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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： 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： SiC-based IGBT   Thermal cycling   Solder fatigue   Finite element analysis   Taguchi optimization   Reliability enhancement  

摘要： The thermal-mechanical reliability of SiC-based hybrid IGBT modules is crucial for ensuring the long-term stability of high-power electronic systems, particularly under cyclic thermal stress. While prior research has extensively investigated traditional solder materials and individual reliability factors, these studies often lack comprehensive optimization strategies. To address this gap, the present study systematically enhances module reliability by combining finite element analysis (FEA) with the Taguchi optimization method. The focus is on enhancing the durability of solder interconnects under severe thermal cycling conditions, ranging from -40 degrees C to 125 degrees C. This work is novel in integrating nano-silver solder evaluation and optimization of Direct Bonded Copper (DBC) liner materials within a structured optimization framework, which significantly differentiates from previous studies. The results indicate that von Mises stresses are concentrated at the chip solder edges, reaching up to 157 MPa, which exceeds the yield strength and accelerates fatigue. The fatigue life predictions based on Engelmaier's modified Coffin-Manson model show that nano-silver solder extends the module's lifespan by approximately 90 % compared to conventional SAC305 solder. Additionally, the optimization results suggest that Si3N4 liners effectively reduce peak stress. These insights provide guidelines for designing highly durable SiCbased IGBT modules applicable to electric vehicles, renewable energy systems, and high-power converters.

关键词： IGBT   Stress performance   Multiphysics coupling model   Thermal-mechanical-electromagnetic   Interaction mechanisms  

摘要： The press-pack Insulated Gate Bipolar Transistor (IGBT) is a critical power device in high-power electronic equipment and widely employed in flexible direct current (DC) transmission systems. Electrothermal stress fatigue are the leading cause of IGBT failures in engineering applications. However, previous studies mainly focused on the stress analysis from individual mechanical field in IGBT, thus the coupling effects of thermalmechanical-electromagnetic multiphysics fields on stress analysis are ignored, moreover, the thermal effect includes not only Joule heating but also electromagnetic losses, which lead to the interaction mechanisms on stress from various fields are currently unclear. In this paper, a novelty model of the IGBT considering mechanical field, thermal field, and electromagnetic field is proposed to comprehensively understand their inherent interaction mechanisms. Detailly, the paper explores the interaction mechanisms between fields by gradually coupling different fields. As a results, compared to the single mechanical field model, after thermal field is coupled into the mechanical field, the maximum stress steep rise to 26.2 MPa from 12.8 MPa. The electromagnetic field is further coupled into the mechanical-thermal fields, and the maximum temperature is increased by 6.2 %, which further leads to a 12.9 % increase in the maximum stress of mechanical field. The multiphysics coupling model has significantly narrowed the gap with the experimental results, the deviation in maximum stress has been reduced from 55.33 % in individual mechanical field to 2 % in Thermal-Mechanical-Electromagnetic multiphysics fields. The results indicate that the sequential coupling of thermal and electromagnetic fields significantly enhances the accuracy of stress analysis of IGBT.

关键词： Insulated gate bipolar transistors (IGBT)  

摘要： This paper proposes a novel Floating Dummy IGBT (FD-IGBT) featuring integrated N- and P-type Schottky Barrier Diodes (SBDs) and investigates its performance through simulation. During the turn-on transient, hole accumulation in the floating P-base region elevates its quasi-Fermi potential, triggering the turn-on of the two series-connected SBDs and thereby clamping the voltage of the floating P-base region. This mechanism effectively reduces the Miller capacitance and significantly suppresses the reverse gate charging current from the floating P-base region to the gate. This reduces turn-on energy loss (EON) and improves dICE/dt controllability. Under short-circuit conditions, the SBDs adaptively turn on, enhancing short-circuit tolerance time (TSC). During turn-off state, the SBDs accelerate hole extraction, reducing turn-off time and energy loss (EOFF). TCAD simulations show that, at the same EON + EOFF (43.8 mJ/cm2), the proposed FD-IGBT reduces dICE/dt by 88.2 % compared to conventional IGBTs. At the same dICE/dt (2.1 kA/μs), it reduces EON + EOFF by 53.4 %. Furthermore, the short-circuit withstand time (TSC) of the proposed device is improved by 169 % compared to conventional IGBTs. © 2025

关键词： TSEP   Temperature distribution   Emitter pad design   Repetitive switching   Internal gate resistance   Artificial front-side aging  

摘要： This work offers a comprehensive study on temperature determination and development of IGBTs via temperature-sensitive parameters (TSEPs) during repetitive switching events. The obtained information is discussed and judged with respect to accuracy for different device technologies. This evaluation is extended by the aspect of artificial front-side aging for different emitter-pad designs. For two different designs investigated, no decreased switching robustness could be verified, even beyond the AQG 324 [1] lifetime border, which is defined by a certain forward voltage drop increase.

关键词： Junction temperature prediction   insulated gate bipolar transistor   PLCES   improved dwarf mongoose optimisation algorithm   extreme learning machine  

摘要： This study has made significant advancements in predicting junction temperature of IGBTs in wind power converters. An improved dwarf mongoose optimisation algorithm (IDMOA) with superior performance was developed. The IDMOA improves the initial solution quality through Hammersley initialisation, balances global search and local optimisation with nonlinear dynamic decreasing weight factors, and enhances population diversity via differential evolution strategy to avoid local optima. The IDMOA optimizes random parameters of extreme learning machine (ELM), overcoming the limitations of traditional manual parameter setting and constructing a high-precision IDMOA optimised ELM (IDMOA-ELM) model. Simulation results indicate that the IDMOA-ELM excels in predicting the IGBT junction temperature, achieving a low RMSE value of 0.1034 degree celsius. This significantly surpasses existing technologies and provides robust support for temperature management in wind power converters. Furthermore, to verify the performance of the DMOA-ELM in practical application scenarios, IGBT accelerated ageing experiments were conducted, yielding a comprehensive validation dataset. The high accuracy and effectiveness of the IDMOA-ELM were confirmed through comparative analysis with experimental data, enhancing the credibility of the research. This study achieved non-destructive and high-precision prediction of IGBT junction temperature in wind power converters and significantly improving the reliability of wind power converters.

关键词： 矢量控制   直接转矩控制   变频器  

摘要： 目前矢量控制与直接转矩控制是高性能永磁同步电机转矩控制的两大主流策略,在实际生产中也得到了广泛的应用推广。本研究对两种控制进行了比较分析,通过比较分析得到稳态条件下的转矩和电流脉动情况,动态条件下的负载突变和转速突变的转速、电流和转矩变化情况,并对两种控制策略的结构进行了比较验证,从结果可以看出,矢量控制和直接转矩控制都有很好的动态性能,但是直接转矩控制不易受参数变化的影响,动态性能较矢量控制好。

关键词： 目标收益养老金计划   通胀风险   保费返还条款   Cobb-Douglas效用函数  

摘要： 研究了通胀风险下目标收益养老金计划的最优控制策略。为了保障在累积阶段死亡的养老金成员的权益,在计划中引入保费返还条款。养老基金管理者可以将资金投资于无风险资产,通胀指数债券和股票组成的金融市场。以收益给付和养老基金终端财富的预期效用最大为优化目标,求解最优投资策略和收益给付策略,其中效用函数采用Cobb-Douglas效用函数。运用动态规划方法,通过求解相应的Hamilton-Jacobi-Bellman(HJB)方程,得到了最优策略以及值函数的显式表达式。最后,通过数值分析讨论了重要参数对最优收益给付和养老基金财富的影响。