Back-to-back three-level double-fed induction motor control system for mine hoist

The stator-flux-oriented vector control strategy for double-fed induction motor was investigated in this paper. Three phase three-level rectifier was used as AC/DC block. This rectifier worked with low harmonic distortion in the grid side. Besides, it maintained a high power factor while the energy flows in bidirectional way. For the DC/AC converter, three-level inverter was adopted. Using stator-flux oriented vector control, the double-fed induction gained a high dynamic performance when the stator side was controlled operating in a unite power factor condition. In this paper a novel simplified space vector pulse width modulation (SVPWM) method was proposed to simplify the calculation. The neutral-point potential balance can be easily realized with this method. The control strategy was verified by experiments.