METHOD FOR CONTROLLING PHASE-WOUND MOTOR Russian patent published in 2003 - IPC

FIELD: electrical engineering; ac drives. SUBSTANCE: method for controlling phase-mound induction motor that has slip rings, rotor impedances, thyristors or triacs and is designed for use in ac drives for hoisting and traveling crane mechanisms operating at reduced (creep) speeds involves estimation of thyristor turn-on moment by comparing setting and reference voltages whose leading edges are mainly monotonously varying across operating sections and turn-on of thyristors or triacs at time moments determined in this way. This turn-on moment is determined for each thyristor or triac irrespective of other ones and its respective reference voltage is generated from actual voltages across supply mains by summing them up and filtering off using different factors and time constants. EFFECT: provision for parametric speed regulation at limited torque fluctuations. 3 cl, 9 dwg