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    Optimal Reconfiguration Method for Thermoelectric Power Array Based on Artificial Bee Colony Algorithm
    YANG Bo, HU Yuanweiji, GUO Zhengxun, SHU Hongchun, CAO Pulin, LI Zilin
    Journal of Shanghai Jiao Tong University    2024, 58 (1): 111-126.   DOI: 10.16183/j.cnki.jsjtu.2022.284
    Abstract2524)   HTML10)    PDF(pc) (9997KB)(97)       Save

    With the rapid development of new energy generation technology, the thermoelectric generation technology (TEG) can make good use of the waste heat generated in new energy generation. However, the change of temperature distribution will worsen the output characteristics and reduce the power generation efficiency of the TEG system. In this paper, a TEG array reconfiguration method based on the artificial bee colony (ABC) algorithm is proposed. In three different temperature distributions, ABC is used for dynamic reconfiguration of symmetric 9×9 and unsymmetric 10×15 TEG arrays. Three meta-heuristic algorithms, the genetic algorithm, the particle swarm optimization algorithm, and the bald eagle search are compared with the proposed method, and the temperature distribution of the TEG array reconfiguration by ABC is given. The results show that ABC can improve the output power of the TEG array, and the output power-voltage curves tend to show a single peak value. In addition, real-time hardware-in-the-loop (HIL) experiment based on the RTLAB platform is undertaken to verify the implementation feasibility.

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    Low-Carbon Operation Strategy of Integrated Energy System Based on User Classification
    ZHANG Chunyan, DOU Zhenlan, BAI Bingqing, WANG Lingling, JIANG Chuanwen, XIONG Zhan
    Journal of Shanghai Jiao Tong University    2024, 58 (1): 1-10.   DOI: 10.16183/j.cnki.jsjtu.2022.321
    Abstract2231)   HTML32)    PDF(pc) (1783KB)(323)       Save

    Integrated energy system (IES) is an important means to achieve the goal of “carbon peaking and carbon neutrality”. However, different types of users in the system have different energy consumption behaviors, which makes the coordinated optimization and low-carbon operation of the integrated energy system more difficult. In order to give full play to the subjective initiative of users, the user behavior of the integrated energy system is modelled based on user behavior analysis, and users are classified into aggressive and conservative types by convolutional neural network (CNN). Then, the decision model of integrated energy system operator is constructed to determine the supply mode of electric heating energy, and the corresponding energy package is designed for different types of users. Finally, the effectiveness of the above models and methods is analyzed based on actual data, and the value of user classification in low-carbon operation of integrated energy systems is verified.

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    Improved Magnetic Circuit-Motion Coupled Model and Fast Simulation of Direct-Acting Electromechanical Motion Device
    JIANG Peng, GUAN Zhenqun, ZHAO Guozhong, ZHANG Qun, QIN Zhiqiang
    Journal of Shanghai Jiao Tong University    2024, 58 (1): 102-110.   DOI: 10.16183/j.cnki.jsjtu.2022.243
    Abstract2098)   HTML3)    PDF(pc) (3985KB)(215)       Save

    The rapid simulation of the dynamic performance of electromechanical devices such as solenoid valves and relays is important for product development and design. A magnetic circuit model of the non-saturated direct-acting electromechanical motion device is improved, and then coupled with the motion equation of the mechanism to realize the rapid simulation of the electromechanical motion device. In contrast to the ideal magnetic resistance in the conventional magnetic circuit model, the non-saturated total magnetic resistance is expressed by a cubic polynomial of the movement displacement of mechanism. The four undetermined coefficients of the polynomial are calibrated by the simulation values of static magnetic force and inductance at the upper and lower motion limits. The improved magnetic circuit model can more accurately predict the changes of magnetic attraction force and inductance with the motion displacement. Furthermore, coupled with the motion equation of the electromechanical motion device, the improved model establishes an improved magnetic circuit-motion coupled model and realizes fast second-level simulation of an electromagnetic brake and valve in the Simulink system, which can greatly reduce the finite element simulation time while maintaining simulation accuracy.

