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Indirect Vector Control of Linear Induction Motors Using Space Vector Pulse Width Modulation 被引量:1
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作者 Arjmand Khaliq Syed Abdul Rahman Kashif +5 位作者 Fahad Ahmad Muhammad Anwar Qaisar Shaheen Rizwan Akhtar Muhammad Arif Shah Abdelzahir Abdelmaboud 《Computers, Materials & Continua》 SCIE EI 2023年第3期6263-6287,共25页
Vector control schemes have recently been used to drive linear induction motors(LIM)in high-performance applications.This trend promotes the development of precise and efficient control schemes for individual motors.T... Vector control schemes have recently been used to drive linear induction motors(LIM)in high-performance applications.This trend promotes the development of precise and efficient control schemes for individual motors.This research aims to present a novel framework for speed and thrust force control of LIM using space vector pulse width modulation(SVPWM)inverters.The framework under consideration is developed in four stages.To begin,MATLAB Simulink was used to develop a detailed mathematical and electromechanical dynamicmodel.The research presents a modified SVPWM inverter control scheme.By tuning the proportional-integral(PI)controller with a transfer function,optimized values for the PI controller are derived.All the subsystems mentioned above are integrated to create a robust simulation of the LIM’s precise speed and thrust force control scheme.The reference speed values were chosen to evaluate the performance of the respective system,and the developed system’s response was verified using various data sets.For the low-speed range,a reference value of 10m/s is used,while a reference value of 100 m/s is used for the high-speed range.The speed output response indicates that themotor reached reference speed in amatter of seconds,as the delay time is between 8 and 10 s.The maximum amplitude of thrust achieved is less than 400N,demonstrating the controller’s capability to control a high-speed LIM with minimal thrust ripple.Due to the controlled speed range,the developed system is highly recommended for low-speed and high-speed and heavy-duty traction applications. 展开更多
关键词 Space vector pulse width modulation linear induction motor proportional-integral controller indirect vector control electromechanical dynamic modeling
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A Pulse Width Modulation Scheme With Zero-sequence Voltage Injection for Single Phase Three-level NPC Rectifiers 被引量:9
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作者 宋文胜 冯晓云 《中国电机工程学报》 EI CSCD 北大核心 2011年第36期I0003-I0003,共1页
直流侧中点电位电压偏移是多电平中性点钳位型变流器的主要缺点。以单相三电平NPC整流器为研究对象,以实现直流侧中点电位无漂移为控制目标,以传统的单相三电平单极性载波脉宽调制方法为基础,首先提出一种基于零序电压分量注入的载... 直流侧中点电位电压偏移是多电平中性点钳位型变流器的主要缺点。以单相三电平NPC整流器为研究对象,以实现直流侧中点电位无漂移为控制目标,以传统的单相三电平单极性载波脉宽调制方法为基础,首先提出一种基于零序电压分量注入的载波脉宽调制算法;然后在此基础上给出基于零序电压分量极限值注入的载波脉宽调制算法;并给出这2种方法的零序电压分量的设计方案;最后,对这2种方法进行了详细的理论分析、计算机仿真和1kW样机实验对比验证。研究结果表明:所提出的2种算法都能有效实现直流侧中点电位平衡控制,其中基于零序电压分量极限值注入的载波调制算法的中点电位控制具有更快动态响应速度,且其网侧电流的高次谐波主要分布在开关频率附近;而基于零序电压分量注入的载波调制算法的网侧电流高次谐波主要分布在2倍开关频率附近。但是在一个调制信号周期内,基于零序电压分量极限值注入的载波调制算法的开关切换次数比基于零序电压分量注入的载波调制算法低25%左右。 展开更多
关键词 三电平 脉冲宽度 零序电压 单相 整流器 中性点电压 调制 直流母线
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Effects of microwave pulse-width damage on a bipolar transistor 被引量:3
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作者 马振洋 柴常春 +3 位作者 任兴荣 杨银堂 陈斌 赵颖博 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第5期675-680,共6页
This paper presents a theoretical study of the pulse-width effects on the damage process of a typical bipolar transistor caused by high power microwaves(HPMs) through the injection approach.The dependences of the mi... This paper presents a theoretical study of the pulse-width effects on the damage process of a typical bipolar transistor caused by high power microwaves(HPMs) through the injection approach.The dependences of the microwave damage power,P,and the absorbed energy,E,required to cause the device failure on the pulse width τ are obtained in the nanosecond region by utilizing the curve fitting method.A comparison of the microwave pulse damage data and the existing dc pulse damage data for the same transistor is carried out.By means of a two-dimensional simulator,ISE-TCAD,the internal damage processes of the device caused by microwave voltage signals and dc pulse voltage signals are analyzed comparatively.The simulation results suggest that the temperature-rising positions of the device induced by the microwaves in the negative and positive half periods are different,while only one hot spot exists under the injection of dc pulses.The results demonstrate that the microwave damage power threshold and the absorbed energy must exceed the dc pulse power threshold and the absorbed energy,respectively.The dc pulse damage data may be useful as a lower bound for microwave pulse damage data. 展开更多
