In order to achieve the improvement of the driving comfort and energy efficiency,an new e-CVT flexible full hybrid electric system(E2FHS) is proposed,which uses an integrated main drive motor and generator to take the...In order to achieve the improvement of the driving comfort and energy efficiency,an new e-CVT flexible full hybrid electric system(E2FHS) is proposed,which uses an integrated main drive motor and generator to take the place of the original automatic or manual transmission to realize the functions of continuously variable transmission(e-CVT).The design and prototype realization of the E2FHS system for a plug-in hybrid vehicle(PHEV) is performed.In order to analyze and optimize the parameters and the power flux between different parts of the E2FHS,simulation software is developed.Especially,in order to optimize the performance of the energy economy improvement of the E2FHS,the effect of the different energy management controllers is investigated,and an adaptive online-optimal energy management controller for the E2FHS is built and validated by the prototype PHEV.展开更多
Global Positioning System (GPS) is a worldwide satellite system that provides navigation, positioning, and timing for both military and civilian applications. GPS based time reference provides inexpensive but highly-a...Global Positioning System (GPS) is a worldwide satellite system that provides navigation, positioning, and timing for both military and civilian applications. GPS based time reference provides inexpensive but highly-accurate timing and synchronization capability and meets requirements in power system fault location, monitoring, and control. In the present era of restructuring and modernization of electric power utilities, the applications of GIS/GPS technology in power industry are growing and covering several technical and man-agement activities. Because of GPS receiver’s error sources are time variant, it is necessary to remove the GPS measurement noise. This paper presents novel recurrent neural networks called the Recurrent Pi-Sigma Neural Network (RPSNN) and Recurrent Sigma-Pi Neural Network (RSPNN). The proposed NNs have been used as predictor in GPS receivers timing errors. The NNs were trained using the dynamic Back Propagation (BP) algorithm. The actual data collection was used to test the performance of the proposed NNs. The ex-perimental results obtained from a Coarse Acquisition (C/A)-code single-frequency GPS receiver strongly support the potential of the method using RPSNN to give high accurate timing. The GPS timing RMS error reduces from 200 to less than 40 nanoseconds.展开更多
Dynamic Programming (DP) algorithm is used to find the optimal trajectories under Beijing cycle for the power management of synergic electric system (SES) which is composed of battery and super capacitor. Feasible rul...Dynamic Programming (DP) algorithm is used to find the optimal trajectories under Beijing cycle for the power management of synergic electric system (SES) which is composed of battery and super capacitor. Feasible rules are derived from analyzing the optimal trajectories, and it has the highest contribution to Hybrid Electric Vehicle (HEV). The methods of how to get the best performance is also educed. Using the new Rule-based power management strat-egy adopted from the optimal results, it is easy to demonstrate the effectiveness of the new strategy in further improvement of the fuel economy by the synergic hybrid system.展开更多
A systematic experimental investigation to understand the effect of heat loss and the thermoelectric aspect ratio (cross sectional area and length) on a flat plate solar thermoelectric system performance was carried o...A systematic experimental investigation to understand the effect of heat loss and the thermoelectric aspect ratio (cross sectional area and length) on a flat plate solar thermoelectric system performance was carried out. The investigation involved a series of experiments on systems with 4 different sizes of thermoelectric generators, and it was tested in 5 different vacuum levels during the steady-state. The detailed experimental investigation provided a substantial amount of data, which revealed that the system performance of both heat and electricity power were improved when the heat lost was minimised. The system’s performance strongly depended on the aspect ratio of the thermoelectric generators. This finding might have a significant impact on the cost of the system by saving the user’s and the manufacturer’s time in examining different TEGs with different aspect ratios in order to get the optimum size optimisation of the hybrid system, as well as reduce the manufacturing cost.展开更多
A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is addressed.This paper mainly focuses on two types of possibly fast timevaryin...A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is addressed.This paper mainly focuses on two types of possibly fast timevarying but bounded uncertainty within the vertical electric stabilization system:model parameter uncertainty and uncertain nonlinearity.First,the vertical electric stabilization system is constructed as an uncertain nonlinear dynamic system that can reflect the practical mechanics transfer process of the system.Second,the dynamical equation in the form of state space is established by designing the angular tracking error.Third,the comprehensive parameter of system uncertainty is designed to estimate the most conservative effects of uncertainty.Finally,an adaptive robust servo control which can effectively handle the combined effects of complex nonlinearity and uncertainty is proposed.The feasibility of the proposed control strategy under the practical physical condition is validated through the tests on the experimental platform.This paper pioneers the introduction of the internal nonlinearity and uncertainty of the vertical electric stabilization system into the settlement of the tracking stability control problem,and validates the advanced servo control strategy through experiment for the first time.展开更多