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    A Method for Carbon Emission Measurement and a Carbon Reduction Path of Urban Power Sector
    HU Zhuangli, LUO Yichu, CAI Hang
    Journal of Shanghai Jiao Tong University    2024, 58 (1): 82-90.   DOI: 10.16183/j.cnki.jsjtu.2022.222
    Abstract1955)   HTML8)    PDF(pc) (1670KB)(259)       Save

    To measure and reduce carbon emissions in the urban power sector, a method for measuring carbon emissions in the urban power sector and a carbon reduction path are proposed. First, a carbon emission measurement model for the urban power sector is established based on the data of local power generation and net inward power. Then, carbon reduction measures for the urban power sector are proposed from the generation side, grid side, load side and energy storage side. After that, an evaluation model for the effect of the carbon reduction measures is established. Finally, taking a typical city F in the Pearl River Delta as an example, the proposed carbon emission calculation model is used to calculate the carbon emissions of power sector of the city, and the effectiveness of carbon reduction in 2030 carbon peak scenario of the city is evaluated based on the carbon reduction measures. The results show that the proposed model can accurately measure the carbon emissions of the urban power sector, and by utilizing carbon reduction measures, carbon emissions of the city can be reduced by at least 10.6 million tons in 2030.

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    Robust Evaluation Method of Integrated Energy System Based on Variable Step Simulation and Improved Entropy Weight Method
    FAN Hong, HE Jie, TIAN Shuxin
    Journal of Shanghai Jiao Tong University    2024, 58 (1): 59-68.   DOI: 10.16183/j.cnki.jsjtu.2022.186
    Abstract1936)   HTML6)    PDF(pc) (5076KB)(177)       Save

    As an important manifestation of the energy Internet, the integrated energy system improves the energy utilization rate. However, it also brings more risks due to the high coupling and the large difference in the response speed between the various systems. From the perspective of system security, it becomes crucial to accurately identify the weak links in the system and evaluate the robustness of the system. Therefore, a robustness evaluation method combining variable step size simulation and improved entropy weight method is proposed in the complex network environment. First, the structure of the integrated energy system is introduced and the coupling links of the system are further explained. Then, the robustness indicators including network damage degree and connectivity factor are proposed, and a variable step according to the difference of the response time of different systems is adopted. Based on the simulation results, an improved entropy weight method is proposed, and a more objective evaluation method is constructed. Finally, the superiority of the evaluation method is verified by a case study.

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    Comprehensive Evaluation of Key Technologies in Power Internet of Things Based on Comprehensive Similarity of Cloud Model
    CHEN Lianfu, ZHONG Haiwang, TAN Zhenfei, RUAN Guangchun
    Journal of Shanghai Jiao Tong University    2024, 58 (1): 19-29.   DOI: 10.16183/j.cnki.jsjtu.2022.420
    Abstract1887)   HTML15)    PDF(pc) (1954KB)(104)       Save

    Currently, the comprehensive evaluation of the application of key technologies in the power Internet of Things (PIoT) has the characteristics of a single evaluation object, and the traditional evaluation methods are not applicable. In order to comprehensively evaluate the technology maturity and operational effectiveness of PIoT projects, a comprehensive evaluation index for key technologies in PIoT is established to comprehensively consider the different development stages. According to the characteristics of application scenario, an evaluation model based on the comprehensive similarity of cloud model is proposed. By reforming the technique for order preference by similarity to an ideal solution (TOPSIS) method, a decision matrix for a single evaluation object is constructed, and the shape-distance comprehensive similarity of the cloud model is used as a measure to characterize the relative closeness of the TOPSIS method, and the accurate evaluation of a single object is realized. Finally, the proposed method is applied to assess a PIoT demonstration project. The results show that the proposed comprehensive evaluation index and evaluation method can objectively and comprehensively evaluate the comprehensive application effect of each key technology in the construction and operation stages of PIoT.

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    Reliability Index Calculation and Reserve Capacity Optimization Considering Multiple Uncertainties
    YE Lun, OUYANG Xu, YAO Jiangang, YANG Shengjie, YIN Jungang
    Journal of Shanghai Jiao Tong University    2024, 58 (1): 30-39.   DOI: 10.16183/j.cnki.jsjtu.2022.366
    Abstract1851)   HTML7)    PDF(pc) (1413KB)(126)       Save

    In power systems with a high proportion of renewable energy, to achieve coordinated optimal scheduling of source and load considering multiple uncertainties is an important issue in power system operation. Therefore, a probabilistic spinning reserve optimization model based on multiple scenarios is constructed. Multiple uncertain factors are considered in the model, such as wind power and solar power forecast errors, load forecast error and unscheduled generator outage. Renewable energy curtailment and load shedding are used as special reserve resources in the day-ahead security-constrained unit commitment (SCUC) to improve the economic operation efficiency. The calculations of reliability indexes, expected energy not served and expected energy curtailment, are simplified, and the inequality constraints related to these two indexes are reduced, which improves the computational performance of the model. The model optimizes the total expected cost considering multiple uncertainties. Case studies based on the IEEE-RTS demonstrate the effectiveness of the proposed model. The numerical results show that the improved calculation method of reliability indexes can effectively reduce the solution time of the SCUC model. The reserve optimization model can realize the dynamic allocation of the spinning reserve capacity of the system and improve economic operation of the system.

