METHOD AND SYSTEM FOR CONTROLLING INDUCTION MOTORS

摘要

The speed of an induction motor fed from a frequency converter is controlled by controlling the primary current by a primary current vector. To this end, a digital quantity corresponding to the slip frequency is sequentially added at a predetermined interval, and a digital quantity proportional to the angle of rotation is added to obtain a sum value. Then the primary current vector is computed from the sum value and a current component which influences only the torque to control the frequency converter. The method is suitable to be carried out with a microcomputer.