varlamov, Oleg V., Dang C. Nguyen i Sergey E. Grychkin. "COMBINATION OF SYNTHETIC HIGH-PERFORMANCE RF AMPLIFICATION TECHNIQUES". T-Comm 15, nr 9 (2021): 11–16. http://dx.doi.org/10.36724/2072-8735-2021-15-9-11-16.

Pełny tekst źródła

Streszczenie:

To amplify modern high crest factor telecommunication radio signals with high efficiency, switching operation modes of transistors and synthetic amplification methods are used. The most common of these are the Kahn method (EER – envelope elimination and restoration) and the outphasing method. However, application of these methods has a number of technological (in terms of element base capabilities) limitations on the bandwidth and dynamic range of amplified signal. To expand high-efficiency RF power amplifiers field of application, the possibilities of combination several different synthetic amplification techniques are being considered. Expressions are obtained for the theoretically achievable efficiency when combining the outphasing method with a bridge power combiner and pulse-step modulation of supply voltage. The dependence of average efficiency on the number of supply voltage levels is determined. RF amplified signal bandwidth and its dynamic range determine the minimum required pulse width of the PWM modulator for the EER amplifier. Variants of these characteristics dependence on the number of supply voltage levels are discussed with combined use of PWM and pulse-step modulation of the supply voltage. Directions for further research are formulated.

Style APA, Harvard, Vancouver, ISO itp.

40

Ameen, Yasir M. Y., Bashar A. Fadheel i Ali J. Mahdi. "Third harmonic injection pulse-width modulation technique for a five-phase voltage source inverter". Indonesian Journal of Electrical Engineering and Computer Science 17, nr 3 (1.03.2020): 1607. http://dx.doi.org/10.11591/ijeecs.v17.i3.pp1607-1617.

Pełny tekst źródła

Streszczenie:

Nowadays application of advanced power electronic technology enables producing an AC supply with a phase number higher than three-phase. Five-phase voltage source inverters (5ph-VSI) have been used in advanced power electronic drives to improve the reliability of the drive system and to boost the power capability of the converter as well as to their other inherent merits. This paper shows the mathematical analysis and simulation of the third harmonic injection pulse width modulation (THI-PWM) 5ph-VSI connected with inductive load in three scenarios i.e. star, Pentagon and pentacle. The presented THI-PWM technique for 5ph-VSI aims to increase the inverter fundamental voltage and hence to maximize the utilization of the DC bus without causing over-modulation. The simulation results are compared with typical sinusoidal pulse width modulation (SPWM) and the 10-step mode operation. The proposed scheme may be considered as a compromise case between the two reference cases; as low harmonic components compared with 10-step mode operation and a high utilization factor compared with SPWM.

Style APA, Harvard, Vancouver, ISO itp.

41

Corrias, Valentina, Giovanni de Vincenzi, Maria Ceraulo, Virginia Sciacca, Antonello Sala, Giuseppe Andrea de Lucia i Francesco Filiciotto. "Bottlenose Dolphin (Tursiops truncatus) Whistle Modulation during a Trawl Bycatch Event in the Adriatic Sea". Animals 11, nr 12 (19.12.2021): 3593. http://dx.doi.org/10.3390/ani11123593.

Pełny tekst źródła

Streszczenie:

Marine mammal vocal elements have been investigated for decades to assess whether they correlate with stress levels or stress indicators. Due to their acoustic plasticity, the interpretation of dolphins’ acoustic signals of has been studied most extensively. This work describes the acoustic parameters detected in whistle spectral contours, collected using passive acoustic monitoring (PAM), in a bycatch event that involved three Bottlenose dolphins during midwater commercial trawling. The results indicate a total number of 23 upsweep whistles recorded during the bycatch event, that were analyzed based on the acoustic parameters as follows: (Median; 25th percentile; 75th percentile) Dr (second), total duration (1.09; 0.88; 1.24); fmin (HZ), minimum frequency (5836.4; 5635.3; 5967.1); fmax (HZ), maximum frequency, (11,610 ± 11,293; 11,810); fc (HZ), central frequency; (8665.2; 8492.9; 8982.8); BW (HZ), bandwidth (5836.4; 5635.3; 5967.1); Step, number of step (5; 4; 6). Furthermore, our data show that vocal production during the capture event was characterized by an undescribed to date combination of two signals, an ascending whistle (upsweep), and a pulsed signal that we called “low-frequency signal” in the frequency band between 4.5 and 7 kHz. This capture event reveals a novel aspect of T. truncatus acoustic communication, it confirms their acoustic plasticity, and suggests that states of discomfort are conveyed through their acoustic repertoire.