BACKGROUND Lack of mobilization and prolonged stay in the intensive care unit(ICU)are major factors resulting in the development of ICU-acquired muscle weakness(ICUAW).ICUAW is a type of skeletal muscle dysfunction an...BACKGROUND Lack of mobilization and prolonged stay in the intensive care unit(ICU)are major factors resulting in the development of ICU-acquired muscle weakness(ICUAW).ICUAW is a type of skeletal muscle dysfunction and a common complication of patients after cardiac surgery,and may be a risk factor for prolonged duration of mechanical ventilation,associated with a higher risk of readmission and higher mortality.Early mobilization in the ICU after cardiac surgery has been found to be low with a significant trend to increase over ICU stay and is also associated with a reduced duration of mechanical ventilation and ICU length of stay.Neuromuscular electrical stimulation(NMES)is an alternative modality of exercise in patients with muscle weakness.A major advantage of NMES is that it can be applied even in sedated patients in the ICU,a fact that might enhance early mobilization in these patients.AIM To evaluate safety,feasibility and effectiveness of NMES on functional capacity and muscle strength in patients before and after cardiac surgery.METHODS We performed a search on Pubmed,Physiotherapy Evidence Database(PEDro),Embase and CINAHL databases,selecting papers published between December 2012 and April 2023 and identified published randomized controlled trials(RCTs)that included implementation of NMES in patients before after cardiac surgery.RCTs were assessed for methodological rigor and risk of bias via the PEDro.The primary outcomes were safety and functional capacity and the secondary outcomes were muscle strength and function.RESULTS Ten studies were included in our systematic review,resulting in 703 participants.Almost half of them performed NMES and the other half were included in the control group,treated with usual care.Nine studies investigated patients after cardiac surgery and 1 study before cardiac surgery.Functional capacity was assessed in 8 studies via 6MWT or other indices,and improved only in 1 study before and in 1 after cardiac surgery.Nine studies explored the effects of NMES on muscle strength and function and,most of them,found increase of muscle strength and improvement in muscle function after NMES.NMES was safe in all studies without any significant complication.CONCLUSION NMES is safe,feasible and has beneficial effects on muscle strength and function in patients after cardiac surgery,but has no significant effect on functional capacity.展开更多
The torque ripples resulting from external electromagnetic excitation and mechanical internal excitation contribute to significant torsional vibration issues within electromechanical coupling systems.To mitigate these...The torque ripples resulting from external electromagnetic excitation and mechanical internal excitation contribute to significant torsional vibration issues within electromechanical coupling systems.To mitigate these fluctuations,a passive control strategy centered around a multi-stable nonlinear energy sink(MNES)is proposed.First,models for electromagnetic torque,gear nonlinear meshing torque,and misalignment torque are established.Building upon this foundation,an electromechanical coupling dynamic model of the electric drive system is formulated.Sensitivity analysis is conducted to determine the sensitive nodes of each mode and to provide guidance for the installation of the MNES.The structure of the MNES is introduced,and an electromechanical coupling dynamic model with the MNES is established.Based on this model,the influence of the misaligned angle on the electromechanical coupling characteristics is analyzed.In addition,the vibration suppression performance of the MNES is studied under both speed and uniform speed conditions.Finally,experimental testing is conducted to verify the vibration suppression performance of the MNES.The results indicate that misalignment triggers the emergence of its characteristic frequencies and associated sidebands.Meanwhile,the MNES effectively mitigates the torsional vibrations in the coupled system,demonstrating suppression rates of 52.69%in simulations and 63.3%in experiments.展开更多
This paper addresses the sampled-data multi-objective active suspension control problem for an in-wheel motor driven electric vehicle subject to stochastic sampling periods and asynchronous premise variables.The focus...This paper addresses the sampled-data multi-objective active suspension control problem for an in-wheel motor driven electric vehicle subject to stochastic sampling periods and asynchronous premise variables.The focus is placed on the scenario that the dynamical state of the half-vehicle active suspension system is transmitted over an in-vehicle controller area network that only permits the transmission of sampled data packets.For this purpose,a stochastic sampling mechanism is developed such that the sampling periods can randomly switch among different values with certain mathematical probabilities.Then,an asynchronous fuzzy sampled-data controller,featuring distinct premise variables from the active suspension system,is constructed to eliminate the stringent requirement that the sampled-data controller has to share the same grades of membership.Furthermore,novel criteria for both stability analysis and controller design are derived in order to guarantee that the resultant closed-loop active suspension system is stochastically stable with simultaneous𝐻2 and𝐻∞performance requirements.Finally,the effectiveness of the proposed stochastic sampled-data multi-objective control method is verified via several numerical cases studies in both time domain and frequency domain under various road disturbance profiles.展开更多
