The dedicated energy-saving frequency conversion controller ofTJNB3000 series pumping unit is used for oil field pumping unitenergy-saving control, during the working process of the pumpingunit, the upstroke is a process that needs electric energy and thedownstroke is a gravity dropping power generation process. In theupstroke, it is “big horse pulls a small carriage”, therefore themotor has excess power supply to the pumping unit, and theenergy-saving frequency conversion controller can save the surplusmotive power, thus achieving energy conservation goals. In thedownstroke of the pumping unit, it is the power generation processof the motor, the energy-saving frequency conversion controllerreturns its generating power to the power grid is a power recoveryprocess by changing the original power consumption into powergeneration process, therefore, the energy-saving effect is evenmore prominent that realizes energy-saving and emission reductioneffect in genuine.