根据大容量谐波抑制兼无功功率补偿的要求,从达到滤波效果和经济成本最小两个方面考虑,该文提出了一种并联混合型注入式有源电力滤波器(Hybrid Active Power Filter,HAPF)结构,并对该新型有源电力滤波器有源和无源部分的参数设计进行了...根据大容量谐波抑制兼无功功率补偿的要求,从达到滤波效果和经济成本最小两个方面考虑,该文提出了一种并联混合型注入式有源电力滤波器(Hybrid Active Power Filter,HAPF)结构,并对该新型有源电力滤波器有源和无源部分的参数设计进行了研究,形成了一套混合型大容量有源滤波器的参数设计方法。以该方法设计的HAPF在某冶炼厂谐波治理工程中得以应用,体现出较好的滤波效果和优良的性价比,具有良好的工程推广应用前景。由于目前国内有源滤波器的工程应用实例极少,因此该套设计方法对其它HAPF的研究与应用还可起到一定的指导和借鉴作用。展开更多
Cardiovascular disease is the leading cause of death globally.This disease causes loss of heart muscles and is also responsible for the death of heart cells,sometimes damaging their functionality.A person’s life may ...Cardiovascular disease is the leading cause of death globally.This disease causes loss of heart muscles and is also responsible for the death of heart cells,sometimes damaging their functionality.A person’s life may depend on receiving timely assistance as soon as possible.Thus,minimizing the death ratio can be achieved by early detection of heart attack(HA)symptoms.In the United States alone,an estimated 610,000 people die fromheart attacks each year,accounting for one in every four fatalities.However,by identifying and reporting heart attack symptoms early on,it is possible to reduce damage and save many lives significantly.Our objective is to devise an algorithm aimed at helping individuals,particularly elderly individuals living independently,to safeguard their lives.To address these challenges,we employ deep learning techniques.We have utilized a vision transformer(ViT)to address this problem.However,it has a significant overhead cost due to its memory consumption and computational complexity because of scaling dot-product attention.Also,since transformer performance typically relies on large-scale or adequate data,adapting ViT for smaller datasets is more challenging.In response,we propose a three-in-one steam model,theMulti-Head Attention Vision Hybrid(MHAVH).Thismodel integrates a real-time posture recognition framework to identify chest pain postures indicative of heart attacks using transfer learning techniques,such as ResNet-50 and VGG-16,renowned for their robust feature extraction capabilities.By incorporatingmultiple heads into the vision transformer to generate additional metrics and enhance heart-detection capabilities,we leverage a 2019 posture-based dataset comprising RGB images,a novel creation by the author that marks the first dataset tailored for posture-based heart attack detection.Given the limited online data availability,we segmented this dataset into gender categories(male and female)and conducted testing on both segmented and original datasets.The training accuracy of our model reach展开更多
为了克服现有的电力电子变压器能量转换效率低,传输容量小等缺点,提出一种适用于10 k V配电网的混合式电力电子变压器。在所提出的拓扑基础上,推导数学模型并设计合适的控制器、控制策略,可以实现电网无功治理、动态电压跌落恢复、一次...为了克服现有的电力电子变压器能量转换效率低,传输容量小等缺点,提出一种适用于10 k V配电网的混合式电力电子变压器。在所提出的拓扑基础上,推导数学模型并设计合适的控制器、控制策略,可以实现电网无功治理、动态电压跌落恢复、一次侧电压故障容错运行等功能。基于MATLAB/Simulink的仿真,验证了所提出的拓扑、数学模型、控制方法的正确性和有效性。展开更多
Hybrid distribution transformers(HDTs)have better performance than traditional distribution transformers in improving power quality through reducing harmonics,unbalance,voltage fluctuations and low power factors in fu...Hybrid distribution transformers(HDTs)have better performance than traditional distribution transformers in improving power quality through reducing harmonics,unbalance,voltage fluctuations and low power factors in future smart power distribution systems.In order to increase the service life and reliability of hybrid distribution transformers,this paper proposes a remote management system using LoRa technology based on fuzzy logic.HDT based on a fuzzy logic judgment system(FLJS)replaces the Boolean logic with fuzzy logic and several power quality problems including power factors,load-side current harmonics and voltage unbalance are considered,as well as grid-side voltage deviation and unbalance.This management system can dynamically adjust the working states of HDT according to the output results of the FLJS to reduce the use time of power electronic devices.Due to the application of LoRa,this management system can remotely adjust the parameters of the FLJS in real time for different distribution network nodes to avoid frequent switching of HDT working states.In addition,it is able to remotely monitor the real-time working states and fault states of HDT to reduce recovery time and maintenance costs in case of HDT failure.Finally,simulation and experimental results are presented to verify the effectiveness of the proposed management system for HDT.展开更多
