VVVF control technique for well pumping units

The application of variable voltage variable frequency(VVVF) control technique on well pumping units has produced mainly numerical control pumping units and intelligent pumping units.They are investigated from the aspects of working principle,structural features,performance indexes,behaviors and oil field tests.The authors analyze the factors affecting the popularization of VVVF control technique on well pumping units.Application of VVVF control technique on well pumping units is put forward at the end of this paper.