Control of twin, geared electric motor drives of withdrawal conveyor serving plastic profile extrusion plant, employs programmable system of frequency converters sensing and correcting differential speed and torque

摘要

Each drive employs a preferably geared electric motor, an angular sensor and a frequency converter with control software. The frequency converter casing includes configurable and/or freely programmable control, with interfaces exchanging data. Connections, construction and motor control assure identical withdrawal conveyor speeds. An Independent claim is included for corresponding control equipment. Preferred features: Synchronous or asynchronous motors are employed. Software control is provided with includes suitable I/O interfacing. One drive operates as master, the other as slave, the former sending data to and/or receiving it from the latter. They operate under speed control. Programmable control of the slave drive frequency converter, varies torque or current vector to achieve required slave speed. A control algorithm, based on a proportionality factor operating on the differential torque between slave and master, is employed. An alternative algorithm is proposed. Further variants based on the foregoing principles are described. Limiters and proportionality factor adjustments are included.