Variable speed master-slave motor control system with continuous position adjustment

Abstract

Abstract A SYSTEM FOR CONTROLLING THE SPEED AND SYNCHRONIZATION OF TWO A-C MOTORS COMPRISES A MASTER VCO (VOLTAGE-CONTROLLED OSCILLATOR) FOR PROVIDING TIMING PULSES TO DRIVE THE MASTER INVERTER WHICH ENERGIZES THE FIRST A-C MOTOR. A SYSTEM SPEED CONTROL POT PROVIDES A SPEED SET SIGNAL TO THE MASTOR VCO, AND ALSO TO A SLAVE VCO WHICH CONTROLS THE SLAVE INVERTER THAT ENERGIZES THE SECOND A-C MOTOR. A PHASE DETECTOR RECEIVES FIRST AND SECOND LOW-FREQUENCY INPUT SIGNALS FROM THE LOADS DRIVEN BY THE MOTORS. A COUNT-UP REGISTER RECEIVES HIGH-FREQUENCY PULSE SIGNALS FROM THE MASTER VCO AND, THROUGH A DAC (DIGITAL-TO-ANALOG CONVERTER), PROVIDES A POSITIVE-GOING RAMP SIGNAL WHICH HAS ITS RESET PORTION DETERMINED BY AN OUTPUT SIGNAL FROM THE PHASE DETECTOR. A COUNT-DOWN REGISTER RECEIVES HIGH-FREQUENCY PULSE SIGNALS FROM THE SLAVE VCO, THROUGH ANOTHER DAC, PROVIDES A NEGATIVE-GOING RAMP SIGNAL WHICH HAS ITS RESET PORTION DETERMINED BY A SECOND RESET SIGNAL FROM THE PHASE DETECTOR. THESE OPPOSITE-SLOPE RAMP SIGNALS ARE SUMMED WITH A SIGNAL FROM THE PHASE DETECTOR TO PROVIDE A D-C CONTROL SIGNAL WHICH IS USED AS A SECOND INPUT SIGNAL TO THE SLAVE VCO, THUS MAINTAINING MOTOR SYNCHRONIZATION. AN OUT-OF-SYNC SIGNAL OVERRIDES THE D-C CONTROL SIGNAL AND PROVIDES A MODIFIED D-C SIGNAL TO THE SLAVE VCO TO DRIVE THE SECOND MOTOR TOWARD SYNCHORNIZATION. THE D-C CONTROL SIGNAL CAN ALSO BE MODIFIED BY A POSITION CONTROL SIGNAL, TO PROVIDE AN UNLIMITED POSITION VARIATION OF THE SECOND A-C MOTOR WITHOUT DISTURBING THE SYNCHRONIZED SPEED RELATIONSHIP OF THE TWO MOTORS. D R A W I N G

Inventors

• 👤 B Bejach
• 👤 E Bernhardt

Bibliographic Details