Control method suitable for direct torque control based motor drive system satisfying voltage and current limitations

This paper proposes a control method suitable for limited armature voltage and current in a permanent-magnet synchronous motor drive system based on direct torque control. First, this paper proposes torque-limiting and flux-weakening control that is suitable for a direct torque control based motor drive system. The proposed method utilizes a mathematical model in a rotating reference frame synchronized to the stator flux linkage. Second, this paper proposes an anti-windup scheme for the torque controller of the direct torque control system. Wind-up of the controller degrades the performances of torque-limiting (current-limiting) control and of torque control. Applying the anti-windup results, improves the performance of the proposed torque limiting method in the transient state. This paper presents a direct torque control based drive system combined with a speed controller. The proposed system can achieve stable control, and its effectiveness is confirmed experimentally.