Cascading faults have been identified as the primary cause of multiple power outages in recent years.With the emergence of integrated energy systems(IES),the conventional approach to analyzing power grid cascading fau...Cascading faults have been identified as the primary cause of multiple power outages in recent years.With the emergence of integrated energy systems(IES),the conventional approach to analyzing power grid cascading faults is no longer appropriate.A cascading fault analysis method considering multi-energy coupling characteristics is of vital importance.In this study,an innovative analysis method for cascading faults in integrated heat and electricity systems(IHES)is proposed.It considers the degradation characteristics of transmission and energy supply com-ponents in the system to address the impact of component aging on cascading faults.Firstly,degradation models for the current carrying capacity of transmission lines,the water carrying capacity and insulation performance of thermal pipelines,as well as the performance of energy supply equipment during aging,are developed.Secondly,a simulation process for cascading faults in the IHES is proposed.It utilizes an overload-dominated development model to predict the propagation path of cascading faults while also considering network islanding,electric-heating rescheduling,and load shedding.The propagation of cascading faults is reflected in the form of fault chains.Finally,the results of cascading faults under different aging levels are analyzed through numerical examples,thereby verifying the effectiveness and rationality of the proposed model and method.展开更多
Electric vehicles use electric motors, which turn electrical energy into mechanical energy. As electric motors are conventionally used in all the industry, it is an established development site. It’s a mature technol...Electric vehicles use electric motors, which turn electrical energy into mechanical energy. As electric motors are conventionally used in all the industry, it is an established development site. It’s a mature technology with ideal power and torque curves for vehicular operation. Conventional vehicles use oil and gas as fuel or energy storage. Although they also have an excellent economic impact, the continuous use of oil and gas threatened the world’s reservation of total oil and gas. Also, they emit carbon dioxide and some toxic ingredients through the vehicle’s tailpipe, which causes the greenhouse effect and seriously impacts the environment. So, as an alternative, electric car refers to a green technology of decarbonization with zero emission of greenhouse gases through the tailpipe. So, they can remove the problem of greenhouse gas emissions and solve the world’s remaining non-renewable energy storage problem. Pure electric vehicles (PEV) can be applied in all spheres, but their special implementation can only be seen in downhole operations. They are used for low noise and less pollution in the downhole process. In this study, the basic structure of the pure electric command vehicle is studied, the main components of the command vehicle power system, namely the selection of the drive motor and the power battery, are analyzed, and the main parameters of the drive motor and the power battery are designed and calculated. The checking calculation results show that the power and transmission system developed in this paper meets the design requirements, and the design scheme is feasible and reasonable.展开更多
A good quality Environmental Impact Statement (EIS) is key for the effectiveness of Environmental Impact Assessment (EIA) processes and consequently to the acceptability of projects subject to EIA. The international l...A good quality Environmental Impact Statement (EIS) is key for the effectiveness of Environmental Impact Assessment (EIA) processes and consequently to the acceptability of projects subject to EIA. The international literature has contributed to the understanding of the essential aspects to be verified regarding the quality of EIS, offering a wide spectrum of good practice examples related to the content of the studies. Even so, there is a need for empirical studies that allow the identification of specific aspects related to the context of application of the EIS, which could lead to the identification of opportunities to improve both the quality of the reports and also the effectiveness of EIA. Therefore, the present paper is focused on the quality review of a number of EIS submitted to the Brazilian Federal Environmental Agency (Ibama) to instruct the assessment of electric power transmission systems. Based on the application of the EIS quality review package as proposed by Lee and Colley (1992), the outcomes reveal opportunities for improving the scope of EIA, analysis of alternatives, prediction of magnitude and the assessment of impact significance. Finally, the development and/or adaptation of a similar tool for the systematic review of the quality of EIA reports is recommended.展开更多
The visualization operation of railway four-electric engineering construction is an important part in railway′s construction,which plays a critical role in improving operation efficiency and it is smoothly finished o...The visualization operation of railway four-electric engineering construction is an important part in railway′s construction,which plays a critical role in improving operation efficiency and it is smoothly finished on railway four-electric majors′professional construction.According to the typical high-speed railway project construction′s technology,these four-electric professional construction′s technology scheme are made into construction method′s video,according to the technology plan′s characteristics of professional,visualization and information,under the premise of improving the efficiency about professional project management and construction of the railway four-electric project,the critical technology problems of railway four-electric project are solved.At the same time,it also improves efficiency of BIM model′s construction,the cooperation management′s efficiency of construction process,and the ability of integrating model information.展开更多
