Lifetime of the photovoltaic (PV) inverters is influenced by its power profile. The reliability of such PV inverters is affected by the thermal fatigue cycles witnessed by the underlying components. However, there is ...
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ISBN:
(纸本)9798350328066
Lifetime of the photovoltaic (PV) inverters is influenced by its power profile. The reliability of such PV inverters is affected by the thermal fatigue cycles witnessed by the underlying components. However, there is a trade-off between the inverter efficiency and the fatigue witnessed by its components. With a systematic formulation of this trade-off, a real-time nonlinear optimization problem is formulated to generate the appropriate reactive power set-points to the PV inverter controller. The proposed approach improves the lifetime of the inverters while keeping its efficiency above desired threshold value. The time domain loss and damage models that uses PV power profile as an input are critical to the proposed optimization framework. The proposed framework provides an option to the customer to operate the PV inverter with an objective of lifetime improvement under the acceptable losses by flattening the component thermal fatigue cycles. The framework is evaluated using the PV power profile of a 10 kVA PV inverter with various simulated case studies.
With the progress of living standards, people are more and more thirsty for green and healthy life, for the purchase of vegetables also has a higher pursuit of hope to buy fresh and cheap vegetables, and due to the sh...
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Multi-access edge computing (MEC) is a critical technology for 5G networks. Computing tasks can be processed in edge servers instead of cloud servers by deploying computing servers at the edge of integrated power comm...
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Besides irrigation and power generation, reservoirs in India also play a vital role in protecting the country from floods. During flood, reservoirs store and release the excess water according to its capacity and futu...
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The study proposes a methodology to address the reconfiguration of electrical distribution networks, formulating it as a mixed integer nonlinear optimization model. The complexity arises from disconnectors, with binar...
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Microgrid provides an effective way to integrate renewable energy into power grid. However, the uncertainty of renewable energy and load demand bring great challenges to the energy management of microgrid. Therefore, ...
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ISBN:
(纸本)9781665490542
Microgrid provides an effective way to integrate renewable energy into power grid. However, the uncertainty of renewable energy and load demand bring great challenges to the energy management of microgrid. Therefore, this paper proposes a double-layer optimization method based on deep reinforcement learning (DRL) to solve this problem. The upper DRL agent takes Soft actor-critic algorithm to fully explore the regulation ability of the energy storage system. The lower nonlinear programming solver optimizes the output of other controllable equipment based on the output of the upper layer, and constantly revises the network parameters of the upper layer according to the optimization results. By combining DRL with traditional nonlinear programming, the convergence speed of the algorithm can be improved and the design difficulty of the DRL reward function can be reduced. Case studies show that the double-layer collaborative optimization method can provide real-time high-quality solutions for energy management of the microgrid only based on the immediate information of the microgrid and can effectively accelerate the convergence speed of the model.
An algorithm for calculating the aerodynamic layout and power plant parameters according to specified technical requirements (TR) at the stage of preliminary aerodynamic design (PAD) has been developed. A low-impact s...
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In this paper, we model an optimal regression tree through a continuous optimization problem, where a compromise between prediction accuracy and both types of sparsity, namely local and global, is sought. Our approach...
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In this paper, we model an optimal regression tree through a continuous optimization problem, where a compromise between prediction accuracy and both types of sparsity, namely local and global, is sought. Our approach can accommodate important desirable properties for the regression task, such as cost-sensitivity and fairness. Thanks to the smoothness of the predictions, we can derive local explanations on the continuous predictor variables. The computational experience reported shows the outperformance of our approach in terms of prediction accuracy against standard benchmark regression methods such as CART, OLS and LASSO. Moreover, the scalability of our approach with respect to the size of the training sample is illustrated. (c) 2021 Published by Elsevier B.V.
The energy efficiency (EE) resource allocation problem for downlink orthogonal frequency division multiple access (OFDMA) heterogeneous networks (HetNets) of wireless communication is investigated in this article. A c...
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The energy efficiency (EE) resource allocation problem for downlink orthogonal frequency division multiple access (OFDMA) heterogeneous networks (HetNets) of wireless communication is investigated in this article. A coordinated multipoint (CoMP) network consisting of a microcell and multiple picocells interconnected via a backhaul network is considered. The mathematical form of EE maximization is a fractional, mixed-integer, nonlinear programming, and NP-hard to solve. Genetic algorithm (GA) based scheme is developed for solving the formulated maximization problem. For GA based scheme, a normal GA is used for resource blocks (RBs) allocation and for the power distribution process, instead of transforming the fractional objective function into a parametric subtractive form, a multi-objective optimization problem (MOOP) is formed and then non-dominated sorting genetic algorithm II (NSGA-II) is applied to tackle the MOOP. Finally, the simulation process is provided to verify the effectiveness of the proposed method and the results show that the performance of GA based scheme outperforms the benchmark scheme.
This paper is concerned with devising nonlinear optimal guidance for intercepting a stationary target with a desired impact time. According to Pontryagin's maximum principle, some optimality conditions for the sol...
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This paper is concerned with devising nonlinear optimal guidance for intercepting a stationary target with a desired impact time. According to Pontryagin's maximum principle, some optimality conditions for the solutions of the nonlinear optimal interception problem are established;and the structure of the corresponding optimal control is presented. By employing the optimality conditions, we formulate a parameterized system so that its solution space is the same as that of the nonlinear optimal interception problem. As a consequence, a simple propagation of the parameterized system, without using any optimization method, is sufficient to generate enough sampled data for the mapping from the current state and time-to-go to the optimal guidance command. By virtue of the universal approximation theorem, a feedforward neural network, trained by the generated data, is able to represent the mapping from the current state and time-to-go to the optimal guidance command. Therefore, the trained network eventually can generate impact-time-constrained nonlinear optimal guidance within a constant time. Finally, the developed nonlinear optimal guidance is exemplified and studied through simulations, showing that the nonlinear optimal guidance law performs better than existing interception guidance laws.
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