Currently,the dominant trend in new energy power supply systems is the heterogeneous inverters-paralleled system(HIPS),which is a combination of grid-following(GFL)and grid-forming(GFM)inverters.The dynamic characteri...Currently,the dominant trend in new energy power supply systems is the heterogeneous inverters-paralleled system(HIPS),which is a combination of grid-following(GFL)and grid-forming(GFM)inverters.The dynamic characteristics of different inverters in HIPS and the differences between GFL and GFM inverters undoubtedly increase the difficulty of the stability analysis and coordinated control.This paper establishes an interactive admittance matrix model of HIPS,fully considers the interactive effects among different inverters,and explores the multi-dimensional resonance characteristics of HIPS by utilizing the modal analysis method.To achieve the coordinated control and oscillation suppression among different inverters,a frequency-divided compensation strategy is proposed,which divides the operation modes of HIPS into three categories,i.e.,GFM,GFL,and hybrid modes.Specifically,the frequency division boundary is determined based on the resonance characteristics of GFL and GFM inverters,with the operation modes of HIPS being dynamically adjusted according to the harmonic power ratio.Finally,the simulation and experimental results demonstrate that the HIPS can flexibly adjust the operation modes to adapt to the complex conditions after adopting the frequency-divided compensation strategy and suppressing the oscillation frequency ratio to less than 2%,ensuring the safe and reliable operation of HIPS.展开更多
Based on the four-element model,this paper reviewed the important research progress in vehicle platoon,compared the advantages and disadvantages of different models in each element longitudinally,and summarized the li...Based on the four-element model,this paper reviewed the important research progress in vehicle platoon,compared the advantages and disadvantages of different models in each element longitudinally,and summarized the linkage between each element horizontally.The stability criteria are briefly reviewed from three dimensions:local stability,string stability,and traffic flow stability.The impact of communication delay on vehicle platoon is quantitatively summarized from two aspects:the variation of controller gains and the variation of headway time values.Aiming at the inevitable communication delay in vehicle platoon,the compensation strategies are analyzed from five levels.(1)Optimizing the communication network structure.(2)Reconstructing acceleration information.(3)Tuning controller gains.(4)Constructing a multi-branch selection structure.(5)Improving the controller.The results show that,although these compensation strategies can alleviate the negative impact of communication delay to a certain extent,they also have some defects such as difficulty in adapting to complex and various real road conditions,poor accuracy and real-time performance,insufficient security,and limited application scenarios.It is necessary to further improve the accuracy and real-time performance of the device,design an encrypted and scalable network architecture to ensure communication security and adaptability,and conduct further real vehicle testing.展开更多
Introduction:This paper uses a dynamic voltage restorer(DVR)to improve the voltage quality from voltage sags.It is difficult to satisfy various of compensation quality and time of the voltage sag by using single compe...Introduction:This paper uses a dynamic voltage restorer(DVR)to improve the voltage quality from voltage sags.It is difficult to satisfy various of compensation quality and time of the voltage sag by using single compensation method.Furthermore,high-power consumption of the phase jump compensation increases the size and cost of a dynamic voltage restorer(DVR).Methods&Results:In order to improve the compensating efficiency of DVR,an optimized compensation strategy is proposed for voltage sag of micro-grid caused by interconnection and sensitive loads.The proposed compensation strategy increases the supporting time for long voltage sags.Discussion:Firstly,the power flow and the maximum compensation time of DVR are analyzed using three basic compensation strategies.Then,the phase jump is corrected by pre-sag compensation.And a quadratic transition curve,which involves the injected voltage phases of pre-sag strategy and minimum energy strategy,is used to transform pre-sag compensation to minimum energy compensation of DVR.Conclusions:The transition utilizes the storage system to reduce the rate of discharge.As a result,the proposed strategy increases the supporting time for long voltage sags.The analytical study shows that the presented method significantly increases compensation time of DVR.The simulation results performed by MATLAB/SIMULINK also confirm the effectiveness of the proposed method.展开更多
