Direct model reference adaptive control of permanent magnet brushless DC motors

A direct model reference adaptive control (DMRAC) algorithm is applied to the speed control of an inverter driven permanent magnet brushless DC motor. The approximation of the nonlinear system, current limitation and the parameter changes are addressed during the development of this controller. The control is described as an outer loop speed control and an inner current loop control, which has faster dynamics than the speed loop. The adaptive control is applied to the outer speed control loop. DMRAC is compared to an indirect adaptive controller and a standard PI controller. Simulation results show that the two adaptive controllers give similar response and are superior to the PI controller. However, the DMRAC algorithm is simpler to implement.