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关键词： Height differences   IGBT cooling   Loop thermosyphon   Start-up characteristics   Vertically placed flat evaporator  

摘要： This study presents a comprehensive experimental investigation into the thermal-hydraulic performance and flow dynamics of a loop thermosyphon system incorporating a vertically oriented flat evaporator designed for insulated gate bipolar transistor (IGBT) module cooling. The effects of critical operational parameters, namely liquid filling ratio (31 %–92 %), heat load (100–900 W), and height difference between evaporator and condenser (0 cm, 20 cm, 40 cm, and 60 cm), on heat transfer characteristics, temperature uniformity, and start-up behavior were systematically examined. Results reveal that increasing the height difference enhances the gravitational driving force, thereby expanding the operational heat load range and reducing the average evaporator temperature;however, it concurrently exacerbates temperature non-uniformity due to complex two-phase flow instabilities. Notably, an optimal filling ratio near 73 % was identified at zero height difference, where the system exhibits heightened sensitivity to filling variations and limited natural circulation capability. Detailed pressure measurements elucidate the interplay between liquid column height and flow resistance, highlighting a saturation phenomenon in driving pressure at elevated heat loads. The study further uncovers transient gas blockage during start-up, manifesting as short-lived dry-up and temperature oscillations, which detrimentally affect system stability. These phenomena are attributed to the coupled effects of liquid film dynamics, bubble behavior, and gravitational forces within the confined geometry of the flat evaporator. The findings provide critical insights into the underlying physical mechanisms governing loop thermosyphon operation with flat evaporators and offer practical guidelines for optimizing design parameters to achieve enhanced thermal management of high-power electronic devices. © 2025 Elsevier Masson SAS

关键词： Condition monitoring  

摘要： A new method for multi-parameter detection of bond wire lift-off, emitter current, and junction temperature using gate voltage waveforms and a convolutional neural network is proposed for the condition monitoring of power modules. This method was demonstrated to classify 80 levels for the full combination of various parameters. In addition, digital gate control (DGC) was utilized to improve not only the switching characteristics but also the detection accuracy. The experimental results show that the sensitivity of the gate voltage waveforms changed significantly due to the influence of the combined parameters. The detection accuracy depends on the control conditions of DGC, and optimized conditions achieved a high accuracy of over 96%, even for multi-parameter detection. © 2025 The Author(s)

关键词： 电气节能   环保机械   变频器   伺服驱动   智能控制  

摘要： 在环保行业中,机械装备的电气能耗占据相当大的比重,电气节能技术的研究与应用显得尤为重要。本文分析环保机械装备的分类与特点,总结当前电气节能技术的应用现状和面临的挑战。从电气节能的基本原理出发,探讨主要的电气节能技术及其在环保机械中的应用。详细介绍变频器技术、伺服驱动系统和智能控制系统的节能效益,并提出电气节能技术的优化设计思路,以期为环保行业的电气节能技术提供参考。

关键词： Loop thermosyphon   IGBT   High-speed train   Mini-channel   Integrated multi-heat sources  

摘要： To solve the thermal management challenges of IGBT components in high-speed train traction converters, a loop thermosyphon system using SF-33 as the working fluid was designed. The condenser was installed on the train roof and cooled by running airflow, which reduced the power consumption of condensation-section cooling fans and improved energy efficiency. This study investigated the startup and operational characteristics of the system under varying filling ratios, heating powers, and cooling airflow rates. Experimental results indicated that the minimum startup power was 100 W. The system satisfied the cooling requirements for train IGBT modules at filling ratios of 32 %-50 %, with optimal thermal performance achieved at a 50 % filling ratio. Within this range, the maximum temperature fluctuation of IGBT-simulated heating blocks during stable operation was 2.3 degrees C, while the minimum temperature difference between heating blocks reached 8.5 degrees C. The system exhibited a minimum thermal resistance of 0.0099 degrees C/W. Under high heating power conditions (1800 W to 2100 W), prolonged operation maintained the highest average temperature of heating blocks below 75 degrees C, complying with IGBT thermal specifications while effectively dissipating a heat flux density of up to 20.13 kW/m2. Additionally, the system demonstrated minimal sensitivity to cooling airflow rate variations. This experimental system provides a novel approach and theoretical foundation for cooling IGBT components in high-speed train traction converters.

关键词： DC microgrid   IGBT reliability   Junction temperature   Droop control   Consensus algorithm   Power supply reliability  

摘要： Due to differences in the heating characteristics of IGBTs in parallel DC/DC converter circuits and line resistance, varying thermal stresses cause IGBTs with higher stress to fail earlier, reducing the overall power supply reliability. In this regard, this paper proposes the coordinated control strategy of the islanded DC microgrid oriented by IGBT operation reliability balance. By adding the temperature equalization term in traditional droop control, the junction temperature of the IGBT in each parallel DC/DC converter tends to be consistent. Moreover, the IGBT reliability balance control of the islanded DC microgrid based on consensus algorithm is proposed, considering the high communication pressure under centralized control. The effectiveness of the proposed strategy was verified by jointly building the simulation model using MATLAB/Simulink and PLECS/Blockset. Finally, the IGBT lifetime damage is analyzed before and after adopting the proposed control strategy. The specific data shows that the maximum IGBT lifetime damage of traditional droop control is 0.2973, and the average IGBT lifetime damage is 0.1071. In contrast, the IGBT lifetime damage of the proposed control strategy is reduced to 0.0201, with the maximum lifetime damage and average lifetime damage reduced by approximately 93.2 % and 81.2 %.

