Comparative Stability Analysis of PMSMs under Feedback FluxWeakening Control

The flux-weakening (FW) method is employed to extend the operation speed range and maximize the torque/power capability. Compared to the feedforward FW control method, the feedback FW control method is simple and robust against parameter mismatches. In this paper, based on the field-oriented control strategy and small signal analysis, the stabilities of two forms of feedback FW control methods are investigated: d-axis current-based voltage feedback FW control (DCVFC), utilizing the dq-axis coordinate system, and current angle-based voltage feedback FW control (CAVFC), employing the polar coordinate system. Firstly, the stability characteristics of two FW control methods are analyzed in interior permanent magnet synchronous machines (IPMSMs) and surface-mounted permanent magnet synchronous machines (SPMSMs), respectively. Subsequently, comparative analyses are performed between IPMSMs and SPMSMs under the two FW control methods. Experiments are conducted on both IPMSM and SPMSM to validate the stability performance. The results indicate that there are inherent differences not only between the DCVFC and CAVFC methods when applied to the same machine but also between IPMSM and SPMSM machines when the same FW control method is utilized.