Table of Content

30 July 2023, Volume 0 Issue 7

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Research & Analysis

Research on Wind Farm Wake Optimization Strategy Considering Floating Foundation Displacement

ZHU Ruonan, WANG Xiaodong, LIU Yingming, ZHANG Yinghao

2023, 0(7):  1-9.  doi:10.16628/j.cnki.2095-8188.2023.07.001

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The wake effect between wind turbines has a direct impact on the power generation,and the modeling and optimization of the wake of floating units are more complex due to their attitude.A wind farm wake optimization strategy based on yaw control is proposed considering the floating foundation displacement.Firstly,considering the influence of floating platform displacement on yaw angle,the Curl wake model is improved.Secondly, the objective function of the relationship between wind farm power generation and wake wind speed and yaw angle is established.Finally,taking the yaw angle as the optimization parameter,optimization is carried out with the Nelder-Mead by the simplex algorithm method to improve the power generation of the wind farm as a whole.Based on NREL 5 MW TLP floating unit, the control strategy is simulated and verified under different working conditions.The results show that the proposed optimization strategy has a more obvious effect on improving the power generation of the floating wind farm than the traditional wake optimization method.

Simplified Current Equivalent Model of Full Bridge CLLC Resonant Converter Under Over-Resonant Condition

DAI Xiangyang, XU Yuzhen, WAN Lufeng

2023, 0(7):  10-17.  doi:10.16628/j.cnki.2095-8188.2023.07.002

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The effective value and peak value of the resonant current are particularly important for the efficiency analysis and device selection of the converter.In response to the problem of low accuracy of using fundamental wave analysis method and complexity of using the time-domain analysis method to calculate resonant current, a new method is proposed.The waveform of resonant current in circuits with operating frequency greater than resonant frequency is analyzed and theoreticaly derived.At the same time, a simplified resonant current model is constructed based on the reasonable assumptions and equivalence of the current.The experimental results show that the simplified model is more accurate than the fundamental wave analysis method and the calculation is simple.

Simulation Analysis and Experimental Research on Contact System of Fast Earthing Switch Based on Explicit Dynamics

XU Minhang, LÜ Pengrui, CUI Aiqiang

2023, 0(7):  18-24.  doi:10.16628/j.cnki.2095-8188.2023.07.003

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Fast earthing switch (FES) is a kind of electrical equipment that provides fast earthing protection.It is often used in power equipment such as medium voltage switchgear to prevent electrical equipment from being damaged by the internal arc faults.According to the development status and engineering application requirements of its contact mechanism design,the contact system collision of FES is studied.Firstly,the transient process of the conical contact system of FES in high-speed collision is analyzed based on the explicit dynamics,and the main parameters affecting the contact system’s action characteristics are identified.Secondly,the structure parameters of the static contact are optimized by using the multi-objective optimization module of Ansys Design Xplorer.Finally,the high-speed collision test is carried out to verify whether the contact system meets the design requirements.The results show that the conical contact system has good dynamic characteristics and can form a stable electrical contact surface during the fast closing process,which can meet the application requirements of FES.

Study on Electrical Properties of Different Silver Tin Oxide Electrical Contact Materials Under DC Conditions

LI Jie, JIN Yangdeng, YAN Xiaofang, BAI Xiaoping, CHEN Yangfang, YOU Yibo, LIU Yingfei, MA Siping

2023, 0(7):  25-29.  doi:10.16628/j.cnki.2095-8188.2023.07.004

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Different AgSnO₂In₂O₃ materials and rivets were prepared by alloy internal oxidation method.Besides,the simulated electrical properties were carried out under the conditions of DC 13.5 V,25 A and resistive load.The mechanical properties and microstructure of three kinds of wires were compared and the influence mechanism on electrical properties of different AgSnO₂In₂O₃ materials was studied.It is concluded that with the increase of Sb₂O₃ content,the density,hardness and tensile strength of wires showed a gradual decreasing trend.When Sb₂O₃ content was low,the mechanism of material transfer was the main mechanism.As the increase of Sb₂O₃ content,the contact mechanism was mainly consumption.When Sb₂O₃ was 1%,the anti-welding resistance was the best.An appropriate amount of Sb₂O₃ could improve the anti-welding resistance of contact materials by increasing the brittleness of the melting bridge.

Mechanism Analysis and Maintenance Research on Deterioration of Aircraft Contactor Contact

MENG Xin, SUN Qihai, YU Chunfeng, ZHANG Yuanfeng

2023, 0(7):  30-35.  doi:10.16628/j.cnki.2095-8188.2023.07.005

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The contactor failure caused by the contact adhesion of aircraft contactor occurs frequently,and the harsh environment makes the contact life of the contactor far lower than the ideal life,which brings great difficulties to the field maintenance work.It is of great significance to study the deterioration mechanism of the contact surface of the contactor under the field conditions to formulate the maintenance plan,improve the maintenance quality and ensure flight safety.The contact surface states from macro and micro angles are observed,the composition of contact spot elements is analyzed,and the fault mechanism of contact resistance increasing in combination with the characteristics of aircraft contactor working environment is researched.Taking the existing misunderstandings and hazards in the current field contactor contact maintenance,the field inspection and maintenance improvement scheme of the contact are studied,which can help the maintenance personnel master the health status and remaining life of the contactor and achieve the purpose to reduce the failure rate of the contactor.

