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关键词： Insulated gate bipolar transistors   Integrated circuit modeling   Silicon carbide   Germanium   Mathematical models   Capacitance   Semiconductor device modeling   Insulated-gate bipolar transistors (IGBTs)   interpolation   semiconductor device modeling   silicon carbide  

摘要： The simple and accurate SiC insulated-gate bipolar transistor (IGBT) model is necessary for circuit designs and optimizations of high-voltage and high-power converters. This article provides a highly accurate SiC IGBT model with static and dynamic tracking capability. The C-V curves are extracted from transient waveforms, rather than datasheet or direct measurement, to model the punchthrough (PT) effect and near-ZCS effect completely. Five controlled current sources and passive components are used to model the static and dynamic characteristics. The interpolation calculation method instead of the conventional polynomial fitting method is adopted to reproduce the I-V curves and C-V curves truly. The I-V curves are almost the same with measured results. The switching waveforms under different bus voltages, gate resistances, and load currents are widely verified, which is suitable for loss evaluation and circuit designs. The proposed model is more concise, more accurate, and faster than the existing complex physics-based model and less accurate behavioral model (BM), which is suitable for system-level circuit simulation based on SiC IGBT.

关键词： Modular multilevel converter (MMC)   Fault diagnosis   Open-circuit failure   Submodules  

摘要： Modular multilevel converters have found a large number of applications in high-voltage and high-power DC transmission due to their modularity, scalability, multi-equality and other advantages. The two typical topologies in MMC systems are half-bridge sub-module structure and full-bridge sub-module structure. Half-bridge sub-module is widely used in MMC systems by virtue of its simple control structure, high conversion efficiency and low cost. Insulated gate bipolar transistor (IGBT) failures, especially open-circuit failures, are a major factor in the reliable operation of MMC systems. Fast and accurate positioning of the open circuit fault location and removal of the fault submodule is of great significance for handling MMC system faults. Aiming at the current situation of the fault location of the MMC system, this paper compares the error of the predicted median capacitance voltage with the actual value, and proposes an accurate diagnosis method for MMC lower IGBT tube open circuit faults. This method is suitable for one or more IGBT lower tube open-circuit fault conditions, and can quickly locate the faulty submodule within 5ms. Finally, an MMC simulation system with 8 sub-modules is built based on MATLAB/Simulink, which effectively verifies the accuracy of the proposed method. (C) 2022 The Author(s). Published by Elsevier Ltd.

关键词： Circuit breaker testing   Circuit modelling   DC circuit breaker   IGBT   Series and parallel connection   Solid-state circuit breaker  

摘要： MVDC systems have attracted a lot attention for the integration of renewable energy and electrification of transport due to their superior system operational performance and high power quality. DC circuit breakers are of significant importance for the development of MVDC systems because they offer fast protection from fault conditions compared to mechanical equivalent. However, unlike AC systems, there is no zero-crossing for the current in DC systems, this makes the DC circuit breakers design more demanding. This paper presents the design of a solid-state DC circuit breaker (SSCB) in details using series and parallel configurations of IGBTs to increase the voltage and current ratings. The operation, electrical design and thermal design of the SSCB are presented and analysed. A PLECS model is developed to simulate the operation of the SSCB. A 1 kV SSCB prototype is built and experimentally tested under both static and dynamic conditions. The prototype demonstrates even current sharing and voltage balancing in the experimental tests. The prototype can carry 150 A current continuously without overheating and demonstrates successful interruption of 1 kA DC current.

关键词： Insulated gate bipolar transistors   Voltage control   Logic gates   Circuit breakers   Electric breakdown   HVDC transmission   Thyristors   Current capacity   high-voltage direct current circuit breaker (DCCB)   ultrahigh driving-voltage (UDV)  

摘要： High-voltage direct current (HVdc) circuit breakers based on power electronic technology usually require a large number of insulated-gate bipolar transistors (IGBTs) to achieve large-capacity breaking. The insufficient current capacity is an important reason for the excessive cost of dc circuit breakers. However, the single switching condition in the circuit breaker makes it possible for IGBTs to control the current of several times rated value in a short time. This article proposed an effective current boosting method for IGBT. By applying an unconventionally ultrahigh driving-voltage (UDV) to the gate of devices, the instantaneous current capability of IGBTs can be significantly improved. The possible failure modes and lifetime issues caused by UDV are also discussed in detail. Through comprehensive theoretical calculations and experimental analysis, a proper UDV selection principle for IGBTs in HVdc circuit breakers is proposed. The single device is verified to have the ability to control 31.2 kA current in milliseconds by using UDV. This conclusion can greatly increase the allowable working area of IGBTs, thereby significantly reducing the cost of HVdc circuit breakers.

