Fractional-order electromagnetic modeling and identification for PMSM servo system.

An accurate electromagnetic model is essential for an optimal controller tuning of the high-performance servo system. This paper proposes a fractional-order electromagnetic model of a permanent magnet synchronous motor (PMSM) servo system and an identification methodology of this model. The reason why the investigated electromagnetic model should be a fractional-order one is addressed with a detailed explanation. The influence of voltage source inverter nonlinearity, which may cause system identification error, is analyzed. An improved inverter nonlinearity model and compensation method are proposed to promote the accuracy of the model parameter identification. Compared with the existing typical electromagnetic models of the PMSM servo system, the current open-loop and closed-loop experiments prove that the proposed fractional-order electromagnetic model with time delay is more accurate for the actual physical system. The effectiveness of the proposed nonlinearity modeling and compensation scheme of the inverter is also verified on an experimental PMSM servo system. • A fractional-order electromagnetic model with time delay, considering the complete servo platform with PMSM, servo drive circuit, inverter nonlinearity, and digital delay, is proposed. • An identification methodology for fractional-order electromagnetic model is proposed. An improved inverter model based on a sigmoid function is used for voltage error compensation to improve the accuracy of parameter identification. • The experimental results on the PMSM current control platform demonstrate that the proposed model is more accurate than the traditional integer-order model. [ABSTRACT FROM AUTHOR]