No abstract

A novel field-weakening technique has been investigated for separately excited DC motor systems that exhibit considerable nonlinearities. Based on proper selection of a Lyapunov function, an adaptive multi-input multi-output backstepping field-weakening control law has been derived for speed tracking. Because of the decoupling effect, this controller achieves speed tracking at any desired set point of operation. Computer tests are carried out for a specific motor to demonstrate the effectiveness of the proposed controller. It has been shown that the controller provides the globally robust speed control performance, while the motor system is operated over a wide dynamic regime of field weakening, even under the presence of uncertainties in both parameters and load torque.