This paper presents and tests three earthing systems (TT, TN and IT) for Micro-Grid (MG) protection against various fault types when the MG transferred to the islanding mode. The main contribution of this work is incl...This paper presents and tests three earthing systems (TT, TN and IT) for Micro-Grid (MG) protection against various fault types when the MG transferred to the islanding mode. The main contribution of this work is including the models of all micro sources which interfaced to the MG by power electronic inverters. Inverters in turns are provided with current limiters and this also included with the inverter models to exactly simulate the real situation in the MG during fault times. Results proved that the most suitable earthing system for MG protection during the islanding mode is the TN earthing system. That system leads to a suitable amount of fault current sufficient to activate over current pro-tection relays. With using TN earthing system, touch voltages at the faulted bus and all other consumer’s buses are less than the safety limited values during islanding mode. For the two others earthing systems (TT and IT), fault currents are small and nearly equal to the over load currents which make over current protection relay can not differentiate between fault currents and overload currents. All models of micro sources, earthing systems, inverters and control schemes are built using Matlab?/Simulink? environment.展开更多
This paper presents, tests and compares three earthing systems (TT, TN and IT) for Micro-Grid (MG) protection against various fault types during the connected mode. The main contribution of this work is including the ...This paper presents, tests and compares three earthing systems (TT, TN and IT) for Micro-Grid (MG) protection against various fault types during the connected mode. The main contribution of this work is including the models of all the micro sources which interfaced to the MG by power electronic inverters. Inverters in turns are provided with current limiters and this also included in the inverter models to exactly simulate the real situation in the MG during fault times. Results proved that the most suitable earthing system for MG protection during the connecting mode is the TN earthing system. That system leads to a suitable amount of fault current sufficient to activate over current protection relays. With using TN system, Touch voltages at the faulted bus and all other consumer’s buses are less than the safety limited value if current limiter is included with the transformer of the main grid which connects MG. For the two others earthing systems (TT and IT), fault current is small and nearly equal to the over load current which make over current protection relay can not differentiate between fault current and overload current. All models of micro sources, earthing systems, inverters, main grid and control schemes are built using Matlab?/Simulink? environment.展开更多
According to the inland micro electro-mechanical system （MEMS） process technique level, a design platform of piezoresistive micro electro-mechanical accelerometer is given. This platform is much more adaptable to th...According to the inland micro electro-mechanical system （MEMS） process technique level, a design platform of piezoresistive micro electro-mechanical accelerometer is given. This platform is much more adaptable to the inland designer compared with the current MEMS CAD software. The design flow is presented in detail, and the key techique in the platform is analyzed amply. The structure design methodology is exemplified in the design of a piezoresistive accelerometer, and the accelerometer is the optimized structure for the given performance requirements. The accelerometer is now being manufactured.展开更多
This paper develops a fast filtering algorithm based on vibration systems theory and neural information exchange approach. The characters, including the derivation process and parameter analysis, are discussed and the...This paper develops a fast filtering algorithm based on vibration systems theory and neural information exchange approach. The characters, including the derivation process and parameter analysis, are discussed and the feasibility and the effectiveness are testified by the filtering performance compared with various filtering methods, such as the fast wavelet transform algorithm, the particle filtering method and our previously developed single degree of freedom vibration system filtering algorithm, according to simulation and practical approaches. Meanwhile, the comparisons indicate that a significant advantage of the proposed fast filtering algorithm is its extremely fast filtering speed with good filtering perfi^rmance. Further, the developed fast filtering algorithm is applied to the navigation and positioning system of the micro motion robot, which is a high real-time requirement for the signals preprocessing. Then, the preprocessing data is used to estimate the heading angle error and the attitude angle error of the micro motion robot. The estimation experiments illustrate the high practicality of the proposed fast filtering algorithm.展开更多
In the micro-grid photovoltaic systems, the random changes of solar radiation enable lead-acid batteries to experience low SOC (State of Charge) or overcharged for periods of time if directly charged with such traditi...In the micro-grid photovoltaic systems, the random changes of solar radiation enable lead-acid batteries to experience low SOC (State of Charge) or overcharged for periods of time if directly charged with such traditional methods as decreased charging current, which will reduce lifetime of batteries. What’s more, it’s difficult to find a proper reduction coefficient in decreasing charging current. To adapt to the random changes of circumstance and avoid selecting the reduction coefficient, a new fast charging method named decreased charging current based on SOC is proposed to apply into micro-grid photovoltaic systems. It combines batteries’ SOC with the maximum charging voltage to determine the charging rate without strictly selecting reduction coefficient. By close-loop current control strategy and related scheme, the experiment proves the new method is feasible and verifies that, comparing with decreased charging current, the improved method make batteries’ SOC reach 100% in shorter time as well as the temperature of batteries raise more slowly.展开更多
