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关键词： 塔底   散热系统   变频器   解决方案  

摘要： 本文主要解决1.5MW双馈机组变频柜在相对密闭的塔筒内高温故障频繁的问题,在分析其原因的基础上介绍了一种应用于某风场的改造案例;此方案满足夏季高温时变频柜及塔基的正常散热需求。该方案成本低,结构简单易于施工,改善了原有冷却系统,保障了机组安全稳定运行。

关键词： 垂直分片机   变频器   抱闸  

摘要： 烟草制丝线垂直分片机主要对烟包进行分片,使烟片易于松散、回潮均匀,以满足后续工艺的要求。改进前通过定时控制的方式控制垂直分片机提升电机,存在变频器过电流报警和纵移动架下滑的情况。我们通过将原来的伦茨变频器换为SEW变频器,采用先建立静止力矩再释放抱闸的方式代替了原来的定时控制方式,并且将电机抱闸主回路设计为通过2个接触器串联控制,必须2个接触器都吸合时抱闸才能释放,从而实现了双保险功能。

关键词： 电气自动化控制   工业生产活动   自动化控制技术   自动化控制的分析   变频器   控制装置   PLC   操作要点  

摘要： 随着自动化控制技术的飞速发展,PLC和变频器逐渐成为工业生产活动中不可或缺的一部分。PLC和变频器在现代控制装置技术中占据着至关重要的位置,且与通信、计算机以及相关行业具有密切关联。基于此,本文首先简要分析了PLC和变频器的基本概述,其次阐述了PLC和变频器实现电气自动化控制的操作要点,以期对相关部门的生产活动有所帮助。

关键词： NPC   三电平逆变器   IGBT   通态损耗   开关损耗  

摘要： 为计算NPC三电平逆变器IGBT模块损耗,提出了一种精确计算方法。首先,结合NPC三电平工作时序,对NPC三电平电路在一个输出周期内进行详细分析,得到正负半周内IGBT模块的工作状态与电流流通路径,给出损耗发生的具体对象与类型,并建立IGBT工作电流函数;其次,基于对IGBT模块损耗相关耦合参数的分析,建立损耗与各个参数的函数关系;最后,结合IGBT模块的热力学模型,通过样机实测温度,得出最终结果。结果表明,所建立的IGBT模块损耗强相关参数函数准确;NPC三电平逆变电路工作时序与IGBT模块损耗分析合理,由此计算的结果可精确反应IGBT实际损耗。

关键词： Switching loss   Switching transient process   Accurate calculation method   Approximate analytical calculation  

摘要： Accurately revealing the generation mechanism and the mathematical relationship with system parameters of the power loss in the switching transients of high-voltage large power IGBT devices is very important for the device selection and circuit design of converter equipment. To reveal the mechanism of generating switching losses, this paper analyzes the switching transient processes of the IGBT devices in the basic commutation circuit in detail. Then this paper proposes an accurate calculation method based on a finite state machine (FSM) for the switching losses of IGBT devices, and verifies the correctness of this method. To further reveal the mathematical relationships among switching losses, device parameters, and loop parameters, approximate analytical formulas for the switching loss of different switching transient processes are mathematically derived, which can provide a theoretical basis for reducing the switching losses in converters.

关键词： 10-kV class   4H-SiC   differential specific ON-resistance   IGBT   laser annealing   waffle substrate  

摘要： The silicon carbide (SiC) waffle-substrate n-channel insulated gate bipolar transistor (IGBT) is a vertical IGBT designed to operate at blocking voltages below about 15 kV. At these voltages, the drift and anode layers are too thin to allow complete removal of the n(+) substrate. Instead, a waffle pattern is etched through the substrate to expose the buried anode layer while preserving the structural integrity of the wafer. The feasibility of this approach is demonstrated by fabricating a 10-kV class n-channel IGBT with a differential specific on-resistance of 160 m ***(2).

关键词： Insulated gate bipolar transistors (IGBT)  

摘要： Owing to the advantages of short-circuit failure mode, double-sided heat dissipation, and low thermal resistance, press-pack insulated gate bipolar transistors (PP-IGBTs) are widely used in high-power-density applications, such as high-voltage direct-current converters. As the core device of large-capacity power equipment, the reliability of a PP-IGBT is directly related to the security of the power system. In recent years, a silver-sintered package has been proposed to improve the electro-thermal performance of PP-IGBTs. However, the long-term reliability of this package has not been proven. In response to this problem, 3300-V/50-A silver-sintered PP-IGBT (SPP-IGBT) modules are used in long-reliability research. First, electro-thermal-stress finite-element models of PP-IGBTs and SPP-IGBTs were proposed and the accuracy of models verified by experiments. Through a simulation comparison, the results show that under the rated operating conditions, the on-voltage and maximum temperature of SPP-IGBTs dropped by 9.3% and 3.7%, respectively. In addition, the temperature and stress of each component were reduced, among which the surface stress of the IGBT chip emitter dropped by as much as 24.7%. Subsequently, a power-cycle test platform was established, and three PP-IGBTs and three SPP-IGBTs were tested. Finally, the experimental results were compared and analyzed, and the reasons for the sharp increase of on-voltage and metal melt were explored. The results show that the silver-sintered package improves the electrical-thermal performance and long-term reliability of the module. © 2022