关键词 bipolar transistor high power microwave pulse width effects
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Evolution of the Pulse Width in Dielectric Barrier Atmospheric Pressure Discharge 被引量:1
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作者 宋新新 谭震宇 +2 位作者 陈波 张远涛 李清泉 《Plasma Science and Technology》 SCIE EI CAS CSCD 2012年第9期808-812,共5页
A study of the evolution of the pulse width in homogeneous dielectric barrier dis- charge at atmospheric pressure with helium as the working gas is reported by using a one- dimensional fluid model. In this paper, a ne... A study of the evolution of the pulse width in homogeneous dielectric barrier dis- charge at atmospheric pressure with helium as the working gas is reported by using a one- dimensional fluid model. In this paper, a new computational method is presented to estimate the pulse width through calculating the time interval between the breakdown voltage and the extinguishing voltage. The effects on the discharge characteristics of the applied voltage and exci- tation frequency are studied based on the computational data. The results of the simulation show that the pulse width is observed to be narrower and the time intervals between two consecutive current pulses decrease with increasing amplitude and excitation frequency, which indicates that the homogeneous discharge is susceptible to the filamentary mode. The simulation results support the conclusion that in order to restrain the transition from the glow mode to filamentary mode, the applied voltage and excitation frequency should be kept within an appropriate range. 展开更多
关键词 pulse width time interval breakdown voltage extinguishing voltage glowmode filamentary mode
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The 266-nm ultraviolet-beam generation of all-fiberized super-large-mode-area narrow-linewidth nanosecond amplifier with tunable pulse width and repetition rate 被引量:1
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作者 Shun Li Ping-Xue Li +4 位作者 Min Yang Ke-Xin Yu Yun-Chen Zhu Xue-Yan Dong Chuan-Fei Yao 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第3期292-298,共7页
We report on a compact, stable, all-fiberized narrow-linewidth(0.045 nm) pulsed laser source emitting laser beam with a wavelength of 266 nm, and tunable pulse width and repetition rate. The system is based on all-fib... We report on a compact, stable, all-fiberized narrow-linewidth(0.045 nm) pulsed laser source emitting laser beam with a wavelength of 266 nm, and tunable pulse width and repetition rate. The system is based on all-fiberized nanosecond amplifier architecture, which consists of Yb-doped fiber preamplifiers and a super-large-mode-area Yb-doped fiber power amplifier. The fiber amplifier with a core of 50 μm is used to raise the threshold of the stimulated Brillouin scattering(SBS) effect and to obtain high output power and single pulse energy. Using lithium triborate(LBO) crystal and betabarium borate(BBO) crystal for realizing the second-harmonic generation(SHG) and fourth-harmonic generation(FHG),we achieve 17 μJ(1.73 W) and 0.66 μJ(66 mW), respectively, at wavelengths of 532 nm and 266 nm and a repetition rate of 100 kHz with pulse width of 4 ns. This source has great potential applications in fluorescence research and solar-blind ultraviolet optical communication. 展开更多
关键词 nanosecond all-fiber amplifier narrow-linewidth ultraviolet beam generation tunable pulse width and repetition rate
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Tunable and Switchable Narrow Bandwidth Semiconductor-Saturable Absorber Mirror Mode-Locked Yb-Doped Fiber Laser Delivering Different Pulse Widths 被引量:1
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作者 王兆坤 邹峰 +2 位作者 王子薇 杜松涛 周军 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第3期36-39,共4页
