Direct Flux-Vector Oriented Control for Interior Permanent Magnet Synchronous Motor

Direct torque control or direct torque and flux control have significant advantages in operating motors in the field-weakening (FW) region. The flux can be controlled simply in the stator flux linkage frame, directly affecting back-EMF, torque, and speed. However, controlling the current limit under the stator flux frame has not been investigated extensively, especially for FW operation. This paper analyzes the trajectory of the flux regarding the fed current form inverters and the characteristic current. From the analysis, a novel Direct Flux Control is proposed as a promising controller for interior permanent magnet synchronous motor (IPMSM) functioning across an extensive speed range. Then, the performance of the proposed method is compared with the conventional direct torque control method. The analysis results reveal that the torque and flux ripples of the proposed method are reduced, the maximum speed is increased compared to the conventional controller. Finally, simulation results by using MATLAB/Simulink are provided, and the hardware-in-the-loop validates and demonstrates the feasibility and performance of the proposed method.