Extended Multi-Operating Mode Control Strategy for Five-Phase Flux-Intensifying Interior Permanent Magnet Motor Based on VSI-MTPA and FW Control

Based on virtual-signal-injection-based maximum torque per ampere (VSI-MTPA) control and flux-weakening (FW) control, an extended multi-operating mode control strategy is developed for the five-phase flux-intensifying interior permanent magnet (FI-IPM) motor in this paper. Due to the special inverse saliency characteristics of the FI-IPM motor, the traditional VSI-MTPA control strategy suffers from the issue of insufficient tracking accuracy of MTPA points, or even cannot be directly applied to the FI-IPM motor. Additionally, the conventional FW control strategy will also face a situation where the reluctance torque is below zero, which will further decrease the load capacity of the motor. Hence, to achieve efficient operation of the five-phase FI-IPM motor under multiple operating conditions, the extended VSI-MTPA control strategy and the adaptive third-harmonic injection FW control strategy are innovatively proposed for flux-intensifying (FI) region and FW region, respectively. By introducing a compensation factor into the virtual torque, the precise tracking accuracy of MTPA points can be achieved in the FI region. Also, with the injection of the adaptive third-harmonic, the torque performance can be further improved and the speed range can be expanded in the FW region. Finally, the effectiveness of the proposed control strategy is verified by experiments.