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3rd IEEE China International Youth Conference on Electrical engineering, CIYCEE 2022

作者： Zou, Jiabao Yuan, Jushigang Li, Shiyu Huang, Jiang School of Electrical and Electronic Engineering Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan430074 China

ISBN: (数字)9781665477321

ISBN: (纸本)9781665477321

The control grid is an important part of the electron curtain accelerator, and its structure and parameters seriously affect the trajectory of the electron beam, which in turn has a certain impact on the beam uniformity and transmission efficiency. In this paper, the transverse electron curtain accelerator model is established, the electron beam trajectory is simulated by CST particle studio, the beam loss in the transmission process is analyzed, and the effects of the control grid structure and parameters of the electron curtain accelerator on the beam uniformity and transmission efficiency are studied. The results show that the overall effect of hexagonal mesh array control grid is better. When the control grid voltage is 100V, the diameter of the hexagonal inscribed circle of the control grid mesh is 4mm, and the distance between the control grid and the center of the reflector is 3.5mm, the beam uniformity and beam transmission efficiency are 94.84% and 0.722 respectively. While the uniformity can meet industrial application standards, it can also maintain a good beam transmission efficiency. The research results of this paper will provide reference and theoretical basis for the design and optimization of electron curtain accelerator. © 2022 IEEE.

关键词： Electrons

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Influence of Winding Structure on Unbalanced Magnetic Pull in Multi-Phase PMSMs

Influence of Winding Structure on Unbalanced Magnetic Pull i...

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2022 International Conference on Electrical Machines, ICEM 2022

作者： Li, Rui Fang, Haiyang Li, Dawei Qu, Ronghai Zhou, Jianlin Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Wuhan430074 China

ISBN: (数字)9781665414326

ISBN: (纸本)9781665414326

The unbalanced magnetic pull (UMP) brings an additional electromagnetic vibration and a decreased life time to the permanent magnet synchronous machines (PMSMs). In this digest, a 6-phase PMSMs with different winding structures is researched in order to investigate the influence of the winding structure on the UMP. The UMP forced on the 6-phase PMSM is analyzed through both the analytical method and the finite element method (FEM). It is found that the circulation current in the parallel branches will restrain the UMP that induced by the manufacturing errors, such as the eccentricity and magnetization error. It is also found that some high frequency UMP harmonics will be induced if the parallel branches in the winding are asymmetrically distributed. © 2022 IEEE.

关键词： Errors

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Crystallization and Dielectric Properties of Polypropylene Film during Sequential Biaxial Stretching

Crystallization and Dielectric Properties of Polypropylene F...

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2022 IEEE International Conference on High Voltage engineering and Applications, ICHVE 2022

作者： Wang, Yucheng Li, Hua Wang, Zhehao Huang, Ziqin Li, Liuxia Lin, Fuchang State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China

ISBN: (数字)9781665407502

ISBN: (纸本)9781665407502

Biaxially oriented polypropylene (BOPP) films used for capacitors need to be stretched in longitudinal and transverse directions. Stretching causes orientation and rearrangement of polymer molecular chains, resulting in variation of crystallinity. In addition, the crystal size and β-crystal content change while stretching. Crystallization morphology affects dielectric properties, which will influence the practical application of capacitors. After pretreatment and melting, the polypropylene resin was cooled and shaped by the casting system to produce cast film. After machine direction (MD) stretching, the MD-stretched film was obtained, and further, BOPP film was obtained after MD and transverse direction (TD) stretching. In this paper, the differential scanning calorimetry (DSC) method was used to measure the heat flow curves of three kinds of films, from which the crystallinity and β-crystal content were obtained. The relative dielectric constant ϵr and the dielectric dissipation factor tanϑ were obtained by the frequency-domain spectroscopy (FDS) method, from which the polarization and dielectric loss characteristics of the films during stretching were analyzed. The results show that the crystallinity increases by 3.8% and the β-crystal content decreases by 14.6% after MD stretching, and TD stretching does not change crystallinity. In addition, the results of FDS show that ϵr and tanδ of cast film are the largest and most sensitive to frequency, ϵr and tanδ of BOPP film are the stablest, and tanδ of MD-stretched film shows an obvious relaxation peak. In this paper, the crystallization and dielectric properties of polypropylene film during sequential biaxial stretching were studied, which to some extent provided theoretical guidance for the stretching process of polypropylene film for capacitors. © 2022 IEEE.

