Digital adjustment of control algorithms for asynchronous variable frequency drives used in transports of continuous production lines

The article presents proposals on how to adjust the dynamics of asynchronous variable frequency drives used in production equipment. Several papers and patents show that dynamic positive feedback (DPF) on the active current of the motor stator yields significant improvement in static speed accuracy and dynamic process quality. However, analog hardware implementation of this adjustment in drives of production machines is both inefficient and cost-ineffective. This article shows how such adjustment could be implemented in industrial controllers originally designed to work with frequency converters (FC) as process parameter controllers. It further shows that this approach opens up broad opportunities to use standard hardware and software in better asynchronous drive control algorithms.