文摘根据大容量谐波抑制兼无功功率补偿的要求,从达到滤波效果和经济成本最小两个方面考虑,该文提出了一种并联混合型注入式有源电力滤波器(Hybrid Active Power Filter,HAPF)结构,并对该新型有源电力滤波器有源和无源部分的参数设计进行了研究,形成了一套混合型大容量有源滤波器的参数设计方法。以该方法设计的HAPF在某冶炼厂谐波治理工程中得以应用,体现出较好的滤波效果和优良的性价比,具有良好的工程推广应用前景。由于目前国内有源滤波器的工程应用实例极少,因此该套设计方法对其它HAPF的研究与应用还可起到一定的指导和借鉴作用。
基金Researchers Supporting Project Number(RSPD2024R576),King Saud University,Riyadh,Saudi Arabia。
文摘Cardiovascular disease is the leading cause of death globally.This disease causes loss of heart muscles and is also responsible for the death of heart cells,sometimes damaging their functionality.A person’s life may depend on receiving timely assistance as soon as possible.Thus,minimizing the death ratio can be achieved by early detection of heart attack(HA)symptoms.In the United States alone,an estimated 610,000 people die fromheart attacks each year,accounting for one in every four fatalities.However,by identifying and reporting heart attack symptoms early on,it is possible to reduce damage and save many lives significantly.Our objective is to devise an algorithm aimed at helping individuals,particularly elderly individuals living independently,to safeguard their lives.To address these challenges,we employ deep learning techniques.We have utilized a vision transformer(ViT)to address this problem.However,it has a significant overhead cost due to its memory consumption and computational complexity because of scaling dot-product attention.Also,since transformer performance typically relies on large-scale or adequate data,adapting ViT for smaller datasets is more challenging.In response,we propose a three-in-one steam model,theMulti-Head Attention Vision Hybrid(MHAVH).Thismodel integrates a real-time posture recognition framework to identify chest pain postures indicative of heart attacks using transfer learning techniques,such as ResNet-50 and VGG-16,renowned for their robust feature extraction capabilities.By incorporatingmultiple heads into the vision transformer to generate additional metrics and enhance heart-detection capabilities,we leverage a 2019 posture-based dataset comprising RGB images,a novel creation by the author that marks the first dataset tailored for posture-based heart attack detection.Given the limited online data availability,we segmented this dataset into gender categories(male and female)and conducted testing on both segmented and original datasets.The training accuracy of our model reach
文摘为了克服现有的电力电子变压器能量转换效率低,传输容量小等缺点,提出一种适用于10 k V配电网的混合式电力电子变压器。在所提出的拓扑基础上,推导数学模型并设计合适的控制器、控制策略,可以实现电网无功治理、动态电压跌落恢复、一次侧电压故障容错运行等功能。基于MATLAB/Simulink的仿真,验证了所提出的拓扑、数学模型、控制方法的正确性和有效性。
基金supported by the State Grid Science and Technology Project from State Grid Corporation of China(B626KY190004)the Key Research and Development Project of Shaanxi Province in 2018(No.2018ZDCXL-GY-07-05)。
文摘Hybrid distribution transformers(HDTs)have better performance than traditional distribution transformers in improving power quality through reducing harmonics,unbalance,voltage fluctuations and low power factors in future smart power distribution systems.In order to increase the service life and reliability of hybrid distribution transformers,this paper proposes a remote management system using LoRa technology based on fuzzy logic.HDT based on a fuzzy logic judgment system(FLJS)replaces the Boolean logic with fuzzy logic and several power quality problems including power factors,load-side current harmonics and voltage unbalance are considered,as well as grid-side voltage deviation and unbalance.This management system can dynamically adjust the working states of HDT according to the output results of the FLJS to reduce the use time of power electronic devices.Due to the application of LoRa,this management system can remotely adjust the parameters of the FLJS in real time for different distribution network nodes to avoid frequent switching of HDT working states.In addition,it is able to remotely monitor the real-time working states and fault states of HDT to reduce recovery time and maintenance costs in case of HDT failure.Finally,simulation and experimental results are presented to verify the effectiveness of the proposed management system for HDT.
