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基于改进型三角积分调制的电磁干扰抑制方法 被引量:2
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作者 薛开昶 李骄松 +2 位作者 林君 周逢道 刘长胜 《电波科学学报》 EI CSCD 北大核心 2013年第5期968-973,1009,共7页
开关电源工作于开关状态,是强电磁干扰源,将集中于开关频率及其谐波频率上的能量分配到更多频率上能较好地抑制电磁干扰峰值.针对开关电源应用需求,扩展分析了三角积分调制中输出平均频率与输入的关系及抑制电磁干扰的机理.针对三角积... 开关电源工作于开关状态,是强电磁干扰源,将集中于开关频率及其谐波频率上的能量分配到更多频率上能较好地抑制电磁干扰峰值.针对开关电源应用需求,扩展分析了三角积分调制中输出平均频率与输入的关系及抑制电磁干扰的机理.针对三角积分调制应用于开关电源的不足,提出改进型三角积分调制.采用m和逆m伪随机序列实现改进型三角积分调制中的随机频率发生器和随机噪声发生器.实测结果证明改进型三角积分调制的电磁干扰峰值低于三角积分调制10dB,具有更好的电磁干扰峰值抑制效果. 展开更多
关键词 开关电源 电磁干扰 三角积分调制 M序列 伪随机
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基于改进调制积分观测器的相控断路器基波提取方法 被引量:1
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作者 吕冬春 刘军 +2 位作者 李孝尊 周亚男 刘润东 《电工技术》 2020年第11期26-29,共4页
相控断路器能有效减小电力系统无功补偿电容器组投切过程中的涌流和过电压,从而准确提取电网电压基波信号,是实施相控开关技术的前提。基于调制积分观测器的基波信号提取方法具有收敛快、误差小的优点,但电网电压频率变化会影响其精度... 相控断路器能有效减小电力系统无功补偿电容器组投切过程中的涌流和过电压,从而准确提取电网电压基波信号,是实施相控开关技术的前提。基于调制积分观测器的基波信号提取方法具有收敛快、误差小的优点,但电网电压频率变化会影响其精度。提出采用线性自抗扰控制的锁相环获取电网电压频率,再设计调制积分观测器,在电网电压波动、谐波与噪声干扰情况下,实现电网电压基波信号的准确提取,并通过系统仿真进行了验证。 展开更多
关键词 相控断路器 调制积分观测器 线性自抗扰控制 频率自适应 基波提取
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Delta-Sigma调制器在空间指向镜位置伺服系统中的应用 被引量:2
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作者 王淳 谢妮慧 林喆 《航天返回与遥感》 2014年第5期54-60,共7页
在目前的空间指向镜位置伺服系统中,数字控制器输出脉宽调制(PWM)的量化误差会导致指向出现小幅角度振荡,使得指向的稳定性降低,进而导致光学遥感成像质量发生退化。针对航天器工程实现的特点,将Delta-Sigma调制器引入到数控软件中,在... 在目前的空间指向镜位置伺服系统中,数字控制器输出脉宽调制(PWM)的量化误差会导致指向出现小幅角度振荡,使得指向的稳定性降低,进而导致光学遥感成像质量发生退化。针对航天器工程实现的特点,将Delta-Sigma调制器引入到数控软件中,在不改变硬件电路与系统参数的前提下,显著的降低了输出量化误差对伺服系统的影响。Matlab仿真结果表明,该方法可使指向镜的指向角度振荡幅值衰减至原来的1/5以下,有效地提高了指向镜的指向稳定性。 展开更多
关键词 三角积分调制 指向镜 伺服系统 量化 空间遥感
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具有马氏调制费率的复合Poisson风险模型的破产概率 被引量:3
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作者 向阳 刘再明 《经济数学》 2002年第4期47-51,共5页
对于给定的初始状态和初始分布 ,本文分别给出了条件破产概率 Ψi(u)和最终破产概率 Ψ(u)所满足的积分方程 ,并给出了零初始资产时破产概率 Ψ(0 )的明确表达式 .