The wavelength-tunable and switchable narrow bandwidth mode-locking operation is demonstrated in an all fiber laser based on semiconductor-saturable absorber mirror (SESAM). Two narrow-band fiber Bragg gratings cent... The wavelength-tunable and switchable narrow bandwidth mode-locking operation is demonstrated in an all fiber laser based on semiconductor-saturable absorber mirror (SESAM). Two narrow-band fiber Bragg gratings centered at 1029.9nm and 1032nm respectively with a polarization controller inserted between them are used to realize the wavelength switchable between 1029.9nm and 1032nm. The laser delivers different pulse widths of 7.5ps for 1030nm and 20ps for 1032nm. The maximum output power for both could reach -6.5mW at single pulse operation. The output wavelength couM be tuned to about 0.gnm intervals ranging from 1030.2nm to 1031.1 nm and from 1032.15nm to 1033.7nm with the temperature change of the fiber Bragg grating, respectively. 展开更多
关键词 mode in Yb of Tunable and Switchable Narrow Bandwidth Semiconductor-Saturable Absorber Mirror Mode-Locked Yb-Doped Fiber Laser Delivering Different pulse widths nm
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Temporal characteristic analysis of single event effects in pulse width modulator 被引量:2
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作者 Wen Zhao Xiao-Qiang Guo +3 位作者 Wei Chen Zu-Jun Wang Hong-Xia Guo Yuan-Ming Wang 《Nuclear Science and Techniques》 SCIE CAS CSCD 2017年第7期59-64,共6页
In this paper,the nature and origin of single event effects(SEE) are studied by injecting laser pulses into different circuit blocks,combining with analysis to map pulse width modulators circuitry in the microchip die... In this paper,the nature and origin of single event effects(SEE) are studied by injecting laser pulses into different circuit blocks,combining with analysis to map pulse width modulators circuitry in the microchip die.A time-domain error-identification method is used in the temporal characteristic analysis of SEE.SEE signatures of different injection times are compared.More serious SEE are observed when the laser shot occurs on a rising edge of the device output for blocks of the error amplifier,current sense comparator,and T and SR latches. 展开更多
关键词 单粒子效应 脉宽调制器 时间特性 误差放大器 电路模块 激光脉冲 时间特征 注射次数
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Pulse-Width Pulse-Frequency Based Optimal Controller Design for Kinetic Kill Vehicle Attitude Tracking Control 被引量:3
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作者 Xingyuan Xu Yuanli Cai 《Applied Mathematics》 2011年第5期565-574,共10页
The attitude control problem of the kinetic kill vehicle is studied in this work. A new mathematical model of the kinetic kill vehicle is proposed, the linear quadratic regulator technique is used to design the optima... The attitude control problem of the kinetic kill vehicle is studied in this work. A new mathematical model of the kinetic kill vehicle is proposed, the linear quadratic regulator technique is used to design the optimal attitude controller, and the pulse-width pulse-frequency modulator is used to shape the continuous control command to pulse or on-off signals to meet the requirements of the reaction thrusters. The methods to select the appropriate parameters of pulse-width pulse-frequency are presented in detail. Numerical simulations show that the performance of the LQR/PWPF approach can achieve good control performance such as pseudo-linear operation, high accuracy, and fast enough tracking speed. 展开更多
关键词 ATTITUDE Control Kinetic KILL Vehicle Linear QUADRATIC pulse-width pulse-Frequency
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Effect of Peak Power and Pulse Width on Coherent Doppler Wind Lidar’s SNR 被引量:4
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作者 REN Yong WU Xuefei +1 位作者 TAO Fa CAO Haishuai 《Instrumentation》 2022年第2期26-32,共7页
