Nonlinear backstepping with time delay estimation for six-phase induction machine

Abstract

In this paper, a robust nonlinear stator currents controller based on a known nonlinear technique is proposed for a six-phase induction machine. First of all, a proportional-integral regulator is used in an outer loop to control the speed. Secondly, the inner loop based on a nonlinear method that combines the nonlinear backstepping control scheme with the time delay estimation consists of controlling the stator currents. The chosen time delay estimation method can approximate the unmeasurable rotor current while the nonlinear backstepping can achieve good tracking performances. The stability analysis of the current closed-loop error dynamics is provided based on a recursive Lyapunov function. Numerical simulations have been conducted to demonstrate the efficiency and the performance of the developed nonlinear control method for the asymmetrical six-phase induction machine.