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SSRN 2022年

作者： Chi, Yingtian Yokoo, Kentaro Nakajima, Hironori Ito, Kohei Lin, Jin Song, Yonghua State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100087 China Department of Hydrogen Energy Systems Graduate School of Engineering Kyushu University Fukuoka Japan Department of Mechanical Engineering Faculty of Engineering Kyushu University Fukuoka Japan Tsinghua-Sichuan Energy Internet Research Institute Chengdu610213 China State Key Laboratory of Internet of Things for Smart City University of Macau 999078 China

Inhomogeneous current and temperature distributions are harmful to the durability of the solid oxide electrolysis cell (SOEC). Segmented SOEC experiments reveal that a high steam utilization, which is favorable for system efficiency, leads to local steam starvation and enhanced the inhomogeneity. It is necessary to consider inhomogeneity and efficiency jointly in optimization studies. Three-dimensional (3D) multiphysics models can simulate the inhomogeneity in a reliable manner, but they are unsuitable for optimization due to the high computational cost. This study proposes a method that combines segmented SOEC experiments, multiphysics simulation, and artificial intelligence to optimize the inhomogeneity and efficiency of SOEC. A 3D cell model is first built and verified by segmented SOEC experiments. Then, fast neural network surrogate models are built from the simulation data and integrated into a multi-objective optimization problem. Its solutions form a Pareto front reflecting the conflicting relationships among different objectives. It is found that the down-stream current is 60%-65% of the up-stream current when the steam utilization is 0.7. To increase the steam utilization to 0.8, the down-stream current further drops to 50%-60% of the up-stream current. The Pareto fronts enable system operators to achieve a balance between efficiency and inhomogeneity. © 2022, The Authors. All rights reserved.

关键词： Multiobjective optimization

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Optimizing the Homogeneity and Efficiency of an SOEC Based on Multiphysics simulation and Data-driven Surrogate Model

arXiv

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arXiv 2022年

Inhomogeneous current and temperature distributions are harmful to the durability of the solid oxide electrolysis cell (SOEC). Segmented SOEC experiments reveal that a high steam utilization, which is favorable for system efficiency, leads to local steam starvation and enhanced the inhomogeneity. It is necessary to consider inhomogeneity and efficiency jointly in optimization studies. Three-dimensional (3D) multiphysics models validated with experiments can simulate the inhomogeneity in a reliable manner, but they are unsuitable for optimization due to the high computational cost. This study proposes a method that combines segmented SOEC experiments, multiphysics simulation, and artificial intelligence to optimize the inhomogeneity and efficiency of SOEC jointly. A 3D cell model is first built and verified by segmented SOEC experiments. Then, fast neural network surrogate models are built from the simulation data and integrated into a multi-objective optimization problem. Its solutions form a Pareto front reflecting the conflicting relationships among different objectives. It is found that the down-stream current is 60%-65% of the up-stream current when the steam utilization is 0.7. To increase the steam utilization to 0.8, the down-stream current will further drop to 50%-60% of the up-stream current. The Pareto fronts enable system operators to achieve a balance between efficiency and inhomogeneity. Copyright © 2022, The Authors. All rights reserved.

关键词： Multiobjective optimization

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Vortex Vibration Energy Harvesting for Road Vehicle Suspension: Modeling, Prototyping and Experimental Validation

SSRN

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SSRN 2023年

作者： Wang, Yushun Yin, Hao Li, Mingxing Chen, Yuanchang Sun, Haoyu Liu, Jiang Key Lab of Industrial Fluid Energy Conservation and Pollution Control Qingdao University of Technology Qingdao266520 China Structural Dynamics and Acoustic Systems Laboratory University of Massachusetts Lowell One University Avenue LowellMA01854 United States Nanjing University of Aeronautics and Astronautics Nanjing211100 China State Key Laboratory of Automotive Simulation and Control Jilin University Changchun130022 China

