In the process of oil production, the submerged oil motor works 1-3 km downhole and is connected to the inverter by a long-wire cable, which generates overvoltage at the motor end due to the problem of matching the im...
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DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately por...
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DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately portray the electrical characteristics of actual MGs while is controller design-friendly has kept the issue active. To this end, this paper establishes a large-signal model containing the comprehensive dynamical behavior of the DC MGs based on the theory of high-order fully actuated systems, and proposes distributed optimal control based on this. The proposed secondary control method can achieve the two goals of voltage recovery and current sharing for multi-bus DC MGs. Additionally, the simple structure of the proposed approach is similar to one based on droop control, which allows this control technique to be easily implemented in a variety of modern microgrids with different configurations. In contrast to existing studies, the process of controller design in this paper is closely tied to the actual dynamics of the MGs. It is a prominent feature that enables engineers to customize the performance metrics of the system. In addition, the analysis of the stability of the closed-loop DC microgrid system, as well as the optimality and consensus of current sharing are given. Finally, a scaled-down solar and battery-based microgrid prototype with maximum power point tracking controller is developed in the laboratory to experimentally test the efficacy of the proposed control method.
We present a simple and effective way to account for non-convex costs and constraints in state feedback synthesis, and an interpretation for the variables in which state feedback synthesis is typically convex. We achi...
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In order to improve the packaging efficiency and quality of package yarn, design and realize the fully automatic package yarn packaging production line and its control system, and realize the automatic control of the ...
In order to improve the packaging efficiency and quality of package yarn, design and realize the fully automatic package yarn packaging production line and its control system, and realize the automatic control of the whole package yarn packaging process, HMI on-site monitoring and centralized monitoring of the host computer. Improving the automation level of enterprises. According to the process flow of package yarn packaging in the enterprise and the modular design idea, the packaging production line is decomposed into package turnover, single yarn packaging shrinkage, buffer type alignment, woven bag packaging, automatic sewing and turning, automatic bundling, online weighing and labeling; the control management system based on Siemens S7-1200PLC, KTP1200 touch screen and remote host computer is designed, combined with PROFIBUS module and input and output module, the on-site monitoring of the running status of the production line is realized through the touch screen. The remote host computer is built to realize remote monitoring and management of the production line. It has been proved by operation that the automatic bobbin packaging production line runs stably and realizes local and remote control management. Compared with traditional manual packaging or low-level automation equipment, it has the advantages of strong stability and flexible configuration of system modules. Improve the packaging efficiency and automation level of spinning enterprises.
This paper investigates the attitude and orbit control for the combined spacecraft formed after a target spacecraft without the autonomous control ability is captured by a service *** optimal controller of fully-actua...
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This paper investigates the attitude and orbit control for the combined spacecraft formed after a target spacecraft without the autonomous control ability is captured by a service *** optimal controller of fully-actuated system is proposed to realize the attitude and orbit stabilization control of combined *** stability of the system is proved by introducing Lyapunov *** simulation of the combined spacecraft and physical experiment based on the combined spacecraft simulator(CSS)are *** simulation and experiment results demonstrate the effectiveness and practicability of the optimal controller of fully-actuated system.
In this study,three kinds of radical scavenger Chimassorb 944,Tinuvin 622,and Tinuvin 770 are used to suppress the growth of electrical trees in cross-linked polyethylene(XLPE)with transient superimposed voltage under...
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In this study,three kinds of radical scavenger Chimassorb 944,Tinuvin 622,and Tinuvin 770 are used to suppress the growth of electrical trees in cross-linked polyethylene(XLPE)with transient superimposed voltage under the temperature *** tree morphology,tree length,accumulated damage,and time to breakdown are used to investigate the effect of radical scavenger on the electrical treeing *** is found that under the temperature gradient caused by the temperature rise on the high voltage side,only Tinuvin 622 can always suppress the electrical tree as the temperature gradient *** the temperature gradient caused by the temperature rise on the ground side,the three radical scavengers can all suppress the electrical *** breakdown of electrical tree exhibits the strong DC polarity ***,energy levels of these three radical scavengers are calculated through quantum chemistry,and the results indicate that radical scavengers have greater electron affinity,smaller ionisation energy,and smaller energy gap than *** to the surface potential decay test results at 60℃,it is found that all three radical scavengers can introduce deep *** different performances of radical scavengers under different temperature gradients and voltages are determined by the trap distribution characteristics,the molecular structure and chemical reaction of the additives *** is concluded that Tinuvin 622 has potential for use in high voltage direct current XLPE cable application.
In the optical-based measurement of the speed of sound in seawater, considering the influence of the measurement system and the media environment, the signal is embodied as a noise signal with acoustic markers in addi...
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This work studies receding-horizon control of discrete-time switched linear systems subject to polytopic constraints for the continuous states and inputs. The objective is to approximate the optimal receding-horizon c...
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Aero-optic imaging deviation research is carried out for infrared-guided vehicle with cone-head side window,with a focus on the propagation characteristics of light in an aero-optic flow *** the light entering the aer...
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Aero-optic imaging deviation research is carried out for infrared-guided vehicle with cone-head side window,with a focus on the propagation characteristics of light in an aero-optic flow *** the light entering the aero-optic flow field from the free-stream should be close to the normal,numerous data indicate that the light is refracted away from the *** paper divides the aero-optic flow field into two parts and uses the gas density distribution in the aero-optic flow field to propose the hypothesis that there are two modes of refraction when light propagates through the flow *** results show that light propagates from the optically denser medium to the optically thinner medium after passing through the shock wave and eventually leads to refraction away from the normal when the light enters the aero-optic flow field.
La,Ce co-doped ZnO nanorods(ZnLC)were synthesized through a one-step solvothermal *** photocatalysts were characterized by X-ray diffraction,Raman spectroscopy,field-emission scanning electron microscopy,energy disper...
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La,Ce co-doped ZnO nanorods(ZnLC)were synthesized through a one-step solvothermal *** photocatalysts were characterized by X-ray diffraction,Raman spectroscopy,field-emission scanning electron microscopy,energy dispersive X-ray,transmission electron microscopy,UV-vis diffuse reflectance spectroscopy and photo luminescence *** La and Ce doping enhanced the visible light absorption ability of ZnLC and a red shift was detected for *** simulated solar light irradiation,the ZnO doped with 3 at%La and 1 at%Ce(ZnLC1)degrades methylene blue(MB)more effectively than those of pure ZnO,La-doped ZnO(ZnL)and commercially available *** improved photocatalytic performance of ZnLC1 can be attributed to the high charge separation efficiency as demonstrated by the photoluminescence ***,the photocatalytic experiments reveal that several parameters have their own impact on the MB *** a variety of radical scavengers,it is discovered that superoxide anion radical plays a crucial role in the degradation of *** ZnLC1 is also reused several times without noticeable decrease of photoactivity,indicating that it has a substantial potential for environmental remediation applications.
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