An Optimal Maximum Torque Per Active Flux and Field Weakening Operation for Deadbeat Direct Torque Control Based IPMSM Drive

This article proposes a new framework for the deadbeat direct torque control for IPMSM. Unlike the conventional deadbeat direct torque and stator flux control (DB-DTFC), the active flux, instead of stator flux, is used as a control variable along with the torque. In the new framework of torque-active flux control, an active flux weakening (AFW) approach is proposed, which enhances the accuracy of flux weakening (FW) operation while reducing computational complexity. The accuracy in AFW operation stems from the inclusion of stator resistance voltage drop. This article also proposes a unique solution for the intersection torque of voltage and current constraints in flux weakening operation. The complexity of solving higher-order non-linear equations for intersection torque is overcome by the proposed solution. In addition, maximum torque per active flux (MTPAF) control up to the base speed is derived in the new control plane. The proposed MTPAF control is inherently simplified than the conventional MTPA control. Theoretical analysis and extensive experimental results demonstrate the effectiveness of the proposed method.