Energy storage can smooth the fluctuations of wind power integrated into the grid.Due to the strong adaptability of the empirical mode decomposition(EMD)algorithm to nonstationary signals,it is widely used in wind pow...Energy storage can smooth the fluctuations of wind power integrated into the grid.Due to the strong adaptability of the empirical mode decomposition(EMD)algorithm to nonstationary signals,it is widely used in wind power smoothing control strategies.However,traditional EMD algorithms cannot guarantee that the upper and lower areas of the calculated intrinsic mode functions(IMFs)are equal,which tends to result in imbalanced calculated energy storage power and thus exceeding the limit of energy storage capacity.Focusing on wind power smoothing control by energy storage,this paper proposes a strategy based on the area-equilibrium EMD,which modifies the upper and lower areas of the IMFs to achieve a more balanced distribution.As a result,the IMFs contain less energy,and consequently,the energy contained in the calculated smoothing power is also reduced.This makes the energy storage capacity less likely to exceed the limit,thereby achieving better wind power smoothing performance under given energy storage capacity.Case studies show that the proposed strategy results in more balanced upper and lower areas of the IMFs,reduces the fluctuating range of calculated energy storage,and improves the wind power smoothing effectiveness.展开更多
Due to their heat/cool storage characteristics, thermostatically controlled loads(TCLs) play an important role in demand response programmers. However, the modeling of the heat/cool storage characteristic of large num...Due to their heat/cool storage characteristics, thermostatically controlled loads(TCLs) play an important role in demand response programmers. However, the modeling of the heat/cool storage characteristic of large numbers of TCLs is not simple. In this paper, the heat exchange power is adopted to calculate the power instead of the average power, and the relationship between the heat exchange power and energy storage is considered to develop an equivalent storage model, based on which the time-varying power constraints and the energy storage constraints are developed to establish the overall day-ahead schedulingmodel. Finally, the proposed scheduling method is verified using the simulation results of a six-bus system.展开更多
Due to the capacity of thermal storage,electric water heater(EWH)is one of the best candidates for demand response programs.However,few attentions are given to the modeling and optimization of EWHs with thermostatical...Due to the capacity of thermal storage,electric water heater(EWH)is one of the best candidates for demand response programs.However,few attentions are given to the modeling and optimization of EWHs with thermostatically-controlled automatic water mixer(TCAWM).In this paper,differential thermodynamic model is established for EWHs with TCAWM and a piecewise linear approximation method is performed for the nonlinear thermodynamic model.The multi-objective optimization model is established by introducing an index reflecting the comfort degree of users,so that the optimal energy usage of the EWH can be obtained by mixed integer linear programming.Testing examples verify the effectiveness of the proposed method.展开更多
Over the last few years, lots of attentions have been given to the demand response(DR) for the frequency control. DR can be incorporated with traditional frequency control method and enhance the stability of the syste...Over the last few years, lots of attentions have been given to the demand response(DR) for the frequency control. DR can be incorporated with traditional frequency control method and enhance the stability of the system. In this paper, the frequency control strategy of DR for a multiarea power system is specially designed. In order to quickly stabilize the frequency of different areas, the tie-line power is adopted as the additional input signal of DR. To get the optimal parameters of the control system, the frequency control problem is formulated as a multi-objective optimization problem, and the parameters such as the integral gains of secondary frequency control, the frequency bias parameters, and coefficients of DR are optimized. Numerical results verify the effectiveness of the proposed method.展开更多
Zebra crossing detection is a fundamental function of the electronic travel aid.It can locate the zebra crossing and estimate its direction to help the visually impaired to cross the road safely.In contrast to the con...Zebra crossing detection is a fundamental function of the electronic travel aid.It can locate the zebra crossing and estimate its direction to help the visually impaired to cross the road safely.In contrast to the conventional methods,a regression approach is adopted to detect zebra crossing based on convolutional neural networks.Specifically,a fixed-size window slides across the image captured at the intersection.The image patches are sequentially fed to the logistic regression model to identify the zebra crossing.Then the image patch of zebra crossing is fed to the regression model to predict the direction.The parameters of models are optimized by the backpropagation algorithm before predictions.Compared with existing methods,the proposed method can improve the precision-recall performance of the zebra crossing identification and reduce the root mean square error of predicted directions.展开更多
基金supported in part by the National Natural Science Foundation of China(No.51707099).
