Although wind power ramp events(WPREs)are relatively scarce,they can inevitably deteriorate the stability of power system operation and bring risks to the trading of electricity *** this paper,an imprecise conditional...
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Although wind power ramp events(WPREs)are relatively scarce,they can inevitably deteriorate the stability of power system operation and bring risks to the trading of electricity *** this paper,an imprecise conditional probability estimation method for WPREs is proposed based on the Bayesian network(BN)*** method uses the maximum weight spanning tree(MWST)and greedy search(GS)to build a BN that has the highest fitting degree with the observed ***,an extended imprecise Dirichlet model(IDM)is developed to estimate the parameters of the BN,which quantificationally reflect the ambiguous dependencies among the random ramp event and various meteorological *** BN is then applied to predict the interval probability of each possible ramp state under the given meteorological conditions,which is expected to cover the target probability at a specified confidence *** proposed method can quantify the uncertainty of the probabilistic ramp event ***,by using the extracted dependencies and Bayesian rules,the method can simplify the conditional probability estimation and perform reliable prediction even with scarce *** results on a real wind farm with three-year operation data illustrate the effectiveness of the proposed method.
This study presents a novel impact time and angle constrained guidance law for homing missiles. The guidance law is first developed with the prior-assumption of a stationary target, which is followed by the practical ...
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This study presents a novel impact time and angle constrained guidance law for homing missiles. The guidance law is first developed with the prior-assumption of a stationary target, which is followed by the practical extension to a maneuvering target scenario. To derive the closed-form guidance law, the trajectory reshaping technique is utilized and it results in defining a specific polynomial function with two unknown coefficients. These coefficients are determined to satisfy the impact time and angle constraints as well as the zero miss distance. Furthermore, the proposed guidance law has three additional guidance gains as design parameters which make it possible to adjust the guided trajectory according to the operational conditions and missile's capability. Numerical simulations are presented to validate the effectiveness of the proposed guidance law. (C) 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.
With the high penetration of renewable energies in modern power systems,deterministic coordination algorithms are facing two major problems:one is degradation in accuracy if fewer scenarios are utilized for uncertaint...
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With the high penetration of renewable energies in modern power systems,deterministic coordination algorithms are facing two major problems:one is degradation in accuracy if fewer scenarios are utilized for uncertainty evaluation while second is the high computational time if a high number of scenarios are considered for better accuracy・In both cases,the efficiency of the algorithm is degraded・To solve these problems in coupled transmission system and distribution systems(TSDS),probabilistic coordination algorithms are adopted to solve with less *** this paper,a TSDS probabilistic coordination model is proposed to solve the coordinated security-constrained unit commitment problem.A mean and standard deviation matching based probabilistic analytical target cascading algorithm has been utilized for evaluation of TSDS coordination *** of solving each scenario as a separate problem,the proposed algorithm considers a single coordination problem with probabilistic characteristics as shared variables and hence,achieves fast convergence・Different case studies are performed to prove the efficacy of the proposed *** verify that the proposed algorithm reduces computational time and resources for large-scale systems.
The position tracking control problem of electrical cylinder in the presence of nonlinear friction load, inertia load and nonlinear disturbance due to its transmission process is addressed in this paper. To compensate...
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ISBN:
(纸本)9781538629185
The position tracking control problem of electrical cylinder in the presence of nonlinear friction load, inertia load and nonlinear disturbance due to its transmission process is addressed in this paper. To compensate all of these disturbances in the case of servo motion, active disturbance rejection control is used to make a continuous and precise transition. Tracking differentiator is used for arranging the transition process to avoid overshoot. Extended state observer is built to estimate the unmeasurable internal disturbance, parametric uncertainties and external uncertainty for a guaranteed robust performance. Nonlinear state error feedback is designed to combine the error feedbacks more reasonable. Simulation and experimental results show that active disturbance rejection controller shows very strong robustness and adaptability compared with traditional PID control algorithm.
A facial expression emotion recognition based human-robot interaction(FEER-HRI) system is proposed, for which a four-layer system framework is designed. The FEERHRI system enables the robots not only to recognize huma...
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A facial expression emotion recognition based human-robot interaction(FEER-HRI) system is proposed, for which a four-layer system framework is designed. The FEERHRI system enables the robots not only to recognize human emotions, but also to generate facial expression for adapting to human emotions. A facial emotion recognition method based on2D-Gabor, uniform local binary pattern(LBP) operator, and multiclass extreme learning machine(ELM) classifier is presented,which is applied to real-time facial expression recognition for robots. Facial expressions of robots are represented by simple cartoon symbols and displayed by a LED screen equipped in the robots, which can be easily understood by human. Four scenarios,i.e., guiding, entertainment, home service and scene simulation are performed in the human-robot interaction experiment, in which smooth communication is realized by facial expression recognition of humans and facial expression generation of robots within 2 seconds. As a few prospective applications, the FEERHRI system can be applied in home service, smart home, safe driving, and so on.
