According to the increasing requirement of the wind energy utilization and the dynamic stability in the variable speed variable pitch wind power generation system, a linear parameter varying （LPV） system model is es...According to the increasing requirement of the wind energy utilization and the dynamic stability in the variable speed variable pitch wind power generation system, a linear parameter varying （LPV） system model is established and a new adaptive robust guaranteed cost controller （AGCC） is proposed in this paper. First, the uncertain parameters of the system are estimated by using the adaptive method, then the estimated uncertain parameters and robust guaranteed cost control method are used to design a state feedback controller. The controller s feedback gain is obtained by solving a set of linear matrix inequality （LMI） constraints, such that the controller can meet a quadratic performance evaluation criterion. The simulation results show that we can realize the goal of maximum wind energy capture in low wind speed by the optimal torque control and constant power control in high wind speed by variable pitch control with good dynamic characteristics, robustness and the ability of suppressing disturbance.展开更多
The wind energy generation,utilization and its grid penetration in electrical grid are increasing world-wide.The wind generated power is always fluctuating due to its time varying nature and causing stability problem....The wind energy generation,utilization and its grid penetration in electrical grid are increasing world-wide.The wind generated power is always fluctuating due to its time varying nature and causing stability problem.This weak interconnection of wind generating source in the electrical network affects the power quality and reliability.The localized energy storages shall compensate the fluctuating power and support to strengthen the wind generator in the power system.In this paper,it is proposed to control the voltage source inverter （VSI） in current control mode with energy storage,that is,batteries across the dc bus.The generated wind power can be extracted under varying wind speed and stored in the batteries.This energy storage maintains the stiff voltage across the dc bus of the voltage source inverter.The proposed scheme enhances the stability and reliability of the power system and maintains unity power factor.It can also be operated in stand-alone mode in the power system.The power exchange across the wind generation and the load under dynamic situation is feasible while maintaining the power quality norms at the common point of coupling.It strengthens the weak grid in the power system.This control strategy is evaluated on the test system under dynamic condition by using simulation.The results are verified by comparing the performance of controllers.展开更多
With the rapid increase of wind farms,the grid code needs to be improved to meet the requirement of wind farms and enhance grid stability.Doubly-fed induction generators are largely used in wind turbines,but they are ...With the rapid increase of wind farms,the grid code needs to be improved to meet the requirement of wind farms and enhance grid stability.Doubly-fed induction generators are largely used in wind turbines,but they are very sensitive to grid disturbances.The voltage swell can be caused by switching on capacitor banks or switching off large loads,which may result in the reversal of the power flow in the grid convertor;the current may flow from the grid into the DC link,which may step up DC voltage,and result in large faults of rotor currents and instantaneous power oscillation.The grid reactive compensation devices can not have the automatic swithing function after the low voltage fault,which will result in local reactive power surplus,so some wind power generators will retreat from the grid under high voltage protection.展开更多
The installation of wind power generators on buildings located in areas with regular winds may be a suitable investment in a renewable power source. Brazil has a high eolic potential, where the annual mean wind speed ...The installation of wind power generators on buildings located in areas with regular winds may be a suitable investment in a renewable power source. Brazil has a high eolic potential, where the annual mean wind speed may reach over eight meters per second. This case study is aimed to assess the economic feasibility of the installation of small wind power plants in urban areas. This work evaluates a project for the installation of a vertical axis wind turbine in three buildings （15-, 22-, and 26-story） including the following stages： （1） installation of a real-time power meter in the 15-store unit; （2） demand analysis of the 26-store building＇s power consumption; （3） winds survey along the coast of the State of Ceara; （4） analysis of the wind turbines available in the market; （5） simulation aimed to choose the system. Vertical wind power generators offer better conditions of use in urban areas. The turnover time was established to be between four and six years in the three studied units. The installation of a wind power generator on buildings in regions with an adequate eolic regimen reaches a financial return of the investment before the end of the equipment＇s lifespan.展开更多
This paper reviews the modularity techniques in the stator manufacture of permanent magnet machines for different applications.Some basic concepts of modular machines are firstly introduced.Modular machines for severa...This paper reviews the modularity techniques in the stator manufacture of permanent magnet machines for different applications.Some basic concepts of modular machines are firstly introduced.Modular machines for several typical applications are then described in details,including domestic appliances,automobiles and electric vehicles,more electric aircrafts and civic applications,wind power generators,etc.Besides,the influence of manufacture tolerance gaps and flux barriers on the electromagnetic performance is discussed.展开更多
