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PWM整流器的无网压传感器DPC研究 被引量:2
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作者 卜文绍 翟利利 +1 位作者 汪显博 袁澜 《电气传动》 北大核心 2013年第2期56-60,共5页
为了更好地实现三相电压型PWM整流器的无电网电压传感器运行控制,给出了基于虚拟磁链的无电网电压传感器的直接功率控制(DPC)策略,根据PWM整流器的直流侧电压、交流电流和开关状态等得到虚拟磁链矢量,并据此对交流电网电压进行实时估算... 为了更好地实现三相电压型PWM整流器的无电网电压传感器运行控制,给出了基于虚拟磁链的无电网电压传感器的直接功率控制(DPC)策略,根据PWM整流器的直流侧电压、交流电流和开关状态等得到虚拟磁链矢量,并据此对交流电网电压进行实时估算;采用SVPWM调制代替传统的开关表,采用连续PI调节器代替了传统的滞环调节器,给出了三相PWM整流器的无电网电压传感器DPC控制系统结构,不但可实现开关频率固定,还可获得更好的工作波形。仿真试验结果表明了所给估算方法和控制策略的有效性和可行性。 展开更多
关键词 无电网电压传感器 虚拟磁链 实时估算模型 直接功率控制
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Video Scene Invariant Crowd Density Estimation Using Geographic Information Systems 被引量:2
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作者 SONG Hongquan LIU Xuejun +2 位作者 LU Guonian ZHANG Xingguo WANG Feng 《China Communications》 SCIE CSCD 2014年第11期80-89,共10页
Crowd density is an important factor of crowd stability.Previous crowd density estimation methods are highly dependent on the specific video scene.This paper presented a video scene invariant crowd density estimation ... Crowd density is an important factor of crowd stability.Previous crowd density estimation methods are highly dependent on the specific video scene.This paper presented a video scene invariant crowd density estimation method using Geographic Information Systems(GIS) to monitor crowd size for large areas.The proposed method mapped crowd images to GIS.Then we can estimate crowd density for each camera in GIS using an estimation model obtained by one camera.Test results show that one model obtained by one camera in GIS can be adaptively applied to other cameras in outdoor video scenes.A real-time monitoring system for crowd size in large areas based on scene invariant model has been successfully used in 'Jiangsu Qinhuai Lantern Festival,2012'.It can provide early warning information and scientific basis for safety and security decision making. 展开更多
关键词 crowd density estimation videoscene invariant GIS video spatial registration
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