Nonlinear load-adaptive MIMO controller for high performance DC motor field weakening

A separately excited DC motor system is modeled by highly nonlinear and coupled differential equations in the field weakening region. A novel constant power field weakening controller, which is based on nonlinear load-adaptive multi-input multi-output linearization, is presented. Due to the effects of coupling and linearization, the controller achieves sized tracking at and desired set point of operation. The results of computer simulation are presented to demonstrate the controller's effectiveness for a representative motor. The performance of this controller is compared with that of the traditional linear PI controllers. It has been shown that the proposed controller provides the globally higher speed control performance, while the motor is operated over a wide dynamic regime of field weakening, even under the presence of load torque disturbance.