大功率变频调速节电在有色冶金行业的应用展望

变频调速节电在国内各行业均得到广泛应用，而大功率变频调速在有色冶金行业的节电应用几乎空白，通过对大功率变频调速节电原理、方案及存在问题的分析，举例说明了有色冶金行业采用大功率变频调速节电的巨大潜力。     

Two optimized models of life prediction based on luminance degradation for VFD under a conventional life test

Focusing on improving the accuracy of existing life prediction models for optoelectronic products, the three‐parameter Weibull right approximation method (TPWRAM) was employed to substitute exponential function based on the least square method in the analysis and two‐staged methods. Two optimized models were established (Model I and Model II), based on maximum likelihood estimation and the Monte Carlo method, respectively. One group of conventional life tests (CLTs) of vacuum fluorescent display (VFD) were conducted to collect luminance degradation data for each sample, and the two optimized models were applied to achieve VFD life prediction and obtain mean time to failure, median life, and confidence intervals. The results indicate that the CLT test design is correct and feasible, the amount of data on luminance degradation is large, and the test data selection method is reasonable. Model I and Model II optimized by TPWRAM both reflect the VFD luminance variation law well, and the predicted life approaches VFD service life from user feedback, proving that the two models are precise, and thus, can provide technical references for researchers and engineers regarding aspects of life prediction.     

一种蓄电池升降压变换方案在DC-BANK系统中的应用

分析了现有DC-BANK抗"晃电"直流支撑系统中蓄电池组的变压方案。针对某型具体DC-BANK系统中系统参数的设定,提出传统系统中蓄电池利用率低的问题。针对蓄电池本身的放电特性及DC-BANK系统对蓄电池组的使用实际,提出采用一种对蓄电池组输出电压进行升降压变换的方案来解决现有系统中不能充分发挥蓄电池性能的不足。仿真证明电路性能达到预定指标,实现了对蓄电池组输出电压的升降压变换和延长系统的设计支撑时间的目的,解决了传统DC-BANK抗"晃电"直流支撑系统中蓄电池组性能不能充分发挥的不足。     

变频器抗“晃电”的直流支撑技术概述

针对连续型生产企业的变频器在电网“晃电”时发生低压跳闸的现象,借鉴UPS系统中备用电池组对系统进行“晃电”瞬时支撑的思想,采用变频器DC-BANK直流支撑技术,结合变频器的结构特点,采用对变频器直流母线进行直流电压支撑的方法,实现了对变频器系统的抗“晃电”改造.介绍了将变频器进行抗“晃电”改造的几种技术路线,通过对几种方案所采用的支撑原理、拓扑结构和电路组成等进行分析对比,明确了各方案的优缺点.