VHDL design and FPGA implementation of direct torque control for induction machines

This paper presents a VHDL design and an FPGA Implementation of a direct torque controller (DTC) used to control induction machines (IM). The use of FPGA at high sampling frequency reduces the torque ripple while maintaining the classical DTC control structure. We have adopted a modular approach, by dividing the global entity into a set of elementary blocks designed and implemented separately, placing all the blocks inside high-level design using component instantiation, and connecting up all the components to each other using port mapping. The performances of this command are to reduce the torque ripple to 0.01Nm and the flux ripple to 0.01wb with a circuit implementing DTC control of 3,256 LEs of complexity and 64 latency clock cycles. To evaluate the performance of our FPGA circuit implementing DTC control, we have performed a co-simulation platform based on Matlab / Simulink and Modelsim programs. Matlab / Simulink was used to simulate the dynamics of the induction machine associated with its inverter and the proposed DTC control strategy was executed under the Modelsim software using the VHDL fixed point. We have operated our circuit FPGA in the loop in a speed variation platform of induction machines and we have obtained the following performances: A zero overrun, response time at speeds of 300 ms and a zero static error as required in the specifications.