Induction motors （IMs） are commonly used in various industrial applications. To improve energy con- sumption efficiency, a reliable IM health condition moni- toring system is very useful to detect IM fault at its ea...Induction motors （IMs） are commonly used in various industrial applications. To improve energy con- sumption efficiency, a reliable IM health condition moni- toring system is very useful to detect IM fault at its earliest stage to prevent operation degradation, and malfunction of IMs. An intelligent harmonic synthesis technique is pro- posed in this work to conduct incipient air-gap eccentricity fault detection in IMs. The fault harmonic series are syn- thesized to enhance fault features. Fault related local spectra are processed to derive fault indicators for IM air- gap eccentricity diagnosis. The effectiveness of the pro- posed harmonic synthesis technique is examined experi- mentally by IMs with static air-gap eccentricity and dynamic air-gap eccentricity states under different load conditions. Test results show that the developed harmonic synthesis technique can extract fault features effectively for initial IM air-gap eccentricity fault detection.展开更多
Air-gapped computers are isolated both logically and physically from all kinds of existing common communication channel, such as USB ports, wireless and wired net- works. Although the feasibility of infiltrating an ai...Air-gapped computers are isolated both logically and physically from all kinds of existing common communication channel, such as USB ports, wireless and wired net- works. Although the feasibility of infiltrating an air-gapped computer has been proved in recent years, data exfiltration from such sys- tems is still considered to be a challenging task. In this paper we present Powermittcr, a novel approach that can exfiltrate data through an air-gapped computer via its power adapter. Our method utilizes the switched-mode pow- er supply, which exists in all of the laptops, desktop computers and servers nowadays. We demonstrate that a malware can indirectly con- trol the electromagnetic emission frequency of the power supply by leveraging the CPU utili- zation. Furthermore, we show that the emitted signals can be received and demodulated by a dedicated device. We present the proof of con- cept design of the power covert channel and implement a prototype of Powermitter consist- ing of a transmitter and a receiver. The trans- mitter leaks out data by using a variant binary frequency shift keying modulation, and the emitted signal can be captured and decoded by software based virtual oscilloscope through such covert channel. We tested Powermitter on three different computers. The experiment re-suits show the feasibility of this power covert channel. We show that our method can also be used to leak data from different types of embedded systems which use switching power supply.展开更多
Many 3D IC applications such as MEMS and RF systems require Through-Silicon Via （TSV） with operations for high-speed vertical communication. In this paper, we introduce a novel air-gap coaxial TSV that is suiTab, fo...Many 3D IC applications such as MEMS and RF systems require Through-Silicon Via （TSV） with operations for high-speed vertical communication. In this paper, we introduce a novel air-gap coaxial TSV that is suiTab, for such RF applications. Firstly, the detailed fabrication process is described to explain how to acquire such a structure. Then, an Resistor Inductance Conductance Capacitance （RLGC） model is developed to profile the transverse electromagnetic field effect of the proposed air-gap TSV. The model is further verified by a 3D field solver program through the S-parameter comparison. With reference to the numerically simulated results, this analytical model delivers a maximum deviation of less than 6%0, on the conditions of varying diameters, outer to inner radius ratios, and SU-8 central angles, etc. Taking advantages of scalability of the model, a number of air-gap-based TSV designs are simulated, providing 1.6-4.0 times higher bandwidth than the con- ventional coaxial TSVs and leading to an efficient high frequency vertical RF interconnection solution for 3D ICs.展开更多
In order to reduce the test samples in the reliability design and assessment,the function process of air-gap detonation transfer interface was simulated by LS-DYNA software.The stress nephograms for the detonation tra...In order to reduce the test samples in the reliability design and assessment,the function process of air-gap detonation transfer interface was simulated by LS-DYNA software.The stress nephograms for the detonation transfer processes of six kinds of design parameters were analyzed.The results show that when the length of air-gap is between 2 and 18 mm,the detonation can be normally transferred which is consistent with the test result of NeyerD method.The result has referential value for design and analysis of similar products.展开更多
The breakdown voltage of long air-gaps in high-voltage transmission systems depends on not only the waveform of the applied voltage, but also the atmospheric conditions. Based on the results of the research project on...The breakdown voltage of long air-gaps in high-voltage transmission systems depends on not only the waveform of the applied voltage, but also the atmospheric conditions. Based on the results of the research project on the minimum air clearance for 800-kV HVDC substations at high altitudes, and also on the monthly and yearly statistics of the atmospheric data of last ten years and the altitude correction of the atmospheric data of last ten years, the altitude correction of the air-gaps for the 800-kV DC system under plan, 500-kV AC system to be built, and 1000-kV AC system under plan in the Inner Mongolia Plateau and the Yungui Plateau in China were studied with parameter G method. Correction factors for switching and lightning impulses were calculatod and then compared with those achieved according to IEC 71. It is shown that IEC 71 is appropriate for damp regions, and correction factors differ between plateau regions in China because of different atmospheric conditions.展开更多