Style APA, Harvard, Vancouver, ISO itp.

42

Wang, C. M., C. H. Su i K. L. Fang. "Zero-voltage-switching pulse-width-modulation full-bridge transformer-isolated step-up/down converter". IET Power Electronics 1, nr 1 (2008): 122. http://dx.doi.org/10.1049/iet-pel:20060359.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

43

Habib, Benbouhenni. "Robust Direct Power Control of a DFIG Fed by a Five- Level NPC Inverter Using Neural SVPWM Technique". Tecnica Italiana-Italian Journal of Engineering Science 65, nr 1 (31.03.2021): 119–28. http://dx.doi.org/10.18280/ti-ijes.650118.

Pełny tekst źródła

Streszczenie:

The work presents a new direct power command (DPC) strategy based on a second order sliding mode controller (SOSMC) of a doubly fed induction generator (DFIG) integrated in a wind energy conversion system (WECS). In the first step we propose to use a five-level inverter based on the neural space vector pulse width modulation (NSVPWM) to supply the DFIG rotor side. This is the harmonic distortion (THD) of the DFIG rotor voltage and then performs provides the power to the grid by the stator side. The traditional DPC with space vector pulse width modulation (DPC-SVPWM) using proportional-integral (PI) controllers has considerable reactive and active power oscillations at a steady-state operation. In order to ensure a robust DFIG DPC-SVPWM technique and minimize the reactive and active power ripples, a SOSMC algorithms is used in the second step. The Simulation results show the efficiency of the designed control scheme especially in terms of the quality of the provided power compared to DPC-SVPWM.

Style APA, Harvard, Vancouver, ISO itp.

44

Uddin, Md Shihab, Shuvra Prokash Biswas, Md Rabiul Islam, Md Shamim Anower, Abbas Z. Kouzani i M. A. Parvez Mahmud. "A New Generalized Step-Down Single-Stage AC/AC Power Converter". Sustainability 12, nr 21 (4.11.2020): 9181. http://dx.doi.org/10.3390/su12219181.

Pełny tekst źródła

Streszczenie:

Most traditional AC/AC power converters suffer from power quality problems and multi-stage power conversion losses. The rectifier and inverter-based AC/AC converter topology not only increases multi-stage power conversion losses, but also increases the volume, weight, and cost, and decreases the longevity of the converter due to the DC-link capacitor, line filter and electromagnetic interference (EMI) filter. High-frequency (about 10 kHz) switching advanced pulse width modulation techniques are generally used in order to compensate the power quality problems, which increase the switching losses and introduce the EMI problems. In this paper, a new generalized step-down single-stage line-frequency switching AC/AC power converter topology is proposed. The proposed converter uses line-frequency switching, and does not require any pulse width modulation techniques. The proposed topology offers promising performances in terms of lower order harmonics, total harmonic distortion, the elimination of DC-link capacitors and EMI filters, and switching losses. The circuit was designed and simulated in a MATLAB/Simulink environment. A scaled-down laboratory prototype of the proposed topology was developed in order to validate the feasibility. The experimental and simulation results reveal the feasibility of the proposed generalized step-down single-stage converter topology, and its excellent features.

Style APA, Harvard, Vancouver, ISO itp.

45

Boutros, Peter J., Nicolas S. Valentin, Kristin N. Hageman, Chenkai Dai, Dale Roberts i Charles C. Della Santina. "Nonhuman primate vestibuloocular reflex responses to prosthetic vestibular stimulation are robust to pulse timing errors caused by temporal discretization". Journal of Neurophysiology 121, nr 6 (1.06.2019): 2256–66. http://dx.doi.org/10.1152/jn.00887.2018.

