With the deepening research on wind farms, wake effects have gradually been paid attention to and used in wind farm optimization. During this development, the engineering wake models are adopted, which could be furthe...
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ISBN:
(数字)9781728176871
ISBN:
(纸本)9781728176888
With the deepening research on wind farms, wake effects have gradually been paid attention to and used in wind farm optimization. During this development, the engineering wake models are adopted, which could be further improved in modeling accuracy. This paper adopts a control-oriented wake model to improve the modeling accuracy, especially in the near wake region. A double-Gaussian wake model is incorporated with appropriate wake deflection and combination models and a vertical wind profile function. Based on a Large-eddy simulated dataset, the proposed model is adopted and verified. The widely-used Gaussian wake model is also adopted and compared with the proposed model. Results show good agreement between the presented model and LES results, especially in the focused near wake region.
The security and stable operation of thermal power units plays a very important role in a power system,so the reliability evaluation of thermal power units has become a critical *** combining the advantages of the Ana...
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ISBN:
(纸本)9781509046584
The security and stable operation of thermal power units plays a very important role in a power system,so the reliability evaluation of thermal power units has become a critical *** combining the advantages of the Analytic Hierarchy Process(AHP) and the Elimination et Choice Translating Reality(ELECTRE) Ⅲ,a reliability evaluation method for thermal power units based on AHP and ELECTRE-Ⅲ is put forward.A new method of proposed "net" procedure is presented to rank these scheme with valued outranking *** advantages and disadvantages of the scheme are expressed from the harmony index and the discordance index,which constitute valued outranking relation by ELECTRE Ⅲ and weights of criteria are determined by *** method is clear and easily to be accepted by the decision maker with the person's actual decision thinking of human *** the results of the example analysis show that the method is feasible for the reliability evaluation of thermal power units.
Tracking maneuvering target is a challenging problem and Interactive Multiple Model (IMM) is proved an effective solution for it. In multiple model, the constant turn model (CT) is usually used to describe the target&...
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Tracking maneuvering target is a challenging problem and Interactive Multiple Model (IMM) is proved an effective solution for it. In multiple model, the constant turn model (CT) is usually used to describe the target's turning motion. However, fixed or partially adaptive turn angular rate μ is usually adopted in CT which leads to tracking accuracy decrease. In this paper, an improved interactive multiple model set based on self-adaptive CT model is proposed. In self-adaptive CT model, the value of the turn angular rate ω is calculated based on both x and y velocity instead of only one of them or fixed value. To verify the improvement, particle filter, which is proved an effective way to solve non Gaussian nonlinear problem, is used to track maneuvering target. The performance of the proposed multiple model set is verified in two different scenarios and compared to two widely used multiple model sets. Simulation results show that the proposed model set has better performance both in tracking accuracy and computational cost.
In this paper, a reinforcement learning based control law is proposed to solve the attitude synchronization problem of the leader-following multi-quadrotor systems. The overall system is composed of a team of quadroto...
In this paper, a reinforcement learning based control law is proposed to solve the attitude synchronization problem of the leader-following multi-quadrotor systems. The overall system is composed of a team of quadrotors, modeled with highly nonlinear and coupled dynamics. An optimal control solution is obtained by solving an augmented HamiltonJacobi-Bellman equation. A reinforcement learning approach is used to learn the optimal control law. Simulation results are provided to verify the effectiveness of the proposed controller.
Localization information of wireless sensor network is an important application in indoor complicate environment. In line-of-sight(LOS) environment, localization accuracy is very high. However, the measurement may b...
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Localization information of wireless sensor network is an important application in indoor complicate environment. In line-of-sight(LOS) environment, localization accuracy is very high. However, the measurement may be contaminated by nonline-of-sight(NLOS) propagation, which will result in localization accuracy degrades. To cover come this problem, this paper proposes a modified Kalman filter(MKF) localization method based on Unscented Kalman filter(UKF). Firstly, test statistic method is employed to identify the NLOS condition. Then we smooth the measurement range using linear Kalman filter(LKF) and mitigate the NLOS effect using MKF. Finally, the method of UKF is used to determine the localization of unknown motion node. The validity of the proposed approach is demonstrated through the numerical simulation and experiment
This paper considers the problem of distributed bandit online convex optimization with time-varying coupled inequality constraints. This problem can be defined as a repeated game between a group of learners and an adv...
