Table of Content

30 August 2025, Volume 0 Issue 8

Previous Issue    Next Issue

Research & Analysis

Research on Asymmetric Fault Ride-Through Control Strategy of Low Voltage Distribution Areas Flexible Interconnection System

LI Jiawei, MIAO Xiren

2025, 0(8):  1-8.  doi:10.16628/j.cnki.2095-8188.2025.08.001

Asbtract ( 77 )   HTML ( 6)   PDF (2793KB) ( 46 )  

Figures and Tables | References | Related Articles | Metrics

The low voltage distribution areas flexible interconnection system should be equipped with AC fault ride-through capability to ensure the reliable operation of the system under the short-circuit fault of the AC port.Therefore, an asymmetric fault ride-through strategy based on low voltage distribution areas flexible interconnection system is proposed.Firstly, the topological structure and control strategy of low voltage distribution areas flexible interconnection system are introduced.Secondly, the influence of grid-side voltage imbalance on the flexible system is analyzed, and a sequence separation control method is presented.Then, a fault ride-through control strategy considering port current control and system active power balance is proposed.Finally, the effectiveness of the proposed strategy is verified by simulation.

Mechanism Analysis of Low Voltage DC Circuit Breaker Based on Parallel Capacitor

YANG Chenxi, JIA Shenli, HUANG Xiaolong, SHEN Saikang

2025, 0(8):  9-16.  doi:10.16628/j.cnki.2095-8188.2025.08.002

Asbtract ( 51 )   HTML ( 3)   PDF (1693KB) ( 24 )  

Figures and Tables | References | Related Articles | Metrics

Some low voltage DC systems such as low-voltage DC distribution network and photovoltaic power generation system have increasingly high requirements for the breaking performance and economy of low voltage DC circuit breakers.The traditional lowvoltage DC circuit breaker characterized by long arc duration and slow breaking speed can not meet the demand, so it is necessary to develop a new type of low voltage DC circuit breaker.In view of the low voltage DC circuit breaker based on the shunt capacitance current transfer principle, the working principle are analyzed.The mathematical model of the current transfer process is established and the accuracy of the mathematical model is verified by experiments.The transfer current under different shunt capacitance values is explored.The method of improving the breaking ability of the DC circuit breaker by the action of the transverse magnetic field is proposed and verified by experiments.The researched low voltage DC circuit breaker has low cost, simple structure, fast breaking speed and high reliability, which can be an important reseach direction for new type low voltage DC circuit breaker.

Analysis and Research on Electromagnetic Characteristics of Electromagnetic Oscillator for Molten Aluminium Purification

YAO Rui, HAN Zijiao, CAI Zhiyuan, CHANG Yiming

2025, 0(8):  17-24.  doi:10.16628/j.cnki.2095-8188.2025.08.003

Asbtract ( 47 )   HTML ( 2)   PDF (2244KB) ( 13 )  

Figures and Tables | References | Related Articles | Metrics

The blade casting performance is an important factor affecting the reliability of mechanical equipment.The traditional purification and deburring methods often exist solidification organisation coarse and uneven composition and other problems,failing to achieve good deburring and purification effect.To this end,the eddy current induction electromagnetic oscillator is designed.The finite element simulation verification method is used to calculate and analyse the electromagnetic distribution inside the oscillator,and its main influence parameters are explored.The results show that the electromagnetic distribution of the electromagnetic oscillator is in line with the characteristics of eddy current distribution.The designed coil is in line with the relevant technical standards.The pulse power supply voltage,duty cycle and winding connection changes will have an impact on the internal field distribution.The research can provide technical support for the design and optimization of eddy current induction electromagnetic oscillator.