关键词 马氏调制 破产概率 积分方程
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气路闭环横向互联空气悬架车身高度调节 被引量:2
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作者 江洪 杨勇福 +2 位作者 余鹏飞 徐兴 李美 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2015年第11期2010-2016,共7页
为进一步改善空气悬架动力性与能耗经济性,结合互联空气悬架系统与高低压罐气路闭环车身高度调节系统的优点,提出气路闭环横向互联空气悬架系统.针对传统空气悬架车身高度控制策略应用于互联悬架存在的移植性缺陷,构建专门适用于横向互... 为进一步改善空气悬架动力性与能耗经济性,结合互联空气悬架系统与高低压罐气路闭环车身高度调节系统的优点,提出气路闭环横向互联空气悬架系统.针对传统空气悬架车身高度控制策略应用于互联悬架存在的移植性缺陷,构建专门适用于横向互联空气悬架的车身高度比例积分微分-脉冲宽度调制(PID-PWM)控制策略,基于MATLAB/Simulink建立整车数学模型并进行仿真分析.仿真结果表明该控制策略响应迅速,且避免了超调现象,解决了传统空气悬架车身高度控制策略应用于横向互联悬架的移植性缺陷等问题.搭建试验台架,进行车身高度调节试验并对储气罐不同初始气压下充放气时间及控制误差进行研究.试验结果表明,提出的控制策略能准确地实现气路闭环横向互联空气悬架系统车身高度的切换,验证了所建模型的正确性以及控制策略的有效性,储气罐不同初始气压对车身高度调节性能的影响研究为车身高度调节的参数选择提供了依据. 展开更多
关键词 空气悬架 闭环 横向互联 比例积分微分-脉冲宽度调制(PID-PWM) 车身高度调节
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一种基于SVPWM的地铁应急空调电源设计 被引量:1
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作者 刘承绪 梅樱 刘志刚 《电力电子技术》 CSCD 北大核心 2008年第8期42-43,64,共3页
在地铁供电系统发生故障时,为了保证空调系统仍能正常工作,特为此设计了一种应急空调电源。该应急空调电源采用DC/DC/AC变换,将110V直流电变换为频率、幅值可调的交流电。DC/DC环节利用PI调节,可提供稳定直流电压;DC/AC环节采用SVPWM,... 在地铁供电系统发生故障时,为了保证空调系统仍能正常工作,特为此设计了一种应急空调电源。该应急空调电源采用DC/DC/AC变换,将110V直流电变换为频率、幅值可调的交流电。DC/DC环节利用PI调节,可提供稳定直流电压;DC/AC环节采用SVPWM,输出可变频调压。输出交流电频率幅值可设定或随温度变化。系统采用全数字控制,可实现快速、精确的响应。最后,对5 kVA样机进行了试验,中间直流电压稳定,输出交流电压频率幅值均可满足要求,验证了电源的实用性。 展开更多
关键词 空气调节器 电源 矢量控制 脉宽调制/比例积分控制
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高动态光学血管造影成像(英文)
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作者 曾亚光 罗佳雄 +4 位作者 韩定安 熊红莲 王雪花 钟俊平 王茗祎 《生物化学与生物物理进展》 SCIE CAS CSCD 北大核心 2019年第6期612-619,共8页
我们提出一种高动态光学血管造影成像(HDOA)方法来实现活体生物样本血管造影成像.该方法通过设置高动态范围曝光时间,依据动态积分效应和吸收效应以实现高动态积分时间调制.通过该方法,不仅能够同时获得各级血管清晰的造影图像,还能消... 我们提出一种高动态光学血管造影成像(HDOA)方法来实现活体生物样本血管造影成像.该方法通过设置高动态范围曝光时间,依据动态积分效应和吸收效应以实现高动态积分时间调制.通过该方法,不仅能够同时获得各级血管清晰的造影图像,还能消除样品厚度不均、吸收系数不同对成像造成的影响.论文以仿体和活体金鱼为样品,通过实验验证了HDOA方法根据动态积分调制效应和吸收效应,能有效实现各级血管同时成像. 展开更多
关键词 高动态光学血管造影成像 高动态积分时间调制 吸收效应
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Performance analysis of a rate adaptive multi-band ultra-wideband system based on quadrature fractal modulation scheme
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作者 LI Yu-hong ZHOU Zheng 《通信学报》 EI CSCD 北大核心 2005年第10期34-40,共7页
A rate adaptive multi-band ultra-wideband (UWB) system based on the quadrature fractal modulation (QFM) scheme was proposed.Exploring the use of homogeneous signals as modulating waveforms in UWB system,the signal wit... A rate adaptive multi-band ultra-wideband (UWB) system based on the quadrature fractal modulation (QFM) scheme was proposed.Exploring the use of homogeneous signals as modulating waveforms in UWB system,the signal within each 528MHz sub-band was divided into 8 different frequency bandwidths using wavelets transform and these data sequences to be transmitted were embedded into homogeneous waveforms.It is found that the use of homogeneous signals in such UWB system is quite feasible,leadings to a novel multi-rate diversity strategy.Within each 528MHz sub-band,the UWB-QFM system can provide much higher data rates than that of the UWB orthogonal frequency division multiplexing (OFDM) system.Simulation results also show that the bit error rate (BER) performance of the UWB-QFM system achieves a greatly improvement over existing UWB-OFDM system.Due to the fractal properties of the homogeneous signals,these data sequences to be transmitted can be recovered using arbitrarily short receiver signal. 展开更多
关键词 多频率传输 积分调制 微波传输 直角频率分割 多路技术
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CLASSIFICATION OF MPSK SIGNALS USING CUMULANT INVARIANTS 被引量:20
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作者 Yang Shaoquan Chen Weidong (School of Electronic Engineering, Xidian University, Xi’an 710071) 《Journal of Electronics(China)》 2002年第1期99-103,共5页
