High performance nonlinear MIMO field weakening controller of a separatelyexcited dc motor

This paper presents a novel technique for field weakening implementation of separately excited de motors. A constant power field weakening controller, which is based on nonlinear load adaptive multi-input multi-output (MIMO) linearization technique, is proposed and developed for achieving speed trac king. Due to the effects of decoupling and linearization, it allows the con troller to be implemented and operated at any desired field weakening point of operation. To demonstrate the effectiveness of the proposed controller, the results of computer simulations are presented for a specific motor. Th e performance of this proposed controller is compared with that of the trad itional linear PI controllers. The results show that the proposed controlle r provides the globally higher speed control performance, while the motor i s operated over a wide dynamic regime of field weakening, even under the pr esence of load torque disturbance. (C) 2000 Elsevier Science S.A. Ail right s reserved.