SYSTEM AND METHOD FOR INDUCTION MOTOR SPEED ESTIMATION USING A SOFT STARTER SYSTEM

摘要

A system and method for estimating operating characteristics of an induction motor is disclosed. The system includes a motor control device that is electrically connectable between a motor and a power source. The motor control device includes a plurality of switching devices comprising at least one thyristor corresponding to a respective phase of the motor. The motor control device also includes a controller programmed to disconnect the power source from the motor for a predetermined time period following a first plurality of cycles of a mains phase voltage of the power source. The controller is further programmed to measure a back-emf voltage during the predetermined time period, estimate an operating characteristic of the motor from the measured back-emf voltage, and trigger the plurality of switching devices to reconnect the power source to the motor following estimation of the operating characteristic.

主权项

1. A motor control device electrically connectable between an AC motor and an AC power source, the motor control device comprising:
a plurality of switching devices comprising at least one thyristor corresponding to a respective phase of the AC motor and a controller programmed to:
disconnect the AC power source from the AC motor for a predetermined time period following a first plurality of cycles of a mains phase voltage of the AC power source;measure a back-emf voltage during the predetermined time period;estimate an operating characteristic of the AC motor from the measured back-emf voltage; andtrigger the plurality of switching devices to reconnect the AC power source to the AC motor.