关键词： IGBT模块   焊层缺陷   超声扫描   判据  

摘要： 焊层缺陷是影响功率模块寿命和可靠性的主要因素之一,主要采用有限元仿真的研究方法,模拟了焊层缺陷位置、大小等因素对IGBT模块热性能的影响,得到不同的缺陷情况与模块热性能的对应关系并进行拟合,计算出焊层空洞大小临界值,提出了一种IGBT模块超声检测缺陷判据标准。芯片-基板焊层单个空洞率需≤2%,基板-底板焊层单个空洞率需≤2%,芯片-基板焊层整体空洞率与基板-底板焊层整体空洞率之和需≤10%。

关键词： 大型设备   皮带输送机   变频器   PLC   软启动  

摘要： 输送机作为煤矿开采过程中的运输设备,起着至关重要的作用。然而,如果输送机在作业时直接启动,则会对整个电路系统及其相关线路上的设备造成一定的冲击损害,同时也会影响自身稳定性,对井下作业的安全有着一定的潜在威胁。因此,在皮带输送机上配置变频器,可以有效避免上述问题,实现设备软启动,并且利用PID控制系统对其进行自动化控制,有效保护电路系统中的相关设备,具有良好的应用前景。

关键词： 压滤机   可编程逻辑控制器(PLC)   柱塞泵   变频器  

摘要： 文章分析了现有压滤系统的现状和不足,通过研究改进压滤系统的工艺流程,采用渣浆泵和柱塞泵组合的工作方式,改善了目前压滤系统能耗大的问题。设计基于可编程逻辑控制器(Programmable Logic Controller,PLC)的压滤机智能入料系统,先增加物联终端实现远程组态监控运行和数据采集,为设备提供全生命周期管理,再利用完善的故障检测系统,既保证了设备安全运行,又实现了无人值守。

关键词： 谐振变换器   双移相   宽电压范围   时域分析  

摘要： 分析了双移相控制下CLLC谐振变换器的工作原理,建立时域模型确定了电路状态变量以及增益曲线的解析解,并进一步对其软开关范围进行分析。时域分析表明,变换器在保证软开关的条件下,能够实现宽电压范围输出,同时其具有恒流源输出特性。搭建了样机对时域分析结果进行实验验证,实验结果表明变换器输出为恒流,且在软开关的条件下最高增益达到了0.54,最低增益几乎为零。

关键词： 多种治疗   HIV感染   最优控制   唯一性  

摘要： 讨论一类具有逆转录酶抑制剂、蛋白酶抑制剂和白细胞介素-2三种药物治疗的HIV感染模型的最优控制问题,通过药物控制实现在有限治疗时间内使游离病毒的浓度和药物副作用达到最小.首先利用Pontryagin最大值原理得到相应的最优系统,证明了当治疗末端时间充分小时最优系统解的唯一性,并给出了末端时间的估计式,最后对最优控制策略下的治疗效果进行了数值模拟.

关键词： 绝缘栅双极型晶体管   电力晶体管   发射极环流  

摘要： 大功率电机做变频驱动设计时,为控制采购成本,大部分的设计方法是进行绝缘栅双极型晶体管(IGBT)并联使用,IGBT是由双极型三极管和绝缘栅型场效应管组成的复合全控型电压驱动式功率半导体器件,兼有金属氧化物半导体场效应晶体管(MOSFET)的高输入阻抗和电力晶体管(GTR)的低导通压降两方面的优点,非常适合应用于直流电压为600 V及以上的变流系统如交流电机、变频器、开关电源、牵引传动等领域。这里分析了IGBT并联产生的发射极环流现象,并就发射极环流的大小控制和部分器件参数计算提出了解决方法。