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    Optimization Design of New Bionic Propeller
    WU Chunxiao, LU Yu, LIU Shewen, GU Zhuhao, SHAO Siyu, SHAO Wu, LI Chuang
    Journal of Shanghai Jiao Tong University    2023, 57 (11): 1421-1431.   DOI: 10.16183/j.cnki.jsjtu.2022.174
    Abstract1735)   HTML27)    PDF(pc) (10709KB)(351)       Save

    A novel method for optimal design of hydrodynamic performance of bionic propeller with a deformable leading edge is proposed. Based on the bionics principle and method of parameterized modeling, the fore-fin concave-convex structure of humpback whales is applied to the propeller leading edge, the leading edge in the propeller to meet flow region according to the exponential decay curve and the standard sine curve smooth leading edge for similar humpback fins protuberant structure of concave and convex deformation, and the leading edge of concave and convex bionic propeller. The hydrodynamic performance, the cavitation performance, and the noise performance of the exponential decay bionic propeller and the sinusoidal function bionic propeller were simulated respectively. The propeller with a better performance is selected, and the simulation based design (SBD) technology is introduced into the optimization design of the new bionic propeller. The parameters controlling the shape of the exponential attenuation curve of the guide edge deformation are taken as optimization design variables, the torque of the parent propeller is taken as the constraint condition, the open water efficiency is selected as the objective function, and the optimization algorithm of Sobol and T-Search is adopted. A bionic propeller optimization system based on the exponential decay curve is constructed. The results show that the application of the concave and convex structure of the humpback whale fore-fin to the guide edge of the propeller improves the cavitation performance and noise performance of the propeller, but the improvement of the open water performance of the propeller is not particularly significant. It is verified that the hydrodynamic performance optimization design method of the bionic propeller established in this paper is effective and reliable, which provides a certain theoretical basis and technical guidance for the performance numerical calculation and configuration optimization design of the bionic propeller.

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    Stepwise Inertial Intelligent Control of Wind Power for Frequency Regulation Based on Stacked Denoising Autoencoder and Deep Neural Network
    WANG Yalun, ZHOU Tao, CHEN Zhong, WANG Yi, QUAN Hao
    Journal of Shanghai Jiao Tong University    2023, 57 (11): 1477-1491.   DOI: 10.16183/j.cnki.jsjtu.2022.157
    Abstract1674)   HTML15)    PDF(pc) (10551KB)(188)       Save

    Stepwise inertial control (SIC) provides a step-increase of power after load fluctuation, which can effectively prevent system frequency decline and ensure the safety of grid frequency. However, in the power recovery stage, secondary frequency drop (SFD) is easy to occur. Therefore, it is necessary to optimize SIC to obtain a better frequency regulation effect. The traditional method has the disadvantages of high calculation dimension and long consuming time, which is difficult to meet the requirements of providing the optimal control effect in different scenarios. In order to realize the optimal stepwise inertial fast control of wind power frequency regulation in load disturbance events, this paper introduces the deep learning algorithm and proposes a stepwise inertial intelligent control of wind power for frequency regulation based on stacked denoising autoencoder(SDAE) and deep neural network(DNN). First, sparrow search algorithm (SSA) is used to obtain the optimal parameters, and SDAE is used to extract the data features efficiently. Then, DNN is used to learn the data features, and the accelerated adaptive moment estimation is introduced to optimize the network parameters to improve the global optimal parameters of the network. Finally, the stepwise inertial online control of wind power frequency regulation after disturbance event is realized according to SDAE-DNN. The simulation analysis is conducted for a single wind turbine and a wind farm in the IEEE 30-bus test system. Compared with the results obtained by the traditional method, shallow BP neural network and original DNN network, it is found that the proposed network structure has a better prediction accuracy and generalization ability, and the proposed method can achieve a great effect of stepwise inertia frequency regulation.

