Robust H∞ Control Based on the Mean Value Theorem for Induction Motor Drive

In this paper, a robust H ∞ control for a field-oriented control (FOC) of an induction motor (IM) based on mean value theorem (MVT) was presented and compared with a conventional control. Using the MVT approach and sector nonlinearity transformation after representing the nonlinear model of the IM in the Takagi–Sugeno form, the nonlinear error dynamics of the state feedback system was carried out in a linear parameter variable representation. By using Lyapunov theorem, stability conditions were expressed in terms of linear matrix inequalities (LMIs), whereby the offline gains of the controller can be calculated through the solving of these LMIs. To study the effectiveness of the proposed robust controller, a FOC experiment applied to a ¼ HP IM is conducted and compared with conventional controller. Practical results were investigated and gave a good speed tracking with a minimum effect, even in the presence of unpredictable load torque variations on the tracking error and assuring field orientation.