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关键词： Compensation   dead time   distortion   distortion   half bridge model   half bridge model   IGBT   IGBT   interlock time   interlock time   nonlinearity   nonlinearity   nonlinearity  

摘要： Voltage and/or current of multiphase systems are usually controlled using frequency converters (FCs). Typically, these FCs consist of several half bridges and, due to their working principle, their output voltage will depend on the output current nonlinearly. Many well known compensation methods (CMs) rely on the assumption that the current is nearly constant during one switching cycle. However, with decreasing load inductances this assumption may not be fulfilled and therefore these methods may not succeed in achieving full compensation. This contribution provides a CM, which takes the so-called ripple current into account and is therefore especially useful when dealing with small load inductances.

关键词： traditional coolant   thermal performance   nano-fluids   thermal conductivity   consideration  

摘要： The thermal performance of Liquid-cooled plate (LCP) can be improved by using different kinds of materials and coolants. Suitable and effective coolant can bring better cooling capacity to cope with the impact of high temperature on IGBT chips, and improve the safety and service life of new energy metallurgical loaders. In this context, the recent progress of the effects of traditional coolants, nano-fluids, ethylene glycol and oil on the heat transfer capacity of the liquid cooling plate is reviewed in detail. Nanofluids have been identified as the most prominent cooling method at present because of their good thermal conductivity. In addition, the considerations and advantages and disadvantages of using different coolants are discussed in depth.

ISBN: (纸本)9787122455666

关键词： 单相光伏逆变器   升压斩波电路   纯正弦波逆变器   转换效率  

摘要： 设计一种单相光伏逆变器，旨在将光伏板输出的10～20 V低压直流电转换为12 V、2 A的标准正弦交流电。其前级采用升压斩波电路，以UC3842芯片为核心，将输入电压升压至35 V；后级通过EG8025芯片驱动的全桥逆变电路实现直流到交流的转换。系统采用纯正弦波逆变器，结合闭环正弦脉冲调制，确保输出电压为平滑正弦波。实验结果表明，该逆变器输出功率为24 W，转换效率达80%，波形畸变率低于5%，实现了低压直流电向标准正弦交流电的高效转换。该逆变器具有结构简单、成本低、稳定性高等特点，适用于小型新能源汽车及光伏发电场景，能够为清洁能源的高效利用提供可靠解决方案。

关键词： 绝缘栅双极型晶体管   故障检测   自注意力   图神经网络   对比学习  

摘要： 随着近年来电力电子技术高速发展,绝缘栅双极型晶体管(Insulated-Gate Bipolar Transistor,IGBT)驱动的大功率逆变系统广泛用于航空航天、清洁能源、电力变换、武器装备、工业生产等领域。然而,其关键功率元器件在工作过程中易受到过载和环境变化等影响而发生故障。这些故障在早期难以察觉,且存在连锁蔓延的特征,最终导致严重财产损失乃至人员伤亡。因此,IGBT逆变系统的故障检测尤为重要。传统无监督故障检测的特征提取过程,往往存在局部信息提取不充分、空间关联不清晰以及有效挖掘效率低等问题。基于此,本文提出了一种基于无监督图神经网络的IGBT逆变器系统故障检测方法。该方法从时序信息、空间信息和有效信息三个方面出发,设计因果图卷积、时空图卷积以及图对比学习方法,结合自注意力机制和不确定性学习进行故障检测。具体贡献如下: 首先,提出了基于多尺度表征学习的因果图卷积故障检测方法。设计异构多头自注意力机制,结合因果图卷积对数据中的局部与全局时间特征深度挖掘。通过捕捉不同时间尺度下的关键特征,提升故障检测的精度。实验证明,针对IGBT键合引线断裂故障,该模型在仿真实验数据下故障检测率98.55%,比传统方法高出近7%;在逆变系统实验平台数据下故障检测率99.10%,比传统方法高出10%。 其次,提出了基于多变量级联学习的时空图卷积故障检测方法。设计空间融合矩阵进行空间特征提取,使其在时空域内同时进行学习。通过详细的数学推导,分析模型的可检测性(稳定性和有效性)。实验结果表明,针对IGBT逆变系统滤波电感故障,该模型在仿真实验数据下故障检测率99.55%,比前一种方法高出近5%;在逆变系统实验平台数据下故障检测率99.80%,比前一种方法高出近5%。 最后,提出了基于多扰动不确定性的图对比学习故障检测方法。引入贝叶斯建模对不确定性进行建模,减少数据噪声或过拟合造成的误判。在数据增强环节施加多种扰动,利用不确定性模拟复杂工业环境中的信号波动,并通过对比学习损失函数关注高置信度的有效信息。实验结果表明,针对IGBT逆变系统电容退化故障,该模型在仿真实验数据下故障检测率94.45%,比前两种方法至少高出3%;在逆变系统实验平台数据下故障检测率99.70%,比前两种方法至少高出8%。 综上所述,本文所提方法为IGBT逆变系统的故障检测提供了新的技术思路,也为相关领域的研究提供了有价值的参考。

