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关键词： 变频器   环境改善   温度操作   通风散热   电子测试  

摘要： 随着变频器在各行业应用越来越广泛,对设备的控制要求较高,其长期大功率运行容易发生故障。通过对周围环境的研究改善,使变频器的环境温度保持在0-40℃之间,周围空气相对湿度保持40-80%之间,并做到合理、正确的维护,如定期维护检测在一年左右,其使用寿命会明显延长,故障频率也会显著降低。如果维护保养工作不及时或缺少维护,就有可能导致变频器的运行不正常,进一步致使其故障频率频发,影响所使用设备的正常运行。因此,需要通过对变频器的环境改善、日常维护与定期检查等措施,达到降低故障发生的目的。

关键词： Java   风机变频器   自动化控制   设计  

摘要： 为有效解决电厂风机存在风量调节不准确、节流损失大、低效率等缺点,本文在分析高压变频器构成、特点、原理的基础上,采用了Java高压变频器对火力发电厂锅炉风机进行变频调速与改造,设计Java锅炉风机变频调速电气控制系统。运用有关生产系统典型控制理论,构成送、引风机自动控制系统,并融入电厂分散控制系统(DCS),实现锅炉风机送、引风量的自动调节。深入研究了系统中风量调节、电机、变频器、联锁、FSSS保护的控制逻辑,研究了PiD串级控制系统的组成、原理、参数整定方法,对变频器的启动、运行调试方法进行研究,分析其工艺流程,使其工作在最优状态。研究结果表明,通过优化变频调速装置对运行情况进行分析,发现对电厂锅炉风机实施变频调速优化是切实可行的,不仅能实现宽范围调速、风量自动调节,还能达到节能减耗的目的。

关键词： 变频器   电机   变频启动   压缩机   共振  

摘要： 随着电力电子技术的发展,变频拖动已经非常成熟,但是随着应用的扩展也会随之出现越来越多的特殊应用。本文通过实际项目案例,从变频器的特殊应用、选型、出现的问题和问题解决办法等过个角度来分析变频器拖动离心式压缩机下的应用,并可以扩展到相关二次型负载的应用。

关键词： 变频调速装置   高温风机   高压变频器   窑尾排风机   循环风机   水泥工厂   大型风机   水泥磨  

摘要： 目前,新建的新型干法水泥生产线,规模大、投资大、技术要求高,特别是节能和控制方面要求越来越高,所以在水泥厂内的大型风机一般都采用变频调速,包括高温风机、窑头排风机、窑尾排风机、煤磨循环风机、生料磨排风机、水泥磨风机等。2017年4月1日开始实施的标准GB 50443—2016《水泥工厂节能设计规范》中的第3.1.2条规定:窑尾高温风机应采用变频调速装置。可见,相对于水泥厂其他风机来说,高温风机采用变频控制的要求是最强烈的。

关键词： 胶带机   永磁同步电动机   矢量控制   节能   大功率异步电动机  

摘要： 为进一步提升选煤厂胶带机的应用性能,充分发挥其工作效率,以沙坪洗煤厂胶带机为例,对该胶带机系统的动力学特性进行仿真,分析在不同启动时间和启动速度下的最大张力及波动情况,提出减少胶带机在启动阶段对系统造成冲击的策略和措施;进行胶带机永磁同步电动机的结构设计和关键参数选型,建立永磁同步电动机矢量控制模型,设定仿真条件、仿真参数等对其矢量控制进行仿真分析,并得出其控制的响应特性和稳定性;通过工业性试验分析永磁同步电动机和传统异步电动机的节能效果。

关键词： Silicon carbide   Silicon   Inverters   Insulated gate bipolar transistors   Topology   Substrates   Multichip modules   High-speed railway   insulated-gate bipolar transistors (IGBTs)   silicon carbide (SiC)   traction inverter  

摘要： A type of 3.3-kV/450-A half-bridge insulated-gate bipolar transistor power module combining the silicon (Si) and silicon carbide (SiC) technologies has been developed and reported in this article, for the miniaturization of the Chinese high-speed railway rolling stock traction inverters. This module is developed by integrating the next-generation industrial standard high-voltage packaging topology and the state-of-the-art 3.3 kV wide bandgap semiconductor chip technology, to reduce the waste power dissipation during operation, which in turn can lead to effective downsizing of key components in the traction inverter design. The module layout characteristics and the SiC Schottky barrier diodes design for substitution of the conventional Si fast recovery diodes will be described in detail. The mechanical, thermal, and electrical performances of the hybrid module are compared comprehensively with the Si-based counterpart. Based on the experimental results, an inverter system level evaluation of both modules is also conducted by electro-thermal simulation. The hybrid module shows advantages in loss reduction leading to great potential of system miniaturization, which is a cost effective solution for massive upgrading of the existing high-speed train traction inverters.

