普通变频器大都采用二极管整流桥将交流电转换成直流，然后采用IGBT逆变技术将直流转化成电压频率皆可调整的交流电控制交流电动机。这种变频器只能工作在电动状态，所以称之为两象限变频器。
Common converters mostly use diode rectifier bridge to convert AC to DC, and then use IGBT inversion beijing.89ix.com zhixiang.07858.netdianxiangan.37ix.cn zhoucheng.37ix.cn chongdianzhuang.07858.net langyashan.37ix.com.cntechnology to convert DC to AC motor with adjustable voltage and frequency. This kind of converter can only work in the electric state, so it is called two quadrant converter.