The major applications of electrical steel(ES) sheets are motors,transformers,etc.In recent years, the raise of crude oil price and increasing environmental consciousness trigger the demands for saving energy and redu...The major applications of electrical steel(ES) sheets are motors,transformers,etc.In recent years, the raise of crude oil price and increasing environmental consciousness trigger the demands for saving energy and reducing CO_2 emissions,which greatly accelerate the development of high quality ES sheets.To meet the quality requirements of high efficiency motors and transformers,high grade ES sheets with high flux density are continuously developed and introduced to the market.Meanwhile,the price competition and quality improvement of general grades are important for the lower end application.The iron loss of 50CS1300(50A1300) is significantly reduced by controlling some key parameters.Other than the normal grade,the highest grades of nonoriented (NO) ES are successfully developed recently.And all specifications of 0.50 and 0.35 mm among JIS C 2552 specification could be provided by CSC.As to the insulation coating development,the Cr-free insulation coating has been introduced to the market due to the environmental concern,and has been enormously adopted in Taiwan market.Furthermore,the thicker insulation coating technology has been successfully developed for specific wind power generator application.The newly developed products and quality improvements of electrical steel sheets in China Steel are introduced in this paper.展开更多
Among the available options for renewable energy integration in existing power system, wind power is being considered as one of the suited options for future electrical power generation. The major constraint of wind p...Among the available options for renewable energy integration in existing power system, wind power is being considered as one of the suited options for future electrical power generation. The major constraint of wind power generating system （WPGS） is that it does not provide inertial support because of power electronic converters between the grid and the WPGS to facilitate frequency stabilization. The proposed control strategy suggests a substantial contribution to system inertia in terms of short-term active power support in a two area restructured power system. The control scheme uses fuzzy logic based design and takes frequency deviation as input to provide quick active power support, which balances the drop in frequency and tie-line power during transient conditions. This paper presents a comprehensive study of the wind power impact with increasing wind power penetration on frequency stabilization in restructured power system scenario. Variation of load conditions are also analyzed in simulation studies for the same power system model with the proposed control scheme. Simula- tion results advocates the justification of control scheme over other schemes.展开更多
The increasing integration of renewable energy sources poses great challenges to the power system frequency se curity.However,the existing electricity market mechanism lacks integration and incentives for emerging fre...The increasing integration of renewable energy sources poses great challenges to the power system frequency se curity.However,the existing electricity market mechanism lacks integration and incentives for emerging frequency regula tion(FR)resources such as wind power generators(WPGs),which may reduce their motivation to provide frequency sup port and further deteriorate the frequency dynamics.In this pa per,a market scheduling and pricing method for comprehen sive frequency regulation services(FRSs)is proposed.First,a modeling approach for flexible FR capabilities of WPGs is pro posed based on the mechanism of inertia control and power re serve control.Subsequently,considering the differences in in verter control strategies,a novel system frequency response model with grid-following and grid-forming inverters is estab lished.Combined with the automatic generation control,the fre quency security constraints of the whole FR process are de rived,and integrated into the market scheduling model to cooptimize the energy and FRSs.Finally,by distinguishing the contributions of various types of resources in different FR stag es,a differentiated pricing scheme is proposed to incentivize producers with various regulation qualities to provide FRSs.The effectiveness of the proposed method is verified on the mod ified IEEE 6-bus system and the IEEE RTS-79 system.展开更多
基金supported by Natural Science Foundation of Hebei Province(No. F2012203088)
文摘According to the increasing requirement of the wind energy utilization and the dynamic stability in the variable speed variable pitch wind power generation system, a linear parameter varying （LPV） system model is established and a new adaptive robust guaranteed cost controller （AGCC） is proposed in this paper. First, the uncertain parameters of the system are estimated by using the adaptive method, then the estimated uncertain parameters and robust guaranteed cost control method are used to design a state feedback controller. The controller s feedback gain is obtained by solving a set of linear matrix inequality （LMI） constraints, such that the controller can meet a quadratic performance evaluation criterion. The simulation results show that we can realize the goal of maximum wind energy capture in low wind speed by the optimal torque control and constant power control in high wind speed by variable pitch control with good dynamic characteristics, robustness and the ability of suppressing disturbance.
文摘The wind energy generation,utilization and its grid penetration in electrical grid are increasing world-wide.The wind generated power is always fluctuating due to its time varying nature and causing stability problem.This weak interconnection of wind generating source in the electrical network affects the power quality and reliability.The localized energy storages shall compensate the fluctuating power and support to strengthen the wind generator in the power system.In this paper,it is proposed to control the voltage source inverter （VSI） in current control mode with energy storage,that is,batteries across the dc bus.The generated wind power can be extracted under varying wind speed and stored in the batteries.This energy storage maintains the stiff voltage across the dc bus of the voltage source inverter.The proposed scheme enhances the stability and reliability of the power system and maintains unity power factor.It can also be operated in stand-alone mode in the power system.The power exchange across the wind generation and the load under dynamic situation is feasible while maintaining the power quality norms at the common point of coupling.It strengthens the weak grid in the power system.This control strategy is evaluated on the test system under dynamic condition by using simulation.The results are verified by comparing the performance of controllers.