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    Refined Simulation of Near-Surface Wind Field of Atmospheric Boundary Layer Based on WRF-LES Model
    LIU Dalin, TAO Tao, CAO Yong, ZHOU Dai, HAN Zhaolong
    Journal of Shanghai Jiao Tong University    2024, 58 (2): 220-231.   DOI: 10.16183/j.cnki.jsjtu.2022.415
    Abstract1674)   HTML22)    PDF(pc) (9950KB)(387)       Save

    Extreme meteorological disasters such as typhoons pose a serious threat to the safety of engineering structures. Therefore, the refined simulation on the near-surface atmospheric boundary layer (ABL) is valuable for civil engineering. Large-eddy simulation (LES) implemented in the weather research and forecating (WRF) model has the advantages of multiple options of numerical schemes and high accuracy. It is generally suitable for the refined simulation of the near-surface wind field, although the performance of simulation results is closely related to the numerical methods. This paper assesses the impacts of vital parameters regarding subfilter-scale (SFS) stress models, mesh size, and spatial difference schemes within WRF-LES to simulate the ideal ABL in order to figure out appropriate numerical schemes for the refined simulation of the near-surface wind field. The wind field characteristics are addressed and analyzed such as mean wind speed profile, turbulence intensity profile, and power of spectrum. Comparisons of simulation results among different SFS stress models indicate that the nonlinear backscatter and anisotropy one (NBA1) SFS stress model can effectively improve the accuracy of simulation in the near-surface wind profiles. Investigations of mesh resolution effects indicate that the nonuniformly refined vertical grid near the surface agrees much better with the expected profiles and reduces the expenditure of computational resources. Furthermore, the results show that the even-order spatial difference schemes produce more small-scale turbulent structures than the odd-order difference schemes. The numerical methods of WRF-LES proposed can provide a technical reference for refined simulation of the near-surface wind field and typhoon boundary layer.

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    Wake Field Characteristics of Non-Ducted and Ducted Propellers in Large-Angle Oblique Flow
    ZHANG Qin, WANG Xinyu, WANG Zhicheng, WANG Tianyuan
    Journal of Shanghai Jiao Tong University    2023, 57 (11): 1432-1441.   DOI: 10.16183/j.cnki.jsjtu.2022.159
    Abstract1662)   HTML11)    PDF(pc) (18498KB)(175)       Save

    In order to explore the wake characteristics of non-ducted and ducted propellers in oblique inflow with a large drift angle, based on the delayed detached eddy simulation, a numerical simulation of non-ducted and ducted propellers in oblique inflow is conducted with an advance coefficient (J=0.4) and a large drift angle (β=45°, 60°). It is found that the deflection degree of the non-ducted propeller wake is higher than that of the ducted propeller. However, the overall distribution area of the wake vortex behind the ducted propeller is kinked. The wake field in the oblique flow shows its complexity, and the evolution process of vortices on the windward side differs from that on the leeward side. The above characteristic of the non-ducted propeller is more prominent. At the same time, the leading edge of the nozzle on the leeward side will produce local shedding vortices and transmit to the downstream due to flow separation. Part of the kinetic energy of the ducted propeller is converted into the nozzle thrust, which makes the turbulence kinetic energy of the wake lower than that of the non-ducted propeller. This phenomenon is more evident with the increase in the drift angle. Compared with the non-ducted propeller, the ducted propeller can maintain a better handling stability in large-angle oblique flow. This paper analyzes the influence of large-angle oblique inflow on the non-ducted and ducted propellers from the perspective of wake field characteristics and explores the theoretical basis for the ducted propeller to maintain a better handling stability in oblique flow.

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    Analysis of Fluid-Structure Coupling Energy Transfer Characteristics Slender Structure with Variable Cross-Section at Low Reynolds Number
    DENG Xiubing, YU Yuemin, PANG Xiyuan
    Journal of Shanghai Jiao Tong University    2023, 57 (11): 1400-1409.   DOI: 10.16183/j.cnki.jsjtu.2022.133
    Abstract1654)   HTML11)    PDF(pc) (18587KB)(149)       Save

    The wavy deformed cross-section cylindrical structure has excellent properties of drag reduction in fluid flow, but the flow-induced vibration characteristics of flexible structure with such variable cross-section are still unclear. In this paper, based on the high-performance spectral element method, a fluid-structure coupled mechanistic model and a numerical algorithm for slender structures are established. The wake characteristics, structural dynamic responses, energy transfers, and spanwise variations of vortex shedding frequencies are discussed. The numerical simulation results show that slender structure with the wavy-deformed cross-section can greatly suppress the vortex-induced vibration response at an appropriate cross-section disturbance wave height, and the special vortex structure formed on both sides of the wavy-shaped slender structure can stabilize the flow around the shear layer and elongate the vortex formation length, thereby reducing the fluid-structure coupling effect between the wake structure and the slender structure, and suppressing the vortex-induced vibration response.