The laser device is the core component of coherent Doppler wind lidar.The peak power and pulse width of laser transmitting pulse have important effects on SNR.Based on coherent Doppler wind pulse lidar,the peak power ... The laser device is the core component of coherent Doppler wind lidar.The peak power and pulse width of laser transmitting pulse have important effects on SNR.Based on coherent Doppler wind pulse lidar,the peak power and pulse width influence on SNR is studied on the theoretical derivation and analysis,and the results show that the higher the peak power can realize the greater the signal-to-noise ratio of coherent Doppler wind lidar.But when the peak power is too large,the laser pulse may appear nonlinear phenomenon,which cause the damage of the laser.So,the peak power must be less than the stimulated brillouin scattering power threshold.Increasing the pulse width can make the laser device to output more energy,but it will also make the spatial resolution lower,and the influence of turbulence on SNR will be greater.After a series of simulation analyses,it can be concluded that when the peak power is 650W and the pulse width is 340ns,the SNR of the system can be maximized.In addition,the coherent Doppler wind lidar system is set up to carry out corresponding experimental verification.The experimental results are consistent with the theoretical analysis and simulation,which verifies the correctness of the theoretical analysis and simulation results.It provides theoretical basis and practical ex-perience for the design of laser transmitting pulse in coherent Doppler wind lidar system. 展开更多
关键词 Coherent Lidar Fiber Laser Peak Power pulse width Signal-to-Noise Ratio(SNR)
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Effect of pulse width on near-infrared supercontinuum generation in nonlinear fiber amplifier
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作者 宋锐 雷成敏 +2 位作者 陈胜平 王泽锋 侯静 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第8期351-355,共5页
The effect of pulse width on near-infrared supercontinuum generation in nonlinear fiber amplifier is investigated theoretically and experimentally. The complex Ginzburg–Landau equation and adaptive split-step Fourier... The effect of pulse width on near-infrared supercontinuum generation in nonlinear fiber amplifier is investigated theoretically and experimentally. The complex Ginzburg–Landau equation and adaptive split-step Fourier method are used to simulate the propagation of pulses with different pulse widths in the fiber amplifier, and the results show that a longer pulse is more profitable in near-infrared supercontinuum generation if the central wavelength of the input laser lies in the normal dispersion region of the gain fiber. A four-stage master oscillator power amplifier configuration is adopted and the output spectra under picosecond and nanosecond input pulses are compared with each other. The experimental results are in good accordance with the simulations which can provide some guidance for further optimization of the system. 展开更多
关键词 fiber laser SUPERCONTINUUM pulse width fiber amplifier
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Self-learning fuzzy neural network control for backside width of weld pool in pulsed GTAW with wire filler
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作者 张广军 陈善本 吴林 《中国有色金属学会会刊:英文版》 CSCD 2005年第S2期47-50,共4页
The weld pool shape control by intelligent strategy was studied. In order to improve the ability of self-learning and self-adaptation of the ordinary fuzzy control, a self-learning fuzzy neural network controller (FNN... The weld pool shape control by intelligent strategy was studied. In order to improve the ability of self-learning and self-adaptation of the ordinary fuzzy control, a self-learning fuzzy neural network controller (FNNC) for backside width of weld pool in pulsed gas tungsten arc welding (GTAW) with wire filler was designed. In FNNC, the fuzzy system was expressed by an equivalence neural network, the membership functions and inference rulers were decided through the learning of the neural network. Then, the FNNC control arithmetic was analyzed, simulating experiment was done, and the validating experiments on varied heat sink workpiece and varied gap workpiece were implemented. The maximum error between the real value and the given one was 0.39mm, the mean error was 0.014mm, and the root-mean-square was 0.14mm. The real backside width was maintained around the given value. The results show that the self-learning fuzzy neural network control strategy can achieve a perfect control effect under different set values and conditions, and is suitable for the welding process with the varied structure and coefficients of control model. 展开更多
关键词 fuzzy neural network CONTROL backside width pulseD GTAW WIRE FILLER intelligent CONTROL
