Light load stability simulation of IM V/f drive system

Induction motor V/f open-loop drive system suffer sustained oscillation problem in light load condition. Many methods have been presented to suppress the oscillation. However, a generally accepted theory about the cause of this oscillation problem is not revealed. This paper mainly focuses on the research of the cause of the sustained oscillation problem of IM V/f drive system. Through simulation modeling, the system instability is analyzed in detail based on the simulation results. Then by theoretical derivation, the reasons that result in the instability under light load condition are studied, and the influences on system stability of various parameters are also analyzed. The conclusions derived in this article are consistent with the actual phenomenon very well. In addition, the derived conclusions can be used to predict the oscillation of the IM V/F open-loop control system.