A new feature based on higher order statistics is proposed for classification of MPSKsignals, which is invariant with respect to translation (shift), scale and rotation transforms of MPSK signal constellations, and ca... A new feature based on higher order statistics is proposed for classification of MPSKsignals, which is invariant with respect to translation (shift), scale and rotation transforms of MPSK signal constellations, and can suppress additive color or white Gaussian noise. Application of the new feature to classification of MPSK signals, at medium signal-to-noise ratio with specified sample size, results in high probability of correct identification. Finally, computer simulations and comparisons with existing algorithms are given. 展开更多
关键词 Higher order statistics Cumulant invariants Modulation classification
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非制冷红外焦平面阵列读出电路设计
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作者 岳森 《电子产品世界》 2014年第4期28-30,共3页
针对SOI二极管型非制冷红外探测器,设计了一种新型读出电路(ROIC)该电路采用栅调制积分(GMI)结构.将探测器输出电压信号转化为电流信号进行积分设计了虚拟电流源结构,消除线上压降(IRdrop)对信号造成的影响。电路采用0.35μ11... 针对SOI二极管型非制冷红外探测器,设计了一种新型读出电路(ROIC)该电路采用栅调制积分(GMI)结构.将探测器输出电压信号转化为电流信号进行积分设计了虚拟电流源结构,消除线上压降(IRdrop)对信号造成的影响。电路采用0.35μ111 2P4MCMOS工艺进行设计,5V电源电压供电当探测器输出信号变化范围为0~5mv时,读出电路仿真结果表明:动态输出范围2V,线性度99.68%,信号输出频率5MHz.功耗116mW. 展开更多
关键词 非制冷红外焦平面阵列 读出电路 调制积分
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ROBUST MODULATION CLASSIFIER BASED ON CUMULANTS FOR MDPSK WITH FREQUENCY OFFSET
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作者 HanGang LiJiandong ChenChen 《Journal of Electronics(China)》 2004年第3期177-183,共7页
This paper presents an improved algorithm for classification of M-Differential Phase-Shift Keying(MDPSK) signals based on eumulant. The feature proposed in the algorithm is invariant with respect to constellation scal... This paper presents an improved algorithm for classification of M-Differential Phase-Shift Keying(MDPSK) signals based on eumulant. The feature proposed in the algorithm is invariant with respect to constellation scale, rotation, the shift and the carrier frequency offset between transmitter and receiver.The invariant property is proved theoretically.Through computer simulation the performance is evaluated and the results show that the improved classification algorithm is better and valuable in practice. 展开更多
关键词 CUMULANT Modulation classification Prequency offset
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Improved control of intelligent excavator using proportional-integral-plus gain scheduling 被引量:5
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作者 顾军 D. SEWARD 《Journal of Central South University》 SCIE EI CAS 2012年第2期384-392,共9页
Consider the design and implementation of an electro-hydraulic control system for a robotic excavator, namely the Lancaster University computerized and intelligent excavator (LUCIE). The excavator was developed to aut... Consider the design and implementation of an electro-hydraulic control system for a robotic excavator, namely the Lancaster University computerized and intelligent excavator (LUCIE). The excavator was developed to autonomously dig trenches without human intervention. One stumbling block is the achievement of adequate, accurate, quick and smooth movement under automatic control, which is difficult for traditional control algorithm, e.g. PI/PID. A gain scheduling design, based on the true digital proportional-integral-plus (PIP) control methodology, was utilized to regulate the nonlinear joint dynamics. Simulation and initial field tests both demonstrated the feasibility and robustness of proposed technique to the uncertainties of parameters, time delay and load disturbances, with the excavator arm directed along specified trajectories in a smooth, fast and accurate manner. The tracking error magnitudes for oblique straight line and horizontal straight line are less than 20 mm and 50 mm, respectively, while the velocity reaches 9 m/min. 展开更多
关键词 robotic excavator gain scheduling control proportional-integral-plus ROBUSTNESS