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    Strategy of Wind-Storage Combined System Participating in Power System Secondary Frequency Regulation Based on Model Predictive Control
    LIU Chuanbin, JIAO Wenshu, WU Qiuwei, CHEN Jian, ZHOU Qian
    Journal of Shanghai Jiao Tong University    2024, 58 (1): 91-101.   DOI: 10.16183/j.cnki.jsjtu.2022.217
    Abstract1627)   HTML5)    PDF(pc) (2262KB)(192)       Save

    With the increasing penetration of wind power in power grids, it is necessary for wind storage joint farms to participate in power grid frequency modulation to maintain frequency stability of the power grid. By analyzing the mechanical characteristics of the wind turbine and the operation characteristics of the energy storage system, this paper determines the adjustability of the wind turbine power output in the pitch angle load shedding operation mode, and proposes a control strategy for the wind farm with an energy storage system to participate in the secondary frequency regulation of the power grid based on model predictive control (MPC). It establishes a prediction model for pitch angle control of the wind farm and an electrochemical energy storage system, optimizing the active power output of the wind turbine and the energy storage system, and better reducing the wind energy loss based on frequency regulation. The pitch angle control is further corrected based on the difference between the active power command value of the superior system and the actual power output of the wind turbine, so that the wind turbine can better track the power command value of the superior system during secondary frequency regulation, quickly respond to the frequency changes, reduce the dynamic frequency deviation, avoid load rejection due to too low frequency drop, and complete the task of secondary frequency regulation. The simulation results show that under the control strategy proposed in this paper, the controllable secondary frequency regulation ability of the wind turbine and the characteristics of fast response and accurate tracking of the energy storage system are comprehensively considered, the active power command issued by the superior system is better tracked, and the task of the wind farm including the energy storage system participating in the secondary frequency regulation is realized.

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    Optimization of Wind Turbine Vortex Generator Based on Back Propagation Neural Network
    XIA Yunsong, TAN Jianfeng, HAN Shui, GAO Jin’e
    Journal of Shanghai Jiao Tong University    2023, 57 (11): 1492-1500.   DOI: 10.16183/j.cnki.jsjtu.2022.169
    Abstract1607)   HTML12)    PDF(pc) (9995KB)(172)       Save

    The optimal Latin hypercube experimental design method is used to refine the vortex generator parameters, determine the test scheme, simulate and calculate the thrust and torque of the wind turbine, and obtain the experimental data. Based on the back propagation (BP) neural network, the aerodynamic performance model of the wind turbine vortex generator optimized by genetic algorithm is constructed. The reliability of the aerodynamic performance model is verified by calculating the error and root mean square of the predicted and simulated values of the aerodynamic performance model. Coupling the fish swarm algorithm and the aerodynamic performance model of the wind turbine vortex generator, an optimization method of the wind turbine vortex generator is established, and the height, length, and installation angle of the vortex generator are solved iteratively to realize the optimization of the vortex generator. The results show that compared with the original vortex generator scheme, the flow separation of the wind turbine blade section optimized by the vortex generator is effectively restrained and delayed, the surface fluid separation phenomenon is improved, the power of the wind turbine is increased by 1.711%, and the thrust of the wind turbine is decreased by 0.875%.