关键词： 半自磨机   传动系统   主电机   传动形式   变频器  

摘要： 随着全球对矿产资源需求的持续增长,半自磨机在矿山磨矿作业中的应用愈发广泛。本文重点讨论了半自磨机传动系统的种类以及该如何进行合理的选择。传动系统分为有齿传动(含同步电机传动和异步电机传动,可再细分单、双侧齿轮传动)和无齿轮传动(环形电机无齿传动)两类。选择传动系统时,主电机、传动形式、变频器等是关键考量因素。此外,双向旋转能力、电力供应稳定性等因素也会影响传动系统的选择。选择最佳的传动系统配置需综合考虑生产需求、矿石性质、供电系统等多方面因素,并由工艺、电气和机械专家协同决策。

关键词： 变频器   工业电机   调速控制   节能应用   优化策略  

摘要： 随着工业自动化水平提升,工业电机应用广泛,传统电机控制方式存在能源浪费问题。变频器作为实现电机调速的电力电子设备,在工业电机调速控制中应用广泛。本文探讨变频器在工业电机调速控制中的节能原理与实际应用,提出合理选择容量、优化参数设置、多台协调控制及定期维护保养等优化策略,以提高工业企业能源利用效率,降低生产成本,促进可持续发展。

关键词： Conformable分数阶导数   分数阶发展包含   紧算子半群   最优控制   不动点定理  

摘要： 用Bohnenblust-Karlin不动点定理得到了Conformable分数阶发展包含mild解的存在性,并利用两次构造极小化序列的方法分别讨论了最优状态控制对和最优时间控制对的存在性.通过一个具体例子验证了结论的有效性.

关键词： Effective thermal cycle   Accurate damage and fatigue life prediction   Fatigue life of IGBT power module   Critical damage parameters   Solder fatigue life models  

摘要： Insulated gate bipolar transistor (IGBT) power module is vital to efficient functioning of several critical systems in electric vehicle (EV), photovoltaic (PV) module, and more/all electric aircrafts (MEA/AEA). As reliability qualification of IGBT immensely depends on system's modelling which employs thermal cycling, identification of effective number of accelerated thermal cycles (ATCs) is important to ensure accurate reliability prediction. This investigation advises on the effective number of ATCs for modelling damage and fatigue life of 96.5 % tin, 3 % silver, and 0.5 % copper (SAC305) solder joints in IGBT module. SolidWorks software is used to create four realistic 3-D finite element (FE) models of typical IGBT module. The IEC 60068-2-14 thermal cycle test and Anand's time independent visco-plastic constitutive model are implemented in static structural package in ANSYS mechanical software to simulate the response of the models to 6 ATCs, 12 ATCs, 18 ATCs and 24 ATCs. Thirty ATCs produced magnitudes of von-Mises stress, equivalent plastic strain and accumulated strain energy density which are almost invariant with application of greater number of ATC. Deployment of four fatigue life constitutive equations from Morrow, Coffin-Manson, and Syed generated polynomial model which produced minimum and consistent lives of the IGBT modules at about 30 ATCs. Based on this finding, 30 ATCs are proposed as the effective number. The generated models establish the relationship between the number of ATCs and fatigue life predicted for IGBT module. It is proposed to be used to evaluate the effect of number of ATCs employed and the resultant predicted fatigue life of IGBT module.

关键词： IGBT power module   operating ambient conditions   solder joint degradation   power electronics   lead-free SAC305 solder  

摘要： Insulated gate bipolar transistor (IGBT) power modules experience power and thermal cycles in field operation which significantly degrade their solder joints, leading to reduced designed life. This investigation evaluates mechanical reliability of an IGBT power module in four key applications to provide new knowledge on the impact of ambient temperatures on the degradation of its solder joints and fatigue life. SolidWorks software is used to create eight 3-D computer-aided design (CAD) models of a typical IGBT module. Power load, induced by field operation, and IEC 60068-2-14 accelerated thermal cycle (ATC) specific to aeronautics, automotive passenger compartment, automotive under-the-hood and railway applications are used as loads. The loads and Anand's visco-plastic model are implemented in the static structural solver within the Ansys mechanical package to simulate the degradation of 96.5% tin, 3.0% silver, and 0.5% copper (SAC305) solder joints in the modules. Aeronautic ambient temperature degrades solder joints in an IGBT power module the most, while railway ambient temperature degrades it the least. Consequently, the module has the shortest average fatigue life of 7.5 years and longest average life of 16.2 years in operations in aeronautic and railway ambient temperatures, respectively. In comparison with operation in the aeronautic condition, the module operates 36.0% and 85.3% longer life in auto under-the-hood and auto passenger ambient temperatures, respectively. Implementation of obtained laboratory test cycles in predicting the field fatigue lives of the modules in years is presented. Stress damage is found to concentrate at the periphery of solder joints which is the area to strengthen to improve device reliability. This study provides new knowledge on the deployment of an IGBT power module in four critical applications.