关键词： Insulated gate bipolar transistors   Voltage   Logic gates   Mathematical models   Capacitance   MOSFET   Charge carrier processes   Behavioral model   excess carrier distribution   finite differential method   high-power insulated gate bipolar transistor (IGBT)   quasi static (QS) and nonquasi static (NQS) assumptions  

摘要： The calculation for carrier distribution in the quasi-neutral base region is necessary for modeling the turn-off process of an insulated gate bipolar transistor (IGBT). The carrier distribution difference between quasi static (QS) and nonquasi static (NQS) conditions and its influences on turn-off characteristics of a high-power IGBT are worthy of further study. In this article, the carrier distribution differences between QS and NQS conditions in different turn-off stages are first analyzed. In addition, based on the derived conclusions, a novel method modeling the turn-off process of high-power IGBTs is further proposed. In the method, the turn-off process before the collector-emitter voltage increases to the direct current (dc) voltage is modeled under the QS condition. In contrast, after the collector-emitter voltage increases to the dc voltage, the turn-off process is modeled under the NQS condition. Subsequently, the method is verified by comparisons with popular models and experiments. By adopting both QS and NQS assumptions, the proposed method can simplify the calculation and avoid considering the two-dimensional carrier distribution effect in the base. The method is implemented into SABER circuit simulator with MAST language and shows a high accuracy and considerable calculation efficiency.

关键词： Performance coefficient   TiO2-H2O Nano fluid   Si-IGBT power module   Micro-nozzle model  

摘要： In this paper, in order to improve the cooling power, the thermal effects of using titanium oxide nanoparticles with different concentrations and perforated nozzles with paddle blades are investigated. In this simulation, by presenting a new design for a Si-IGBT power module, three types of paddle blades with a simple nozzle type to pump cooling fluid are evaluated and compared. The boundary condition is that a constant heat flux enters from the top of the module, i.e., IGBT and the Diode. In order to further investigate the thermal effects, an attempt has been made to investigate the temperature of the module under a heat flux of 150 W cm(-2), 180 W cm(-2), 255 W cm(-2), so that the IGBT heat flux is always higher than the Diode input flux. In this robust and three-dimensional simulation extracted from ANSYS-FLUENT commercial software, it was found that turbulent kinetic energy increases with increasing number of nozzle blades. At the same time, increasing the volume fraction of nanoparticles from 0.01 to 0.05 leads to improved heat transfer and ultimately reduces the thermal peak created in the study space. In addition, increasing the transverse mass flow rate improves cooling, which reduces the performance coefficient (COP) of the system.

关键词： hybrid high voltage direct current circuit breaker   circuit breakers   fast short-circuit current isolation   MOV branch   power grids   IGBT   short-circuit currents   HVDC power convertors   hybrid HVDC circuit breaker prototype   insulated gate bipolar transistor   insulated gate bipolar transistors   power transmission faults   voltage stress   Zhangbei four-terminal voltage source converter-HVDC project   voltage-source convertors   PSCAD-EMTDC computer simulation   varistors   HVDC power transmission   electrical stress   short-circuit current isolation   metal oxide varistors  

摘要： This paper proposes a +/- 535 kV hybrid high voltage direct current (HVDC) circuit breaker. In this paper, the interruption processes of the main branch, transferring branch, and MOV (metal oxide varistors) branch are studied by PSCAD/EMTDC computer simulation. Simulation results indicate that an insulated gate bipolar transistor (IGBT) in the main branch will withstand the highest electrical stress (3305 V/2200 A) and the IGBT in the transferring branch will withstand the highest voltage stress (3327 V). Finally, the +/- 535 kV hybrid HVDC circuit breaker prototype is manufactured;the test is carried out. Test results suggest that the +/- 535 kV hybrid HVDC circuit breaker prototype developed for the Zhangbei four-terminal voltage source converter (VSC)-HVDC project can interrupt a +/- 25 kA (high current) within 2.84 ms. The simulation results agreed very well with the actual test results of our novel +/- 535 kV hybrid HVDC circuit breaker. The novel +/- 535 kV hybrid HVDC circuit breaker functioned exceptionally well in achieving fast short-circuit current isolation.