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2022 ◽  
Vol 2022 ◽  
pp. 1-17
Author(s):  
Yonglan Li ◽  
Wen Shu

The research is aimed at verifying the application effect of the online automatic evaluation system in English translation teaching and at understanding the satisfaction of students with different feedback methods. The research uses three classes of human resource management majors in Xi’an Technological University as the research object and uses questionnaire survey and comparative experiment methods to compare and analyse the three feedback methods: teacher feedback, online automatic feedback, and teacher feedback combined with online automatic feedback. The research answers the following three questions: (1) will the three feedback methods affect students’ English translation performance? (2) Which of the three feedback methods will improve students’ English performance better? (3) What about students’ satisfaction with current feedback methods? The research results show that the significance value between the control group (CG) and the experimental group 1 (EG1) is 0.029, that between CG and the experimental group 2 (EG2) is 0.432, and that between EG1 and EG2 is 0.001. There are obvious differences in the posttest scores of the three groups of students. EG2 has the largest average posttest score, which is 9.8182; there is no obvious difference in posttest translation scores between CG and EG2. It indicates that “teacher feedback + online automatic feedback” and teacher feedback have the equivalent effect on improving students’ translation. The results of the questionnaire survey show that students have the highest degree of recognition of “teacher feedback + online automatic feedback.” The research is helpful for teachers to better understand the shortcomings in the translation teaching process, so that they can take effective measures against these problems in the follow-up teaching process to improve their teaching effect.


2021 ◽  
Vol 2136 (1) ◽  
pp. 012020
Author(s):  
Shengqing Li ◽  
Zhijian Wang

Abstract Grid-connected group-series photovoltaic cluster inverter system will cause resonance, which will adversely affect the system. To suppress grid-connected resonance, the mathematical model, resonance mechanism and resonance characteristics of the cluster inverters are analyzed, and a global resonance suppression strategy based on hybrid damping is proposed. In the current loop of the inverter, capacitive current feedback and parallel voltage proportional feed-forward are introduced as active dampers to reduce the harmonics of the parallel current. On this basis, RLC type second-order resonance suppression circuit is added as passive damping to suppress system resonance, so that the output current of the inverters can meet the grid-connected conditions when the cluster is connected to the grid. The simulation and experimental results show that the total harmonic distortion of the grid-connected current decreases from 10.54% to 1.97% after three series photovoltaic cluster inverters adopt this strategy, which effectively suppresses the grid-connected resonance.


2021 ◽  
Vol 2136 (1) ◽  
pp. 012012
Author(s):  
Shengqing Li ◽  
Xin Yao ◽  
Ziran Peng ◽  
Zhichao Shen

Abstract Photo-voltaic inverts usually use LCL filter for filtering, and LCL filter will bring resonance problems to the system. This paper focuses on invert-er side current feedback control (invert-er side current feedback, ICF). This paper proposes a method for suppressing resonance of photo-voltaic invert-er clusters based on capacitor voltage feed-forward. First, establish the ICF mathematical model based on HPF and CVF under the weak grid, qualitatively analyze the resonance mechanism of the cluster invert-er, then analyze the system control structure and stability according to the proposed method, and finally verify the effectiveness of the proposed method through simulation and experiment sexuality and correctness.


2021 ◽  
Vol 2136 (1) ◽  
pp. 012032
Author(s):  
Shengqing Li ◽  
Wang Han ◽  
Xiaobao Li ◽  
Zhijian Wang

Abstract To address the serious harmonic problem of grid connected current in photovoltaic grid-connected inverter, a harmonic suppression strategy based on Repetitive and PI control is proposed in this thesis. According to this strategy, the mathematical model of LCL photovoltaic grid-connected inverter is established with the harmonic mechanism analyzed, the repetitive and PI control is added into the current controller, and the capacitive-current feedback is added to enhance the system damping. Furthermore, it puts PI control on the inner loop and the repetitive control on the outer loop to improve the dynamic performance and achieve the harmonic suppression of the system. Moreover, the simulation results show that this method improves the dynamic response ability of the system, and effectively suppress the grid-connected current harmonics as THD of grid-connected current is 19.65% lower than that of PI controller.


2021 ◽  
Author(s):  
Juan M. Carrillo ◽  
Miguel A. Dominguez ◽  
Raquel Perez-Aloe ◽  
J. Francisco Duque-Carrillo ◽  
Guido Torelli

Mechatronics ◽  
2021 ◽  
Vol 78 ◽  
pp. 102631
Author(s):  
David Brunner ◽  
Stephan Albert ◽  
Marcus Hennecke ◽  
Franz Darrer ◽  
Georg Schitter

Author(s):  
Peiran Yang ◽  
Zhao Jing ◽  
Bingrong Sun ◽  
Lixin Wu ◽  
Bo Qiu ◽  
...  

AbstractEncountering of energetic ocean eddies and atmosphere storms makes the winter Kuroshio extension a hotspot for air-sea interactions. This second part investigates the regulation of vertical eddy heat transport QT in the winter Kuroshio extension mixed layer by different types of air-sea interactions, including the atmosphere synoptic forcing, eddy thermal feedback resulting from eddy-induced surface heat flux anomalies, and eddy current feedback from eddy current’s imprint on wind stress.Atmosphere synoptic forcing modulates intra-seasonal variation of QT by boosting its component contributed by the turbulent thermal wind balance during strong cooling events associated with intense winds. In addition, the magnitude of QT is influenced by the direction of synoptic wind stress primarily via , with the latter exhibiting enhancement both in the downfront- and upfront-wind forcing. Enhanced by the downfront-wind forcing is attributed to increased turbulent vertical viscosity and front intensity caused by the destabilizing wind-driven Ekman buoyancy flux, whereas interaction of uniform wind stress with smaller turbulent vertical viscosity at the front center than periphery (a so-called internal Ekman pumping) accounts for the increased in the upfront-wind forcing. The eddy thermal feedback reduces QT significantly through weakening the fronts. In contrast, the eddy current feedback exerts negligible influences on QT, although it weakens eddy kinetic energy (EKE) evidently. This is due to the much reduced effect of eddy current feedback in damping the fronts compared to EKE and also due to the compensation from Ekman pumping induced by the eddy current feedback.


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