Green energy conservation is the mainstream trend in the current development of the construction industry.The application of energy-saving technology in building electrical system design can effectively reduce energy ...Green energy conservation is the mainstream trend in the current development of the construction industry.The application of energy-saving technology in building electrical system design can effectively reduce energy consumption,avoid unnecessary energy consumption,and truly achieve energy conservation and environmental protection.Based on this,the article elaborates on the principles of energy-saving design in building electrical systems,and actively explores the application of energy-saving technologies from different perspectives such as optimizing power supply and distribution system design,adopting high-efficiency energy-saving lighting equipment,applying renewable energy,promoting smart home technology,and improving the efficiency of building electrical equipment.展开更多
Aim To research and develop a battery management system(BMS)with the state of charge(SOC)indicator for electric vehicles (EVs).Methods On the basis of analyzing the electro-chemical characteristics of lead-acid. batte...Aim To research and develop a battery management system(BMS)with the state of charge(SOC)indicator for electric vehicles (EVs).Methods On the basis of analyzing the electro-chemical characteristics of lead-acid. battery, the state of charge indicator for lead-acid battery was developed by means of an algorithm based on combination of ampere-hour, Peukert's equation and open-voltage method with the compensation of temperature,aging,self- discharging,etc..Results The BMS based on this method can attain an accurate surplus capa- city whose error is less than 5% in static experiments.It is proved by experiments that the BMS is reliable and can give the driver an accurate surplus capacity,precisely monitor the individual battery modules as the same time,even detect and warn the problems early,and so on. Conclusion A BMS can make the energy of the storage batteries used efficiently, develop the batteries cycle life,and increase the driving distance of EVs.展开更多
As a matured technique used in many fields,the distributed computer system is still a new management method for the aeronautical electrical power distribution system in our country. In this paper, a novel aircraft ele...As a matured technique used in many fields,the distributed computer system is still a new management method for the aeronautical electrical power distribution system in our country. In this paper, a novel aircraft electrical power distribution system based on the distributed computer system is proposed. The principles, features and structure of the aircraft electrical power distribution system and the distributed computer system named electrical load management system (ELMS) are studied. The ELMS composed of four electrical load management centers (ELMCs) and two power source processors (PSPs) operates in the 1553B buses. Principles of the ELMCs and the PSPs are introduced. With the application of the distributed computer system, the aircraft electrical power distribution system is simple, adaptable and flexible.展开更多
A kind of management system for electric vehicle (EV) battery series was developed. The system can predict residual capacity for EV battery series and mileages. The system can determine if it is necessary for the batt...A kind of management system for electric vehicle (EV) battery series was developed. The system can predict residual capacity for EV battery series and mileages. The system can determine if it is necessary for the battery series to be charged. The system can determine which battery is necessary to be updated for the reason of damage or aging. The system can display the total voltage of battery series, extreme voltage and temperature of every battery in the series. The system can display the accumulative discharge for every battery in the series. The system can alarm when both total or extreme voltage is at low level, or temperature of a battery in the series is at high level. The system provided with a microprocessor as key part can collect and record signal of charging and discharging current, total voltage, extreme voltage and temperature for every battery. The mathematical model of residual capacity for EV lead acid batteries was discussed in details. The system operates well in the laboratory and meets the requirement.展开更多
Aiming at the comparatively laggard level of power plant electrical system automation, this paper analyzes the feasibility,necessity and some key points of the application of integrated automation technology to power ...Aiming at the comparatively laggard level of power plant electrical system automation, this paper analyzes the feasibility,necessity and some key points of the application of integrated automation technology to power plant electrical system. New idea using fieldbus control system technology is presented. This paper also gives the outline and detailed schemes.展开更多
In view of the current sensors failure in electric pitch system,a variable universe fuzzy fault tolerant control method of electric pitch control system based on single current detection is proposed.When there is sing...In view of the current sensors failure in electric pitch system,a variable universe fuzzy fault tolerant control method of electric pitch control system based on single current detection is proposed.When there is single or two-current sensor fault occurs,based on the proposed method the missing current information can be reconstructed by using direct current(DC)bus current sensor and the three-phase current can be updated in time within any two adjacent sampling periods,so as to ensure stability of the closed-loop system.And then the switchover and fault tolerant control of fault current sensor would be accomplished by fault diagnosis method based on adaptive threshold judgment.For the reconstructed signal error caused by the modulation method and the main control target of electric pitch system,a variable universe fuzzy control method is used in the speed loop,which can improve the anti-disturbance ability to load variation,and the robustness of fault tolerance system.The results show that the fault tolerant control method makes the variable pitch control system still has ideal control characteristics in case of sensor failure although part of the system performance is lost,thus the correctness of the proposed method is verified.展开更多