Industrial robots are integral to modern manufacturing systems,enabling high precision,high throughput,and flexibility.However,errors in accuracy and repeatability,which arise from a variety of sources such as mechani...Industrial robots are integral to modern manufacturing systems,enabling high precision,high throughput,and flexibility.However,errors in accuracy and repeatability,which arise from a variety of sources such as mechanical wear,calibration issues,and environmental factors,can significantly impact the performance of industrial robots.This paper aims to explore the theoretical modeling of errors in industrial robot systems and propose compensation strategies to enhance their accuracy and repeatability.Key factors contributing to errors,such as kinematic,dynamic,and environmental influences,are discussed in detail.Additionally,the paper explores various compensation techniques,including geometric error compensation,dynamic compensation,and adaptive control approaches.Through the integration of error modeling and compensation methods,industrial robots can achieve improved performance,ensuring higher operational efficiency and product quality.The paper concludes by highlighting the challenges and future research directions for improving the accuracy and repeatability of industrial robots in practical applications.展开更多
Attempts are made to explore the relationship between culture and translation, reasons are illustrated for the phenomenonof cultural vacancy and compensation methods for cultural vacancy are demonstrated in Chinese-En...Attempts are made to explore the relationship between culture and translation, reasons are illustrated for the phenomenonof cultural vacancy and compensation methods for cultural vacancy are demonstrated in Chinese-English translation. Such strate-gies as literal translation, liberal translation, transliteration, annotation and cultural omission are of great guidance to our transla-tion practice.展开更多
English teaching in China has attached too much importance to the input of the target language culture,while neglecting our native culture.As a result,students cannot express Chinese culture in English,completely sepa...English teaching in China has attached too much importance to the input of the target language culture,while neglecting our native culture.As a result,students cannot express Chinese culture in English,completely separating Chinese culture from English learning,leading to the serious native culture aphasia.This paper not only analyzes the reasons for this phenomenon from the aspects of curriculum setting,learning motivation,and teachers’quality,but also explains the necessity of integrating Chinese native culture in English teaching.On this basis,effective solutions are put forward from the perspective of classroom teaching,textbook compilation,curriculum arrangement,and so on.展开更多
The modular multilevel converter （MMC） is a highly modular, easy to expand; the output voltage waveform is good, especially suitable for application in high voltage power system. This article first introduces the ci...The modular multilevel converter （MMC） is a highly modular, easy to expand; the output voltage waveform is good, especially suitable for application in high voltage power system. This article first introduces the circuit topology and principle of MMC, and the main technical characteristics of MMC. And according to the relationship between the drop power voltage and the load power factor, proposed three working modes of the minimum energy compensation strategy. It is shown that MMC has good application prospect in future medium or high- voltage high power applications, especially be one of candidates for HVDC system application.展开更多
We present a system-level model with an on-chip temperature compensation technique for a CMOS-MEMS monolithic calorimetric flow sensing SoC.The model encompasses mechanical,thermal,and electrical domains to facilitate...We present a system-level model with an on-chip temperature compensation technique for a CMOS-MEMS monolithic calorimetric flow sensing SoC.The model encompasses mechanical,thermal,and electrical domains to facilitate the co-design of a MEMS sensor and CMOS interface circuits on the EDA platform.The compensation strategy is implemented on-chip with a variable temperature difference heating circuit.Results show that the linear programming for the low-temperature drift in the SoC output is characterized by a compensation resistor Rc with a resistance value of 748.21Ωand a temperature coefficient of resistance of 3.037×10−3℃^(−1) at 25℃.Experimental validation demonstrates that within an ambient temperature range of 0–50℃ and a flow range of 0-10 m/s,the temperature drift of the sensor is reduced to±1.6%,as compared to±8.9%observed in a counterpart with the constant temperature difference circuit.Therefore,this on-chip temperature-compensated CMOS-MEMS flow sensing SoC is promising for low-cost sensing applications such as respiratory monitoring and smart energy-efficient buildings.展开更多
The advantages and promoting applications of the microgrids community(MGC)allows for a critical step being taken toward a smart grid.An energy management strategy(EMS)is essential to intelligently coordinate the opera...The advantages and promoting applications of the microgrids community(MGC)allows for a critical step being taken toward a smart grid.An energy management strategy(EMS)is essential to intelligently coordinate the operations of the MGC.This paper presents a multi-time-scale EMS consid-ering battery operational modes for grid-connected MGCs.The proposed strategy consists of two modules:day-ahead integrated optimization and realtime distributed compensation.The first module aims to minimize the operational cost of the MGC considering battery free-overcharging protecting.This problem is solved by the mixed integer linear programming(MILP)sim-ulating two charging/discharging modes:limited-current mode and constant-voltage mode.The second module is installed in local MGs to correct the optimizing deviations of the day-ahead static scheduling,which are caused by predicting errors of renewable energy and loads.The main contribution of this work is integrating the advantages of global optimization of the centralized method and the fast computing speed of the distributed method.Experimental results prove the proposed EMS is feasible and effective.The computing time at each updating step is reduced by 75%on average,which has the potential to be adopted in engineering.展开更多
