A nonlinear time–frequency control based FOC for permanent magnet synchronous motors

Abstract

PI control based field oriented control (FOC) scheme is the predominant method for the control of permanent magnet synchronous motors (PMSMs) in applications requiring high performance. A novel nonlinear time–frequency control based FOC design for the fast, accurate, and robust control of PMSMs is presented. Featuring a single nonlinear time–frequency controller and a PI controller as the 2 primary components in the control configuration, the new scheme is evaluated against a classic PI control based FOC design for performances in response to rapid speed-switching and abrupt external torque variation. The scheme displays significantly smaller steady-state tracking errors undergoing speed shifting and no high frequency current oscillations or electromagnetic torque ripple in the motor, as does the PI based scheme. The tracking errors corresponding to changes in torque are free of distortion and oscillation that would otherwise indicate instability and inaccuracy. Precision positioning control is also realized through incorporating a P controller into the controller configuration. When the motor reference position is briskly flipped between 360° and 1°, the novel controller design is shown to perform well with a rotor position error that is less than 0.13°.