Control system for controlling revolution speed of electric motor.

摘要

A motor speed control system takes one approach to establish dummy load models having characteristics equivalent to an electric motor to be controlled. One of the dummy load model is established for feedback controlling the electric motor on the basis of the speed of the dummy model. The dummy model is divided into first and second models. The first model is designed to have equivalent characteristics to output a first motor speed representative data. The current to supply to the first model is so adjusted as to reduce a difference between the motor speed representative data and a desired motor speed data to zero. A frequency signal is added to the current applied to the first model and supplied to the electric motor to drive the latter. The second model receives the frequency signal to output a frequency signal dependent second motor speed representative value. Sum of the first and second motor speed representative value is compared with a measured motor speed indicative value to derive a speed difference compensation value based on the error therebetween. Based on the speed difference between the sum value and the measured motor speed and the frequency signal, intertia condition on the motor is assumed for controlling transfer characteristics so that the inertia condition in the first model becomes coincident with that of the motor.