基金supported by the National Natural Science Foundation of China(No.52077222)the Shandong Provincial Natural Science Foundation(No.ZR2023QE156)。
文摘Currently,the dominant trend in new energy power supply systems is the heterogeneous inverters-paralleled system(HIPS),which is a combination of grid-following(GFL)and grid-forming(GFM)inverters.The dynamic characteristics of different inverters in HIPS and the differences between GFL and GFM inverters undoubtedly increase the difficulty of the stability analysis and coordinated control.This paper establishes an interactive admittance matrix model of HIPS,fully considers the interactive effects among different inverters,and explores the multi-dimensional resonance characteristics of HIPS by utilizing the modal analysis method.To achieve the coordinated control and oscillation suppression among different inverters,a frequency-divided compensation strategy is proposed,which divides the operation modes of HIPS into three categories,i.e.,GFM,GFL,and hybrid modes.Specifically,the frequency division boundary is determined based on the resonance characteristics of GFL and GFM inverters,with the operation modes of HIPS being dynamically adjusted according to the harmonic power ratio.Finally,the simulation and experimental results demonstrate that the HIPS can flexibly adjust the operation modes to adapt to the complex conditions after adopting the frequency-divided compensation strategy and suppressing the oscillation frequency ratio to less than 2%,ensuring the safe and reliable operation of HIPS.
基金supported in part by the Fundamental Research Funds for the Central Universities,CHD,under grant 300102243713in part by the National Natural Science Foundation of China under grant 61973045+2 种基金in part by the Natural Science Basic Research Program of Shaanxi Province under grant 2023-JC-JQ-45in part by the Natural Science Basic Research Program of Shaanxi under grant 2023-JC-QN-0667in part by the Fundamental Research Funds for the Central Universities,CHD,under grant 300102242102。
文摘Based on the four-element model,this paper reviewed the important research progress in vehicle platoon,compared the advantages and disadvantages of different models in each element longitudinally,and summarized the linkage between each element horizontally.The stability criteria are briefly reviewed from three dimensions:local stability,string stability,and traffic flow stability.The impact of communication delay on vehicle platoon is quantitatively summarized from two aspects:the variation of controller gains and the variation of headway time values.Aiming at the inevitable communication delay in vehicle platoon,the compensation strategies are analyzed from five levels.(1)Optimizing the communication network structure.(2)Reconstructing acceleration information.(3)Tuning controller gains.(4)Constructing a multi-branch selection structure.(5)Improving the controller.The results show that,although these compensation strategies can alleviate the negative impact of communication delay to a certain extent,they also have some defects such as difficulty in adapting to complex and various real road conditions,poor accuracy and real-time performance,insufficient security,and limited application scenarios.It is necessary to further improve the accuracy and real-time performance of the device,design an encrypted and scalable network architecture to ensure communication security and adaptability,and conduct further real vehicle testing.
基金supported by National Nature Science Foundation under Grant 51477070,and the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Introduction:This paper uses a dynamic voltage restorer(DVR)to improve the voltage quality from voltage sags.It is difficult to satisfy various of compensation quality and time of the voltage sag by using single compensation method.Furthermore,high-power consumption of the phase jump compensation increases the size and cost of a dynamic voltage restorer(DVR).Methods&Results:In order to improve the compensating efficiency of DVR,an optimized compensation strategy is proposed for voltage sag of micro-grid caused by interconnection and sensitive loads.The proposed compensation strategy increases the supporting time for long voltage sags.Discussion:Firstly,the power flow and the maximum compensation time of DVR are analyzed using three basic compensation strategies.Then,the phase jump is corrected by pre-sag compensation.And a quadratic transition curve,which involves the injected voltage phases of pre-sag strategy and minimum energy strategy,is used to transform pre-sag compensation to minimum energy compensation of DVR.Conclusions:The transition utilizes the storage system to reduce the rate of discharge.As a result,the proposed strategy increases the supporting time for long voltage sags.The analytical study shows that the presented method significantly increases compensation time of DVR.The simulation results performed by MATLAB/SIMULINK also confirm the effectiveness of the proposed method.
