A Robust Field-Weakening Algorithm Based on Duty Ratio Regulation for Direct Torque Controlled Synchronous Reluctance Motor

This paper presents a robust field weakening method for the direct torque controlled (DTC) synchronous reluctance motors (RSMs). The proposed method ensures a smooth and stable transition between the maximum torque per ampere and field weakening including the maximum torque per flux regions. In addition, it is also robust to the variation in the machine dq-axes inductances in the field weakening region. The proposed algorithm is amalgamated with a duty ratio regulation based DTC to achieve high performance torque and flux control in the field weakening region. The effectiveness of the RSM drive is verified by both simulations and experiments.