文档介绍：目录
一引言·······················································2
二设计要求及介绍·············································3
·······································3
·········································3
··············································5
三总体方案设计···············································5
·······································5
··············································12
四变频器(查阅资料)·········································15
通用变频器的发展·····································19
变频器的选择·································