文摘Industrial robots are integral to modern manufacturing systems,enabling high precision,high throughput,and flexibility.However,errors in accuracy and repeatability,which arise from a variety of sources such as mechanical wear,calibration issues,and environmental factors,can significantly impact the performance of industrial robots.This paper aims to explore the theoretical modeling of errors in industrial robot systems and propose compensation strategies to enhance their accuracy and repeatability.Key factors contributing to errors,such as kinematic,dynamic,and environmental influences,are discussed in detail.Additionally,the paper explores various compensation techniques,including geometric error compensation,dynamic compensation,and adaptive control approaches.Through the integration of error modeling and compensation methods,industrial robots can achieve improved performance,ensuring higher operational efficiency and product quality.The paper concludes by highlighting the challenges and future research directions for improving the accuracy and repeatability of industrial robots in practical applications.
文摘Attempts are made to explore the relationship between culture and translation, reasons are illustrated for the phenomenonof cultural vacancy and compensation methods for cultural vacancy are demonstrated in Chinese-English translation. Such strate-gies as literal translation, liberal translation, transliteration, annotation and cultural omission are of great guidance to our transla-tion practice.
文摘English teaching in China has attached too much importance to the input of the target language culture,while neglecting our native culture.As a result,students cannot express Chinese culture in English,completely separating Chinese culture from English learning,leading to the serious native culture aphasia.This paper not only analyzes the reasons for this phenomenon from the aspects of curriculum setting,learning motivation,and teachers’quality,but also explains the necessity of integrating Chinese native culture in English teaching.On this basis,effective solutions are put forward from the perspective of classroom teaching,textbook compilation,curriculum arrangement,and so on.
文摘The modular multilevel converter （MMC） is a highly modular, easy to expand; the output voltage waveform is good, especially suitable for application in high voltage power system. This article first introduces the circuit topology and principle of MMC, and the main technical characteristics of MMC. And according to the relationship between the drop power voltage and the load power factor, proposed three working modes of the minimum energy compensation strategy. It is shown that MMC has good application prospect in future medium or high- voltage high power applications, especially be one of candidates for HVDC system application.
基金supported by the National Natural Science Foundation of China(62474115,52105582)Natural Science Foundation of Guangdong Province(2024A1515030026,2022A1515010894)+1 种基金Fundamental Research Foundation of Shenzhen(JCYJ20210324095210030,JCYJ20220818095810023,ZDSYS20220527171402005)the State Key Laboratory of Radio Frequency Heterogeneous Integration(Independent Scientific Research Program No.2024013)for Linze Hong,Ke Xiao,Xiangyu Song,and Wei Xu.
文摘We present a system-level model with an on-chip temperature compensation technique for a CMOS-MEMS monolithic calorimetric flow sensing SoC.The model encompasses mechanical,thermal,and electrical domains to facilitate the co-design of a MEMS sensor and CMOS interface circuits on the EDA platform.The compensation strategy is implemented on-chip with a variable temperature difference heating circuit.Results show that the linear programming for the low-temperature drift in the SoC output is characterized by a compensation resistor Rc with a resistance value of 748.21Ωand a temperature coefficient of resistance of 3.037×10−3℃^(−1) at 25℃.Experimental validation demonstrates that within an ambient temperature range of 0–50℃ and a flow range of 0-10 m/s,the temperature drift of the sensor is reduced to±1.6%,as compared to±8.9%observed in a counterpart with the constant temperature difference circuit.Therefore,this on-chip temperature-compensated CMOS-MEMS flow sensing SoC is promising for low-cost sensing applications such as respiratory monitoring and smart energy-efficient buildings.
基金This work was supported in part by the China Scholarship Council under the Grant(201606290197).
文摘The advantages and promoting applications of the microgrids community(MGC)allows for a critical step being taken toward a smart grid.An energy management strategy(EMS)is essential to intelligently coordinate the operations of the MGC.This paper presents a multi-time-scale EMS consid-ering battery operational modes for grid-connected MGCs.The proposed strategy consists of two modules:day-ahead integrated optimization and realtime distributed compensation.The first module aims to minimize the operational cost of the MGC considering battery free-overcharging protecting.This problem is solved by the mixed integer linear programming(MILP)sim-ulating two charging/discharging modes:limited-current mode and constant-voltage mode.The second module is installed in local MGs to correct the optimizing deviations of the day-ahead static scheduling,which are caused by predicting errors of renewable energy and loads.The main contribution of this work is integrating the advantages of global optimization of the centralized method and the fast computing speed of the distributed method.Experimental results prove the proposed EMS is feasible and effective.The computing time at each updating step is reduced by 75%on average,which has the potential to be adopted in engineering.