文摘Energy storage can smooth the fluctuations of wind power integrated into the grid.Due to the strong adaptability of the empirical mode decomposition(EMD)algorithm to nonstationary signals,it is widely used in wind power smoothing control strategies.However,traditional EMD algorithms cannot guarantee that the upper and lower areas of the calculated intrinsic mode functions(IMFs)are equal,which tends to result in imbalanced calculated energy storage power and thus exceeding the limit of energy storage capacity.Focusing on wind power smoothing control by energy storage,this paper proposes a strategy based on the area-equilibrium EMD,which modifies the upper and lower areas of the IMFs to achieve a more balanced distribution.As a result,the IMFs contain less energy,and consequently,the energy contained in the calculated smoothing power is also reduced.This makes the energy storage capacity less likely to exceed the limit,thereby achieving better wind power smoothing performance under given energy storage capacity.Case studies show that the proposed strategy results in more balanced upper and lower areas of the IMFs,reduces the fluctuating range of calculated energy storage,and improves the wind power smoothing effectiveness.
基金supported in part by the Postgraduate Innovation Cultivating Project in Jiangsu Province (No. KYCX18_1221)the National Natural Science Foundation of China (No. 51707099)China Postdoctoral Science Foundation (No. 2017M611859)
文摘Due to their heat/cool storage characteristics, thermostatically controlled loads(TCLs) play an important role in demand response programmers. However, the modeling of the heat/cool storage characteristic of large numbers of TCLs is not simple. In this paper, the heat exchange power is adopted to calculate the power instead of the average power, and the relationship between the heat exchange power and energy storage is considered to develop an equivalent storage model, based on which the time-varying power constraints and the energy storage constraints are developed to establish the overall day-ahead schedulingmodel. Finally, the proposed scheduling method is verified using the simulation results of a six-bus system.
基金supported by National Natural Science Foundation of China(No.51707099)Natural Science Fund for Colleges and Universities of Jiangsu Province(No.16KJB470009)China Postdoctoral Science Foundation(No.2017M611859).
文摘Due to the capacity of thermal storage,electric water heater(EWH)is one of the best candidates for demand response programs.However,few attentions are given to the modeling and optimization of EWHs with thermostatically-controlled automatic water mixer(TCAWM).In this paper,differential thermodynamic model is established for EWHs with TCAWM and a piecewise linear approximation method is performed for the nonlinear thermodynamic model.The multi-objective optimization model is established by introducing an index reflecting the comfort degree of users,so that the optimal energy usage of the EWH can be obtained by mixed integer linear programming.Testing examples verify the effectiveness of the proposed method.
基金supported in part by the University Science Research Project of Jiangsu Province (No. 16KJB470009)
文摘Over the last few years, lots of attentions have been given to the demand response(DR) for the frequency control. DR can be incorporated with traditional frequency control method and enhance the stability of the system. In this paper, the frequency control strategy of DR for a multiarea power system is specially designed. In order to quickly stabilize the frequency of different areas, the tie-line power is adopted as the additional input signal of DR. To get the optimal parameters of the control system, the frequency control problem is formulated as a multi-objective optimization problem, and the parameters such as the integral gains of secondary frequency control, the frequency bias parameters, and coefficients of DR are optimized. Numerical results verify the effectiveness of the proposed method.
文摘Zebra crossing detection is a fundamental function of the electronic travel aid.It can locate the zebra crossing and estimate its direction to help the visually impaired to cross the road safely.In contrast to the conventional methods,a regression approach is adopted to detect zebra crossing based on convolutional neural networks.Specifically,a fixed-size window slides across the image captured at the intersection.The image patches are sequentially fed to the logistic regression model to identify the zebra crossing.Then the image patch of zebra crossing is fed to the regression model to predict the direction.The parameters of models are optimized by the backpropagation algorithm before predictions.Compared with existing methods,the proposed method can improve the precision-recall performance of the zebra crossing identification and reduce the root mean square error of predicted directions.