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Comparison of performance between bipolar and unipolar double-frequency sinusoidal pulse width modulation in a digitally controlled H-bridge inverter system
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作者 雷博 肖国春 吴旋律 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第6期277-284,共8页
By deriving the discrete-time models of a digitally controlled H-bridge inverter system modulated by bipolar sinu- soidal pulse width modulation (BSPWM) and unipolar double-frequency sinusoidal pulse width modulati... By deriving the discrete-time models of a digitally controlled H-bridge inverter system modulated by bipolar sinu- soidal pulse width modulation (BSPWM) and unipolar double-frequency sinusoidal pulse width modulation (UDFSPWM) respectively, the performances of the two modulation strategies are analyzed in detail. The circuit parameters, used in this paper, are fixed. When the systems, modulated by BSPWM and UDFSPWM, have the same switching frequency, the stabil- ity boundaries of the two systems are the same. However, when the equivalent switching frequencies of the two systems are the same, the BSPWM modulated system is more stable than the UDFSPWM modulated system. In addition, a convenient method of establishing the discrete-time model of piecewise smooth system is presented. Finally, the analytical results are confirmed by circuit simulations and experimental measurements. 展开更多
关键词 bipolar sinusoidal pulse width modulation (SPWM) unipolar double-frequency SPWM H-bridgeinverter discrete-time model
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Realization of Space Vector Pulse Width Modulation Method Based on DSP
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作者 HAN Rukun ZHAO Yulin 《Journal of Northeast Agricultural University(English Edition)》 CAS 2008年第3期56-59,共4页
In order to compensate for the deficiency of Sine Pulse Width Modulation(SPWM), on the base of analyzing the principle of space w tot pulse width modulation and being compared with SPWM, the method of solving workin... In order to compensate for the deficiency of Sine Pulse Width Modulation(SPWM), on the base of analyzing the principle of space w tot pulse width modulation and being compared with SPWM, the method of solving working time of adjacent vector and the method of generate space voltage vector were introduced. The experiment to the inverter which consists of IGBT proves that SVPWM centrol algorithm can reduce harmonic effectively, it is beneficial to enhancing the utilization rate of voltage source inverter direct current power supply. 展开更多
关键词 space vector pulse width modulation DSP space vector
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Neuron self-learning PSD control for backside width of weld pool in pulsed GTAW with wire filler
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作者 张广军 陈善本 吴林 《China Welding》 EI CAS 2003年第2期87-91,共5页
In this paper, the weld pool shape control by intelligent strategy was studied. A neuron self-learning PSD controller for backside width of weld pool in pulsed GTAW with wire filler was designed. The PSD control arith... In this paper, the weld pool shape control by intelligent strategy was studied. A neuron self-learning PSD controller for backside width of weld pool in pulsed GTAW with wire filler was designed. The PSD control arithmetic was analyzed, simulating experiment by MATLAB software was done, and the validating experiments on varied heat sink workpiece and varied gap workpiece were successfully implemented. The study results show that the neuron self-learning PSD control method can attain a perfect control effect under different set values and conditions, and is suitable for the welding process with the varied structure and coefficients of control model. 展开更多
关键词 pulsed GTAW with wire filler backside width control intelligent control neuron self-learning PSD
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Measurement of Ultra-short Pulse-width by Using Noncollinear Sum-Frequency Generation
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作者 LI Ming ZHANG Xiulan +2 位作者 LIU Xiang ZHANG Dongxiang DENG Daoqun 《Chinese Physics Letters》 SCIE CAS CSCD 1992年第12期640-642,共3页
