FPGA implementation of a robust DTC-SVM based Sliding Mode Flux Observer for a double star induction motor: Hardware in the loop validation

Abstract

This paper presents an implementation of a robust Direct Torque Control (DTC)-Space Vector Modulation (SVM) strategy for a Double Star Induction Machine (DSIM) using a Field Programmable Gate Array (FPGA). The proposed control technique combines SVM and DTC strategies, incorporating the Sliding Mode Flux Observer (SMFO) to improve robustness and overcome the drawbacks of stator resistance variations. First, SVM is used to improve DTC performance by reducing torque and flux ripples generated with classical DTC strategies. Then, the SMFO is employed to estimate the mechanical speed and stator flux module, ensuring robustness in the face of stator resistance variations. A comparative study between conventional DTC, DTC-SVM, and DTC-SVM-SMFO is presented. Simulation tests of the three DTC strategies were conducted using Matlab/Simulink tools, demonstrating the robustness and high performance of the DSIM under DTC-SVM-SMFO. To further validate these results, the technique was implemented using Xilinx System Generator (XSG) on a parallel processing software environment, the FPGA Virtex 5. Hardware in the loop results confirms the effectiveness of the DSIM under the improved DTC-SVM-SMFO control strategy.