关键词： RC-IGBT   Collector short resistance   Snapback effect   Trade-off characteristics  

摘要： A novel Reverse-Conducting Insulated Gate Bipolar Transistor (RC-IGBT) with Multiple Extraction Channels (MEC) is proposed and investigated. The MEC is characterized by two transistors NPN1 (N-buffer/P-barrier/N-collector), NPN2 (N-buffer/P-float/N-poly) and short R-gap in the collector. The P-Collector, N-Collector, polysilicon and R-gap are shorted together, thus the NPN1, NPN2 and R-gap are parallel with the PNP transistor (P-body/N-buffer/P-collector). At the forward conduction, the unipolar mode is effectively suppressed by the electron barriers P-barrier (the base of the NPN1) and P-float (the base of the NPN2), thus the snapback effect can be completely eliminated. At the turn-off, the electrons are quickly extracted by three channels of the NPN1, NPN2 and R-gap, thus the E-off can be remarkably decreased. Results show at the same V-on of 2.8 V, the E-off of the MEC RC-IGBT is reduced by 20%, 37%, 45% and 59% compared to AB, FPL, DFS and TOC RC-IGBT, respectively. Therefore the excellent trade-off characteristics with snapback free are achieved.

关键词： discrete fourier transform   igbt fault detection   open circuit fault   Single-phase pwm rectification  

摘要： Aiming at the problem that single-phase rectifier transformation is prone to failure in the use of three-phase rectifier transformation, this paper introduces fuzzy logic genetic algorithm into the fault detection process of IGBT single-phase bridge arm structure. The algorithm mainly analyzes the DC side current in detail in the frequency domain to judge the fault of IGBT open circuit. In the fault diagnosis of single-phase bridge arm structure, the system circuit model is analyzed by sensors by using fuzzy logic genetic algorithm to judge the type of fault. Finally, the experimental results show that this method can detect faults in a fixed sampling period and in the frequency domain. It can effectively eliminate the interference of other frequency signals and increase the reliability of the system and the accuracy of fault diagnosis.

关键词： three-phase inverter   high-speed switching   Si-IGBT   SiC-IGBT   microcontroller   aircraft applications  

摘要： The converters used to integrate the ground power station of planes with the utility grid are generally created with silicon-insulated gate bipolar transistor (Si-IGBT)-based semiconductor technologies. The Si-IGBT switch-based converters are inefficient, oversized, and have trouble achieving pure sine wave voltages requirements. The efficiency of the aircraft ground power units (AGPU) can be increased by replacing existing Si-IGBT transistors with silicon carbide (SiC) IGBTs because of the physical constraints of Si-IGBT switches. The primary purpose of this research was to prove that the efficiency increase could be obtained in the case of using SiC-IGBTs in conventional AGPU systems with the realized experimental studies. In this study, three different experimental systems were discussed for this purpose. The first system was the traditional APGU system. The other two systems were single-phase test (SPT) and three-phase inverter systems, respectively. The SPT system and three-phase inverter systems were designed and implemented to compare and make analyses of Si-IGBTs and SiC-IGBTs performance. The efficiency and detailed hard switching behavior comparison were performed between the 1200-V SiC-IGBT- and 1200-V Si-IGBT-based experimental systems. The APGU system and Si-IGBT modules were examined, the switching characteristic and efficiency of the system were obtained in the first experimental study. The second experimental study was carried out on the SPT system. The single-pulse test system was created using Si-IGBTs and SiC-IGBTs switches in the second experimental system. The third experiment included a three-phase-inverter-based test system. The system was created with Si-IGBTs and SiC-IGBTs to compare the two different switch-based inverters under RL loads. The turning off and turning on processes of the IGBT switches were examined and the results were presented. The Si-IGBT efficiency was 77% experimentally in the SPT experimental system. The efficiency of t

关键词： Power losses   IGBT   Inverter   MATLAB-Simulink  

摘要： The power loss estimation is a crucial step for power electronics design, especially for high-power-density systems. Many mathematical approaches are known for power loss estimation, but the system design time can be lowered significantly if a simulation approach is used. This paper discusses the MATLAB-based simulation method for estimating power losses in the three-phase VSI. This simulation is using a real characteristic of the used IGBT transistors for power loss estimation. Next, the model uses the simulated power losses and calculates temperatures at different points in the simulated model. For the visualization, Fusion360 was used to simulate the thermal spreading at the heatsink. Finally, the inverter power losses are measured at the different loads to confirm the accuracy of the model. The temperature of the heatsink is measured with a thermal imaging camera and surface mounted probes.