永久磁石同期モータを駆動する直接トルク制御のためのトルクと磁束の指令値作成法とトルク制御器のワインドアップ対策

抄録

This paper discusses a permanent magnet synchronous motor (PMSM) drive system based on direct torque control. First, in this paper we propose a novel torque-limiting and flux-weakening method. Torque limiting method capable of current limiting is based on the power equation instead of the motor model in the rotating d-q frame, which is synchronized to the rotor magnet. In this torque limiting method, the motor parameters need not be determined and this simplifies the limitation calculation. The proposed method incorporates a flux-weakening control that does not require motor parameters other than the armature resistance. These proposed schemes are implemented in a calculator for calculating the reference torque and reference flux. Second, we also propose an anti-windup scheme for torque control based on proportional and integral control. Generally, the controller winds up when the terminal output voltage of the inverter is saturated. The wind-up degrades the torque limiting and torque control performance. In the proposed anti-windup scheme, the gain of the integral element is varied on the basis of the degree of voltage saturation, which is detected by using the estimated flux-linkage. In this paper, the direct-torque-control-based drive system combined with a speed controller is presented, and the proposed system achieves stable operation. The proposed system is validated through experiments.