The Study of Direct Torque Control Based Counter-Tangent Function

A main shortcoming of direct torque control in permanent magnet synchronous motor (PMSM) is high torque ripple, one of important factors is the variation of stator resistance according to the peripheral environment. Aiming at the influence of this factor, a new direct torque control means is proposed. Embedding a module which compensates stator resistance based on counter-tangent function into the control system. The input of the function module is the error between actual flux value and reference flux value as its input, and the output is the variation value of stator resistance. The simulation results verify the validity of the method. The algorithm can improve the ripple of the flux and torque, and enhance the robustness of the system.