关键词： Inverters   Voltage   Voltage measurement   Capacitance   Logic gates   Equivalent circuits   Motors   Monitoring   Data mining   High-frequency current   insulated gate bipolar transistors (IGBTs)   RC detection circuit   robustness   voltage rise time   voltage rise time  

摘要： This study shows that junction temperature significantly affects the performance of insulated gate bipolar transistors (IGBTs), and the junction temperature of an IGBT can be accurately assessed through its voltage rise time. This parameter is crucial for evaluating the health status of both the IGBT and the entire inverter system. To enable low-intrusiveness detection of IGBTs during inverter operation, a new method is proposed in this article: a parallel RC high-frequency detection circuit at the inverter output terminal to monitor the IGBT's voltage rise time. This method not only accurately identifies and measures the voltage rise time of IGBTs in a three-phase inverter, but also accounts for practical operating conditions. Simulations and experimental validation are carried out for different operating conditions, load connection methods, cable lengths, and uncertainties in parasitic parameters, and the experimental results verify the effectiveness as well as the strong robustness of the method.

关键词： 电梯   永磁同步电动机   矢量控制   位置传感器   转子位置   转子转速  

摘要： 在对电梯驱动系统中的永磁同步电动机(PMSM)进行控制时，需要准确获得转子磁链的空间位置。传统的获取方法是加装机械式位置传感器来进行测量。机械式位置传感器存在损坏风险，一旦损坏，会破坏电梯驱动系统的稳定性，因此有必要研究PMSM无位置传感器的转子位置与转速的估算方法。首先分析了基于dq坐标轴变换的PMSM的动态模型和基于转子磁场定向的矢量控制原理，得出转子位置信息对于电压、电流从三相ABC坐标轴系向旋转dq坐标轴系转换起到桥梁作用。由此，提出了一种PMSM转子位置与转速的估算方法。该估算方法可在没有机械式位置传感器的前提下，利用PMSM的输入输出关系计算得到转子位置与转速。仿真试验结果表明：该估算方法可准确估计转子位置与转子转速，可以作为备用方法用于有机械式位置传感器的PMSM，以提升电梯驱动系统的鲁棒性。

关键词： Inverters   Logic gates   High-voltage techniques   Wireless communication   Resonant frequency   Insulation   Coils   Wireless power transfer   Insulated gate bipolar transistors   Wireless sensor networks   IGBT   gate drive circuit   galvanic isolation   inductive wireless transfer   three-phase inverter  

摘要： When driving an IGBT in a high-voltage inverter, the gate drive circuit requires high insulation for both the control signal and the power supply circuit. Non-integrated photo couplers are often used to isolate control signal circuits, and custom-made transformers for DC-DC converters are used to isolate power supply circuits. Because the floating gate drive circuit is located on the high-voltage side, the system with non-integrated photo couplers and custom-made transformers has low reliability and complexity, therefore, there is a high demand for robust and simple isolation methods. In this paper, a highly reliable and simple isolation method that utilizes simultaneous inductive wireless transfer for both the control signal and power is proposed, and the gate drive circuit is moved to the low-voltage side for high-voltage inverters used in large industrial motors and DC power transmission converters. Using the proposed method, it is easy to access the gate drive circuit and the insulation configuration becomes robust and simple compared with conventional systems. The effectiveness of this method is verified using a 40-V prototype three-phase inverter. A three-phase motor is successfully driven using the proposed prototype.