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Predictive Functional Controller with a Similar Proportional Integral Optimal Regulator Structure:Comparison with Traditional Predic-tive Functional Controller and Application to Heavy Oil Coking Equipment 被引量:1
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作者 张日东 王树青 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2007年第2期247-253,共7页
By extending the system's state variables,a novel predictive functional controller has been developed.The structure of this controller is similar to that of classical proportional integral(PI)optimal controller an... By extending the system's state variables,a novel predictive functional controller has been developed.The structure of this controller is similar to that of classical proportional integral(PI)optimal controller and in-cludes a control block that can perform a feed-forward control of future P-step set points.It considers both the state variables and the output errors in its cost function,which results in enhanced control performance compared with traditional state space predictive functional control(TSSPFC)methods that consider only the predictive output er-rors.The predictive functional controller(PFC)has been compared with TSSPFC in terms of tracking ability,dis-turbance rejection,and also based on its application to heavy oil coking equipment.The results obtained show the effectiveness of the controller. 展开更多
关键词 state space model PI optimal regulator predictive functional control
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Design of a fractional PI~λD~μ controller using the cohort intelligence method 被引量:1
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作者 Pritesh SHAH Sudhir AGASHE Anand J.KULKARNI 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2018年第3期437-445,共9页
The cohort intelligence (CI) method has recently evolved as an optimization method based on artificial intelligence. We use the CI method for the first time to optimize the parameters of the fractional proportional-... The cohort intelligence (CI) method has recently evolved as an optimization method based on artificial intelligence. We use the CI method for the first time to optimize the parameters of the fractional proportional- integral-derivative (PID) controller. The performance of the CI method in designing the fractional PID controller was validated and compared with those of some other popular algorithms such as particle swarm optimization, the genetic algorithm, and the improved electromagnetic algorithm. The CI method yielded improved solutions in terms of the cost function, computing time, and function evaluations in comparison with the other three algorithms. In addition, the standard deviations of the CI method demonstrated the robustness of the proposed algorithm in solving control problems. 展开更多
关键词 Cohort intelligence Fractional calculus Fractional PID controller Tuning
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Modulation space estimates for the fractional integral operators 被引量:3
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作者 ZHONG Yong CHEN JieCheng 《Science China Mathematics》 SCIE 2011年第7期1479-1489,共11页
We obtain the boundedness for the fractional integral operators from the modulation Hardy space μp,q to the modulation Hardy space μr,q for all 0 < p < ∞. The result is an extension of the known result for th... We obtain the boundedness for the fractional integral operators from the modulation Hardy space μp,q to the modulation Hardy space μr,q for all 0 < p < ∞. The result is an extension of the known result for the case 1 < p < ∞ and it contains a larger range of r than those in the classical result of the Lp → Lr boundedness in the Lebesgue spaces. We also obtain some estimates on the modulation spaces for the bilinear fractional operators. 展开更多
关键词 modulation spaces modulation Hardy spaces fractional integral operator bilinear fractional integral operator
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