Equivalent structure of a double-fed induction motor with a change in frequency of additional voltage for electric drive systems of mine winders

Using a double-fed machine (DFM) circuit is a promising means of upgrading asynchronous electric drives in mine winders. However, the control range of the DFM speed is limited by an excessive drop in the critical torque and decrease in the rigidity of the mechanical characteristics at a speed reduction. Usage of synchronous mode of DFM operation for high-powered winders is fraught with considerable difficulties, in particular, with the instability of machine operation in this mode. The paper proposes a method for determining and evaluating the effect of the corrective action on the frequency of the rotor additional voltage on the critical torque and the rigidity of the DFM mechanical characteristics; the equivalent structure of a double-fed induction motor with a change in the of the additional voltage frequency on the rotor additional voltage and the results of experimental studies suggesting the possibility and necessity of implementing the method for using the DFM in electric drives of winders are given.