关键词： Crystallinity

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Complex Power Quality Disturbance Classification Based on Fuzzy Transfer Field and DPN-17

Complex Power Quality Disturbance Classification Based on Fu...

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2024 IEEE China International Youth Conference on Electrical engineering, CIYCEE 2024

作者： Jieting, Wu Zhiwei, Huang Miao, Yuan Weilun, Xie Zifeng, Lu Kaicheng, Li Yi, Luo Dongguan Power Supply Bureau of Guangdong Power Grid Co. Ltd. Dongguan523000 China School of Electrical and Electronic Engineering Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan430074 China

ISBN: (纸本)9798331530174

Disturbances of power quality in modern power systems tend to be complicated due to the diversification of electrical equipment and the complexity of equipment working conditions. Traditional classification methods are difficult to meet the classification requirement of multiple power quality disturbances (PQDs). In this paper, a hybrid power quality disturbance classification method based on fuzzy transfer field and DPN-17 is proposed. Fuzzy transfer field is a conversion scheme proposed to solve the confusion problem in the process of amplitude-dependent signal transformation in the existing mainstream dimension conversion methods. Fuzzy idea is used to blur the specific coordinates of signal points, and precisely encode the timing relationship and distribution of signal points, so that it can effectively encode the timing relationship and distribution information of signals. It can retain the features well in the process of downsampling;DPN-17 is implemented by referring to the shallow residual network model and using dual-path neural network modular fast combination stack. Simulation and experiments show that the proposed method can effectively solve the confusion problem of dimension conversion schemes, and can achieve accurate and rapid identification of complex power quality disturbances with an accuracy rate of 97.40%. © 2024 IEEE.

关键词： Signal encoding

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Research on Sensitivity of Slot-Pole Combination to Unbalanced electromagnetic Force Introduced by Rotor Eccentricity

Research on Sensitivity of Slot-Pole Combination to Unbalanc...

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2022 International Conference on Electrical Machines, ICEM 2022

作者： Zhou, Jianlin Fang, Haiyang Li, Rui Qu, Ronghai Li, Dawei Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Wuhan430074 China

ISBN: (数字)9781665414326

ISBN: (纸本)9781665414326

Rotor eccentricity, which is commonly introduced during manufacturing, is an inevitable obstacle in achieving better vibration, noise, and harshness (NVH) performance. Therefore, a proper slot-pole combination less sensitive to eccentricity must be found to limit its negative effect. This paper investigates the sensitivity of slot-pole combinations to unbalanced electromagnetic forces introduced by static and dynamic eccentricity in permanent magnet synchronous machines (PMSMs) based on 72-slot/8-pole and 36-slot/24-pole PMSMs. The results show little difference in the magnitudes of new components introduced by the static and dynamic eccentricity for the same machine. More importantly, the negative effects of rotor eccentricity in fractional-slot PMSMs are twice more than that in integer-slot PMSMs, which means unbalanced electromagnetic forces in the low-frequency range are more sensitive to rotor eccentricity in fractional-slot PMSMs. Besides, the effectiveness of paralleled windings in suppressing unbalanced electromagnetic forces is different in the integer-slot and fractional-slot PMSMs. © 2022 IEEE.

关键词： Sensitivity analysis

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Mechanism of Seebeck coefficient variation at the output of NiCr/NiSi thin film thermocouple with different wires 3

Mechanism of Seebeck coefficient variation at the output of ...

