Table of Content

30 March 2022, Volume 0 Issue 3

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Research & Analysis

Distributed Optimization Strategy of Photovoltaic Electric Bus Charging Stations Based on ADMM

HE Xin, LI Zheng, SUN Guoqi, WEI Xiaobin, CAI Xu, CAO Yunfeng

2022, 0(3):  1-9.  doi:10.16628/j.cnki.2095-8188.2022.03.001

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With the rapid increase of the number of electric public transport and the vigorous development of photovoltaic energy,the construction of optical storage charging station has become a better solution.Aiming at the problem of improving the return rate of photovoltaic energy storage and reducing the cost of charging stations while large-scale access of electric bus,an optimized model of optical storage electric bus charging station with the lowest cost and the highest combined benefit of light storage is established.The algorithm of alternating direction multiplier method (ADMM) is introduced to transform the centralized optimization problem into the sub-optimization problem based on the bus and the optical storage,which reduces the computational complexity.Simulation by real data shows that the proposed model can effectively maximize the return of photovoltaic energy storage while reducing charging costs,and converges more quickly than centralized optimization algorithms.

Research on Dynamic Carbon Emission Accounting Technology of Residential Community Based on Energy Consumption Traceability

WU Heng, YIN Li, HUANG Li, FU Meng

2022, 0(3):  10-14.  doi:10.16628/j.cnki.2095-8188.2022.03.002

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With the advancement of the “dual carbon” goal,the residential communities in the future will be a complexes of optical storage and charging.The application of carbon emission reduction and carbon trading with scattered resources will be a general trend.However,there is the lack of scientific carbon emission measurement methods on the community side at present. Therefore,a dynamic carbon emission factor calculation method is proposed,which considers the local consumption of clean energy and the proportion of power grid energy output.Further the potential carbon emission reduction modes in residential communities are explored,considering the interaction effects of different low-carbon behaviors.By tracing energy consumption,a calculation model of carbon emission reduction is proposed.The feasibility of the proposed method is verified by the application analysis of a typical residential area.

Analysis on Charging Safety Fault Characteristics of Electric Vehicle Charging Facilities Based on Data Mining

XU Xiao, GAO Xiang, LI Guangxi, XU Weihe

2022, 0(3):  15-22.  doi:10.16628/j.cnki.2095-8188.2022.03.003

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Aiming at the problem of high failure rate of charging pile,taking DC charging facilities as the research object,the working principle and influencing factors of operation safety are analyzed. Based on the principal component analysis (PCA) algorithm of data mining,the characteristics of charging facilities operation data such as voltage,current and temperature are mined.The integrated fault tree of charging facilities is established,whose top events are instrument failure,mechanical failure and communication fault.And the internal relationship between fault sources of each layer and specific fault types are analyzed.Using the operation data of charging facilities in Jiangsu Province from March to April 2021,the practicability of the proposed data mining method for the analysis of fault characteristics of charging facilities is verified.

Improving Method of Non-Intrusive Load Forecasting Sample Imbalance Based on Improved Generative Confrontation Network

QIU Xin, YIN Shihong, ZHANG Zhihan, XIE Zhiwei, JIANG Minfeng, GUO Xinglin, YANG Jianming, ZHENG Jianyong

2022, 0(3):  23-29.  doi:10.16628/j.cnki.2095-8188.2022.03.004

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When the neural network is used to identify and train the load,because the number of original samples of uncommon load is small and the number of common load samples is large,the distribution of training samples is unbalanced.Using the traditional generative adversarial networks (GAN) and the auxiliary classifier GAN (ACGAN),the original model is prone to the problems such as gradient disappearance when the sample is expanded and trained.Based on the original ACGAN model,the gradient penalty function is added to the loss function for distinguishing true and false,so that the gradient of the discriminator and generator will fall faster during the mutual optimization process,and it is easier to achieve Nash equilibrium.The imbalance of the original sample has been effectively improved.Through the test and analysis of the public data set PLAID,the effectiveness of the proposed method is verified.

