Steady-State Torque Control System with Secondary-Current Feedback for 3 Phase Squirrel-Cage Induction Motors

Abstract

This paper presents a highly stable steady state torque control system with a feedback of a secondary current signal.
The torque control system is constructed with a feedback of the secondary current (I₂) signal using a quick response magnetic-field sensor constructed with an amorphous core multivibrator bridge, which can solve the secondary resistance change problem for temperature variation in the IM. Moreover, we added a state feedback to the system to improve the response speed for the unit step function of a torque order.
The I₂ sensor method has advantageous especially at a low-speed range, in which conventional method using an integrator shows control errors.