Optimized feedback type flux weakening control of non-salient permanent magnet synchronous machines in MTPV region with improved stability

This paper introduces an enhanced approach for optimizing the flux-weakening performance of a non-salient permanent magnet synchronous machine (PMSM), by incorporating the maximum torque per voltage (MTPV) region into a conventional voltage magnitude feedback control strategy. The MTPV control strategy is initially optimized for steady-state performance by incorporating the effect of resistance, which plays a crucial role in small power motors. To maintain stability and good dynamics in the flux-weakening region, a current command feedback MTPV controller is utilized, as opposed to a voltage command feedback approach. Additionally, to address stability concerns in the MTPV region, a feedback type proportional-integral (PI) MTPV controller is designed and implemented. The stability in both the over-modulation and various flux-weakening regions is further enhanced using a voltage vector modifier (VVM). Therefore, the proposed feedback-based flux-weakening control enhances system steady-state performance, dynamic response, and stability across both linear and over modulation regions under various flux-weakening conditions, making it suitable for general-purpose applications. The effectiveness of the proposed method is validated through experimental results.