环境因素导致高压变频器故障的预防及治理

通过对我公司一起高压变频器事故分析，总结出影响高压变频器运行的几大环境因素，通过改善外部条件或运用技术手段，制定出可行的预防及治理措施，降低高压变频器故障率，确保设备的正常运转。     

凝泵变频器无出力问题分析及处理

某300 MW火电机组的凝泵变频器在机组运行过程中，出现变频器给DCS（集散控制系统）的反馈频率突然降低现象，引起变频器停止工作，联启凝泵工频运行。通过对凝泵电机、DCS运行状态、变频器控制柜等逐项排查分析，最终确认变频器主控板出现故障，更换新的主控板后问题得到解决，为分析类似高压变频器问题提供思路。     

开滦热电引风机节能技术改造

本文通过比较电动机调速方式的优缺点,最终选用高压变频器对引风机进行节能技术改造,运行实践证明高压变频器节能技术具有很好的节能效果,在发电厂有值得推广应用的广阔空间。     

高压变频技术在矿山机电设备中的应用举例

本文首先对我国煤矿机电设备特点及运行现状进行了简单的分析,然后指出了当前煤矿机电设备主要维护方式,在此基础上,对煤矿机电设备维护要点和更新改造技术进行了较为详细的探讨。高压变频技术能有效的节省电能,提高煤矿机电设备的使用寿命,本文分析了高压变频技术在煤矿机电设备运用的重要性,同时,论述了高压变频器合理选型的方法及应用举例。     

风机高压变频调速系统故障的分析及解决措施

云浮发电厂一次风机变频器投运后多次出现故障,长时间不能正常投入运行,严重影响机组的安全经济操作,通过对风机变频器的常用故障进行归纳及总结分析,找出了故障产生原因,并制定了相应的整改措施,整改完成后变频器恢复正常运行。     

高压变频器在火力发电厂运行中常见问题分析

随着现代科学技术的蓬勃发展,火力发电厂的各项生产技术也逐渐趋成熟。科技化、节能化、绿色化和高效性的新科学技术是现代电力企业的发展方向。高压变频器在火力发电厂的使用经过多年的发展实践,取得了很大的经济效益,过程中也积累了较多的经验,日渐趋向成熟,但高压变频器在火力发电厂的使用属于高技术设备,国内的生产管理条件还存在很多安全隐患。本文从高压变频器的自身缺陷、设备运行环境和设备控制系统等几方面阐述高压变频器在火力发电厂运行中常出现的问题,并进行分析,给出一些改进建议。     

凝结水泵进行变频改造的运行分析

北方联合电力乌拉山发电厂凝结水泵由工频改为变频运行,变频器采用高压变频器调速,经实际运行证明:变频改造后在保证凝结水泵水量的自动调整的同时,还实现了节能降耗的目标。     

高压变频器在发电厂中的运行与维护

节能降耗是发电厂的一项重要工作,其关系到发电企业的经济效益及生存能力,从而使高压变频器在火力发电厂中应用变得较为广泛,通过高压变频改造可以降低厂用电率和供电煤耗,提高上网电价的竞争力。在实现发电厂高压变频器在节能降耗的基础上,同时确保发电机组安全运行。     

交直交高压变频器在煤矿主通风机中的应用

煤矿风井主通风机通过采用交直交高压变频器,实现通风机运行的变频调速,取得显著的节能效果,降低通风机的机械强度和电气冲击,延长使用寿命,提高负载功率因素,杜绝工作人员的误操作现象,提高通风机的安全运行系数和运行周期。阐述变频器调速的原理,介绍交直交高压变频器的系统结构和工作原理。     

高压变频器矢量控制技术在煤矿提升机的应用分析

本文将主要对高压变频器矢量控制原理进行详细的介绍,并结合实际的例子对高压变频器矢量控制技术在煤矿提升机中的应用进行详细的分析,希望能为相关的研究提供新的思路。     

High-efficient three-phase on-line UPS by using T-source inverter with third harmonic injected maximum constant boost PWM control

This paper presents the analysis of three-phase on-line uninterruptible power supply (UPS) by employing T-source inverter (TSI) with third harmonic injected maximum constant boost PWM control and the results are compared with traditional UPS. Traditional UPS consists of step-up transformer or DC–DC booster along with voltage source inverter which decreases the efficiency and increases energy conversion cost. The proposed three-phase UPS using TSI has high-voltage boost capability through shoot-through zero state which is not present in traditional voltage source inverter (VSI) and current source inverter. This proposed UPS with TSI increases the efficiency with fewer components, reduces the harmonics, increases the voltage gain, and reduces the voltage stress. The performance of three-phase on-line UPS based on TSI is analyzed and evaluated in MATLAB/SIMULINK software and the results are compared with Z-source inverter-fed UPS and VSI-fed UPS. Experimental results are presented for the validation of the simulation and theoretical analysis.     

