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复杂腔体本征电磁场空间分布的统计方法 被引量:11
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作者 陆希成 王建国 +1 位作者 韩峰 刘钰 《强激光与粒子束》 EI CAS CSCD 北大核心 2011年第8期2167-2173,共7页
利用半经典近似方法分析了电大复杂腔体内电磁波传播的混沌特征,从而引入了3维矢量本征函数的随机平面波假设。根据电磁波传播的随机极化特征,利用统计方法推导出基于该假设本征电磁场空间分布的统计模型。应用数值方法对3维Sinai微波... 利用半经典近似方法分析了电大复杂腔体内电磁波传播的混沌特征,从而引入了3维矢量本征函数的随机平面波假设。根据电磁波传播的随机极化特征,利用统计方法推导出基于该假设本征电磁场空间分布的统计模型。应用数值方法对3维Sinai微波腔体进行模拟计算,其计算结果与统计模型符合较好。这些统计模型与腔体的具体细节特征无关。 展开更多
关键词 复杂腔体 电磁混沌 随机平面波假设 电磁统计
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Boost变换器自激混沌抑制EMI的实验研究 被引量:2
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作者 张建军 丘水生 《电力电子技术》 CSCD 北大核心 2006年第6期121-123,共3页
提出了基于闭环电流模式Boost变换器的封闭三维离散时间映射,应用该映射得到了电感电流关于输入电压的分叉图和输出电压的负载特性。通过对分叉图的研究,可以选择合适的参数使闭环电流模式Boost变换器工作在混沌状态,即自激混沌。实验... 提出了基于闭环电流模式Boost变换器的封闭三维离散时间映射,应用该映射得到了电感电流关于输入电压的分叉图和输出电压的负载特性。通过对分叉图的研究,可以选择合适的参数使闭环电流模式Boost变换器工作在混沌状态,即自激混沌。实验结果表明,闭环电流模式Boost变换器自激混沌抑制EMI的效果良好,在实际负载范围内都能自激混沌,且对输出电压的纹波影响较小。 展开更多
关键词 变换器 干扰 电磁兼容性/自激混沌
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Sliding mode control of chaos in the noise-perturbed permanent magnet synchronous motor with non-smooth air-gap 被引量:6
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作者 Ma Caoyuan Wang Longshun +2 位作者 Yin Zhe Liu Jianfeng Chen Diyi 《Mining Science and Technology》 EI CAS 2011年第6期835-838,共4页
Permanent magnet synchronous motor (PMSM) is widely used in mining, and there exists chaotic behav- ior when it runs. In order to dispel its adverse effect on security in mining, the chaotic system of PMSM was analyze... Permanent magnet synchronous motor (PMSM) is widely used in mining, and there exists chaotic behav- ior when it runs. In order to dispel its adverse effect on security in mining, the chaotic system of PMSM was analyzed. With noise disturbances, the complex dynamic characteristics of chaos were also analyzed, and proved the objective existence of chaos. As we all know, it is very difficult for conventional PMSM control to meet the design requirements, therefore, in order to ensure the robustness of the system, the chaotic orbits were stabilized to arbitrary chosen fixed points and periodic orbits by means of sliding mode method. Finally MATLAB simulations were presented to confirm the validity of the controller. The results show that the PMSM with the sliding mode control has a good dynamic performance and steady state accuracy. 展开更多
关键词 PMSM Chaos Sliding mode control Noise disturbance
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Chaotic characteristics of electromagnetic emission signals during deformation and fracture of coal 被引量:8
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作者 NIE Bai-sheng HE Xue-qiu +2 位作者 LIU Fang-bin ZHU Cheng-wei WANG Ping 《Mining Science and Technology》 EI CAS 2009年第2期189-193,共5页
Electromagnetic emission(EME) is a kind of physical phenomenon accompanying the process of deformation and fracture of loaded coal and rock and it is of importance in quantitatively analyzing its characteristics.This ... Electromagnetic emission(EME) is a kind of physical phenomenon accompanying the process of deformation and fracture of loaded coal and rock and it is of importance in quantitatively analyzing its characteristics.This will reveal the process of deformation and fracture of coal and predicting dynamic disasters in coal mines.In this study,the G-P(Grassberger and Procaccia) algorithm,calculation steps of the(if only 1 dimension) correlation dimension of time series and the identification standards of chaotic signals are introduced.Furthermore,the correlation dimensions of EME and the acoustic emission(AE) signals of time series during deformation and fracture of coal bodies are calculated and analyzed.The results show that the time series of pulses number of EME and the time series of AE count rate are chaotic and that the saturation embedding dimensions of a K3 coal sample are,respectively,5 and 6.The results can be used to provide basic parameters for predicting of EME and AE time series. 展开更多
关键词 coal and rock electromagnetic emission correlation dimension chaotic characteristics
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Dynamic friction modelling and parameter identification for electromagnetic valve actuator 被引量:6
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作者 SHAO Da XU Si-chuan DU Ai-min 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第12期3004-3020,共17页
A new modified LuGre friction model is presented for electromagnetic valve actuator system.The modification to the traditional LuGre friction model is made by adding an acceleration-dependent part and a nonlinear cont... A new modified LuGre friction model is presented for electromagnetic valve actuator system.The modification to the traditional LuGre friction model is made by adding an acceleration-dependent part and a nonlinear continuous switch function.The proposed new friction model solves the implementation problems with the traditional LuGre model at high speeds.An improved artificial fish swarm algorithm(IAFSA)method which combines the chaotic search and Gauss mutation operator into traditional artificial fish swarm algorithm is used to identify the parameters in the proposed modified LuGre friction model.The steady state response experiments and dynamic friction experiments are implemented to validate the effectiveness of IAFSA algorithm.The comparisons between the measured dynamic friction forces and the ones simulated with the established mathematic friction model at different frequencies and magnitudes demonstrate that the proposed modified LuGre friction model can give accurate simulation about the dynamic friction characteristics existing in the electromagnetic valve actuator system.The presented modelling and parameter identification methods are applicable for many other high-speed mechanical systems with friction. 展开更多
关键词 LuGre friction model artificial fish swarm algorithm Gauss mutation chaotic search parameter identification electromagnetic valve actuator
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