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2023 3rd International Conference on Measurement Control and Instrumentation, MCAI 2023

作者： Liu, Zhihui Guo, Tengda Cheng, Yongjun Wang, Bi Shen, Kai Hu, Kai Zhou, Jiankang Zhang, Chuanbing Wang, Zixi Ding, Wanyu State Key Laboratory of Tribology in Advanced Equipment Tsinghua University Beijing100084 China College of Materials Science and Engineering Dalian Jiaotong University Dalian116028 China Laboratory of Low Frequency Electromagnetic Communication Technology Wmcrt Cssc China State Key Laboratory of High-end Compressor and System Technology Hefei Anhui230031 China

In this paper, by using magnetron sputtering to prepare NiCr/NiSi thin film thermocouples, the static calibration method is used for NiCr/NiSi thermocouples with rapid temperature calibration experiments. Different temperature calibration curves are obtained. The Seebeck coefficient of NiCr/NiSi thin film thermocouples connected to NiCr/NiSi wires is significantly higher (41.39 μV/°C) than that of NiCr/NiSi wires (0 μV/°C). The Seebeck coefficient (41.39 μV/°C) of the NiCr/NiSi thin-film thermocouple connected to copper wire is significantly higher than that of the thermocouple connected to copper wire (0 μV/°C). The problem of the Seebeck coefficient of the K-type thermocouple is analyzed by experimental data, which provides the relevant parameter basis for the use of the K-type thermocouple. The method has the advantages of simple equipment, convenient operation, accurate and reliable data, and provides a basis for the sensor to measure the temperature measurement. © Published under licence by IOP Publishing Ltd.

关键词： Temperature measurement

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Thermal Balance-Based Evaluation Method for Safe Operating Areas and Its Degradation of IGBT Power Module

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IEEE Journal of Emerging and Selected Topics in Power Electronics 2025年

作者： Han, Tongyao Luo, Yifei Liu, Binli Yuan, Hao Shi, Zenan Naval University of Engineering National Key Laboratory of Electromagnetic Energy China Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan430033 China State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong University Xi’an710049 China

Insulated gate bipolar transistors (IGBTs) power module experience significant thermal stress during short-time overload conditions, and their electro-thermal characteristics exhibit strong nonlinearities. As a result, the two-dimensional safe operating area (SOA) provided in the datasheet is unable to meet the need of device reliability assessments. In this paper, we propose a quantitative assessment method based on the thermal balance principle to define the SOA for IGBTs and assess its degradation. A three-dimensional SOA that incorporates voltage, current, and junction temperature is established to prevent IGBT from thermal failures. The proposed SOA indicates that IGBT can operate safely at more than twice the rated current, and the junction temperature can exceed 448.15K(175° C) without thermal failures. This work provides theoretical support for IGBT application design and reliability assessment. According to the physical mechanisms associated with thermal failures of IGBT power module, a criterion to characterize the thermal instability of devices is established. Further, the net heat flux analysis model that integrates semiconductor physics with heat conduction theory is established, enabling the formulation of the three-dimensional SOA of IGBT. Moreover, the effects of the degradation of electro-thermal characteristics on the SOA throughout the long-term operation of the device is considered. In addition, an electro-thermal coupling model that simulates the electro-thermal characteristics of the device is established. The results from both simulation and experiment demonstrate that the established SOA and its degradation effectively predict the reliability of the IGBT under short-time overload conditions. © 2013 IEEE.

关键词： Insulated gate bipolar transistors (IGBT)

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Industrial Flexible Load Scheduling Optimization Method Based on Probabilistic Demand Response Potential Evaluation

Industrial Flexible Load Scheduling Optimization Method Base...

