Control schemes for field weakening of induction machines: A review

This paper provides an extensive overview of the control schemes that can be used for field-weakening operation of induction motors. Although almost all commercial drives offer this capability, a multitude of solutions have been proposed and the need of a classification arises. Therefore this paper attempts to illustrate the most used solutions that can be found in the literature. The control schemes can be classified according to different criteria, such as the control principle, the method used for the calculation of the optimal flux level (look-up tables, explicit equations, regulator-based solutions), the robustness against variations of the machine parameters and the exploitation of the dc-link voltage.