Research on the Optimal Control Strategy for the Maximum Torque per Ampere of Brushless Doubly Fed Machines

Abstract

This paper presents an optimization strategy for a brushless doubly fed motor (BDFM) to achieve the maximum torque per ampere (MTPA). This method resolves the issue of high stator currents in slip frequency vector feedback linearization control (SFV-FLC) during both no-load and light-load conditions. Firstly, the paper establishes a reduced-order state-space (SS) model of the BDFM in arbitrary rotating reference coordinates. Secondly, the expression of BDFM is obtained after the control motor rotor field orientation. To ensure a minimal stator current at a specific torque, this paper constructs an auxiliary function based on Lagrange’s theorem, which forces the control motor stator current derivative to be zero, resulting in the MTPA criterion. Finally, the superiority of the MTPA optimization algorithm proposed in the paper is validated through simulation experiments.