Method and system for motor speed control

摘要

This invention relates to methods and devices for motor speed control. The invention has particular application in the control of motors over packet networks. In embodiments of the invention, phase-locked loop principles are used to remotely control the speed of an electric motor over a packet network. The setpoint for the motor is supplied by arriving timestamps from a speed-mapped variable frequency source. The shaft speed of the motor is measured with a tachometer with its output proportional to the motor speed. Any deviation of the actual speed from the setpoint is amplified by the power amplifier whose output drives the motor. Speed control over packet networks allow smoother operation of a process, acceleration control, different operating speeds for each process recipe, compensation for changing process variables, slow operation for setup purposes, adjustments to the rate of production, accurate positioning, and control torque or tension of a system.

主权项

1. A system for controlling the speed of a motor, the system including:
the motor; and an analogous phase locked loop connected to a network and arranged to receive a timing signal from that network and to control the speed of the motor according to that timing signal, wherein the analogous phase locked loop is arranged to generate an error signal which is the difference between the timing signal received from the network and a counter signal from a counter which is incremented according to the speed of the motor, and to adjust the speed of the motor according to the error signal.