Aiming at the micro power supply for vehicle suspension control, we propose a new harvester to recycle the vortex vibration energy behind the shock absorber. Different from the traditional regenerative suspensions utilizing the vertical motion, we recycle the vortex vibration energy laterally. A suspension dynamics model was built and simulated the spring compression process to discuss the break wind condition. A stable Karman vortex street would be developed after the spring is compressed to a certain height, proving that the car spring’s wind break effect could be neglect in many driving conditions. Then the spring and shock absorber was simplified to a cylinder with two cross sections. The fluid analysis was performed and the vortex form showed three features. A bidirectional fluid-structure coupling model was built for the new harvester and the simulation verified that the electric voltage positively correlated with the vehicle’s velocity. At last, a full size sample prototype test was performed for validation. The designed harvester may provide enough electricity for a suspension control unit or sensors, as a potential solution for the near field energy supply. When the car is driving with a common speed in cities, the recycled electric voltage could reach to 0.8V. © 2023, The Authors. All rights reserved.

关键词： Vortex flow

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Unit Commitment Considering Demand Response Behavior Based on Utility Maximization

Unit Commitment Considering Demand Response Behavior Based o...

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IEEE Conference on Energy Internet and Energy System Integration

作者： Yumin Zhang Xueshan Han Bo Xu Li Zhang Donglei Sun Xiaofeng Miao Jiayin Jiang Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong University State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment (Department of Electrical Engineering Tsinghua University) Economic & Technology Research Institute of State Grid Shandong Electric Power Company State Grid Shandong Electric Power Company Yantai Electric Power Company

ISBN: (纸本)9781538614280

The active participation of demand side resources in power grid operation not only benefits the individual participant but also benefits the whole system. The optimal goal can promote by excavating the active behaviors of demand side. The welfare maximization of market participant is the driving force of such active behaviors. Considering the independence of each user's behavior, the consumer's utility function is selected to depict consumer's preference and demand response behavior. In order to coordinate the consumers' maximum welfare with social welfare maximization, consumers' utility function and units' operation cost are integrated into Unit Commitment (UC) model. The objective function is to maximize social welfare, by subtracting units' operation cost from consumers' total utility, and this objective can be acquired. Considering the proposed model should be solved in a distributed manner, the idea of the centralized coordination and the decentralized decision-making is proposed. Based on the Lagrangian relaxation (LR) principle and distributed real-time pricing scheme, a closed-loop feedback mechanism is constructed to reflect the relationship among generator output, price level, and load demand. The ten generating units example can illustrate the effectiveness of the proposed method.

关键词： Demand utility Decomposition coordination Electricity market Lagrangian relaxation Real-time pricing Unit commitment

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Analysis and Design for Hydrogen-Fueled Cascade Solid Oxide Fuel Cell System

SSRN

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SSRN 2023年

作者： Liu, Peiyuan Zhang, Yongliang Zhu, Jianzhong Han, Minfang Sun, Kaihua Zhong, Haijun Zhang, XueRui State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Energy and Power Engineering Tsinghua University Beijing100084 China Xuzhou Huatsing Jingkun Energy Co. Ltd. Jiangsu Province 221005 China Petrochemical Research Institute China National Petroleum Corporation Beijing112206 China Institute of Process Engineering Chinese Academy of Sciences Beijing100190 China

Maximizing total fuel utilization is the key to improving the electrical efficiency of solid oxide fuel cell (SOFC) systems. The cascade system can achieve this effectively, but there are fewer studies on hydrogen-fueled cascade systems, and the determination of suitable rated power ratios needs a basis. Because of the characteristics of cascade systems, a fast model that can predict performance at low flow rates and low hydrogen partial pressures is required. Using multiple sets of experimental data, this study developed and validated an improved semi-empirical model, which accurately predicted the industrial-sized cell performance at different flow rates and hydrogen partial pressures. On this basis, the basic parallel and cascade system models were established. The effects of fuel flow rate, rated power ratio, split ratio, and constraints on the system performance were studied and analyzed, and the appropriate design and operation parameters of the cascade system were determined. The results indicated that the cascade system can significantly improve electrical efficiency compared to the parallel system by selecting suitable design parameters. In the example of a 10-kW rated power system design, the cascade system improved the electrical efficiency by over 9% at rated power compared to the parallel system. The results obtained provide valuable reference for related research and offer guidance for system design. © 2023, The Authors. All rights reserved.

