A new torque control technique is presented for a high performance control of a brushless direct drive motor(BLDDM). In order to reduce the torque pulsation caused by the non-sinusoidal flux distribution of the BLDDM, an instantaneous torque control technique is proposed in this paper. The linkage flux of the BLDDM is first estimated by using the model reference adaptive system(MRAS) technique and the instantaneous torque of the BLDDM is then estimated from the mathematical model including this estimated linkage flux. By using the estimated instantaneous torque of the BLDDM, the minor torque control loop to suppress the undesirable torque pulsation is designed. To show the effectiveness of the proposed control scheme, the simulations and experiments are carried out for the DSP-based BLDDM drive system with a power rate of 120W. It is well demonstrated from these results that the torque and speed control performance of the BLDDM is much improved by employing the proposed control scheme.