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Asia Conference on Energy and Environment engineering (ACEEE)

作者： Peiyu Liu Suhua Lou Yuanyuan Zhao Ming Shao State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (数字)9798350350241

ISBN: (纸本)9798350350258

With the increasing penetration rate of new energy, the reliability and flexible operation ability of new power system are limited, and the application of demand response technology can effectively solve the contradiction of insufficient peak regulation of power grid. In order to solve the problem of how industrial flexible loads participate in system scheduling, this paper proposes an optimization method of industrial flexible coincidence scheduling based on probabilistic demand response potential assessment, and analyzes the typical industrial loads. Firstly, the basic idea of iterative adaptive clustering algorithm is introduced, and an improved fuzzy C-means clustering algorithm based on adaptive clustering center selection is proposed to generate typical daily load scenarios. Then, the load production characteristics of typical continuous and non-continuous production industries are studied, and their adjustable potential is analyzed. Secondly, the demand response potential evaluation method is established for two types of demand response types: peak cutting and valley filling. Finally, with the aim of minimizing the comprehensive operation cost of power system, the optimal scheduling model of industrial flexible load based on probabilistic demand response potential evaluation is established. Numerical results show that the proposed method is effective and reasonable.

关键词： Job shop scheduling Optimization methods Clustering algorithms Optimal scheduling Production Probabilistic logic Demand response

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A Preliminary Look at the Unity of Frequency Support for Grid-Following and Grid-Forming Wind Turbines

A Preliminary Look at the Unity of Frequency Support for Gri...

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Electrical engineering (CIYCEE), IEEE China International Youth Conference on

作者： Hongyu Zhou Wei Yao Qihang Zong Jinyu Wen State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (数字)9798331530174

ISBN: (纸本)9798331530181

Grid-connected wind turbines for frequency support of the grid is conducive to improving the grid frequency security level. Grid-following (GFL) converters and gridforming (GFM) converters are two important types of equipment to support renewable energy integration into the grid. Both GFM and GFL have a variety of different control strategies when performing frequency support. Clarifying the relationship be-tween different strategies of GFM and GFL when performing frequency support will provide guidance for renewable energy frequency support. In this paper, four levels of frequency support uniformity are first established at the generation unit level. (1) The governor and damping branch of the virtual synchronous generator (VSG) control based GFM converter are unified. (2) The VSG based GFM and the droop based GFM are unified. (3) Integrated inertial control based GFL and droop based GFL are unified. Finally, the theoretical analysis is synthetically verified by MATLAB/Simulink simulation platform.

关键词： Damping Renewable energy sources Grid following Frequency conversion Synchronous generators Wind turbines Security MATLAB Frequency control Grid forming

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Second Order Generalized Integrator Filtering For Enhanced Sliding Mode Observer with Fuzzy Logic Switching Function

Second Order Generalized Integrator Filtering For Enhanced S...

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International Conference on Electrical Machines and Systems (ICEMS)

作者： Kunsheng Cai Shuanghong Wang Zixin Li State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Sciecnce and Technology Wuhan China

ISBN: (数字)9784886864406

ISBN: (纸本)9798350379105

Traditional Sliding Mode Observers (SMO) in sensorless control of Permanent Magnet Synchronous Motors (PMSM) encounter issues such as chattering and phase delay, resulting in significant discrepancies between the estimated and actual rotor speed and position. Therefore, this paper proposes an improved SMO based on a Fuzzy Logic Controller (FLC) and an Open-Loop Frequency Estimation-based Second-Order Generalized Integrator Frequency Adaptive Filter (OLFE-SOGI) structure. The FLC implements an SMO with a selfadjusting shape factor for the sigmoid function. This strategy accelerates the convergence speed of the SMO while reducing chattering caused by the boundary layer thickness. Additionally, to mitigate the adverse effects brought by lowpass filters (LPF), the OLFE-SOGI is employed to accurately extract the back electromotive force (back-EMF) without phase delay and effectively eliminate high-order harmonic components. Simulation results verify the effectiveness and accuracy of the proposed strategy.

关键词： Fuzzy logic Filtering Simulation Force Adaptive filters Sensorless control Observers Permanent magnet motors Frequency estimation Frequency control

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