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关键词： Insulated gate bipolar transistors   Resistance   Salt   Temperature measurement   Leakage currents   Humidity   Semiconductor device measurement   Circuit faults   Current measurement   Stress  

摘要： Currently, insulated-gate bipolar transistor (IGBT) modules are developing rapidly and have been used to operate in many different environments. However, when IGBT modules are used in marine environments, there is high humidity and salt spray in the environment. These environmental causes will result in the formation of conductive paths between the different interfaces (internal and external) of the IGBT module. Under the influence of high humidity and salt spray in the marine environment, the conductive path greatly reduces the blocking capability of the IGBT module and severely disrupts the IGBT module’s stable operation. To address this issue, this article simulates marine environment experiments on IGBT modules by salt spray and high voltage, high humidity, high temperature, and reverse bias (HV-H3TRB) experiments. It turns out that after treatment in the marine environment, conductive channels are formed both inside and outside the IGBT module. This is equivalent to connecting a resistance in parallel outside the IGBT module. It makes blocking capacity decrease significantly. Therefore, this article establishes a nonlinear relationship between the blocking resistance and voltage of the IGBT module. It can measure the faulty resistance of the conductive paths of the IGBT modules. In practice, the blocking capability can be determined by measuring the leakage current of the IGBT modules through the relationship between the faulty resistance and the leakage current of the device. This can provide an important reference for the stable operation of IGBT modules in marine environments.

关键词： 中压变频器   石油化工管道   高压风机   同异步切换   软起技术  

摘要： 新型中压变频器在石油化工管道高压风机大容量负载场景下的应用,特别是同异步切换软起技术,代表了现代电力传动领域的一项重要技术创新。本文针对石油化工管道高压风机系统中大容量负载的特殊要求,探讨了一种新型中压变频器在实现软启动过程中的同异步切换技术。随着石油化工工业自动化程度的提升和能源效率要求的日益严格,管道高压风机作为关键设备之一,在确保系统稳定运行的同时,其启动方式对整个系统的能耗和可靠性具有重要影响。传统的硬启动方式已难以满足现代工业对设备保护和能效管理的需求。

关键词： Loop thermosyphon   Vertical flat plate evaporator   Filling ratio   Heat load   Instability  

摘要： As a key component of new energy conversion systems and high voltage power supply switching devices, effective heat dissipation will greatly improve its service life and operational stability. Loop thermosyphon is an efficient two-phase heat transfer device. It has no internal moving parts, consumes no external energy, and can transfer heat over long distances. These advantages enable it to solve the IGBT heat dissipation problem. However, the research on the application of loop thermosyphon to vertical working IGBTs, which requires the arrangement of vertical flat evaporators and high-temperature uniformity, is not sufficient. In this paper, a loop thermosyphon with a vertical flat evaporator is designed and tested. Thus, various important influencing factors, such as filling ratios (31 %-87 %), heat loads (100 W-900 W), and cooling water temperatures (10 degrees C-40 degrees C), on the heat transfer capacity of the loop thermosyphon and temperature uniformity of the evaporator were studied. The experimental results show that the optimal filling ratio is 52 %, which is the result of combining the maximum temperature and temperature uniformity of the evaporator substrate. When Q = 500 w, the maximum temperature (Te1 = 52 degrees C) remains unchanged between 37 % and 52 %. Increasing the filling ratio can improve the temperature uniformity. At the same time, when Q = 600 W, the top of the evaporator appears to have a dry- up phenomenon, which is the main reason for the deterioration of temperature uniformity. Increasing the filling ratio or decreasing the heat load can effectively solve this problem. Meanwhile, through the internal pressure and mass flow rate changes of the system, the variation law of mass flow rate under different experimental conditions is summarized. In addition, the instability of loop thermosyphon under different heat loads and different cooling water temperatures is analyzed.

关键词： 小波分析   高压变频器   功率单元   故障检测分析  

摘要： 在现代工业中,高压变频器作为重要的电力调节设备,广泛应用于各种生产过程。然而,随着使用频率的提升,变频器的故障率也显著上升,因此,开发有效的故障检测技术、及时发现并处理潜在故障,已成为行业内亟待解决的问题。小波分析技术以其在信号处理中的独特优势,能有效提取电压信号的瞬时特性与频率成分,为故障识别提供了新的思路。本研究以小波分析为基础,通过分析高压变频器功率单元的电压信号,提出了一种基于小波包分解、信号特征熵、包络提取及支持向量机诊断模型相结合的故障检测方法,以提高故障诊断的精度和实时性,保障高压变频器的安全可靠运行。