Inverter-based distributed generations(IBDGs)are the main approach to utilizing clean energy in distribution networks(DNs).Compared with synchronous source,fault response of IBDG is very *** a result,in DNs with high ...
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Inverter-based distributed generations(IBDGs)are the main approach to utilizing clean energy in distribution networks(DNs).Compared with synchronous source,fault response of IBDG is very *** a result,in DNs with high penetration of IBDGs,legacy protection schemes will no longer be *** this paper,an energy-based directional pilot protection scheme suitabie for DNs with IBDGs is *** scheme considers the large range of phase angle caused by IBDG integration and uses improved energy polarity criterion to determine fault *** addition,magnitude of energy is used to distinguish between faults and load switching to overcome maloperation of directional pilot protection caused by internal unmeasured load *** proposed scheme first uses local measured information to determine fault direction sign and then exchanges the direction sign with the remote *** scheme does not require high-bandwidth communication and strict data synchronization,so it can be implemented at a low ***,simulation studies verify effectiveness of the proposed scheme.
Active distribution grids cause bi-directional power flow between transmission system(TS)and distribution system(DS),which not only affects the optimal cost but also the secure operation of the power *** paper propose...
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Active distribution grids cause bi-directional power flow between transmission system(TS)and distribution system(DS),which not only affects the optimal cost but also the secure operation of the power *** paper proposes a hybrid coordination method to solve the risk-aware distributed optimal power flow(RA-DOPF)problem in coordinated TS and *** operation risk evaluation,the weather-based contingencies are considered in both TS and DS.A hybrid coordination method is developed that entails analytical target cascading(ATC)and Benders decomposition(BD).Moreover,the risk-aware optimal power flow(RAOPF)in TS and risk-based security-constrained optimal power flow in DS have been performed using the BD method considering basic optimal power flow as a master problem,whereas N-1 and N-2 contingencies are considered as *** case studies are performed using the IEEE 30-bus system with generation reserves as a TS and a 13-bus system as a *** results demonstrate the efficacy of the proposed method.
The terminal guidance problem for an unpowered lifting reentry vehicle against a sta- tionary target is considered. In addition to attacking the target with high accuracy, the vehicle is also expected to achieve a des...
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The terminal guidance problem for an unpowered lifting reentry vehicle against a sta- tionary target is considered. In addition to attacking the target with high accuracy, the vehicle is also expected to achieve a desired impact angle. In this paper, a sliding mode control (SMC)-based guidance law is developed to satisfy the terminal angle constraint. Firstly, a specific sliding mode function is designed, and the terminal requirements can be achieved by enforcing both the sliding mode function and its derivative to zero at the end of the flight. Then, a backstepping approach is used to ensure the finite-time reaching phase of the sliding mode and the analytic expression of the control effort can be obtained. The trajectories generated by this method only depend on the initial and terminal conditions of the terminal phase and the instantaneous states of the vehicle. In order to test the performance of the proposed guidance law in practical application, numerical simulations are carried out by taking all the aerodynamic parameters into consideration. The effec- tiveness of the proposed guidance law is verified by the simulation results in various scenarios.
To enhance the reliability of rotating machinery, cross-domain fault diagnosis becomes vital for detecting faults under unknown operating conditions. However, multi-source domain imbalanced data present significant ch...
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A novel high-order sliding mode control strategy is proposed for the attitude control problem of reentry vehicles in the presence of parametric uncertainties and external disturbances, which results in the robust and ...
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A novel high-order sliding mode control strategy is proposed for the attitude control problem of reentry vehicles in the presence of parametric uncertainties and external disturbances, which results in the robust and accurate tracking of the aerodynamic angle commands with the finite time convergence. The proposed control strategy is developed on the basis of integral sliding mode philosophy, which combines conventional sliding mode control and a linear quadratic regulator over a finite time interval with a free-final-state and allows the finite-time establishment of a high-order sliding mode. Firstly, a second-order sliding mode attitude controller is designed in the proposed high-order siding mode control framework. Then, to address the control chattering problem, a virtual control is introduced in the control design and hence a third-order sliding mode attitude controller is developed, leading to the chattering reduction as well as the control accuracy improvement. Finally, simulation examples are given to illustrate the effectiveness of the theoretical results.
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