The third-order correlation function G^((3))(0,T)can be measured by using the method of noncollinear sum-frequency,by which the pulse-width of the ultr-ashort pulse light produced by modelocked laser is deduced to be ... The third-order correlation function G^((3))(0,T)can be measured by using the method of noncollinear sum-frequency,by which the pulse-width of the ultr-ashort pulse light produced by modelocked laser is deduced to be 35ps.This result is the same as that by other standrd method. 展开更多
关键词 pulse method. width
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Impacts of laser pulse width and target thickness on laser micro-propulsion performance
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作者 Sibo WANG Bangdeng DU +6 位作者 Baosheng DU Yongzan ZHENG Yanji HONG Jifei YE Baoyu XING Chenglin LI Yonghao ZHANG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2022年第10期113-126,共14页
In order to optimize the laser ablation performance of a micro-thruster with 1U dimensions,which employs a micro semiconductor laser,the impacts of pulse width and glycidyl azide polymer(GAP)thickness on thrust perfor... In order to optimize the laser ablation performance of a micro-thruster with 1U dimensions,which employs a micro semiconductor laser,the impacts of pulse width and glycidyl azide polymer(GAP)thickness on thrust performance were researched.The results showed that with a GAP thickness of 200μm,the single-pulse impulse(I)increased gradually with the increase in the laser pulse width from 50 to 800μs,while the specific impulse(I_(sp)),impulse coupling coefficient(Cm)and ablation efficiency(η)all reached optimal values with a 200μs pulse width.It is worth noting that the optimal pulse width is identical to the ignition delay time.Both Cmandηpeaked with a pulse width of 200μs,reaching 242.22μN W^(-1)and 35.4%,respectively.With the increase in GAP thickness,I and Cmincreased gradually.GAP of different thicknesses corresponded to different optimal laser pulse widths.Under a certain laser pulse width,the optimal GAP thickness should be the most vertical thickness of the ablation pit,and the various propulsion performance parameters at this time were also optimal.With the current laser parameters,the optimal GAP thickness was approximately 150μm,I_(sp)was approximately 322.22 s,andηwas approximately 34.94%. 展开更多
关键词 laser micro-propulsion pulse width target thickness specific impulse ablation efficiency
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Digital Pulse Width Modulation Control in Power Electronic Circuits Design
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作者 Hsu Myat Tin Swe Hla Myo Tun Maung Maung Latt 《Journal of Power and Energy Engineering》 2020年第4期1-10,共10页
The paper mainly focuses on the digital pulse width modulation (DPWM) control techniques for high performance power electronic circuit design. The problem to be solved in this study addresses the DPWM converter design... The paper mainly focuses on the digital pulse width modulation (DPWM) control techniques for high performance power electronic circuit design. The problem to be solved in this study addresses the DPWM converter design for DC to DC conversion process. The control techniques have been utilized the Fuzzy Logic Rules Base method for proposed SIMULINK model of high performance power electronic circuit. The analytical calculations for real circuit design have been completed based on the mathematical modeling of the system. The results from the developed SIMULINK model confirm the target specifications of the high performance condition for power electronic circuit which was met the objective of this study. The numerical results have been carried out with the help of MATLAB/SIMULINK. 展开更多
关键词 DIGITAL pulse width Modulation Power ELECTRONICS Analytical MODELING MATHEMATICAL MODELING SIMULINK Model MATLAB
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Research and Making of a High-Power Switching Supply Using Pulse Width Modulation
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作者 焦斌 《Journal of Donghua University(English Edition)》 EI CAS 2005年第2期87-89,共3页
Compared with the traditional SCR phase-shift regulated power supply, a new type of power semiconductor , noncrystalline state magnetic material and pulse width modulation technology, high-power switching supply has m... Compared with the traditional SCR phase-shift regulated power supply, a new type of power semiconductor , noncrystalline state magnetic material and pulse width modulation technology, high-power switching supply has many advantages: small volume, high converting efficiency, good dynamic performance, small harmonic componont and small pollution to AC supply. 展开更多