Electrical Design & Discussion

Design of an Anti-Radiation POL Power Supply with Wide Voltage Input and Dual-Channel Output

YANG Zhengnan, HU Mei, OU Changjiang, HAO Zhenyu

2023, 0(7):  36-41.  doi:10.16628/j.cnki.2095-8188.2023.07.006

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Aiming at the requirements of miniaturization of satellite equipment and lightweight of the whole system,a design scheme of anti radiation POL power supply with 4.5~16 V wide voltage input and dual-channel output is proposed.Firstly,the topology structure of the circuit is designed according to the requirements of the power supply index.Secondly,the solution of anti-radiation index is proposed.Finally,the difficulties of process design are studied and solved.The proposed power supply is realized by simulation and prototype verification.It has the advantages of small volume,light weight and high power density and so on,which can provide miniaturized and lightweight tertiary power supply solutions for aerospace electronic equipment systems.

Electrical Design & Discussion

Design of Safety Fire Switch for Photovoltaic Module

HE Jiajun, BAO Guanghai

2023, 0(7):  42-47.  doi:10.16628/j.cnki.2095-8188.2023.07.007

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A fire safety switch based on carrier communication is designed to address the fire safety issues of photovoltaic modules.The specific design of the breaker and the controller are carried out.The circuit breaker collects the voltage and current data of each PV module,transmits them to the controller via power line carrier communication,and then uploads them to the PV system monitoring platform via RS-485 to display the operation status of the PV module in real time.In addition,the PV module can be turned off through the PV system monitoring platform or manually pressing the shutdown button on the controller,which can greatly reduce the high voltage on the DC side of the PV in case of fire to ensure the personal safety.

Research on Power Supply Design Optimization and System Stability of Spaceborne SAR

ZHI Shubo, CHEN Si, ZHANG Kun, SI Xueyuan, JI Mingming, WANG Jianping

2023, 0(7):  48-54.  doi:10.16628/j.cnki.2095-8188.2023.07.008

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The modeling analysis on the secondary load power supply and pulse load of the synthetic aperture radar (SAR) are conducted to meet the requirements of SAR satellite power system features and relatively high stability of the power bus.Meanwhile,the experiment on features of the impedance is carried out on the satellite power DC distributed power supply system.The method is put forward to enhance the stability of the work system.The sytem stability reseach is conducted concerning various load modes.The experiment results are consistent with the theoretical ones,which can show that the power supply system is stable and satisfy the needs SAR satellite payload.

Identification & Prediction Technology

Research on Non-Intrusive Load Identification Method Based on Multi-Feature Fusion

WEI Xinqi, ZHANG Chenyu, MIAO Huiyu, CHEN Shu

2023, 0(7):  55-60.  doi:10.16628/j.cnki.2095-8188.2023.07.009

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Aiming at the problem that the accuracy of traditional non-intrusive load identification algorithms is low in low-frequency sampling data,a non-intrusive load identification algorithm based on the gram angle field (GAF) and feature fusion is proposed.The collected power information is converted into color image features by GAF technology to improve the identification.The image and power data are input into the convolutional neural network and the backpropagation neural network respectively for feature extraction to achieve feature fusion,which is used as the new feature for identification.The identification method is verified in many aspects of the public data set and compared with different classification algorithms.The results show that the image features carry more information,strengthen the representation of features,and feature fusion can solve the problem of information loss in the process of image coding,and improve the load identification ability of the model.

Model Prediction Control Strategy of Multi-Port Interline DC Power Flow Controller

WANG He, XU Xiangsheng, SHEN Guanye, BIAN Jing

2023, 0(7):  61-69.  doi:10.16628/j.cnki.2095-8188.2023.07.010

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In order to solve the problem of insufficient freedom of power flow control in flexible DC power grid and improve dynamic performance,a model predictive control strategy for multi-port interline power flow controller (MI-PFC) is proposed.Firstly,the mathematical modeling of the multi-port DC network containing MI-PFC is discretized.Secondly,the cost function and weight factor are designed and the control is accomplished by sub-module ranking algorithm and modulation strategy.Finally,the control performance of the proposed model predictive control strategy is verified by MATLAB/Simulink simulation platform.The final proof shows that the proposed control strategy has advantages such as strong dynamic performance,multi-objective control,and simple structure.

Identification & Prediction Technology

Early-Warning Evaluation Method of Intelligent Control Cabinet Interior Environment Based on Similar Days and Optuna-LightGBM

YIN Kang, ZHONG Tingting, HUANG Xinying, LI Li

2023, 0(7):  70-76.  doi:10.16628/j.cnki.2095-8188.2023.07.011

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A temperature and humidity prediction method based on similar days and Optuna-LightGBM is proposed to address the issue of low prediction accuracy of temperature and humidity in event driven intelligent control cabinets,which can’t provide the timely warning of abnormal temperature and humidity inside the cabinets.The similar day algorithm is used to select the suitable model training data sets.A temperature and humidity prediction model is constructed based on LightGBM.Using Optuna the model parameters are optimized.Finally,a threshold calculation method for warning parameters based on the curve inflection point detection is proposed.The temperature and humidity curve characteristics obtained from the prediction model are analyzed to achieve temperature and humidity warning.The experimental results show that the temperature prediction error MAPE of the proposed method is 0.35%,and the humidity prediction error MAPE is 0.73%,which can achieve the accurate prediction of temperature and humidity inside the cabinet and timely warning.