The transition to sustainable energy systems is one of the defining challenges of our time, necessitating innovations in how we generate, distribute, and manage electrical power. Micro-grids, as localized energy hubs,...The transition to sustainable energy systems is one of the defining challenges of our time, necessitating innovations in how we generate, distribute, and manage electrical power. Micro-grids, as localized energy hubs, have emerged as a promising solution to integrate renewable energy sources, ensure energy security, and improve system resilience. The Autonomous multi-factor Energy Flow Controller (AmEFC) introduced in this paper addresses this need by offering a scalable, adaptable, and resilient framework for energy management within an on-grid micro-grid context. The urgency for such a system is predicated on the increasing volatility and unpredictability in energy landscapes, including fluctuating renewable outputs and changing load demands. To tackle these challenges, the AmEFC prototype incorporates a novel hierarchical control structure that leverages Renewable Energy Sources (RES), such as photovoltaic systems, wind turbines, and hydro pumps, alongside a sophisticated Battery Management System (BMS). Its prime objective is to maintain an uninterrupted power supply to critical loads, efficiently balance energy surplus through hydraulic storage, and ensure robust interaction with the main grid. A comprehensive Simulink model is developed to validate the functionality of the AmEFC, simulating real-world conditions and dynamic interactions among the components. The model assesses the system’s reliability in consistently powering critical loads and its efficacy in managing surplus energy. The inclusion of advanced predictive algorithms enables the AmEFC to anticipate energy production and consumption trends, integrating weather forecasting and inter-controller communication to optimize energy flow within and across micro-grids. This study’s significance lies in its potential to facilitate the seamless incorporation of RES into existing power systems, thus propelling the energy sector towards a more sustainable, autonomous, and resilient future. The results underscore the potential of such a system to revolutionize energy management practices and highlight the importance of smart controller systems in the era of smart grids.展开更多
This paper summarized and reviewed recent studies of micro transportation systems (MTS) in the MEMS (Micro Electro-Mechanical System) field. Micro transportation systems can be identified and classified into three cat...This paper summarized and reviewed recent studies of micro transportation systems (MTS) in the MEMS (Micro Electro-Mechanical System) field. Micro transportation systems can be identified and classified into three categories based on the contact types between the objects and the actuators (i.e. liquid-based, solid- based and air-bearing type). Their advantages and disadvantages were also analyzed and compared. The au- thors have proposed and developed three types of solid-based MTS utilizing electrostatic comb-drive actua- tors and ratchet mechanisms to drive the micro container in straight and curved paths. These MTSs have been fabricated with silicon-on-insulator (SOI)-MEMS technology and tested successfully. In the near future, MTSs can be applied in different fields such as medicine (to classify and test blood cells), in bioengineering (to capture, sort and combine bio-cells, DNA), or in micro robot systems.展开更多
The main aim of this research is to get a better knowledge and understanding of the micro-scale oscillatory networks behavior in the solid propellants reactionary zones. Fundamental understanding of the micro-and nano...The main aim of this research is to get a better knowledge and understanding of the micro-scale oscillatory networks behavior in the solid propellants reactionary zones. Fundamental understanding of the micro-and nano-scale combustion mechanisms is essential to the development and further improvement of the next-generation technologies for extreme control of the solid propellant thrust. Both experiments and theory confirm that the micro-and nano-scale oscillatory networks excitation in the solid propellants reactionary zones is a rather universal phenomenon. In accordance with our concept,the micro-and nano-scale structures form both the fractal and self-organized wave patterns in the solid propellants reactionary zones. Control by the shape, the sizes and spacial orientation of the wave patterns allows manipulate by the energy exchange and release in the reactionary zones. A novel strategy for enhanced extreme thrust control in solid propulsion systems are based on manipulation by selforganization of the micro-and nano-scale oscillatory networks and self-organized patterns formation in the reactionary zones with use of the system of acoustic waves and electro-magnetic fields, generated by special kind of ring-shaped electric discharges along with resonance laser radiation. Application of special kind of the ring-shaped electric discharges demands the minimum expenses of energy and opens prospects for almost inertia-free control by combustion processes. Nano-sized additives will enhance self-organizing and self-synchronization of the micro-and nano-scale oscillatory networks on the nanometer scale. Suggested novel strategy opens the door for completely new ways for enhanced extreme thrust control of the solid propulsion systems.展开更多
