DISPOSITIF ET PROCEDE PERMETTANT DE FAIRE FONCTIONNER UN MOTEUR ASYNCHRONE DANS UN MODE A GLISSEMENT ELEVE, AVEC UNE ROTATION ET UN COUPLE PRATIQUEMENT NULS

• Main Author: LOREN HAINES WALKER ET JOHN HOFFMAN CUTLER
• Format: Patent
• Language: French
• Published: 21.11.1980
• Subjects: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORSOR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; GENERATION

L'INVENTION CONCERNE LA COMMANDE DES MOTEURS ELECTRIQUES.UN DISPOSITIF 10 EST ASSOCIE A UN SYSTEME DE COMMANDE D'UN MOTEUR ELECTRIQUE 18 POUR FAIRE FONCTIONNER CE MOTEUR DANS UN MODE A GLISSEMENT ELEVE AVEC UN COUPLE PRATIQUEMENT NUL ET UNE ROTATION PRATIQUEMENT NULLE. DANS CE BUT, LORSQUE LE SYSTEME PLACE LE MOTEUR DANS UN ETAT A ROTATION ET COUPLE PRATIQUEMENT NULS, AVEC UNE FREQUENCE DU COURANT D'ATTAQUE PRATIQUEMENT NULLE, LE DISPOSITIF REGLE LA VALEUR DU COURANT D'ATTAQUE A UN NIVEAU PREDETERMINE ET IL ELEVE RAPIDEMENT LA FREQUENCE DE CE COURANT POUR PRODUIRE UN GLISSEMENT RELATIF SUPERIEUR A 0,1.APPLICATION A LA COMMANDE DES MOTEURS ASYNCHRONES. Apparatus and method for high slip operation of an AC electric motor at substantially zero rotation and substantially zero torque in an AC electric motor drive system is disclosed. The electric motor produces a rotation in response to an outgoing signal, such as a drive current, of variable magnitude and frequency supplied by the drive system. An idle control signal is furnished when the drive system is in a substantially zero rotation and substantially zero torque state, where the frequency of the current is approximately zero. The idle control signal causes substantially simultaneously an adjustment of the magnitude of the current to a predetermined magnitude level and a rapid raising of the frequency of the current to a higher frequency value to produce per-unit slip s=(n1-n)/nb greater than 0.1, where n1 is the synchronous rotation of the stator field of the motor, n is the rotation of the rotor of the motor, and nb is the synchronous speed of the stator field at motor rated rpm. The adjustment in the magnitude and the rapid increase in the frequency of the current causes the motor to produce substantially zero rotation and substantially zero torque because the motor is operating in the high slip region of its torque-rotation curve. The apparatus and method of the present invention allows the motor to accelerate rapidly on command from the substantially zero rotation and substantially zero torque high slip mode.