Improved Transmission Line Method for Parallel Finite Element Calculation in Temperature Field of Electrical Apparatus

QIU Zilan, YANG Wenying, PENG Fei, ZHAI Guofu

2022, 0(3):  30-38.  doi:10.16628/j.cnki.2095-8188.2022.03.005

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Higher solution accuracy and solution efficiency of the temperature field simulation are required,to satisfy the optimization design and the development of multi-physical field coupling simulation of high-power electrical apparatus.The transmission line iteration method (TLM) is used to accelerate the finite element analysis of three-dimensional nonlinear heat conduction problem.In order to further improve the efficiency of TLM,the transmission line admittance determination principle and relaxation iteration method are proposed.The parallel computing technology is used to realize the acceleration of TLM.The improved TLM is applied to solve the temperature field of the direct-acting relay,and the accuracy of the algorithm is verified by comparing the solution results with commercial software COMSOL and Newton-Raphson iteration.Compared with the traditional Newton-Raphson iteration,TLM can achieve a stable solution efficiency improvement.

Short Term Prediction of Wind Power Based on Nuclear Improvement to Reduce Particles of Learning Machines

TIAN Yanfeng, WANG Shun, WANG Zhe, LIU Yang, XING Zuoxia

2022, 0(3):  39-44.  doi:10.16628/j.cnki.2095-8188.2022.03.006

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Randomness of wind speed and wind direction leads to large fluctuations in wind fleet capacity.Accurate forecasting of wind energy can provide an important basis for improving the power grid performance,enhancing the power grid's ability to receive wind power and timely arranging the maintenance plan of wind farm.This document provides the particle Legion optimization kernel restricted learning machine (PSO-KELM) algorithm.Preprocess SCADA data of wind turbine generator,supplement and correct abnormal data;Aiming at the multicollinearity problem of extreme learning machine,A foreign learning machine is proposed on the basis of nuclear operation to prevent accidents from driving out a foreign learning machine.The optimization algorithm of particle emissions (PSO) is used to optimize the penile factor and the radiation parameters of the KELM nucleus and generate an external learning model based on optimization of particle emissions.Go on.Compared to other ways like BPNN and RBFNN,this model is confirmed by real wind farm data.

Electrical Design & Discussion

Modeling and Compensation Parameters Design of Isolated Half Bridge Circuit

JIN Ningde, WANG Haixin, HUANG Haihong

2022, 0(3):  45-50.  doi:10.16628/j.cnki.2095-8188.2022.03.007

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Firstly,the energy conservation theory is used to idealize the isolated half bridge circuit.Then the AC small signal mathematical model of the isolated half bridge circuit is established according to the average model method of switching network,and the open-loop transfer function of the system is obtained.On the basis,the amplitude frequency and phase frequency characteristics of the mathematical model are analyzed,and the corresponding closed-loop parameter compensation and system correction are carried out.The simulation and experimental results further verify the validity of the theoretical modeling and the rationality of the compensation parameters.

Modeling and Loop Design of Double Closed-Loop Synchronous Rectifier Circuit Under Digital Control

ZHENG Kun, SONG Chao, LIU Song

2022, 0(3):  51-55.  doi:10.16628/j.cnki.2095-8188.2022.03.008

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Firstly,aiming at the full-bridge synchronous rectifier circuit its voltage and current double closed-loop model under digital control is established.Then,the product of sampling switch,zero order holder and digital duty cycle update link in the digital control system are equivalently approximated by the mathematical method,and the transfer function of the internal and external loop of the system is obtained.According to the established model and combined with an example,using bode diagram and control theory,the design idea and method of the inner and outer loop of full-bridge synchronous rectifier circuit under the digital control are established:the inner loop current controller adopts the form of two complex zeros plus one zero pole plus one high frequency pole,the outer loop voltage controller adopts the form of one zero pole plus one high frequency pole plus one zero.Finally,the correctness of the design idea is verified by experiments.

Design of Three-Phase Electric Quantity Sampling Device Based on dsPIC30F Series Chip and Quasi-Synchronous Sampling Algorithm

ZHAO Yu, YANG Xi, CHEN Hao, WANG Ran, WANG Qiuyin, YANG Tingna, YAN Shuncai

2022, 0(3):  56-62.  doi:10.16628/j.cnki.2095-8188.2022.03.009

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A new three-phase electric quantity acquisition device is designed,which can realize the high-precision sampling of electric quantity parameters such as voltage,current and harmonic.The CPU of device adopts dsPIC30F6014A series single chip microcomputer with high-performance DSP operation core.The AC electrical parameters sampling and measurement method based on quasi-synchronous sampling principle is used.In the process of data sampling,it is not necessary to keep strict synchronized with the power grid frequency.Through the verification of the electric quantity acquisition device,the purpose and the effect of simple structure and reliable operation are realized on the premise of ensuring the sampling accuracy of the device.