Micro-arc oxidation （MAO） process was cartied out in an optimized dual electrolyte system to fabricate a compact, smooth, and corrosion resistant coating on ZK60 Mg alloy. The microstructural characteristics of coat...Micro-arc oxidation （MAO） process was cartied out in an optimized dual electrolyte system to fabricate a compact, smooth, and corrosion resistant coating on ZK60 Mg alloy. The microstructural characteristics of coating were investigated by scanning electron microscopy （SEM） coupled with an energy dispersive spectrometer （EDS） and X-ray diffraction （XRD）. Test of mass loss was conducted at a 3.5 % NaCl solution to assess the resistance to corrosion. The bonding strength between the coating and ZK60 substrate was evaluated using scratch experiment. The results reveal that MgA1204 and MgO are the main phases of ceramic coating obtained in the dual electrolyte system. The corrosion rate of coating prepared in the optimized dual electrolyte is only 0.0061 g.m-2.h-1, which demonstrates excellent corrosion resistance. This is mainly due to the compact, uniform coating with high bonding strength.展开更多
文摘This paper presents and tests three earthing systems (TT, TN and IT) for Micro-Grid (MG) protection against various fault types when the MG transferred to the islanding mode. The main contribution of this work is including the models of all micro sources which interfaced to the MG by power electronic inverters. Inverters in turns are provided with current limiters and this also included with the inverter models to exactly simulate the real situation in the MG during fault times. Results proved that the most suitable earthing system for MG protection during the islanding mode is the TN earthing system. That system leads to a suitable amount of fault current sufficient to activate over current pro-tection relays. With using TN earthing system, touch voltages at the faulted bus and all other consumer’s buses are less than the safety limited values during islanding mode. For the two others earthing systems (TT and IT), fault currents are small and nearly equal to the over load currents which make over current protection relay can not differentiate between fault currents and overload currents. All models of micro sources, earthing systems, inverters and control schemes are built using Matlab?/Simulink? environment.
文摘This paper presents, tests and compares three earthing systems (TT, TN and IT) for Micro-Grid (MG) protection against various fault types during the connected mode. The main contribution of this work is including the models of all the micro sources which interfaced to the MG by power electronic inverters. Inverters in turns are provided with current limiters and this also included in the inverter models to exactly simulate the real situation in the MG during fault times. Results proved that the most suitable earthing system for MG protection during the connecting mode is the TN earthing system. That system leads to a suitable amount of fault current sufficient to activate over current protection relays. With using TN system, Touch voltages at the faulted bus and all other consumer’s buses are less than the safety limited value if current limiter is included with the transformer of the main grid which connects MG. For the two others earthing systems (TT and IT), fault current is small and nearly equal to the over load current which make over current protection relay can not differentiate between fault current and overload current. All models of micro sources, earthing systems, inverters, main grid and control schemes are built using Matlab?/Simulink? environment.
文摘According to the inland micro electro-mechanical system （MEMS） process technique level, a design platform of piezoresistive micro electro-mechanical accelerometer is given. This platform is much more adaptable to the inland designer compared with the current MEMS CAD software. The design flow is presented in detail, and the key techique in the platform is analyzed amply. The structure design methodology is exemplified in the design of a piezoresistive accelerometer, and the accelerometer is the optimized structure for the given performance requirements. The accelerometer is now being manufactured.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.60901074,51075092,61005076,and 61175107)the National High Technology Research and Development Program of China(Grant No.2007AA042105)the Natural Science Foundation of Heilongjiang Province,China(Grant No.E200903)
文摘This paper develops a fast filtering algorithm based on vibration systems theory and neural information exchange approach. The characters, including the derivation process and parameter analysis, are discussed and the feasibility and the effectiveness are testified by the filtering performance compared with various filtering methods, such as the fast wavelet transform algorithm, the particle filtering method and our previously developed single degree of freedom vibration system filtering algorithm, according to simulation and practical approaches. Meanwhile, the comparisons indicate that a significant advantage of the proposed fast filtering algorithm is its extremely fast filtering speed with good filtering perfi^rmance. Further, the developed fast filtering algorithm is applied to the navigation and positioning system of the micro motion robot, which is a high real-time requirement for the signals preprocessing. Then, the preprocessing data is used to estimate the heading angle error and the attitude angle error of the micro motion robot. The estimation experiments illustrate the high practicality of the proposed fast filtering algorithm.
文摘In the micro-grid photovoltaic systems, the random changes of solar radiation enable lead-acid batteries to experience low SOC (State of Charge) or overcharged for periods of time if directly charged with such traditional methods as decreased charging current, which will reduce lifetime of batteries. What’s more, it’s difficult to find a proper reduction coefficient in decreasing charging current. To adapt to the random changes of circumstance and avoid selecting the reduction coefficient, a new fast charging method named decreased charging current based on SOC is proposed to apply into micro-grid photovoltaic systems. It combines batteries’ SOC with the maximum charging voltage to determine the charging rate without strictly selecting reduction coefficient. By close-loop current control strategy and related scheme, the experiment proves the new method is feasible and verifies that, comparing with decreased charging current, the improved method make batteries’ SOC reach 100% in shorter time as well as the temperature of batteries raise more slowly.