关键词： Electrical efficiency

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Multi-view adaptive fusion network for 3D object detection

arXiv

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arXiv 2020年

作者： Wang, Guojun Tian, Bin Zhang, Yachen Chen, Long Cao, Dongpu Wu, Jian State Key Laboratory of Automotive Simulation and Control Jilin University Changchun130022 China State Key Laboratory of Management and Control for Complex Systems Institute of Automation Chinese Academy of Sciences School of Artificial Intelligence University of Chinese Academy of Sciences Beijing100190 China School of Data and Computer Science Sun Yat-Sen University Guangzhou510275 China Lab University of Waterloo Canada College of Automotive Engineering Jilin University China

3D object detection based on LiDAR-camera fusion is becoming an emerging research theme for autonomous driving. However, it has been surprisingly difficult to effectively fuse both modalities without information loss and interference. To solve this issue, we propose a single-stage multi-view fusion framework that takes LiDAR Birds-Eye View, LiDAR Range View and Camera View images as inputs for 3D object detection. To effectively fuse multi-view features, we propose an Attentive Pointwise Fusion (APF) module to estimate the importance of the three sources with attention mechanisms which can achieve adaptive fusion of multi-view features in a pointwise manner. Besides, an Attentive Pointwise Weighting (APW) module is designed to help the network learn structure information and point feature importance with two extra tasks: foreground classification and center regression, and the predicted foreground probability will be used to reweight the point features. We design an end-to-end learnable network named MVAF-Net to integrate these two components. Our evaluations conducted on the KITTI 3D object detection datasets demonstrate that the proposed APF and APW module offer significant performance gain and that the proposed MVAF-Net achieves state-of-the-art performance in the KITTI benchmark. Copyright © 2020, The Authors. All rights reserved.

关键词： Object recognition

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An integrated multifunction DC/DC converter for PV generation systems

An integrated multifunction DC/DC converter for PV generatio...

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IEEE International Symposium on Industrial Electronics (ISIE)

作者： Lin Ma Kai Sun Remus Teodorescu Josep M. Guerrero Xinmin Jin Department of Energy Technology Aalborg University Aalborg Denmark School of Electrical Engineering Beijing Jiao Tong University Beijing China State Key Lab of Power Systems Tsinghua University Beijing China Dept. of Automatic Control Systems and Computer Engineering Universitat Politecnica de Catalunya Barcelona Spain

Due to the stochastic characteristic of photovoltaic (PV) generation, energy storage devices are indispensable to smooth the power flow and provide the electric energy with high quality. In this paper, an integrated DC/DC converter is proposed to realize high performance interfaces for PV array, battery and load. This converter consists of a boost converter for the PV array and a buck/boost converter for the battery, which can realize multifunction including power generation, charge and discharge. The grid-connected and stand-alone operation modes of this converter are analyzed. From this analysis, the control strategies are developed for both modes. A coordination scheme is proposed for the power balance at the stand-alone mode. simulation and experiments verify the practical feasibility and effectiveness of this multi-function converter.

关键词： Batteries Arrays DC-DC power converters Voltage control Inverters Load flow

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Multi-Stage Expansion Planning for Decarbonizing Thermal Generation Supported Renewable power systems Using Hydrogen and Ammonia Storage

arXiv

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arXiv 2023年

作者： Yu, Zhipeng Lin, Jin Liu, Feng Li, Jiarong Chi, Yingtian Song, Yonghua Ren, Zhengwei State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100087 China Sichuan Energy Internet Research Institute Tsinghua University Chengdu610213 China Department of Electrical and Computer Engineering University of Macau 999078 China Department of Electrical Engineering Tsinghua University Beijing100087 China

