With the continued advancement of deep electrification across various industries, the demand for higher power density in electric machines is steadily increasing. However, realizing high power density remains a signif...With the continued advancement of deep electrification across various industries, the demand for higher power density in electric machines is steadily increasing. However, realizing high power density remains a significant technical challenge and has become a major bottleneck in machine development. The design of such machines is inherently constrained by the strong coupling among electromagnetic(EM), thermal, and mechanical domains, while systematic analyses of these challenges remain insufficient. This paper clarifies the interdependent relationships among these domains during the machine design process. It reviews key enabling strategies, including machine design based on advanced electromagnetic theory, innovative thermal management techniques, cutting-edge material advancements, and state-of-the-art manufacturing technologies, that collectively enhance the performance and feasibility of high power density machines(HPDMs). The insights provided aim to support the development of nextgeneration machine systems with higher power density, compact size, and robust, sustainable performance across a wide range of industrial and technological applications.展开更多
The adaptive H_∞ control problem of multi-machine power system in the case of disturbances and uncertain parameters is discussed,based on a Hamiltonian model.Considered the effect of time delay during control and tra...The adaptive H_∞ control problem of multi-machine power system in the case of disturbances and uncertain parameters is discussed,based on a Hamiltonian model.Considered the effect of time delay during control and transmission,a Hamilton model with control time delay is established.Lyapunov-Krasovskii function is selected,and a controller which makes the system asymptotically stable is got.The controller not only achieves the stability control for nonlinear systems with time delay,but also has the ability to suppress the external disturbances and adaptive ability to system parameter perturbation.The simulation results show the effect of the controller.展开更多
Cloud computing is becoming a key factor in the market day by day. Therefore, many companies are investing or going to invest in this sector for development of large data centers. These data centers not only consume m...Cloud computing is becoming a key factor in the market day by day. Therefore, many companies are investing or going to invest in this sector for development of large data centers. These data centers not only consume more energy but also produce greenhouse gases. Because of large amount of power consumption, data center providers go for different types of power generator to increase the profit margin which indirectly affects the environment. Several studies are carried out to reduce the power consumption of a data center. One of the techniques to reduce power consumption is virtualization. After several studies, it is stated that hardware plays a very important role. As the load increases, the power consumption of the CPU is also increased. Therefore, by extending the study of virtualization to reduce the power consumption, a hardware-based algorithm for virtual machine provisioning in a private cloud can significantly improve the performance by considering hardware as one of the important factors.展开更多
The aim of this study was to investigate the effects of eccentric workloads generated by a powered rowing machine on the cardiorespiratory,cardiovascular and musculoskeletal systems.It was hypothesized that beneficial...The aim of this study was to investigate the effects of eccentric workloads generated by a powered rowing machine on the cardiorespiratory,cardiovascular and musculoskeletal systems.It was hypothesized that beneficial physiological effects would result by training with high eccentric workloads.Conventional rowing machines are utilized for performance improvements through concentric workloads alone;however for this research,a conventional machine was modified with an electric motor and an advanced control system to allow the machine to also include eccentric capabilities.The ability to combine concentric and eccentric actions in any exercise has the potential to improve training effectiveness.The study followed an experimental design,exposing ten subjects(5 male,5 female)to multiple eccentric workloads generated by the powered rowing machine.Each subject participated in two 12-min exercise trials corresponding to full body row(FBR)and low body row(LBR).Each of these trials included four 3-min stages that gradually increased the eccentric workload.Increased eccentric muscle contractions and metabolic cost were confirmed in the experiments.The results on oxygen consumption reveal a significant increase between stages 1 and 2 for both exercises(FBR p=0.0001 and LBR p=0.004)with no significant increases between the remaining stages.Results on heart rate reveal a significantly increase with each stage for both exercises(p=<0.05).Results on muscle activation also reveal an overall increase for all muscle groups as eccentric workload is increased.展开更多
In a long-term planning for neutrino experiments in China, a medium baseline neutrino beam is proposed which uses a continue wave（CW） superconducting linac of 15 MW in beam power as the proton driver. The linac will...In a long-term planning for neutrino experiments in China, a medium baseline neutrino beam is proposed which uses a continue wave（CW） superconducting linac of 15 MW in beam power as the proton driver. The linac will be based on the technologies which are under development by the China-ADS project, namely it is also composed of a3.2 Me V normal conducting RFQ and five different types of superconducting cavities. However, the design philosophy is quite different from the China-ADS linac because of the much weaker requirement on reliability here. The nominal design energy and current are 1.5 Ge V and 10 m A, respectively. The general considerations and preliminary results on the physics design will be presented here. In addition, the alternative designs such as 2.0 Ge V and 2.5 Ge V, which may be required by the general design, can be easily extended from the nominal one.展开更多
基金supported in part by the National Key Research and Development Program of China (No. 2020YFA0710500)in part by the National Natural Science Foundation of China (NSFC)(No. 52277066)in part by the State Key Laboratory of Electrical Insulation and Power Equipment Foundation (No. EIPE23131)。
文摘With the continued advancement of deep electrification across various industries, the demand for higher power density in electric machines is steadily increasing. However, realizing high power density remains a significant technical challenge and has become a major bottleneck in machine development. The design of such machines is inherently constrained by the strong coupling among electromagnetic(EM), thermal, and mechanical domains, while systematic analyses of these challenges remain insufficient. This paper clarifies the interdependent relationships among these domains during the machine design process. It reviews key enabling strategies, including machine design based on advanced electromagnetic theory, innovative thermal management techniques, cutting-edge material advancements, and state-of-the-art manufacturing technologies, that collectively enhance the performance and feasibility of high power density machines(HPDMs). The insights provided aim to support the development of nextgeneration machine systems with higher power density, compact size, and robust, sustainable performance across a wide range of industrial and technological applications.