Optimization Design of DC Electromagnetic Relay Based on Orthogonal Experiment

ZHU Yiqing

2022, 0(3):  63-71.  doi:10.16628/j.cnki.2095-8188.2022.03.010

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In order to improve the product performance and optimize the product design of relay,the influence of relay structural parameters on dynamic characteristics are studied,and the relay optimization parameters by orthogonal test method are detemined.Firstly,the consistency between the relay dynamic characteristic simulation model and the physical prototype is verified,and the influence of different structural parameters of the relay on the dynamic characteristics is explored with the help of the simulation model.Taking the contact gap,the initial angle of armature and the length of working air gap as adjustment parameters,and the contact pressure and the stable closing time of magnetic circuit as evaluation indexes,the orthogonal experimental design of three factors and four levels is carried out.By analyzing the test results,the influence of three factors on the evaluation indexes is obtained.Finally,based on the test data,the optimal parameter combination is selected,and the optimization scheme is proposed,which improves the product design efficiency and provides a reference for the prototype manufacturing.

Detection & Experiment

Function Analysis of Oscillation Circuit Regulation in Low Voltage Electric Apparatus Breaking Test

CHEN Xi, YUAN Zhiliang

2022, 0(3):  72-76.  doi:10.16628/j.cnki.2095-8188.2022.03.011

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The function of oscillation circuit regulation in the low-voltage electric apparatus breaking test is expounded.The requirements of relevant standards for these parameters and the connection method of adjustment circuit are listed.Through the analysis of the test results under the different oscillation regulation combinations,it shows that the oscillation frequency regulation can be used to avoid the reignition phenomenon of the product in the test,and the oscillation coefficient regulation can be used to limit the maximum arcing voltage.The method of regulating oscillation circuit is provided for relevant technicians.

Application and Analysis of EV Charging Spot Testing Technology

SONG Mengqiong, Kang Yiqun

2022, 0(3):  77-80.  doi:10.16628/j.cnki.2095-8188.2022.03.012

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With fast development of EV industry and charging technology,the performance and safety of charging equipments are widely followed.Detection test is important method to the equipment performance evaluation and analysis faults.The automatic and intelligent testing technology of the charging piles is improving and applied.Aiming at the abnormal state its phenomenon and causes are analyzed,which can provide reference for the related works.

Research on Fast Temperature Rise Test Method of Switchgear

DAI Jianzhuo, JIA Yongyong, ZHANG Sicong, ZHAO Heng, SONG Siqi, CHU Zhaojie

2022, 0(3):  81-85.  doi:10.16628/j.cnki.2095-8188.2022.03.013

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Aiming at the low efficiency of the current temperature rise test methods for switchgear,the fast temperature rise test method is proposed through analyzing the relationship between the current amplitude and frequency and the temperature rise of the switchgear.Firstly,the rapid temperature rise limit of the corresponding switchgear is obtained through the statistical analysis of the historical test samples.Secondly,the test currents whose amplitude and frequency are over the rated value are imposed to the switchgear until the temperature rise reach the limited value.Lastly,the test current is restored to the rated value until the temperature rise reaches the stable value.The test results show that increasing current amplitude and frequency simultaneously can reduce the temperature rise test time of switchgear by 21.31%.The proposed fast temperature rise test method can reliably improve the temperature rise test efficiency of switchgear.

Study on Pulse Burst Test Intensity of Charging Port of New Energy Vehicle

CHEN Huo

2022, 0(3):  86-89.  doi:10.16628/j.cnki.2095-8188.2022.03.014

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The fast pulse group interference is injected into the input end of the DC charging pile,and the coupling waveform is collected at the output end of the DC charging pile.The coupling status of the vehicle DC charging port is obtained,so as to the pulse group test strength of the DC charging port of the new energy vehicles is explored.It can provide references for development and research of vehicle charging standardization.

Application

Application of Three-Level SVPWM Without Large Vectors in Direct Torque Control System

TAN Fenglei, GAO Shiyu, GONG Chenlong

2022, 0(3):  90-95.  doi:10.16628/j.cnki.2095-8188.2022.03.015

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A method of three-level SVPWM without large vectors is proposed,which is able to reduce vectors and vector regions and simplify algorithm by using the remaining 3 zero vectors,12 small vectors and 6 medium vectors to re-divide the vector space into 18 effective regions with 6 large vectors eliminated.On the basis of studying the traditional three-level SVPWM diagram deeply,this method is obtained with reminding vectors for dividing sectors and arranging switch sequence with large vectors eliminated.It is applied in direct torque control system for simulation analysis,which verifies its feasibility and validity.