This paper describes the key issues of high-speed brushless permanent magnet motor design, such as rotor design, stator design, and determination of the main dimensions, and the overall design process was given. In th...This paper describes the key issues of high-speed brushless permanent magnet motor design, such as rotor design, stator design, and determination of the main dimensions, and the overall design process was given. In this paper, a two-pole three-phase high-speed brushless PM （permanent magnet） motor with ratings air-gap length and stator slot number on the motor performance of 7.5 kW, 30,000 rpm is designed, and the effect of the different was analyzed. The results show that larger number of stator slot decreases the rotor loss and the rotor torque ripple. Larger air-gap length decreases the rotor loss.展开更多
Fractional-slot concentrated-coil electric machines are often used in those applications where a number of rotor poles close to the number of stator slots is required. A major criticality of such machines is the occur...Fractional-slot concentrated-coil electric machines are often used in those applications where a number of rotor poles close to the number of stator slots is required. A major criticality of such machines is the occurrence of large air-gap field harmonics due to winding distribution and to slotting effects. Predicting such harmonics analytically with adequate accuracy is a good way to significantly speed-up subsequent investigations, concerning the rotor effects of the field harmonics in terms of rotor losses. This paper proposes different analytical formulations for this purpose, covering the case of a generic number of stator phases and differing by how slotting effects are taken into account. The various approaches proposed are evaluated by comparing analytical results with finite-element analysis computations on a sample machine geometries.展开更多
漏磁效应对永磁饱和型故障限流器(permanent-magnet-biased saturation based fault current limiter,PMFCL)的动态特性具有重要影响。针对一种直线式PMFCL的磁拓扑,以铁心磁通的工作零点作为分界阐明了其2个阶段的限流机理,指出铁心磁...漏磁效应对永磁饱和型故障限流器(permanent-magnet-biased saturation based fault current limiter,PMFCL)的动态特性具有重要影响。针对一种直线式PMFCL的磁拓扑,以铁心磁通的工作零点作为分界阐明了其2个阶段的限流机理,指出铁心磁通自过零反向后将发生畸变,永磁体不再参与限流过程。基于磁场分割原理实现2类等效磁路模型中总漏磁导和漏磁系数的计算,针对拟圆环截面磁通管的漏磁导,提出基于曲线拟合而改变积分变量的求解方法。在Matlab/Simulink环境下建立了考虑漏磁效应的PMFCL仿真模型,分别与小电流和大电流工况的实验结果进行对比,验证了建模方法的有效性。展开更多
在简单介绍了姿态角和地磁场的基础上,分析了电子罗盘工作原理,设计了基于磁阻传感器、MEMS加速度传感器及SoC(System on Chip)MCU的电子罗盘。根据其构成的主要器件,分析、补偿和计算了系统误差。该电子罗盘具有体积小、重量轻、功耗...在简单介绍了姿态角和地磁场的基础上,分析了电子罗盘工作原理,设计了基于磁阻传感器、MEMS加速度传感器及SoC(System on Chip)MCU的电子罗盘。根据其构成的主要器件,分析、补偿和计算了系统误差。该电子罗盘具有体积小、重量轻、功耗低、价格低和精度高等优点。试验结果表明其能够很好地用于微型和超小型飞行器的姿态控制与导航。展开更多
基金Supported in part by Natural Sciences and Engineering Research Council of Canada(NSERC)eMech Systems IncBare Point Water Treatment Plant in Thunder Bay,Ontario,Canada
文摘Induction motors （IMs） are commonly used in various industrial applications. To improve energy con- sumption efficiency, a reliable IM health condition moni- toring system is very useful to detect IM fault at its earliest stage to prevent operation degradation, and malfunction of IMs. An intelligent harmonic synthesis technique is pro- posed in this work to conduct incipient air-gap eccentricity fault detection in IMs. The fault harmonic series are syn- thesized to enhance fault features. Fault related local spectra are processed to derive fault indicators for IM air- gap eccentricity diagnosis. The effectiveness of the pro- posed harmonic synthesis technique is examined experi- mentally by IMs with static air-gap eccentricity and dynamic air-gap eccentricity states under different load conditions. Test results show that the developed harmonic synthesis technique can extract fault features effectively for initial IM air-gap eccentricity fault detection.
基金supported by the National High Technology Research and Development Program of China ("863" Program) (Grant No. 2015AA016002)the National Basic Research Program of China ("973" Program) (Grant No. 2014CB340600)
文摘Air-gapped computers are isolated both logically and physically from all kinds of existing common communication channel, such as USB ports, wireless and wired net- works. Although the feasibility of infiltrating an air-gapped computer has been proved in recent years, data exfiltration from such sys- tems is still considered to be a challenging task. In this paper we present Powermittcr, a novel approach that can exfiltrate data through an air-gapped computer via its power adapter. Our method utilizes the switched-mode pow- er supply, which exists in all of the laptops, desktop computers and servers nowadays. We demonstrate that a malware can indirectly con- trol the electromagnetic emission frequency of the power supply by leveraging the CPU utili- zation. Furthermore, we show that the emitted signals can be received and demodulated by a dedicated device. We present the proof of con- cept design of the power covert channel and implement a prototype of Powermitter consist- ing of a transmitter and a receiver. The trans- mitter leaks out data by using a variant binary frequency shift keying modulation, and the emitted signal can be captured and decoded by software based virtual oscilloscope through such covert channel. We tested Powermitter on three different computers. The experiment re-suits show the feasibility of this power covert channel. We show that our method can also be used to leak data from different types of embedded systems which use switching power supply.
