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Investigation of electron cyclotron current drive efficiency on the J-TEXT tokamak

Plasma Science and technology 2022年第12期24卷 183-189页

作者： Jiangang FANG Wei YAN Zhongyong CHEN Xiaobo ZHANG Xixuan CHEN Junli ZHANG Feiyue MAO You LI Lingke MOU Yu ZHONG Feng Li Weikang ZHANG Fanxi LIU Guinan ZOU Song ZHOU Da LI Li GAO Donghui XIA Zhoujun YANG Zhipeng CHEN Nengchao WANG Yonghua DING Yunfeng LIANG Yuan PAN the J-TEXT Team International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People's Republic of China Institute of Plasma Physics Chinese Academy of SciencesHefei 230031People's Republic of China Forschungszentrum Jülich GmbH Institut für Energie-und Klimaforschung-PlasmaphysikD-52425 JülichGermany

Electron cyclotron current drive(ECCD) efficiency research is of great importance for the neoclassical tearing mode(NTM) *** ECCD efficiency is beneficial for the NTM stabilization and the ECCD power threshold *** efficiency has been investigated on the J-TEXT *** electron cyclotron wave(ECW) power scan was performed to obtain the current drive *** current drive efficiency is derived to be approximately η_(0)=(0.06-0.16)×10^(19)A m^(-2)W^(-1)on the J-TEXT *** effect of the residual toroidal electric field has been included in the determination of the current drive efficiency,which will enhance the ECCD *** the plasma current of I_(p)=100 kA and electron density of n_(e)=1.5×10^(19)m^(-3),the ratio of Spitzer conductivity between omhic(OH)and ECCD phases is considered and the experimental data have been *** correction results show that the current drive efficiency η_(1)caused by the fast electron hot conductivity decreases by approximately 79%.It can be estimated that the driven current is approximately 24 kA at 300 kW ECW power.

关键词： electron cyclotron current drive current drive efficiency residual toroidal electric field

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A Review on the Control Strategies for Differential Boost Inverter

A Review on the Control Strategies for Differential Boost In...

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International Conference on Electrical Machines and Systems (ICEMS)

作者： Mengyuan Li Jin Wang Hu Wang Youlun Dai Libing Zhou State Key Laboratory of Advanced Electromagnetic Engineering and Technology (School of Electrical and Electronic Engineering) Huazhong University of Science and Technology Wuhan China

The differential boost inverter (DBI) has gained a great deal of interest in academia due to its advantages. Compared with conventional cascaded topology composed of a DC-DC boost circuit and a voltage source inverter, DBI needs only one-level topology to achieve boost inverter, thus has higher efficiency and lower cost. The three-phase DBI can be applied to motor drives and grid connection. Based on analyzing the structure and operating principle of three-phase DBI, this paper presents an elaborate and in-depth review of typical control strategies for three-phase DBI, including their basic principles, key features, exiting issues, and relevant suggestions, and finally reports the development tendency of the control strategies.

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A Method to Simplify the Markov Model of Protective Systems 6

A Method to Simplify the Markov Model of Protective Systems

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6th IEEE Conference on Energy Internet and Energy System Integration, EI2 2022

作者： Wang, Xingzhu Chen, Yongxin Wen, Minghao Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China Grid Center State Grid Hubei Electric Power Research Institute Wuhan China

ISBN: (纸本)9798350347159

The state space approach is a common method for conducting reliability assessment of protective systems. However, as more factors affecting the reliability of protective relay are considered, the system Markov model is becoming more and more complex and its solving efficiency is decreasing. To avoid this, a method to simplify the Markov model of protective system is proposed in this paper. Based on the continuous-time Markov process (CTMP), the theory underlying the state space approach, the method illustrates that the duration of the protective system in the switching states can be neglected. In other words, the protection switching state can be ignored when developing a Markov model of protective system. This method is applied to two existing models, one for a protection/component system and the other for redundant protective systems. The study results show that the method significantly reduces the complexity of the Markov model and improves the solving efficiency without reducing the capability of Markov model to describe the reliability of protective systems. © 2022 IEEE.