To evaluate the thermal performance of a low-temperature electrical radiant floor heating system,an experimental facility equipped with a constant temperature chamber and different specimen floors is designed and buil...To evaluate the thermal performance of a low-temperature electrical radiant floor heating system,an experimental facility equipped with a constant temperature chamber and different specimen floors is designed and built.The heating cable is installed in the floor slab with a unit-rated power of 30 W/m.Twenty-four different schemes are worked out and tested,which include three kinds of composite floor structures and eight kinds of cable distances.The cable distances are 30,40,50,60,80,100,130,150 mm.The main affective factors of the thermal performance and their influencing regularity are discussed.The experimental results show that the system has good stability and reliability,and the ratio of the radiation heat-transfer rate to the gross heat-transfer rate is greater than 50%.When the floor structure and the cable distance are fixed,the gross heat-transfer rate of the upper floor surface has a maximum value at an optimal cable distance.Under the experimental conditions in this paper,the optimal cable distance is 50 mm.展开更多
The paper deals with the designing of an electric drive system used for hybrid electric vehicles. The driving system is realized with an induction motor and a voltage source inverter. Specifically, the application is ...The paper deals with the designing of an electric drive system used for hybrid electric vehicles. The driving system is realized with an induction motor and a voltage source inverter. Specifically, the application is for a series hybrid vehicle powered by electric storage batteries charged by solar batteries. In the first part of the paper the designing of the electric storage batteries and of the photoelectric system is presented. In the second part of the paper some aspects regarding the designing of the induction motor are presented. Then some aspects concerning the voltage source inverter designing are exposed.展开更多
基金Project(2007CB209707) supported by the National Basic Research Program of China
文摘In order to achieve the improvement of the driving comfort and energy efficiency,an new e-CVT flexible full hybrid electric system(E2FHS) is proposed,which uses an integrated main drive motor and generator to take the place of the original automatic or manual transmission to realize the functions of continuously variable transmission(e-CVT).The design and prototype realization of the E2FHS system for a plug-in hybrid vehicle(PHEV) is performed.In order to analyze and optimize the parameters and the power flux between different parts of the E2FHS,simulation software is developed.Especially,in order to optimize the performance of the energy economy improvement of the E2FHS,the effect of the different energy management controllers is investigated,and an adaptive online-optimal energy management controller for the E2FHS is built and validated by the prototype PHEV.
文摘Global Positioning System (GPS) is a worldwide satellite system that provides navigation, positioning, and timing for both military and civilian applications. GPS based time reference provides inexpensive but highly-accurate timing and synchronization capability and meets requirements in power system fault location, monitoring, and control. In the present era of restructuring and modernization of electric power utilities, the applications of GIS/GPS technology in power industry are growing and covering several technical and man-agement activities. Because of GPS receiver’s error sources are time variant, it is necessary to remove the GPS measurement noise. This paper presents novel recurrent neural networks called the Recurrent Pi-Sigma Neural Network (RPSNN) and Recurrent Sigma-Pi Neural Network (RSPNN). The proposed NNs have been used as predictor in GPS receivers timing errors. The NNs were trained using the dynamic Back Propagation (BP) algorithm. The actual data collection was used to test the performance of the proposed NNs. The ex-perimental results obtained from a Coarse Acquisition (C/A)-code single-frequency GPS receiver strongly support the potential of the method using RPSNN to give high accurate timing. The GPS timing RMS error reduces from 200 to less than 40 nanoseconds.
文摘Dynamic Programming (DP) algorithm is used to find the optimal trajectories under Beijing cycle for the power management of synergic electric system (SES) which is composed of battery and super capacitor. Feasible rules are derived from analyzing the optimal trajectories, and it has the highest contribution to Hybrid Electric Vehicle (HEV). The methods of how to get the best performance is also educed. Using the new Rule-based power management strat-egy adopted from the optimal results, it is easy to demonstrate the effectiveness of the new strategy in further improvement of the fuel economy by the synergic hybrid system.
文摘A systematic experimental investigation to understand the effect of heat loss and the thermoelectric aspect ratio (cross sectional area and length) on a flat plate solar thermoelectric system performance was carried out. The investigation involved a series of experiments on systems with 4 different sizes of thermoelectric generators, and it was tested in 5 different vacuum levels during the steady-state. The detailed experimental investigation provided a substantial amount of data, which revealed that the system performance of both heat and electricity power were improved when the heat lost was minimised. The system’s performance strongly depended on the aspect ratio of the thermoelectric generators. This finding might have a significant impact on the cost of the system by saving the user’s and the manufacturer’s time in examining different TEGs with different aspect ratios in order to get the optimum size optimisation of the hybrid system, as well as reduce the manufacturing cost.