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Electric load forecasting is a vital role in obtaining effective management of modern power systems. The accuracy forecasting results will lead to the improvement of the energy efficiency and reduction of production c...
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Electric load forecasting is a vital role in obtaining effective management of modern power systems. The accuracy forecasting results will lead to the improvement of the energy efficiency and reduction of production cost. This paper presents a novel electric load forecasting model by using BP neural network and improved bat algorithm with extremal optimization called IBA-EO-BP model. First, to enhance the global search ability and diversity of original bat algorithm (BA), we propose IBA-EO by improving original BA and combining with extremal optimization. Then, considering traditional BP is more likely converge to local optimal values, the IBA-EO is employed to find out the optimal connection weight parameters in BP. Two datasets from energy market operation in Australia are selected as case study. The simulation results demonstrate that the proposed IBA-EO-BP model is much more accurate than the traditional BP forecasting model and persistence model in terms of three widely used performance indices and two statistical tests.
Virtual prototyping of power electronic modules aims to allow rapid evaluation of potential designs without building and testing physical prototypes. Among the interests in thermal models of the virtual modules, proce...
Virtual prototyping of power electronic modules aims to allow rapid evaluation of potential designs without building and testing physical prototypes. Among the interests in thermal models of the virtual modules, process of compact thermal models needs effective methodology to fast generate small models describing the thermal performance of a potential design. This study chooses the Generalized Minimized Residual (GMRES) Algorithm to process thermal models due to its efficiency. Based on that, a machine learning aided surrogate model is proposed for the prediction of thermal performance since existing approaches take much time to determine the thermal response to a particular input power. This surrogate model is created by training a dedicated artificial neural network (ANN) on simulation data, after that this model can quickly map the module temperature and the power input in time domain. In the training process, cross-validation method is introduced to determine which neuron structure should be selected for the practical data generated by thermal equations. The test group is noted in cross-validation to give the prediction performance of structure candidates. To verify the proposed method, the resulting data of trained surrogate models are compared with the accurate simulation data after the ANN based cross-validation.
Firefly algorithm (FA) has widely used to solve various complex optimization problems. However, FA has significant drawbacks in slow convergence rate and easily trapped into local optimum. To tackle these defects, thi...
Firefly algorithm (FA) has widely used to solve various complex optimization problems. However, FA has significant drawbacks in slow convergence rate and easily trapped into local optimum. To tackle these defects, this paper proposes an improved FA combined with extremal optimization (EO), named IFA-EO, where three strategies are incorporated. First, to balance tradeoff between exploration and exploitation, we adopt a new attraction model for FA operation, which combines the full attraction model and the single attraction model through the probability choice strategy. In single attraction model, inspired by the simulated annealing idea, small probability accepts the worse solution to improve the diversity of the offspring. Second, the adaptive step size is proposed according to the number of iterations. Third, we combine EO algorithm with powerful ability in local-search. IFA-EO is employed to handle three different parameters identification problems of photovoltaic model. For comparisons, we choose three swarm intelligence algorithms to compare with IFA-EO. Simulation results demonstrate the superiority of IFA-EO to other three competitors.
With the increasingly rampancy of network attacks and the steady progress of the national smart grid construction, the security protection of the power industrial control system is facing severe challenges. It is an e...
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With the increasingly rampancy of network attacks and the steady progress of the national smart grid construction, the security protection of the power industrial control system is facing severe challenges. It is an effective means to improve the overall defense capability of the power industrial control system by formulating the security collaborative defense strategy and dynamically configuring the relevant equipment to make them have linkage response. For this purpose, a method of conflict detection for cooperative defense strategy in power industrial control system is proposed in this paper. Based on the formal description of cooperative defense strategy, the type of policy conflicts is analyzed according to the relationship between policy actions and system states. And the policy execution is simulated for detecting conflict by establishing the temporal relationship between policy actions. The experimental results show that this method can reduce the dependence on the system administrator, and can quickly and accurately find the conflicts in the collaborative defense strategy.
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