Pełny tekst źródła

Streszczenie:

Electrical stimulation of vestibular afferent neurons to partially restore semicircular canal sensation of head rotation and the stabilizing reflexes that sensation supports has potential to effectively treat individuals disabled by bilateral vestibular hypofunction. Ideally, a vestibular implant system using this approach would be integrated with a cochlear implant, which would provide clinicians with a means to simultaneously treat loss of both vestibular and auditory sensation. Despite obvious similarities, merging these technologies poses several challenges, including stimulus pulse timing errors that arise when a system must implement a pulse frequency modulation-encoding scheme (as is used in vestibular implants to mimic normal vestibular nerve encoding of head movement) within fixed-rate continuous interleaved sampling (CIS) strategies used in cochlear implants. Pulse timing errors caused by temporal discretization inherent to CIS create stair step discontinuities of the vestibular implant’s smooth mapping of head velocity to stimulus pulse frequency. In this study, we assayed electrically evoked vestibuloocular reflex responses in two rhesus macaques using both a smooth pulse frequency modulation map and a discretized map corrupted by temporal errors typical of those arising in a combined cochlear-vestibular implant. Responses were measured using three-dimensional scleral coil oculography for prosthetic electrical stimuli representing sinusoidal head velocity waveforms that varied over 50–400°/s and 0.1–5 Hz. Pulse timing errors produced negligible effects on responses across all canals in both animals, indicating that temporal discretization inherent to implementing a pulse frequency modulation-coding scheme within a cochlear implant’s CIS fixed pulse timing framework need not sacrifice performance of the combined system’s vestibular implant portion. NEW & NOTEWORTHY Merging a vestibular implant system with existing cochlear implant technology can provide clinicians with a means to restore both vestibular and auditory sensation. Pulse timing errors inherent to integration of pulse frequency modulation vestibular stimulation with fixed-rate, continuous interleaved sampling cochlear implant stimulation would discretize the smooth head velocity encoding of a combined device. In this study, we show these pulse timing errors produce negligible effects on electrically evoked vestibulo-ocular reflex responses in two rhesus macaques.

Style APA, Harvard, Vancouver, ISO itp.

46

SAADI, Ramzi, i Mohamed Yacine HAMMOUDI. "Parallel Distributed Compensation for Three-Phase pulse width modulation converter". Electrotehnica, Electronica, Automatica 71, nr 2 (15.05.2023): 38–45. http://dx.doi.org/10.46904/eea.23.71.2.1108005.

Pełny tekst źródła

Streszczenie:

In applications such as industrial drive systems and power supply systems, the use of a three-phase voltage-source Rectifier pulse width modulation converter is becoming increasingly common. Examples of these types of applications include: Power Factor Corrections and the reduction of harmonics. The critical control requirements of an application involving a three-phase voltage-source Rectifier pulse width modulation converter are to achieve a unity power factor and to regulate the dc voltage. The unity power factor guarantees the highest possible efficiency, while the dc voltage regulation guarantees that the converter will operate as desired. In this study, a novel control method for stabilizing a Rectifier-Inverter pulse width modulation converter is designed and simulated to reach higher levels of stability while also improving dynamic performances. In the first step, the nonlinear equation system of the converter is transformed into a polytopic form. This is done with the help of the sector nonlinearity transformation. After that, a Takagi-Sugeno fuzzy controller that uses the parallel distributed compensation operating concept is applied. The design of the control system takes into account practical control requirements, such as a fast voltage tracking strategy and line-currents regulation. In order to obtain the controller gain, a series of linear matrix inequalities must be resolved. Simulations performed using Matlab/Simulink make it abundantly evident that the proposed method possesses excellent performance in terms of both voltage tracking control and unity power factor regulation.

Style APA, Harvard, Vancouver, ISO itp.

47

Dabas, Bhawana, Jivesh Kaushal, Monika Rajput i R. K. Sinha. "Study of Self Phase Modulation in Chalcogenide Glass Photonic Crystal Fiber". Applied Mechanics and Materials 110-116 (październik 2011): 53–56. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.53.