变频器在烟草行业风机节能改造中的应用

随着大功率高压变频技术的日益成熟,大功率的变频器在烟草行业得到了广泛的应用,本文针对保定卷烟厂制丝车间风机变频改造的应用与实践,阐述了变频器在烟草行业节能技术改造中的节能与技术原理。结果表明：风机采用变频调速控制运行,能够获得显著的节能效果和经济效益。     

基于LT3757的地质雷达高频高压转换系统设计

针对高压转换系统存在的一些问题,设计了一种基于LT3757的地质雷达高频高压转换系统。主要从工作原理、电路结构和主元件的选择等方面给出了系统的设计过程。经过实验测试,该系统具有宽输入电压范围,可产生地质雷达所需的50V～500V稳定的输出电压,工作频率可达到1MHz。该系统体积小,可直接集成到地质雷达发射源电路上,功耗低,可有效提高电池野外工作时间。     

晶体管逆变空气等离子切割电源的研制

本文研制了一种晶体管逆变空气等离子切割电源。为解决高压晶体管的安全工作问题,采取了各种有效的保护措施。最后获得了空载电压为210V,切割电流为7.5～30A 的恒流外特性,达到了设计要求。     

Entrainment of particles and gas induced by draft fan over the particles bed

The draft fan is used to generate a controlled transportation of particles to enhance entrainment of gas and particles from the particles bed. Present investigations show the entrainment behavior of particles induced by an axial 4-blade draft fan hovering over the particles bed. The distributions of velocities and volume fractions of gas and particles are simulated using Euler-Euler two-fluid model (TFM) with kinetic theory of granular flow (KTGF) at different hovering heights and rotational speeds of the draft fan. The dense region with high solids volume fraction and low particles velocity and the dilute region with low solids volume fraction and high particles velocity exist beneath the draft fan along hovering heights. The entrainment of particles increases with the decrease of hovering height and increase of rotational speed of the draft fan. Present numerical simulations confirm that the gas-solid TFM with the kinetic theory of granular flow and multiple reference frame model can be effectively applied to analysis for entrainment of particles induced by draft fan.     

High-frequency link symmetrical active edge resonant snubbers-assisted ZCS-PWM DC?DC converter

A novel symmetrical zero current switching (ZCS)-pulse width modulation (PWM) cells-assisted high-frequency transformer link DC-DC converter using insulated gate bipolar transistor (IGBT) modules is presented. The proposed soft switching scheme is based on the switched-capacitor and inductive snubber in the high-voltage side inverter, assisted by active switching of MOSFET synchronous rectifier in the secondary-side low-voltage converter stage. By introducing the ZCS-PWM snubber cells, soft switching commutation which is less sensitive to the current level through the IGBTs can be achieved under the wide output power ranges. The converter circuit topology and the ZCS snubber cell operation are examined and evaluated with simulation results, and the feasibility of the converter topology is verified by experiments using a 1.0 kW-25 kHz prototype system.     

10kV/1000A高压电能计量标准及其量值溯源的研究

为了保证高压电能测量量值的准确可靠,提出了建立10kV高压电能计量标准及其量传系统的新方法,以实现高压电能计量器具的室内计量检定,进而实现电网高压电能计量器具的量值溯源。基于I/V和V/V技术,研制了高压电能计量标准,并对研究成果进行了不确定度分析及溯源验证,其三相电能的测量准确度达到0.02%;以高压电能计量校准装置作为被检对象,其三相电能的测量准确度在功率因数PF为0.5时达到0.12%。     

解读韩国化学物质注册和评估法规草案

本文将从该法规提案的立法背景、与韩国现有法规的差异，以及对我国的影响等三方面对该新法规草案进行分析，并提出我国应采取的具体应对措施。     

A High-Voltage Switching Power Supply for Cold Plasma Jets

Technical Physics Letters - The parameters of a number of high-voltage solid-state switches are studied. Based on the analysis of their work, a high-voltage pulse source with a size of 105 ×...     

Simulation and experimental study on the stone powder separator of a vertical shaft impact crusher

During the sand-making process, the stone powder produced by means of a vertical shaft impact (VSI) crusher affects the sand quality and pollutes the environment. This paper focuses on experiments and simulations with a stone powder separator (SPS) that is installed in a VSI crusher. Using FLUENT software, a coupling model of computational fluid dynamics (CFD) and the discrete phase model (DPM) is used to simulate the airflow distribution and particle traces in a VSI crusher. The stone powder separation and large particle retention performance are evaluated considering two important factors: the structure of the SPS and the air volume of the induced draft fan. The simulation results show that the air volume of the induced draft fan intuitively influences the particle traces and the distributions of particles of different sizes in the crushing chamber and the SPS chamber. There are many vortexes in the crushing chamber that cause the aggregate particles to be fully dispersed under the action of turbulence, and the SPS structure with radius decreasing from bottom to top can form an airflow velocity gradient in the SPS chamber and selectively remove particles according to size, thus improving the stone powder separation performance (SPSP). For this structure, when the air volume of the induced draft fan is set to approximately 40% of the maximum value, it can not only avoid large particles being massively removed but also ensure better SPSP of the device. Finally, the simulation results are verified by experiments. The results of this paper provide a reliable numerical model for the calculation of the flow field in a VSI crusher and provide a reference for the structural optimization of the stone powder separation device and for the selection of the best air volume of the induced draft fan.