Hexagon voltage manipulating control (HVMC) for AC motor drives operating at voltage limits

This paper proposes a hexagon voltage manipulating control (HVMC) method for ac motor drives operating at voltage limits. The command output voltage can be simply determined by the torque command and the hexagon voltage boundary in the absence of PI control gains, additional MTPV tracking controllers, and observers for closed-loop control. These attributes reduce the time and effort required for the calibration of the controller in the nonlinear voltage-limited region. The proposed hexagon voltage manipulating controller (HVMC) accomplishes the “true” maximum available voltage utilization, allowing a higher efficiency than that of the current vector controller (CVC) alone in the MTPV domain. Model-based voltage control (MVC) or CVC can be performed under the MTPA region and control authority is handed automatically over to the proposed HVMC in the voltage shortage region. Successful application of the control approach has been corroborated by a graphical and analytical analysis. The proposed control approach is potentially applicable to a broad family of control designs for ac drives.