关键词： Reliability

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Viscous effects on plasmoid formation from nonlinear resistive tearing growth in a Harris sheet

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Plasma Science and technology 2022年第1期24卷 18-29页

作者： Nisar AHMAD Ping ZHU Ahmad ALI Shiyong ZENG CAS Key Laboratory of Geospace Environment and Department of Engineering and Applied Physics University of Science and Technology of ChinaHefei 230026People's Republic of China International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People's Republic of China Department of Engineering Physics University of Wisconsin-MadisonMadisonWisconsin 53706United States of America Pakistan Tokamak Plasma Research Institute Islamabad 44000Pakistan Department of Plasma Physics and Fusion Engineering University of Science and Technology of ChinaHefei 230026People’s Republic of China

In this work,the evolution of a highly unstable m=1 resistive tearing mode,leading to plasmoid formation in a Harris sheet,is studied in the framework of full MHD model using the Non-Ideal Magnetohydrodynamics with Rotation,Open Discussion *** the initial nonlinear growth of the primary m=1 island,the X-point develops into a secondary elongated current sheet that eventually breaks into *** distinctive viscous regimes are found for the plasmoid formation and *** the low viscosity regime(i.e.P_(r)■1),the plasmoid width increases sharply with viscosity,whereas in the viscosity dominant regime(i.e.P_(r)■1),the plasmoid size gradually decreases with *** a finding quantifies the role of viscosity in modulating the plasmoid formation process through its effects on the plasma flow and the reconnection itself.

关键词： viscosity reconnection plasmoids Prandtl number

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A Fast Transient Control Method for Dual-Bridge Series Resonant Converter

A Fast Transient Control Method for Dual-Bridge Series Reson...

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Power Electronics and Application Symposium (PEAS), IEEE International

作者： Zhuolan Li Yu Zhang State Key of Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

Under extended-phase-shift (EPS) modulation, both the internal phase-shift angle and the external phase-shift angle will have large step changes when the dual-bridge series resonant converter (DBSRC) rapidly adjusts the transmission power. This will cause serious oscillations in the resonant current and resonant voltage of DBSRC and threaten the safety of the converter. This paper analyzes the transient process produced by sudden changes in phase shift angles under EPS modulation. Then a fast transient control method is proposed for suppressing the oscillation by utilizing both internal and external phase-shift angles, which controls the transient process within one switching cycle and achieves a smooth transition of transmission power. Besides, impact and oscillation on the resonant current and resonant voltage during transient processes are significantly reduced. Finally, the performance of the control method is verified based on experimental and simulation results.

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An Optimal Direct Torque Control Scheme for DC-biased Vernier Reluctance Machine Drives

An Optimal Direct Torque Control Scheme for DC-biased Vernie...

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IEEE Energy Conversion Congress and Exposition, ECCE

作者： Zimin Li Wubin Kong Ronghai Qu State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

An optimal direct torque control (OPT-DTC) scheme is proposed for DC-biased vernier reluctance machines (VRMs) to improve the steady and dynamic performance of drive system. Firstly, the nonlinear model of DC-biased VRM is proposed in synchronous rotating frame. Then, the optimal control theory is employed to the model by designing an optimal torque controller with the ability of regulating zero-sequence current. The feedforward control terms are designed to improve the dynamic response, and the feedback control terms are designed to improve the steady performance. An optimal load torque observer is designed for speed control. Finally, comparative experiments with conventional DTC schemes for DC-biased VRMs are carried out to verify the superior performance of the proposed method, including higher accuracy of torque and flux and faster dynamic response.

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Optimization Methodologies for Reserve with Large-scale Renewables Integration 2

Optimization Methodologies for Reserve with Large-scale Rene...

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2nd International Conference on Energy Utilization and Automation, ICEUA 2023

作者： Hu, Xin Li, Zeke Lv, Yan Fan, Haiwei Li, Li Ding, Linglong Chen, Xinyu State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China State Grid Fujian Electric Power Co. LTD Fuzhou350003 China China Electric Power Research Institute Beijing100192 China

Renewable energy has unpredictable intermittency and variability, increasing the complexity of grid dispatch. Fuzziness theory is introduced under the uncertainty of large-scale intermittent power supply. Renewable power is characterized by fuzziness parameters. Meanwhile, the conventional deterministic unit commitment model is transformed into a chance-constraint unit commitment with fuzziness parameters. The explicit equivalence classes of chance constraints with triangular fuzziness parameters are presented to clarify chance constraints. Also, the effectiveness of the proposed model is validated in a standard IEEE test system. © Published under licence by IOP Publishing Ltd.

