Direct Torque Control of Induction Motors Based on Double-Fuzzy Space Vector Modulation Technology

A new direct torque control (DTC) strategy of induction motors based on double-fuzzy space vector modulation (SVM) was proposed. In conventional SVM-DTC, two PI controllers were used to generate reference voltage vector. The parameters of PI controller are difficult to determine. In order to improve away the disadvantages of conventional SVM-DTC system, flux and torque fuzzy controller were designed to substitute the original flux and torque PI controller. The flux and torque fuzzy controller has two inputs (flux/torque error and its change rate) and one output (the flux/torque component of reference voltage vector). Simulations were carried out to verify the proposed strategy, and the simulation results were compared with conventional SVM-DTC. The simulation verifies that double-fuzzy SVM-DTC is capable of effectively improving the control performance, especially the new strategy can improve low-speed performance of SVM-DTC system.