文摘With the rapid increase of wind farms,the grid code needs to be improved to meet the requirement of wind farms and enhance grid stability.Doubly-fed induction generators are largely used in wind turbines,but they are very sensitive to grid disturbances.The voltage swell can be caused by switching on capacitor banks or switching off large loads,which may result in the reversal of the power flow in the grid convertor;the current may flow from the grid into the DC link,which may step up DC voltage,and result in large faults of rotor currents and instantaneous power oscillation.The grid reactive compensation devices can not have the automatic swithing function after the low voltage fault,which will result in local reactive power surplus,so some wind power generators will retreat from the grid under high voltage protection.
文摘The installation of wind power generators on buildings located in areas with regular winds may be a suitable investment in a renewable power source. Brazil has a high eolic potential, where the annual mean wind speed may reach over eight meters per second. This case study is aimed to assess the economic feasibility of the installation of small wind power plants in urban areas. This work evaluates a project for the installation of a vertical axis wind turbine in three buildings （15-, 22-, and 26-story） including the following stages： （1） installation of a real-time power meter in the 15-store unit; （2） demand analysis of the 26-store building＇s power consumption; （3） winds survey along the coast of the State of Ceara; （4） analysis of the wind turbines available in the market; （5） simulation aimed to choose the system. Vertical wind power generators offer better conditions of use in urban areas. The turnover time was established to be between four and six years in the three studied units. The installation of a wind power generator on buildings in regions with an adequate eolic regimen reaches a financial return of the investment before the end of the equipment＇s lifespan.
文摘This paper reviews the modularity techniques in the stator manufacture of permanent magnet machines for different applications.Some basic concepts of modular machines are firstly introduced.Modular machines for several typical applications are then described in details,including domestic appliances,automobiles and electric vehicles,more electric aircrafts and civic applications,wind power generators,etc.Besides,the influence of manufacture tolerance gaps and flux barriers on the electromagnetic performance is discussed.
文摘The major applications of electrical steel(ES) sheets are motors,transformers,etc.In recent years, the raise of crude oil price and increasing environmental consciousness trigger the demands for saving energy and reducing CO_2 emissions,which greatly accelerate the development of high quality ES sheets.To meet the quality requirements of high efficiency motors and transformers,high grade ES sheets with high flux density are continuously developed and introduced to the market.Meanwhile,the price competition and quality improvement of general grades are important for the lower end application.The iron loss of 50CS1300(50A1300) is significantly reduced by controlling some key parameters.Other than the normal grade,the highest grades of nonoriented (NO) ES are successfully developed recently.And all specifications of 0.50 and 0.35 mm among JIS C 2552 specification could be provided by CSC.As to the insulation coating development,the Cr-free insulation coating has been introduced to the market due to the environmental concern,and has been enormously adopted in Taiwan market.Furthermore,the thicker insulation coating technology has been successfully developed for specific wind power generator application.The newly developed products and quality improvements of electrical steel sheets in China Steel are introduced in this paper.
文摘Among the available options for renewable energy integration in existing power system, wind power is being considered as one of the suited options for future electrical power generation. The major constraint of wind power generating system （WPGS） is that it does not provide inertial support because of power electronic converters between the grid and the WPGS to facilitate frequency stabilization. The proposed control strategy suggests a substantial contribution to system inertia in terms of short-term active power support in a two area restructured power system. The control scheme uses fuzzy logic based design and takes frequency deviation as input to provide quick active power support, which balances the drop in frequency and tie-line power during transient conditions. This paper presents a comprehensive study of the wind power impact with increasing wind power penetration on frequency stabilization in restructured power system scenario. Variation of load conditions are also analyzed in simulation studies for the same power system model with the proposed control scheme. Simula- tion results advocates the justification of control scheme over other schemes.
基金supported by the National Key Research and Development Program of China(No.2023YFB2406800).
文摘The increasing integration of renewable energy sources poses great challenges to the power system frequency se curity.However,the existing electricity market mechanism lacks integration and incentives for emerging frequency regula tion(FR)resources such as wind power generators(WPGs),which may reduce their motivation to provide frequency sup port and further deteriorate the frequency dynamics.In this pa per,a market scheduling and pricing method for comprehen sive frequency regulation services(FRSs)is proposed.First,a modeling approach for flexible FR capabilities of WPGs is pro posed based on the mechanism of inertia control and power re serve control.Subsequently,considering the differences in in verter control strategies,a novel system frequency response model with grid-following and grid-forming inverters is estab lished.Combined with the automatic generation control,the fre quency security constraints of the whole FR process are de rived,and integrated into the market scheduling model to cooptimize the energy and FRSs.Finally,by distinguishing the contributions of various types of resources in different FR stag es,a differentiated pricing scheme is proposed to incentivize producers with various regulation qualities to provide FRSs.The effectiveness of the proposed method is verified on the mod ified IEEE 6-bus system and the IEEE RTS-79 system.