基金supported in part by the Nation Natural Science Foundation of China under Grant No.52175099China Postdoctoral Science Foundation under Grant No.2020M671494Jiangsu Planned Projects for Postdoctoral Research Funds under Grant No.2020Z179。
文摘A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is addressed.This paper mainly focuses on two types of possibly fast timevarying but bounded uncertainty within the vertical electric stabilization system:model parameter uncertainty and uncertain nonlinearity.First,the vertical electric stabilization system is constructed as an uncertain nonlinear dynamic system that can reflect the practical mechanics transfer process of the system.Second,the dynamical equation in the form of state space is established by designing the angular tracking error.Third,the comprehensive parameter of system uncertainty is designed to estimate the most conservative effects of uncertainty.Finally,an adaptive robust servo control which can effectively handle the combined effects of complex nonlinearity and uncertainty is proposed.The feasibility of the proposed control strategy under the practical physical condition is validated through the tests on the experimental platform.This paper pioneers the introduction of the internal nonlinearity and uncertainty of the vertical electric stabilization system into the settlement of the tracking stability control problem,and validates the advanced servo control strategy through experiment for the first time.
文摘BACKGROUND Lack of mobilization and prolonged stay in the intensive care unit(ICU)are major factors resulting in the development of ICU-acquired muscle weakness(ICUAW).ICUAW is a type of skeletal muscle dysfunction and a common complication of patients after cardiac surgery,and may be a risk factor for prolonged duration of mechanical ventilation,associated with a higher risk of readmission and higher mortality.Early mobilization in the ICU after cardiac surgery has been found to be low with a significant trend to increase over ICU stay and is also associated with a reduced duration of mechanical ventilation and ICU length of stay.Neuromuscular electrical stimulation(NMES)is an alternative modality of exercise in patients with muscle weakness.A major advantage of NMES is that it can be applied even in sedated patients in the ICU,a fact that might enhance early mobilization in these patients.AIM To evaluate safety,feasibility and effectiveness of NMES on functional capacity and muscle strength in patients before and after cardiac surgery.METHODS We performed a search on Pubmed,Physiotherapy Evidence Database(PEDro),Embase and CINAHL databases,selecting papers published between December 2012 and April 2023 and identified published randomized controlled trials(RCTs)that included implementation of NMES in patients before after cardiac surgery.RCTs were assessed for methodological rigor and risk of bias via the PEDro.The primary outcomes were safety and functional capacity and the secondary outcomes were muscle strength and function.RESULTS Ten studies were included in our systematic review,resulting in 703 participants.Almost half of them performed NMES and the other half were included in the control group,treated with usual care.Nine studies investigated patients after cardiac surgery and 1 study before cardiac surgery.Functional capacity was assessed in 8 studies via 6MWT or other indices,and improved only in 1 study before and in 1 after cardiac surgery.Nine studies explored the effects of NMES on muscle strength and function and,most of them,found increase of muscle strength and improvement in muscle function after NMES.NMES was safe in all studies without any significant complication.CONCLUSION NMES is safe,feasible and has beneficial effects on muscle strength and function in patients after cardiac surgery,but has no significant effect on functional capacity.
基金Project supported by the National Natural Science Foundation of China(Nos.52075084 and 52475094)the Fundamental Research Funds for the Central Universities of China(No.N2303005)。
文摘The torque ripples resulting from external electromagnetic excitation and mechanical internal excitation contribute to significant torsional vibration issues within electromechanical coupling systems.To mitigate these fluctuations,a passive control strategy centered around a multi-stable nonlinear energy sink(MNES)is proposed.First,models for electromagnetic torque,gear nonlinear meshing torque,and misalignment torque are established.Building upon this foundation,an electromechanical coupling dynamic model of the electric drive system is formulated.Sensitivity analysis is conducted to determine the sensitive nodes of each mode and to provide guidance for the installation of the MNES.The structure of the MNES is introduced,and an electromechanical coupling dynamic model with the MNES is established.Based on this model,the influence of the misaligned angle on the electromechanical coupling characteristics is analyzed.In addition,the vibration suppression performance of the MNES is studied under both speed and uniform speed conditions.Finally,experimental testing is conducted to verify the vibration suppression performance of the MNES.The results indicate that misalignment triggers the emergence of its characteristic frequencies and associated sidebands.Meanwhile,the MNES effectively mitigates the torsional vibrations in the coupled system,demonstrating suppression rates of 52.69%in simulations and 63.3%in experiments.
文摘This paper addresses the sampled-data multi-objective active suspension control problem for an in-wheel motor driven electric vehicle subject to stochastic sampling periods and asynchronous premise variables.The focus is placed on the scenario that the dynamical state of the half-vehicle active suspension system is transmitted over an in-vehicle controller area network that only permits the transmission of sampled data packets.For this purpose,a stochastic sampling mechanism is developed such that the sampling periods can randomly switch among different values with certain mathematical probabilities.Then,an asynchronous fuzzy sampled-data controller,featuring distinct premise variables from the active suspension system,is constructed to eliminate the stringent requirement that the sampled-data controller has to share the same grades of membership.Furthermore,novel criteria for both stability analysis and controller design are derived in order to guarantee that the resultant closed-loop active suspension system is stochastically stable with simultaneous𝐻2 and𝐻∞performance requirements.Finally,the effectiveness of the proposed stochastic sampled-data multi-objective control method is verified via several numerical cases studies in both time domain and frequency domain under various road disturbance profiles.