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    Experimental Investigation of Dynamic Response of Pile-Supported Wharf in Liquefiable Ground Under Wave Action
    BI Jianwei, SU Lei, XIE Libo, ZHANG Yu, LING Xianzhang
    Journal of Shanghai Jiao Tong University    2023, 57 (11): 1442-1454.   DOI: 10.16183/j.cnki.jsjtu.2022.163
    Abstract1601)   HTML9)    PDF(pc) (8259KB)(239)       Save

    Pile-supported wharf (PSW) is widely used in the deep-water port engineering construction, most of which are located in liquefiable ground. The effect of wave action on the working performance of PSW in liquefiable ground cannot be ignored, but few studies have been reported. This study performs the wave flume test of PSW in liquefiable ground considering the soil-structure-wave interaction. This test really reproduces the operating condition of PSW, and explores the internal response difference of wharf structure under wave. The influence of wave height on dynamic response of the PSW system is discussed systematically. The result shows that the acceleration and displacement of the PSW deck gradually increase first and finally remain relatively stable with the increase of wave action. The hydrodynamic pressure and deformation of each pile in pile group are obviously different, and the response variation is related to the pile position. The pore pressure of the soil layer in the free field and around the pile decreases with the increase of depth, and the existence of the pile group can reduce the pore pressure in the soil layer around the pile, and increase the acceleration of the soil layer. The effect of wave height on the soil layer decreases with the increase of depth. The above results can provide reference for the similar PSW test under wave and the support for the design and wave protection of PSW.

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    Robust Optimization of Power Grid Investment Decision-Making Considering Regional Development Stage Uncertainties
    HUANG Wandi, ZHANG Shenxi, CHENG Haozhong, CHEN Dan, ZHAI Xiaomeng, WU Shuang
    Journal of Shanghai Jiao Tong University    2023, 57 (11): 1455-1464.   DOI: 10.16183/j.cnki.jsjtu.2022.053
    Abstract1575)   HTML14)    PDF(pc) (2782KB)(89)       Save

    Aimed at the problem of uncertainties in the regional development stage and the difficulties in quantifying regional investment demand in different development stages, a robust optimization method for power grid investment decision-making considering regional development stage uncertainties is proposed to promise the matching degree between power grid investment decisions and development needs, and to improve the ability of decision-making results to deal with portfolio risks and uncertainties in regional development stage. First, investment risk constraints are constructed based on the modern portfolio theory. Then, a box uncertainty set is used to characterize uncertainties in regional development stage, and a robust optimization model for power grid investment decision-making considering uncertainties in development stage is established. In the optimization model, the outer minimization problem is used to solve the uncertain variables in regional development stage in the worst scenario, while inner maximization problem is used to obtain the decision-making plan that can maximize investment return in the worst scenario. Furthermore, according to the strong duality theory, the double-layer optimization model is transformed into a single-layer model that can be solved directly, and the big-M method is used to solve the model proposed. Finally, an actual example of 13 cities in an eastern coastal province verifies the applicability and effectiveness of the power grid investment decision-making model.

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    An Improved NLC and Capacitor Voltage Control Method for Medium-/Low-Voltage MMCs
    ZHANG Wei, HAN Junfei, ZHONG Ming, WANG Yuqiang
    Journal of Shanghai Jiao Tong University    2023, 57 (11): 1465-1476.   DOI: 10.16183/j.cnki.jsjtu.2022.172
    Abstract1503)   HTML12)    PDF(pc) (2806KB)(146)       Save

    The modular multilevel converter (MMC) suffers from low output level and high harmonic distortion in medium-/low-voltage applications such as direct current (DC) distribution networks. In addition, the capacitor voltage of MMC is coupled with DC bus voltage in the traditional modulation method, leading to large fluctuations of capacitor voltages and deviation from the rated value under DC bus voltage margin. In order to solve the problems above, this paper proposes an improved nearest level control method, which can increase the output level of medium-/low-voltage MMCs by introducing a step wave correction. Based on the proposed modulation method, a capacitor voltage feedback control is thus proposed to limit the range of capacitor voltage fluctuations and improve equipment safety. The effectiveness of the proposed method is verified by MATLAB/Simulink simulation and real-time digital simulation system hardware-in-the-loop test.

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    Source-Load Matching Analysis and Optimal Planning of Wind-Solar-Thermal Coupled System Considering Renewable Energy Ramps
    XIA Qinqin, LUO Yongjie, WANG Rongmao, ZOU Yao, LUO Huanhuan, LI Jincan, ZHOU Niancheng, WANG Qianggang
    Journal of Shanghai Jiao Tong University    2024, 58 (1): 69-81.   DOI: 10.16183/j.cnki.jsjtu.2022.260
    Abstract1396)   HTML8)    PDF(pc) (3526KB)(99)       Save