—Large-scale centralized development of wind and solar energy and peer-to-grid transmission of renewable energy source (RES) via high voltage direct current (HVDC) has been regarded as one of the most promising ways to achieve goals of peak carbon and carbon neutrality in China. Traditionally, large-scale thermal generation is needed to economically support the load demand of HVDC with a given profile, which in turn raises concerns about carbon emissions. To address the issues above, hydrogen energy storage system (HESS) and ammonia energy storage system (AESS) are introduced to gradually replace thermal generation, which is represented as a multi-stage expansion planning (MSEP) problem. Specifically, first, HESS and AESS are established in the MSEP model with carbon emission reduction constraints, and yearly data with hourly time resolution are utilized for each stage to well describe the intermittence of RES. Then, a combined Dantzig-Wolfe decomposition (DWD) and column generation (CG) solution approach is proposed to efficiently solve the large-scale MSEP model. Finally, a real-life system in China is studied. The results indicate that HESS and AESS have the potential to handle the intermittence of RES, as well as the monthly imbalance between RES and load demand. Especially under the goal of carbon neutrality, the contribution of HESS and AESS in reducing levelized cost of energy (LCOE) reaches 12.28% and 14.59%, respectively, which finally leads to a LCOE of 0.4324 RMB/kWh. Copyright © 2023, The Authors. All rights reserved.

关键词： Carbon

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Test and Analysis of Conducted Disturbance Sources of the Truck Crane under Stable Conditions

Test and Analysis of Conducted Disturbance Sources of the Tr...

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International Symposium on Electromagnetic Compatibility

作者： Li Xiao Zhanqing Yu Shuiming Chen Bo Zhang Rong Zeng Chijie Zhuang Yang Zeng Xiaoying Yu Qian Zhang State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Research Institute Zoomlion Heavy Industry Science & Technology Development Co. Ltd.

ISBN: (纸本)9781467307185

The Electromagnetic Compatibility (EMC) is a major issue for the truck crane designing, due to the large dimension. The conducted disturbance sources of truck crane was measured under stable conditions, the time domain characteristics of possible conducted disturbance sources was analyzed, and typical waveforms were concluded to solve the EMC (Electromagnetic Compatibility) issue. The electromagnetic disturbance characteristics at different test points under different operation conditions were compared, and the influence of different factors was studied. The amplitude and frequency parameters of the major disturbance sources were compared with the standard immunity test pulses suggested by ISO7637-2. The differences between them indicate that the extant standard might not apply to the test of the truck crane. The presented results could form a basis for the development of a special standard for the EMC test of the truck crane and further relevant EMC research.

关键词： Truck crane EMC Conducted disturbance source Time domain characteristics Electromagnetic immunity test

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Optimal Sizing of Isolated Renewable power systems with Ammonia Synthesis: Model and Solution Approach

arXiv

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arXiv 2023年

作者： Yu, Zhipeng Lin, Jin Liu, Feng Li, Jiarong Zhao, Yuxuan Song, Yonghua The State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100087 China Sichuan Energy Internet Reasearch Institute Tsinghua University Chengdu610213 China The Department of Electrical and Computer Engineering University of Macau 999078 China The Department of Electrical Engineering Tsinghua University Beijing100087 China

Isolated renewable power to ammonia (IRePtA) has been recognized as a promising way to decarbonize the chemical industry. Optimal sizing of the renewable power system is significant to improve the techno-economic of IRePtA since the investment of power sources exceeds 80% of the total investment. However, multi-timescale electricity, hydrogen, and ammonia storages, minimum power supply for system safety, and the multiyear uncertainty of renewable generation lead to difficulties in planning. To address the issues above, an IGDT-MILFP model is proposed. First, the levelized cost of ammonia (LCOA) is directly formulated as the objective, rendering a mixed integer linear fractional programming (MILFP) problem. Information gap decision theory (IGDT) is utilized to handle the multiyear uncertainty of renewable generation. Second, a combined Charnes-Cooper (C&C) transformation and Branch-and-Bound (B&B) method is proposed to efficiently solve the large-scale IGDT-MILFP model, giving robust and opportunistic planning results. Then, Markov Chain Monte Carlo (MCMC) sampling-based posteriori analysis is leveraged to quantify the long-run performance. Finally, a real-life system in Inner Mongolia, China, is studied. The results indicate that the proposed methods could reduce the computational burden by orders of magnitude for solving a large-scale MILFP problem. Moreover, the proposed IGDT-MILFP model is necessary and accurate to obtain an optimal capacity allocation with the lowest expected LCOA (3610 RMB/t) in long-run simulations. Copyright © 2023, The Authors. All rights reserved.

关键词： Ammonia

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