Novel direct flux and direct torque control of six-phase induction machine with nearly square air-gap flux density

In this paper, a novel control method for a six-phase induction machine with nearly square air-gap flux density is proposed and evaluated. In this method, the stator phase windings alternately act as either flux- or torque-producing phases. In this way, the flux and the torque of the induction machine are directly controlled with no vector transformation used. Theoretical and finite-element analyses are used to calculate, among other things, the torque and the decouple control constant of the drive. The steady-state measured results of a small six-phase induction machine drive with the proposed control scheme implemented show good agreement with calculated results. The proposed control drive system is also shown to have a fast torque response. Index Terms--Direct control, finite-element (FE) analysis, flux, six-phase induction machine, torque.