The design of the speed controller greatly affects the performance of an electric drive. A common strategy to control an induction machine is to use direct torque control combined with a PI speed controller These schemes require proper and continuous tuning and therefore adaptive controllers are proposed to replace conventional PI controllers to improve the drive\u27s performance. This paper presents a comparison between four different speed controller design strategies based on artificial intelligence techniques: two are based on tuning of conventional PI controllers, the third makes use of a fuzzy logic controller and the last is based oil hybrid fuzzy sliding mode control theory. To provide a numerical comparison between different controllers, a performance index based on speed error is assigned. All methods are applied to the direct torque control scheme and each control strategy has been tested for its robustness and disturbance rejection ability. (C) 2008 Elsevier B.V. All rights reserved
