Second-Order Terminal Sliding-Mode Speed Controller for Induction Motor Drives With Nonlinear Control Gain

For the high-end industrial application of induction motors (IMs), the speed controller is expected to possess strong torque rejection capability to suppress the speed fluctuation. To accomplish this goal, this article proposes a second-order terminal sliding-mode (SO-TSM) speed controller with nonlinear control gain. First, a SO-TSM manifold is designed to introduce the convergence trajectory without speed overshoot. Second, an integral term control law is constructed to compensate external disturbance with the antiwindup mechanism. The analysis of convergence trajectory shows that the torque rejection capability of the studied method is represented by the gain value of the integral term. Thus, the studied nonlinear control gain can improve the torque rejection capability and suppress the chattering simultaneously. Finally, the experimental results from a 3.7 kW IM test bench reveal the strong torque rejection capability of the studied method.