基金supported by Shanghai Rising-Star Program(No.22QA1403900)the National Natural Science Foundation of China(No.71804106)the Noncarbon Energy Conversion and Utilization Institute under the Shanghai Class IV Peak Disciplinary Development Program.
文摘Cascading faults have been identified as the primary cause of multiple power outages in recent years.With the emergence of integrated energy systems(IES),the conventional approach to analyzing power grid cascading faults is no longer appropriate.A cascading fault analysis method considering multi-energy coupling characteristics is of vital importance.In this study,an innovative analysis method for cascading faults in integrated heat and electricity systems(IHES)is proposed.It considers the degradation characteristics of transmission and energy supply com-ponents in the system to address the impact of component aging on cascading faults.Firstly,degradation models for the current carrying capacity of transmission lines,the water carrying capacity and insulation performance of thermal pipelines,as well as the performance of energy supply equipment during aging,are developed.Secondly,a simulation process for cascading faults in the IHES is proposed.It utilizes an overload-dominated development model to predict the propagation path of cascading faults while also considering network islanding,electric-heating rescheduling,and load shedding.The propagation of cascading faults is reflected in the form of fault chains.Finally,the results of cascading faults under different aging levels are analyzed through numerical examples,thereby verifying the effectiveness and rationality of the proposed model and method.
文摘Electric vehicles use electric motors, which turn electrical energy into mechanical energy. As electric motors are conventionally used in all the industry, it is an established development site. It’s a mature technology with ideal power and torque curves for vehicular operation. Conventional vehicles use oil and gas as fuel or energy storage. Although they also have an excellent economic impact, the continuous use of oil and gas threatened the world’s reservation of total oil and gas. Also, they emit carbon dioxide and some toxic ingredients through the vehicle’s tailpipe, which causes the greenhouse effect and seriously impacts the environment. So, as an alternative, electric car refers to a green technology of decarbonization with zero emission of greenhouse gases through the tailpipe. So, they can remove the problem of greenhouse gas emissions and solve the world’s remaining non-renewable energy storage problem. Pure electric vehicles (PEV) can be applied in all spheres, but their special implementation can only be seen in downhole operations. They are used for low noise and less pollution in the downhole process. In this study, the basic structure of the pure electric command vehicle is studied, the main components of the command vehicle power system, namely the selection of the drive motor and the power battery, are analyzed, and the main parameters of the drive motor and the power battery are designed and calculated. The checking calculation results show that the power and transmission system developed in this paper meets the design requirements, and the design scheme is feasible and reasonable.
文摘A good quality Environmental Impact Statement (EIS) is key for the effectiveness of Environmental Impact Assessment (EIA) processes and consequently to the acceptability of projects subject to EIA. The international literature has contributed to the understanding of the essential aspects to be verified regarding the quality of EIS, offering a wide spectrum of good practice examples related to the content of the studies. Even so, there is a need for empirical studies that allow the identification of specific aspects related to the context of application of the EIS, which could lead to the identification of opportunities to improve both the quality of the reports and also the effectiveness of EIA. Therefore, the present paper is focused on the quality review of a number of EIS submitted to the Brazilian Federal Environmental Agency (Ibama) to instruct the assessment of electric power transmission systems. Based on the application of the EIS quality review package as proposed by Lee and Colley (1992), the outcomes reveal opportunities for improving the scope of EIA, analysis of alternatives, prediction of magnitude and the assessment of impact significance. Finally, the development and/or adaptation of a similar tool for the systematic review of the quality of EIA reports is recommended.
文摘The visualization operation of railway four-electric engineering construction is an important part in railway′s construction,which plays a critical role in improving operation efficiency and it is smoothly finished on railway four-electric majors′professional construction.According to the typical high-speed railway project construction′s technology,these four-electric professional construction′s technology scheme are made into construction method′s video,according to the technology plan′s characteristics of professional,visualization and information,under the premise of improving the efficiency about professional project management and construction of the railway four-electric project,the critical technology problems of railway four-electric project are solved.At the same time,it also improves efficiency of BIM model′s construction,the cooperation management′s efficiency of construction process,and the ability of integrating model information.
文摘Green energy conservation is the mainstream trend in the current development of the construction industry.The application of energy-saving technology in building electrical system design can effectively reduce energy consumption,avoid unnecessary energy consumption,and truly achieve energy conservation and environmental protection.Based on this,the article elaborates on the principles of energy-saving design in building electrical systems,and actively explores the application of energy-saving technologies from different perspectives such as optimizing power supply and distribution system design,adopting high-efficiency energy-saving lighting equipment,applying renewable energy,promoting smart home technology,and improving the efficiency of building electrical equipment.