关键词 IGBT pulse width modulation SWITCHING supply
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All-fiberized very-large-mode-area Yb-doped fiber based high-peak-power narrow-linewidth nanosecond amplifier with tunable pulse width and repetition rate
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作者 Min Yang Ping-Xue Li +5 位作者 Dong-Sheng Wang Ke-Xin Yu Xue-Yan Dong Ting-Ting Wang Chuan-Fei Yao Wei-Xin Yang 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第11期343-349,共7页
We demonstrate an all-fiberized narrow-linewidth nanosecond amplifier with high peak power,tunable pulse width,and repetition rate.A fiber-coupled narrow-linewidth laser diode operating at 1064.1 nm is employed as the... We demonstrate an all-fiberized narrow-linewidth nanosecond amplifier with high peak power,tunable pulse width,and repetition rate.A fiber-coupled narrow-linewidth laser diode operating at 1064.1 nm is employed as the seed source,which is gain-switched to generate nanosecond pulses with tunable pulse widths of 1-200 ns and tunable repetition rates of10 Hz-100 kHz.By utilizing a very-large-mode-area Yb-doped fiber with a core diameter of 50 μm in the power amplifier,thresholds of the stimulated Brillouin scattering at different pulse widths and repetition rates are increased.The maximum average power reaches 30.8 W at the pulse width of 4 ns and a repetition rate of 100 kHz,corresponding to an optical-tooptical conversion efficiency of ~55.2%.Pulse energy and peak power are calculated to be 0.2 mJ and 50 kW,respectively,which are limited by stimulated Brillouin scattering.The 3-dB spectral linewidth remains around 0.05 nm during the power scaling process.The stimulated Brillouin scattering limited output powers at different pulse widths and repetition rates are investigated.Peak power of 47.5 kW(0.19 mJ) is obtained for the 4 ns pulses at a repetition rate of 50 kHz,which is nearly the same as that of 4 ns pulses at 100 kHz.When the pulse width of the seed source is increased to 8 ns,peak powers/pulse energies are decreased to 19.6 kW/0.11 mJ and 13.3 kW/0.08 mJ at repetition rates of 50 kHz and 100 kHz,respectively. 展开更多
关键词 nanosecond all-fiber amplifier very-large mode area tunable pulse width and repetition rate
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Evaluation of a Pulse Width Modulated Bypass Nozzle for the Development of a Variable Load Residential Oil Burner
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作者 Mebougna L. Drabo Narinder K. Tutu +2 位作者 Thomas Butcher George Wei Rebecca Trojanowski 《Engineering(科研)》 2018年第10期643-654,共12页
Due to the need for energy conservation in buildings and the simultaneous benefit of cost savings, the development of a low firing rate load modulating residential oil burner is very desirable. One of the two main req... Due to the need for energy conservation in buildings and the simultaneous benefit of cost savings, the development of a low firing rate load modulating residential oil burner is very desirable. One of the two main requirements of such a burner is the development of a burner nozzle that is able to maintain the particle size distribution of the fuel spray in the desirable (small) size range for efficient and stable combustion. The other being the ability to vary the air flow rate and air distribution around the fuel nozzle in the burner for optimal combustion at the current fuel firing rate. In this paper, which deals with the first requirement, we show that by using pulse width modulation in the bypass channel of a commercial off-the-shelf bypass nozzle, this objective can be met. Here we present results of spray patterns and particle size distribution for a range of fuel firing rates. The results show that a desirable fuel spray pattern can be maintained over a fuel firing rate turndown ratio (Maximum Fuel Flow Rate/Minimum Fuel Flow Rate) of 3.7. Thus here we successfully demonstrate the ability to electronically vary the fuel firing rate by more than a factor of 3 while simultaneously maintaining good atomization. 展开更多
关键词 RESIDENTIAL Oil BURNER VARIABLE Load pulse width Modulated BURNER NOZZLE BYPASS NOZZLE Droplet Spray Size Distribution VARIABLE Fuel FIRING Rate
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