A Waveform Feature Extraction and Recognition Method for Electric Bicycle Charging Load

ZHAO Jie, ZHANG Yanping, DING Yuanyuan

2025, 0(8):  25-33.  doi:10.16628/j.cnki.2095-8188.2025.08.004

Asbtract ( 58 )   HTML ( 6)   PDF (2046KB) ( 53 )  

Figures and Tables | References | Related Articles | Metrics

In order to realize the identification of the electric bicycle charging load on the user side, the load current on the user side is collected in real time through the Internet of Things (IoT) circuit breaker.The disturbance time point of the current curve is quickly identified.The influence of the periodic load is filtered out, and the basic characteristics of the disturbance current curve are extracted to form the absolute value increment curve.According to the formation criteria of the initial transient pulse peak, time limit width of the charging current curve and the pulse peak, time limit width and symmetry of the current waveform at the beginning of steady-state charging, combined with the change of power increment and harmonic increment before and after charging, the charging load of the electric bicycle is identified to alarm or trip the circuit breaker, so as to ensure that the charging load of the electric bicycle is forbidden in the charging area of the non-electric bicycle.Experiments show that the proposed method is simple and effective, and can be implemented locally through the IoT circuit breaker.

Electrical Design & Discussion

Design of a Switching Power Supply with Digital Control and Thick-Film Hybrid Integration

ZOU Yang, SONG Qin, WU Chenglong

2025, 0(8):  34-38.  doi:10.16628/j.cnki.2095-8188.2025.08.005

Asbtract ( 49 )   HTML ( 2)   PDF (2633KB) ( 12 )  

Figures and Tables | References | Related Articles | Metrics

Based on the principle of the digital power controller and the thick-film hybrid integration process,a prototype of a digitally controlled and thick-film hybrid integrated switching power supply with 28 V input and 5 V/40 A output was designed. Principle analysis and parameter design were carried out focusing on the main circuit and the digital control circuit,and simulation was conducted on the digital control loop with input voltage feedforward and output voltage feedback. Subsequent experimental results show that the prototype has excellent steady-state and dynamic characteristics,which can verifie the correctness and feasibility of the design scheme.

Research on Quick Calibration System of Thermal Overload Relay

YU Qiang, LI Xinye, ZHAO Yingying, ZHENG Tianyun, ZHOU Yanhua, WU Sipei

2025, 0(8):  39-44.  doi:10.16628/j.cnki.2095-8188.2025.08.006

Asbtract ( 64 )   HTML ( 3)   PDF (1776KB) ( 20 )  

Figures and Tables | References | Related Articles | Metrics

A quick electrical calibration scheme is proposed to address the low efficiency and consistency of thermal overload relay calibration.The equivalent step ped current method is adopted.The first-step high current enables the bimetal strip to bend quickly.The second-step current tends to stabilize the bend of bimetal strip to eliminate the thermal inertia.When the third-step current ends, the bimetal strip reaches the preset position and maintains for a short while, then the product will be twisted to trip.In addition, corresponding validation and empirical parameters are provided in terms of component consistency, assembly process consistency, and parameters for quick electrical calibration.The proposed scheme can not only significantly improves production efficiency, but also effectively ensurs the consistency of components and processes, guaranteeing the stability of product performance.

Detecting & Experiment

Simulation and Experimental Analysis of Seismic Performance for Medium Voltage Vacuum Circuit Breakers

CHEN Tao, WANG BeiBei

2025, 0(8):  45-51.  doi:10.16628/j.cnki.2095-8188.2025.08.007

Asbtract ( 54 )   HTML ( 2)   PDF (3403KB) ( 25 )  

Figures and Tables | References | Related Articles | Metrics

Earthquakes,as severe natural disasters, pose significant threats to the safe and stable operation of power systems.Circuit breakers, critical components for ensuring continuous and reliable power supply, require thorough investigation of their seismic performance.A medium voltage vacuum circuit breaker is focused on, and its behavior under seismic conditions is evaluated by employing response spectrum analysis, multibody dynamics simulation, and seismic performance testing.The results demonstrate that the circuit breaker exhibits high safety margins in structural strength, operational integrity of components, and contact bounce control, meeting operational requirements during earthquake.

