Current control of induction motors at low speeds

Current control of an inverter/induction motor system is considered for the special situation of a position control system where speed is low. The study concentrates on switching-line-type controllers, including the hysteresis controller, since they are simple to implement. Investigations are made of the effects of clocking the controller, injecting zero sequence into the current reference, and rotating the switching lines. These modifications are shown to yield significant improvements in current control for both large and small disturbances