Pełny tekst źródła

Streszczenie:

In this paper, Self Phase Modulation (SPM) in chalcogenide As2Se3glass Photonic Crystal Fiber (PCF) is numerically studied by combining the fully vectorial effective index method (FVEIM) and Split Step Fourier Method (SSFM). The FVEIM is used to calculate the variation of effective refractive index of guided mode (neff), effective area (Aeff), dispersion and non-linear coefficient (γ) with wavelength for different designs of chalcogenide As2Se3PCF. The FVEIM solves the vector wave equations and SSFM solves non linear Schrödinger Equation (NLSE) for the different designing parameter of As2Se3PCF. In case of Self Phase Modulation (SPM), spectral width of the obtained output pulse at d/Λ=0.7 is 1.5 times greater than width of the output pulse obtained at d/L=0.3 using SSFM. Thus we can get the desired spectral broadening just by tailoring the design parameters of the PCF.

Style APA, Harvard, Vancouver, ISO itp.

48

XU, SHUWU, YUNXIA HUANG i XIANMING JI. "MANIPULATION OF THE MOLECULAR ORIENTATION BY COMBINED ELECTROSTATIC AND PHASE-SHAPED LASER FIELDS". Journal of Nonlinear Optical Physics & Materials 21, nr 04 (grudzień 2012): 1250045. http://dx.doi.org/10.1142/s0218863512500452.

Pełny tekst źródła

Streszczenie:

We theoretically show that the field-free molecular orientation induced by the combined electrostatic and laser fields can be manipulated through shaping the femtosecond laser pulse with periodic phase step modulation. By adjusting the modulation time τ or the modulation depth δ, the maximum degree of the molecular orientation can be fully suppressed or reconstructed by the combined electrostatic and the transform-limited laser fields. The relations between the maximum degree of the field-free molecular orientation and the laser intensity, the amplitude of the electrostatic field, as well as the rotational temperature are also investigated.

Style APA, Harvard, Vancouver, ISO itp.

49

Hu Hao, 胡昊, 王红星 Wang Hongxing, 孙晓明 Sun Xiaoming, 徐建武 Xu Jianwu i 刘敏 Liu Min. "Multilevel Coded Modulation of Free Space Optical Communication Based on Pulse Position Modulation with Multiple-Step Demodulation and Decoding Algorithm". Chinese Journal of Lasers 39, nr 4 (2012): 0405006. http://dx.doi.org/10.3788/cjl201239.0405006.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

50

Chen, Guang Hua, Gui Zhi Sheng, Feng Jiao Wang, Wen Zhou i Bin Jie Xiao. "An LED Driver Based on MCU for LCD Backlight". Advanced Materials Research 765-767 (wrzesień 2013): 2464–68. http://dx.doi.org/10.4028/www.scientific.net/amr.765-767.2464.

Pełny tekst źródła

Streszczenie:

in order to provide LCD backlight with multiple strings of LEDs, an LED driver based on MCU is proposed in the paper. A PWM signal is generated by the Pulse Width Modulation (PWM) module on the MCU chip, which is used to drive a DC-DC boost converter for LED power. The voltage and current of the boost circuit, along with all the channels current of LED, are measured by the Analog Digital Converter (ADC) module on the MCU chip, which are used to adjust the voltage of the boost circuit and supply comprehensive protection for the LED driver. To minimize the step size of the output voltage, the joint frequency-pulse width modulation scheme is proposed to regulate the output voltage of the boost circuit to an ideal value in the range of error, which increases the efficiency of the power. The measurement results show that the LED driver is extremely efficient and steady. Most of the output voltage step size is about 0.1V, the maximum step size is less than 0.3V. The conversion efficiency of the DC-DC converter is up to 94%. Thus the LED driver not only meets the demand of the parameter of LED, but also has high cost performance.

Style APA, Harvard, Vancouver, ISO itp.

Artykuły w czasopismach na temat „Pulse Step Modulation (PSM)”

Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych