Model Predictive Flux Control With Cost Function-Based Field Weakening Strategy for Permanent Magnet Synchronous Motor

This paper proposes a model predictive flux control (MPFC) strategy with cost function-based field weakening (FW) strategy for permanent magnet synchronous motor (PMSM). The stator flux vector is used as the control variable and the cost function of the proposed MPFC is configured in the form of flux increment, which can reflect the saturation degree of the inverter output. A novel space flux vector plane is introduced to explain the principle of optimal switching state selection in the proposed MPFC. The voltage and current limitations of the inverter in the high-speed region are analyzed in the flux plane to reveal the objective of FW compensation. The value of the cost function is controlled with a proportional integral controller in the proposed cost function-based FW strategy. Moreover, the reference flux vector is compensated with the output of the FW controller to enlarge the operation region of the stator flux vector. With the proposed FW strategy, the operation range of the PMSM is extended and the torque output in high-speed range is increased. Experimental studies are carried out to verify the validity and effectiveness of the proposed strategy.