基金Sponsored by the Natural Science Foundation of Hebei Province,China(Grant No.F2016203006)
文摘The adaptive H_∞ control problem of multi-machine power system in the case of disturbances and uncertain parameters is discussed,based on a Hamiltonian model.Considered the effect of time delay during control and transmission,a Hamilton model with control time delay is established.Lyapunov-Krasovskii function is selected,and a controller which makes the system asymptotically stable is got.The controller not only achieves the stability control for nonlinear systems with time delay,but also has the ability to suppress the external disturbances and adaptive ability to system parameter perturbation.The simulation results show the effect of the controller.
基金supported by the National Research Foundation (NRF) of Korea through contract N-14-NMIR06
文摘Cloud computing is becoming a key factor in the market day by day. Therefore, many companies are investing or going to invest in this sector for development of large data centers. These data centers not only consume more energy but also produce greenhouse gases. Because of large amount of power consumption, data center providers go for different types of power generator to increase the profit margin which indirectly affects the environment. Several studies are carried out to reduce the power consumption of a data center. One of the techniques to reduce power consumption is virtualization. After several studies, it is stated that hardware plays a very important role. As the load increases, the power consumption of the CPU is also increased. Therefore, by extending the study of virtualization to reduce the power consumption, a hardware-based algorithm for virtual machine provisioning in a private cloud can significantly improve the performance by considering hardware as one of the important factors.
文摘The aim of this study was to investigate the effects of eccentric workloads generated by a powered rowing machine on the cardiorespiratory,cardiovascular and musculoskeletal systems.It was hypothesized that beneficial physiological effects would result by training with high eccentric workloads.Conventional rowing machines are utilized for performance improvements through concentric workloads alone;however for this research,a conventional machine was modified with an electric motor and an advanced control system to allow the machine to also include eccentric capabilities.The ability to combine concentric and eccentric actions in any exercise has the potential to improve training effectiveness.The study followed an experimental design,exposing ten subjects(5 male,5 female)to multiple eccentric workloads generated by the powered rowing machine.Each subject participated in two 12-min exercise trials corresponding to full body row(FBR)and low body row(LBR).Each of these trials included four 3-min stages that gradually increased the eccentric workload.Increased eccentric muscle contractions and metabolic cost were confirmed in the experiments.The results on oxygen consumption reveal a significant increase between stages 1 and 2 for both exercises(FBR p=0.0001 and LBR p=0.004)with no significant increases between the remaining stages.Results on heart rate reveal a significantly increase with each stage for both exercises(p=<0.05).Results on muscle activation also reveal an overall increase for all muscle groups as eccentric workload is increased.
基金Supported by National Natural Science Foundation of China(11375122,91126003,11235012)
文摘In a long-term planning for neutrino experiments in China, a medium baseline neutrino beam is proposed which uses a continue wave（CW） superconducting linac of 15 MW in beam power as the proton driver. The linac will be based on the technologies which are under development by the China-ADS project, namely it is also composed of a3.2 Me V normal conducting RFQ and five different types of superconducting cavities. However, the design philosophy is quite different from the China-ADS linac because of the much weaker requirement on reliability here. The nominal design energy and current are 1.5 Ge V and 10 m A, respectively. The general considerations and preliminary results on the physics design will be presented here. In addition, the alternative designs such as 2.0 Ge V and 2.5 Ge V, which may be required by the general design, can be easily extended from the nominal one.
