Variable-speed drives incorporating interacting multiloop adaptive controllers

A detailed design procedure for multiloop adaptive controllers for a DC drive is presented. Details of the main features of a partitioned-estimator identification scheme, the controller structure and the pole-placement design procedure are discussed. Results are presented for both twin- and triple-loop adaptive controller configurations. Drive responses obtained with the twin-loop configuration are compared to the corresponding performance obtained with fixed gain controllers. The effects of sampling interval, tuning start-up delay, controller and estimator initialisation and drive parameter variation are discussed, and recommendations are made. The basic transient response of the drive is shown to be insensitive to changes in operating conditions and drive parameters. An important feature is that the adaptive controllers can be implemented from an initial open loop configuration thereby eliminating the need for any detailed a priori design. The responses obtained show that excellent performance can be obtained from the proposed adaptive triple-loop controller scheme over a range of rotor speeds up to 175% of the rated value.