METHOD AND APPARATUS FOR CONTROL OF A SYNCHRONOUS PERMANENT MAGNET MOTOR, PARTICULARLY OVER A LONG CABLE IN A WELL

摘要

A synchronous permanent magnet motor is controlled independently of position sensing means by determining the system parameters including the motor impedance and back-emf and the cable impedance and supplying power according to a predefined voltage:frequency ratio which is determined based on said system parameters to provide a desired rate of acceleration determined by the supply voltage.