文摘Aim To research and develop a battery management system(BMS)with the state of charge(SOC)indicator for electric vehicles (EVs).Methods On the basis of analyzing the electro-chemical characteristics of lead-acid. battery, the state of charge indicator for lead-acid battery was developed by means of an algorithm based on combination of ampere-hour, Peukert's equation and open-voltage method with the compensation of temperature,aging,self- discharging,etc..Results The BMS based on this method can attain an accurate surplus capa- city whose error is less than 5% in static experiments.It is proved by experiments that the BMS is reliable and can give the driver an accurate surplus capacity,precisely monitor the individual battery modules as the same time,even detect and warn the problems early,and so on. Conclusion A BMS can make the energy of the storage batteries used efficiently, develop the batteries cycle life,and increase the driving distance of EVs.
文摘As a matured technique used in many fields,the distributed computer system is still a new management method for the aeronautical electrical power distribution system in our country. In this paper, a novel aircraft electrical power distribution system based on the distributed computer system is proposed. The principles, features and structure of the aircraft electrical power distribution system and the distributed computer system named electrical load management system (ELMS) are studied. The ELMS composed of four electrical load management centers (ELMCs) and two power source processors (PSPs) operates in the 1553B buses. Principles of the ELMCs and the PSPs are introduced. With the application of the distributed computer system, the aircraft electrical power distribution system is simple, adaptable and flexible.
文摘A kind of management system for electric vehicle (EV) battery series was developed. The system can predict residual capacity for EV battery series and mileages. The system can determine if it is necessary for the battery series to be charged. The system can determine which battery is necessary to be updated for the reason of damage or aging. The system can display the total voltage of battery series, extreme voltage and temperature of every battery in the series. The system can display the accumulative discharge for every battery in the series. The system can alarm when both total or extreme voltage is at low level, or temperature of a battery in the series is at high level. The system provided with a microprocessor as key part can collect and record signal of charging and discharging current, total voltage, extreme voltage and temperature for every battery. The mathematical model of residual capacity for EV lead acid batteries was discussed in details. The system operates well in the laboratory and meets the requirement.
文摘Aiming at the comparatively laggard level of power plant electrical system automation, this paper analyzes the feasibility,necessity and some key points of the application of integrated automation technology to power plant electrical system. New idea using fieldbus control system technology is presented. This paper also gives the outline and detailed schemes.
基金Natural Science Foundation of Gansu Province(Joint)Project(No.213244)Natural Science Foundation of Gansu Province(No.145RJZA136)Youth Science Foundation of Lanzhou Jiaotong University(No.2013040)
文摘In view of the current sensors failure in electric pitch system,a variable universe fuzzy fault tolerant control method of electric pitch control system based on single current detection is proposed.When there is single or two-current sensor fault occurs,based on the proposed method the missing current information can be reconstructed by using direct current(DC)bus current sensor and the three-phase current can be updated in time within any two adjacent sampling periods,so as to ensure stability of the closed-loop system.And then the switchover and fault tolerant control of fault current sensor would be accomplished by fault diagnosis method based on adaptive threshold judgment.For the reconstructed signal error caused by the modulation method and the main control target of electric pitch system,a variable universe fuzzy control method is used in the speed loop,which can improve the anti-disturbance ability to load variation,and the robustness of fault tolerance system.The results show that the fault tolerant control method makes the variable pitch control system still has ideal control characteristics in case of sensor failure although part of the system performance is lost,thus the correctness of the proposed method is verified.
文摘To evaluate the thermal performance of a low-temperature electrical radiant floor heating system,an experimental facility equipped with a constant temperature chamber and different specimen floors is designed and built.The heating cable is installed in the floor slab with a unit-rated power of 30 W/m.Twenty-four different schemes are worked out and tested,which include three kinds of composite floor structures and eight kinds of cable distances.The cable distances are 30,40,50,60,80,100,130,150 mm.The main affective factors of the thermal performance and their influencing regularity are discussed.The experimental results show that the system has good stability and reliability,and the ratio of the radiation heat-transfer rate to the gross heat-transfer rate is greater than 50%.When the floor structure and the cable distance are fixed,the gross heat-transfer rate of the upper floor surface has a maximum value at an optimal cable distance.Under the experimental conditions in this paper,the optimal cable distance is 50 mm.
文摘The paper deals with the designing of an electric drive system used for hybrid electric vehicles. The driving system is realized with an induction motor and a voltage source inverter. Specifically, the application is for a series hybrid vehicle powered by electric storage batteries charged by solar batteries. In the first part of the paper the designing of the electric storage batteries and of the photoelectric system is presented. In the second part of the paper some aspects regarding the designing of the induction motor are presented. Then some aspects concerning the voltage source inverter designing are exposed.