文摘The transition to sustainable energy systems is one of the defining challenges of our time, necessitating innovations in how we generate, distribute, and manage electrical power. Micro-grids, as localized energy hubs, have emerged as a promising solution to integrate renewable energy sources, ensure energy security, and improve system resilience. The Autonomous multi-factor Energy Flow Controller (AmEFC) introduced in this paper addresses this need by offering a scalable, adaptable, and resilient framework for energy management within an on-grid micro-grid context. The urgency for such a system is predicated on the increasing volatility and unpredictability in energy landscapes, including fluctuating renewable outputs and changing load demands. To tackle these challenges, the AmEFC prototype incorporates a novel hierarchical control structure that leverages Renewable Energy Sources (RES), such as photovoltaic systems, wind turbines, and hydro pumps, alongside a sophisticated Battery Management System (BMS). Its prime objective is to maintain an uninterrupted power supply to critical loads, efficiently balance energy surplus through hydraulic storage, and ensure robust interaction with the main grid. A comprehensive Simulink model is developed to validate the functionality of the AmEFC, simulating real-world conditions and dynamic interactions among the components. The model assesses the system’s reliability in consistently powering critical loads and its efficacy in managing surplus energy. The inclusion of advanced predictive algorithms enables the AmEFC to anticipate energy production and consumption trends, integrating weather forecasting and inter-controller communication to optimize energy flow within and across micro-grids. This study’s significance lies in its potential to facilitate the seamless incorporation of RES into existing power systems, thus propelling the energy sector towards a more sustainable, autonomous, and resilient future. The results underscore the potential of such a system to revolutionize energy management practices and highlight the importance of smart controller systems in the era of smart grids.
文摘This paper summarized and reviewed recent studies of micro transportation systems (MTS) in the MEMS (Micro Electro-Mechanical System) field. Micro transportation systems can be identified and classified into three categories based on the contact types between the objects and the actuators (i.e. liquid-based, solid- based and air-bearing type). Their advantages and disadvantages were also analyzed and compared. The au- thors have proposed and developed three types of solid-based MTS utilizing electrostatic comb-drive actua- tors and ratchet mechanisms to drive the micro container in straight and curved paths. These MTSs have been fabricated with silicon-on-insulator (SOI)-MEMS technology and tested successfully. In the near future, MTSs can be applied in different fields such as medicine (to classify and test blood cells), in bioengineering (to capture, sort and combine bio-cells, DNA), or in micro robot systems.
基金supported by the Western-Caucasus Research Center
文摘The main aim of this research is to get a better knowledge and understanding of the micro-scale oscillatory networks behavior in the solid propellants reactionary zones. Fundamental understanding of the micro-and nano-scale combustion mechanisms is essential to the development and further improvement of the next-generation technologies for extreme control of the solid propellant thrust. Both experiments and theory confirm that the micro-and nano-scale oscillatory networks excitation in the solid propellants reactionary zones is a rather universal phenomenon. In accordance with our concept,the micro-and nano-scale structures form both the fractal and self-organized wave patterns in the solid propellants reactionary zones. Control by the shape, the sizes and spacial orientation of the wave patterns allows manipulate by the energy exchange and release in the reactionary zones. A novel strategy for enhanced extreme thrust control in solid propulsion systems are based on manipulation by selforganization of the micro-and nano-scale oscillatory networks and self-organized patterns formation in the reactionary zones with use of the system of acoustic waves and electro-magnetic fields, generated by special kind of ring-shaped electric discharges along with resonance laser radiation. Application of special kind of the ring-shaped electric discharges demands the minimum expenses of energy and opens prospects for almost inertia-free control by combustion processes. Nano-sized additives will enhance self-organizing and self-synchronization of the micro-and nano-scale oscillatory networks on the nanometer scale. Suggested novel strategy opens the door for completely new ways for enhanced extreme thrust control of the solid propulsion systems.
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions and the Key Laboratory of Advanced Welding Technology of Jiangsu Province, China (No. JSAWT-11)
文摘Micro-arc oxidation （MAO） process was cartied out in an optimized dual electrolyte system to fabricate a compact, smooth, and corrosion resistant coating on ZK60 Mg alloy. The microstructural characteristics of coating were investigated by scanning electron microscopy （SEM） coupled with an energy dispersive spectrometer （EDS） and X-ray diffraction （XRD）. Test of mass loss was conducted at a 3.5 % NaCl solution to assess the resistance to corrosion. The bonding strength between the coating and ZK60 substrate was evaluated using scratch experiment. The results reveal that MgA1204 and MgO are the main phases of ceramic coating obtained in the dual electrolyte system. The corrosion rate of coating prepared in the optimized dual electrolyte is only 0.0061 g.m-2.h-1, which demonstrates excellent corrosion resistance. This is mainly due to the compact, uniform coating with high bonding strength.
