Direct Torque Control Based on a Fast Modeling Method for a Segmented-Rotor Switched Reluctance Motor in HEV Application

Abstract

This article proposes a fast-nonlinear modeling method for the direct torque control (DTC) of a segmented-rotor switched reluctance motor (SSRM), excluding the rotor clamping device. First, the torque-balanced method is used to measure the flux-linkage values at five crucial positions. The flux-linkage profile of the SSRM is represented by the fourth-order Fourier series based on the measured values. Then, the Kriging model is employed to further describe flux linkage and torque characteristics based on the Fourier series. A combination of Fourier series and Kriging model can greatly incorporate their merits and improve the accuracy of the models. Compared with the conventional methods, the finite-element analysis data are not required for the modeling process in the proposed method. Finally, the simulations and experiments of the DTC and the current chopping control (CCC) methods based on the modeling method are carried out. The amplitude of flux linkage under DTC can be well controlled, while that under CCC is increased with the enlargement of load torque. Compared with the CCC mode, DTC greatly reduces the torque ripple and exhibits the better speed response, while the torque per ampere with CCC mode is higher.