基金Sponsored by the National Natural Science Foundation of China(No.61271149)
文摘Many 3D IC applications such as MEMS and RF systems require Through-Silicon Via （TSV） with operations for high-speed vertical communication. In this paper, we introduce a novel air-gap coaxial TSV that is suiTab, for such RF applications. Firstly, the detailed fabrication process is described to explain how to acquire such a structure. Then, an Resistor Inductance Conductance Capacitance （RLGC） model is developed to profile the transverse electromagnetic field effect of the proposed air-gap TSV. The model is further verified by a 3D field solver program through the S-parameter comparison. With reference to the numerically simulated results, this analytical model delivers a maximum deviation of less than 6%0, on the conditions of varying diameters, outer to inner radius ratios, and SU-8 central angles, etc. Taking advantages of scalability of the model, a number of air-gap-based TSV designs are simulated, providing 1.6-4.0 times higher bandwidth than the con- ventional coaxial TSVs and leading to an efficient high frequency vertical RF interconnection solution for 3D ICs.
基金Joint Funds of ational Natural Science Foundation of China(No.U1530135)
文摘In order to reduce the test samples in the reliability design and assessment,the function process of air-gap detonation transfer interface was simulated by LS-DYNA software.The stress nephograms for the detonation transfer processes of six kinds of design parameters were analyzed.The results show that when the length of air-gap is between 2 and 18 mm,the detonation can be normally transferred which is consistent with the test result of NeyerD method.The result has referential value for design and analysis of similar products.
文摘The breakdown voltage of long air-gaps in high-voltage transmission systems depends on not only the waveform of the applied voltage, but also the atmospheric conditions. Based on the results of the research project on the minimum air clearance for 800-kV HVDC substations at high altitudes, and also on the monthly and yearly statistics of the atmospheric data of last ten years and the altitude correction of the atmospheric data of last ten years, the altitude correction of the air-gaps for the 800-kV DC system under plan, 500-kV AC system to be built, and 1000-kV AC system under plan in the Inner Mongolia Plateau and the Yungui Plateau in China were studied with parameter G method. Correction factors for switching and lightning impulses were calculatod and then compared with those achieved according to IEC 71. It is shown that IEC 71 is appropriate for damp regions, and correction factors differ between plateau regions in China because of different atmospheric conditions.
文摘This paper describes the key issues of high-speed brushless permanent magnet motor design, such as rotor design, stator design, and determination of the main dimensions, and the overall design process was given. In this paper, a two-pole three-phase high-speed brushless PM （permanent magnet） motor with ratings air-gap length and stator slot number on the motor performance of 7.5 kW, 30,000 rpm is designed, and the effect of the different was analyzed. The results show that larger number of stator slot decreases the rotor loss and the rotor torque ripple. Larger air-gap length decreases the rotor loss.
文摘Fractional-slot concentrated-coil electric machines are often used in those applications where a number of rotor poles close to the number of stator slots is required. A major criticality of such machines is the occurrence of large air-gap field harmonics due to winding distribution and to slotting effects. Predicting such harmonics analytically with adequate accuracy is a good way to significantly speed-up subsequent investigations, concerning the rotor effects of the field harmonics in terms of rotor losses. This paper proposes different analytical formulations for this purpose, covering the case of a generic number of stator phases and differing by how slotting effects are taken into account. The various approaches proposed are evaluated by comparing analytical results with finite-element analysis computations on a sample machine geometries.
文摘漏磁效应对永磁饱和型故障限流器(permanent-magnet-biased saturation based fault current limiter,PMFCL)的动态特性具有重要影响。针对一种直线式PMFCL的磁拓扑,以铁心磁通的工作零点作为分界阐明了其2个阶段的限流机理,指出铁心磁通自过零反向后将发生畸变,永磁体不再参与限流过程。基于磁场分割原理实现2类等效磁路模型中总漏磁导和漏磁系数的计算,针对拟圆环截面磁通管的漏磁导,提出基于曲线拟合而改变积分变量的求解方法。在Matlab/Simulink环境下建立了考虑漏磁效应的PMFCL仿真模型,分别与小电流和大电流工况的实验结果进行对比,验证了建模方法的有效性。
文摘在简单介绍了姿态角和地磁场的基础上,分析了电子罗盘工作原理,设计了基于磁阻传感器、MEMS加速度传感器及SoC(System on Chip)MCU的电子罗盘。根据其构成的主要器件,分析、补偿和计算了系统误差。该电子罗盘具有体积小、重量轻、功耗低、价格低和精度高等优点。试验结果表明其能够很好地用于微型和超小型飞行器的姿态控制与导航。
