Torque Derivative Value Manipulated Type Torque Feedback Control for Synchronous Reluctance Motors

In recent years, synchronous reluctance motors (SynRMs) have been evaluated due to features such as being rareearth-free, high-efficiency compared with other rare-earth-free motors e.g., induction motors, and maintenance-free. The field oriented control of AC motors has been generally used for instantaneous torque control. In SynRM, the dq-axes inductances vary significantly depending on the operating point, which results in a deterioration of the torque control performance based on field oriented control using the PI-gains designed by pole-zero cancellation without considering these variations. Here, the authors propose an innovative torque controller based on torque derivative value manipulation which has a low sensitivity against dq-axes inductance variance for high-performance torque control for SynRMs. The effectiveness of the proposed torque control system is verified through experiments and the sensitivity toward inductance variation is analyzed.