A switchable DB-PI controller for DC-motor drives with transient requirements

A reliable and rugged controller design for controlling the transient response of the armature current of a DC motor using a dead-beat-proportional-plus-integral (DB-PI) controller is described. A modified finite-settling-time technique, a type of DB controller, is used as the start-up algorithm. The controller is designed in such a manner that the armature current does not exceed a certain limit when the motor is subjected to the most severe input expected. For smaller inputs than this one. the current certainly will not exceed that limit. A DB controller is designed so that the armature current does not exceed twice the nominal motor current. Then, a traditional PI controller is designed to meet the operation specification with regard to constant speed/position, percentage overshoot, risetime, and steady-state error. A switching mechanism is introduced so that proper coordination between the two controllers can take place. Simulation results are presented