    Wind, photovoltaic, and thermal power generation can form a coupled system through the same grid-connected point, which is a high coordination and low-carbon approach of renewable energy and flexible regulating power source at generation side in northern China. By considering renewable energy ramps and source-load matching analysis, this paper studies the optimal capacity planning of a wind-solar-thermal coupled system to provide reference for coupled system planning. First, the operation model and the uncertainty method of coupled system are briefly described. Then, considering the wind-solar complementary, ramp events, and critical load characteristics, relevant indices are selected and proposed for source-load matching evaluation. After that, considering the constraints of source-load characteristics, matching, and cost, an optimal capacity planning model of wind-solar-thermal coupled system is established. Finally, based on the actual data in Liaoning Province, a case study is conducted to acquire the optimal capacity of the wind and solar generation in the area, and the interaction between the source-load relevant indices and the planning results is analyzed, which provides reference and suggestion for the optimal capacity planning of renewable energy generation.

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    Simulation Study of Reentry Dynamics of a Deep-Water Drilling Riser System Based on Model Predictive Control
    ZHANG Chenyu, MENG Shuai
    Journal of Shanghai Jiao Tong University    2023, 57 (11): 1389-1399.   DOI: 10.16183/j.cnki.jsjtu.2022.235
    Abstract1361)   HTML25)    PDF(pc) (2622KB)(210)       Save

    A marine drilling riser at normal operation condition is required to disconnect the lower marine riser package (LMRP) and blow-out preventer (BOP) in case of severe weather. When the weather gets fine, it must reconnect the LMRP and the BOP. This process is called riser reentry. Marine drilling operations have been driven into extreme deep-waters characterized by severe weather which inevitably leads to a much higher incidence of disconnection. In addition, it requires to accomplish the reentry in a fast way owing to the capricious ocean environment. This study tries to develop a novel reentry control system based on model predictive control (MPC). First, the transverse governing equation of the hanging-off riser system with an end-mass is established based on the modified Hamilton’s principle. The optimization function and constraints in MPC are designed by use of the riser prediction model and the target location. A nonlinear disturbance observer is established for compensation of the model uncertainties and ocean environment disturbances. Finally, simulations are conducted after introducing the dynamic position system (DPS). The riser dynamics employing MPC are compared with that when adopting proportional-integral-derivative (PID) controller. It has found that the drilling riser system based on MPC has a higher response speed, which can complete the reentry process in a faster and more stable manner. It can handle the hydrodynamic force model uncertainties well and has a good robustness for current velocity disturbances. As the flexibility of the riser system is notably enhanced with the significant increase of aspect ratio, the higher-order mode of the flexible hanging-off riser can be triggered in the fast reentry process subjected to the excitations of the mother vessel and ocean environment.

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    Fast Stability of New Power System Based on a PMU Gradient Dynamic Deviation Method
    YU Miao, HU Jingxuan, ZHANG Shouzhi, WEI Jingjing, SUN Jianqun, WU Yixiao
    Journal of Shanghai Jiao Tong University    2024, 58 (1): 40-49.   DOI: 10.16183/j.cnki.jsjtu.2022.370
    Abstract1348)   HTML3)    PDF(pc) (2171KB)(120)       Save

    The high proportion of renewable energy and power electronic equipment is emerging as a significant trend and key characteristic of the power system development driven by the dual promotion of the energy transformation and scientific technological advancement. Major modifications have been made to the dynamic behavior of the new power system. The traditional small signal stability analysis approach is difficult to apply, and there are still urgent issues to be resolved for the quick change of operating conditions. In this paper, a Lyapunov direct analysis method of gradient dynamic deviation based on phasor measurement unit (PMU) data is proposed to analyze the small signal stability of the new power system. First, the PMU data matrix is used to reduce the dimension to obtain the low dimension matrix, which is substituted into the power system matrix model with a doubly-fed induction generator (DFIG). The diagonal matrix is obtained by solving the Lyapunov equation, and the positive definiteness of the matrix is determined to judge the system stability. Then, the dynamic deviation of corresponding state variable is calculated by solving the obtained diagonal matrix. The gradient descent method is applied to the corresponding state variable curve to iterate the extreme point value of curve. The time-weighted dynamic deviation of the whole oscillation process is calculated by time weighting, which provides guidance for the subsequent configuration position of damping stability controller, i.e., power system stabilizer (PSS). The method can improve the small interference stability of the system. The effectiveness of the fast stability analysis of the new power system is verified by simulations of the new England 10-machine 39-bus system with DFIG.

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