大功率电机平稳切换的理论探讨与方法研究

根据感应电动机的定子电压方程和相量图,对大功率电机变频转工频所存在的问题进行了理论分析,并且指出大功率电机变频转工频的关键在于变频转工频的瞬间,工频电源和变频输出电源相位是否一致.在现场工业试验中引入鉴频鉴相控制器,成功地实现了大功率电机变频到工频的平稳切换,转换电流小,基本上实现了电机的无冲击起动.

Discussion in Theory and Research in Method of Smooth Transformation for High-power Electromoter

According to electrical equivalent circuit and vector graph of induction electromotor, discussion is made in theory about the problem ,that exists in the course of transformation from variable frequency to work frequency. Furthermore it is pointed out that whether the high-power electromotor can be switched from VF to WF lies on phase consistency between work frequency phase voltage and corresponding work frequency phase voltage. Frequency and phase discriminator is adopted in the industry test to complete the transformation from VF to WF successfully. As the transformation electrical current is small, non-impact start of the high-power electromotor is realized.