关键词： 带式输送机   上仓皮带   改造   逐点张力计算方法   轴功率   智能永磁直驱电机   变频器   水冷箱  

摘要： 阐述智能永磁直驱系统取消了减速器、机械软启动装置、高速联轴器等中间传动环节,是机械传动行业的一次技术革命,对原矿仓皮带机智能永磁直驱电机进行改造,将仓上原电机、减速器和液粘软起动装置取消,驱动胶带从原地面油库位置下引,驱动滚筒移至原地面油库位置,驱动装置安装在地面,配套水冷箱用软管连接,放置于智能永磁直驱电机附近,智能控制系统及主体变频器安装于电控室。鉴于带式输送机为恒转矩负载,根据胶带实际缠绕方式,采用逐点张力及算法计算出带式输送机所需轴功率,同时根据现场所需减量确保单机运行原则,采用合理备用系数,保证设备单机故障时能保证生产正常运行,另外根据负载变化可以实现台阶速度稳定运行,从而达到进一步节能运行的目的。

关键词： 火电机组   低压辅机变频器   超级电容阵列   低电压穿越  

摘要： 探究了火电机组低压辅机变频器低电压穿越方案的设计要点。目前常用的串联UPS和直流母线处并联升压电路等低电压穿越技术,存在能量损失严重、系统故障率高、器件之间存在通信冲突等问题。因此提出了一种基于超级电容和双向DC-DC变换器的低电压穿越方案,超级电容阵列串联数54个,并联数10个;采用非隔离型双向DC-DC变换器,由Boost升压电路和Buck降压电路反并联而成,储能电感0.4 mH,滤波电容400 uF,在满足低电压穿越要求的基础上,表现出可靠性高、通信效果好等优点。

关键词： 车载充电机   CLLC谐振变换器   软启动   变频控制   移相控制  

摘要： 目的解决两级式车载充电机后级CLLC谐振变换器输出滤波电容在启动时使电路中产生较大冲击电流的问题.方法对传统的降频软启动和移相软启动控制策略在消除启动过程产生的冲击电流的不足进行分析,研究变换器在变频控制下的增益特性曲线,以及移相控制输出电压和有效占空比的非线性关系,提出一种先移相后降频的改进软启动策略.结果仿真结果表明,改进的软启动策略消除了降频软启动策略启动瞬间存在的电流尖峰,抑制了移相软启动策略启动过程中存在的电流过冲.结论改进的软启动策略结合了两种传统软启动策略的优点,能更好地消除启动过程中产生的冲击电流,启动效果更佳.

关键词： 1D-CNN   error optimization   modular multilevel converter (MMC)   open-circuit fault  

摘要： Because of sampling errors and circuit parameter inaccuracies in an actual modular multilevel converter (MMC) model, existing fault diagnosis strategies suffer from poor robustness and difficulty in threshold selection. To solve these problems, this paper proposes a multi-IGBT open circuit fault diagnosis strategy based on capacitor voltage prediction sampling optimization. Here the capacitive voltage, output current and circulating current after segmental error optimization are used as dominant characteristics of fault diagnosis, and a one-dimensional convolutional neural network (1D-CNN) with simple structure and strong adaptability is used as a new fault location scheme to realize high-precision MMC open-circuit fault diagnosis. The proposed method can quickly and accurately locate multi-IGBT faults of the submodule at the initial stage of the capacitor voltage variation without adding additional sensors. Compared with existing diagnosis strategies based on capacitance voltage, this method significantly reduces system parameter errors and enhances the robustness of the fault diagnosis network. Finally, simulations and experiments verify the effectiveness of the proposed fault diagnosis strategy. © 2025 Power System Protection and Control Press. All rights reserved.

关键词： 变频器   电机   谐波   应对措施  

摘要： 变频器与电机距离较远将会产生较大谐波,对系统运行产生影响。本文主要探讨谐波的实际影响与应对措施,根据谐波产生的基本原理,明确不同类型的谐波影响问题,并结合某谐波治理案例进行分析,发现安装电抗器、滤波器可有效抑制谐波,缩短变频器与电机的距离可避免谐波危害系统,由此提出多相脉冲整流改造系统、科学选择电抗器与滤波器、加强谐波控制三项措施,保障系统稳定运行。

关键词： 智能灌溉   电机控制   同步电动机   SVPWM   矢量控制  

摘要： 水泵电机作为农田灌溉系统中的关键设备,其性能好坏直接影响着农田灌溉的质量和效率。为此,针对传动水泵控制方式单一、控制精度差等问题,采用永磁同步电动机,引入SVPWM技术进行矢量控制,完成了基于电机控制的智能灌溉系统设计,并分析了永磁同步电动机结构和工作原理,建立了电动机在三维坐标下的数学模型,通过矢量控制技术实现对电机的转速和转矩的控制。同时,完成了智能灌溉系统的总体方案和硬件电路设计,并通过模拟仿真实验完成对基于电机控制的智能灌溉系统的性能验证。结果表明:系统能够精确控制电机转速、转矩和转矩电流等参数,达到了设计目的。