Comparison between sliding model control and vector control for a DSP-based position control applied to squirrel-cage induction motor

The principle of vector control of AC machine enables the dynamic control of AC motors, and induction motors in particular to a level comparable to that of a DC machine. The vector control of currents and voltages results in control of spatial orientation of the electromagnetic fields in the machine and has led to term field orientation [1]. Field oriented control schemes provide significant improvement to the dynamic performance of ac motors. The usual method of induction motor position and torque control, which is becoming an industrial standard [2], uses the indirect field orientation principle in which the rotor speed is sensed or estimated by rotor position and slip frequency is added to form the stator impressed frequency. Sliding-mode control has gained wide attention because of its simple design and implementation, fast dynamic response, and robustness to parameters variations and load disturbances. This paper proposes a performance comparison between sliding mode-control and field oriented control using synchronous reference applied to a small squirrel-cage induction motor using space vector pulse width modulation(SVPWM) for position and torque control and a digital signal processor and relay feedback method to evaluate the controller parameters.