Design for Residual Current Detection in Mode 2 Charging of Electric Vehicles

ZHOU Zhiliang, GUO Chengtong

2025, 0(8):  52-57.  doi:10.16628/j.cnki.2095-8188.2025.08.008

Asbtract ( 46 )   HTML ( 5)   PDF (2549KB) ( 14 )  

Figures and Tables | References | Related Articles | Metrics

In the field of new energy electric vehicle charging piles,residual current detection is an important measure to ensure personal safety and has been implemented as a mandatory standard.At present,residual current detection is realized by means of magnetic ring induction for current signals and single-chip microcomputer processing for acquisition.This method not only requires self-inspection to verify the working status at power-on initialization but also has a long response time,leading to high design costs for the power-off protection actuator.Meanwhile,the single-chip microcomputer processing mode has the risk of system freeze,which easily causes the failure of residual current detection.In view of the above shortcomings,a method for detecting residual current using discrete components is proposed,which eliminates the need for self-inspection,avoids the risk of system freeze,and features a fast response speed.The response time can be reduced to less than 50% of that of existing products,providing sufficient action time for the power-off protection actuator.

Research on Residual Current Detection Method for Dual-Core Magnetic Modulation Based on Kalman Filtering Algorithm

HE Sheng

2025, 0(8):  58-69.  doi:10.16628/j.cnki.2095-8188.2025.08.009

Asbtract ( 47 )   HTML ( 2)   PDF (2946KB) ( 15 )  

Figures and Tables | References | Related Articles | Metrics

Residual current detection is a key technology to ensure the safe operation of low voltage DC distribution systems.Aiming at the traditional single-core magnetic modulation residual current sensor with low precision and poor anti-interference ability,a residual current detection method based on dual-core magnetic modulation is proposed,and the corresponding simulation model is constructed.The modulated signal of the dual-core sensor is filtered and demodulated by the Kalman filtering algorithm,and the simulation results are compared and analyzed with the single-core scheme.The results show that the detection method has the advantages of even harmonic enhancement,detection range expansion and zero drift suppression,which can provide the effective and improved scheme for the detection of tiny residual current signals in high-current scenarios.

Power Quality

Optimization Design and Control of Power Quality for Light-Loaded Server Power Supplies

LI Yongle, ZHANG Shuwei, ZHANG Wenkang, MAO Xingkui

2025, 0(8):  70-78.  doi:10.16628/j.cnki.2095-8188.2025.08.010

Asbtract ( 55 )   HTML ( 3)   PDF (2349KB) ( 38 )  

Figures and Tables | References | Related Articles | Metrics

The issue of degraded power quality in server power supplies under light-load conditions is addressed by proposing a light-load power quality optimization control strategy.By analyzing the traditional control strategies and the characteristics of EMI filter circuits,an X-capacitor current compensation control strategy is proposed to improve the power factor under light-load conditions.A hybrid control strategy combining offset lifting,variable gain,and average current restoration in discontinuous conduction mode (DCM) is adopted to optimize the input current total harmonic distortion (THD) under light-load conditions.A 1 300 W server power supply prototype is developed.The experimentcl results demonstrate that the proposed optimization control strategy significantly improves power quality under light-load conditions,with both power factor and input current THD meeting the specification requirements,which verifies the effectiveness and superiority of the proposed strategy.

Design of a Simple Single Phase Electrical Appliance Monitoring and Analysis Device

RONG Jun, CHEN Song, LI Mingze

2025, 0(8):  79-84.  doi:10.16628/j.cnki.2095-8188.2025.08.011

Asbtract ( 48 )   HTML ( 2)   PDF (1739KB) ( 18 )  

Figures and Tables | References | Related Articles | Metrics

A simple type of electrical appliance category and working status recognition device is designed to address the low testing accuracy of the market electrical appliance analysis and detection devices.The active power calculation and eigenvalue extraction judgment methods based on Fourier analysis are adopted,combined with positioning recognition algorithms, is proposed to identify the type and number of connected electrical appliances.Firstly, the active power and power factor of the electrical appliance are calculated, and then the harmonic power of each order is obtained through Fourier analysis.Finally, by using four parameters including active power as similarity indicators, the template matching algorithm is used to learn and recognize the categories and states of electrical appliances.After testing, the device has a learning function and can accurately identify the status and category of electrical appliances.Its testing accuracy for the types and numbers of electrical appliances reaches 100%, indicating certain application value.