FPGA-based intelligent control of AC motors

Abstract

The most commonly used controller in the industry field is the proportional- plus-integral (PI) controller, which requires a mathematical model of the system. Fuzzy logic controller (FLC) provides an alternative to conventional PI controller, especially when the available system models are inexact or unavailable. Also, rapid advances in digital technologies have given designers the option of implementing controllers using field programmable gate array (FPGA) which depends on parallel programming. This method has many advantages over classical microprocessors. In this research work, a FLC, which is fabricated on modern FPGA card (Spartan-3A, Xilinx Company), is proposed to implement a prototype of a speed controller for three-phase induction motor (squirrel cage type). The FLC and the PWM inverter strategies which have been built in FPGA appeared fast speed response and good stability in controlling the three-phase induction motor. For comparison purpose, a conventional PI controller has been implemented in the same FPGA card to examine the performance of the FLC. These controllers have been tested using MATLAB/Simulink program under various reference speeds. The designed FPGA-based closed-loop FLC’s performance is weighed against with that of a conventional PI controller. The system has been simulated in MATLAB/ Simulink, and the results have been attached. The simulation and experimental results obtained using a FPGA-based conventional PI controller and the FPGAbased FLC have been compared in terms of settling time, and it has been found out that the proposed FPGA-based FLC shows a better performance than the conventional PI controller.