关键词： Equivalence classes

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Thermal Characteristics of Iron Phosphate Lithium Batteries Under High Rate Discharge 18th

Thermal Characteristics of Iron Phosphate Lithium Batteries ...

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18th Annual Conference of China Electrotechnical Society, ACCES 2023

作者： Leng, Mingjun Liu, Kun Gao, Yinghui Chen, Hongtao Cao, Xu Liu, Xin Shandong University of Science and Technology Qingdao266510 China Institute of Electrical Engineering Chinese Academy of Sciences Beijing100190 China Qilu Zhongke Electric Advanced Electromagnetic Drive Technology Research Institute Jinan250013 China Key Laboratory of Power Electronics and Electrical Drives Chinese Academy of Sciences Beijing100190 China

ISBN: (纸本)9789819714193

An accelerated calorimeter (ARC) was used to accurately measure the total heat production of the battery under high rate discharge, calculate the heat production of the battery by the simplified Bernadi equation, calculate the irreversible heat of the battery by the potential method and the internal resistance method respectively, calculate the reversible heat by measuring the entropy heat coefficient, sum the irreversible heat and the reversible heat measured by different methods and compare them with the total heat production respectively, and conclude that under high magnification discharge using potential method is more accurate for heat generation estimation, and proposes a more accurate method for heat generation prediction of batteries in engineering, and provides a basis for battery assembly. Moreover, the experimental results indicate that under high-rate discharge (30C), the trend of the battery’s internal resistance with ambient temperature remains essentially the same as that observed during low-rate discharge (below 1C). © Beijing Paike Culture Commu. Co., Ltd. 2024.

关键词： Entropy

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Multiple Stages Coordinated Control of Wind Turbine Generators and Energy Storage Systems for Frequency Support Considering Multiple Constraints

Multiple Stages Coordinated Control of Wind Turbine Generato...

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IEEE Asia Power and Energy engineering Conference (APEEC)

作者： Kangyi Sun Dahu Li Wei Yao Hongyu Zhou State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China Hubei Electric Power Corporation Wuhan Hubei Province China

ISBN: (数字)9798331517540

ISBN: (纸本)9798331517557

The current method of primary frequency support for the system using wind farms didn't consider the rotor speed and torque constraints at the same time. To improve the support effect while ensure the rotor speed and torque safety, this paper proposes a multiple stages coordinated control (MSCC) using wind turbine generators (WTGs) and energy storage systems (ESSs). In the beginning of the frequency event, the wind farm is under consensus coordinated control to fully utilize the WTGs' kinetic energy. ESSs act under adaptive droop control. When the torques of some WTGs reach the limit, these WTGs are switched to torque limit control (TLC). At the same time, the power reference values of ESSs are updated to make up for power shortage of TLC. In the recovery stages, the WTGs use gradual recovery control, while the ESSs use adaptive ramp recovery control. Both of the recovery controls alleviate the second frequency drop (SFD). Based on MATLAB/Simulink platforms, the two-area power system with wind farm and ESSs is analyzed. Simulation results show that the proposed TLDC method has a better effect compared with other frequency support methods, and also ensure the rotor speed and torque safety.

关键词： Torque Rotors Switches Wind farms Control systems Generators Wind turbines Safety Frequency control Energy storage

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Modified Nine-Switches High Step-up Ratio Boost-Only Y-inverter with Common Ground

Modified Nine-Switches High Step-up Ratio Boost-Only Y-inver...

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International Conference on Electrical Machines and Systems (ICEMS)

作者： Youlun Dai Jin Wang Hu Wang Mengyuan Li Libing Zhou State Key Laboratory of Advanced Electromagnetic Engineering and Technology (School of Electrical and Electronic Engineering) Huazhong University of Science and Technology Wuhan China

The article proposes a modified nine-switches high step-up ratio boost-only Y-inverter with common ground. This new inverter inherits the major advantages of the double dual topology and Y-inverter, and the circuit is modified so that both input and output are common-grounded, which ensures high voltage gain in three-phase systems. Meanwhile, the circuit topology reduces three switches, without increasing voltage stress, magnetic volume, or reducing voltage gain. Eventually, a double-loop control scheme in which input current and output voltage are used as control variables is designed here for the proposed Y-inverter. The feasibility is confirmed by Simulink simulation, which has provided a basis for future research.

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