Design and FPGA implementation of 1-degree-of-freedom discrete PID controller for power switching converter

This paper describes the design, simulation, optimisation and implementation of a 1-Degree-of-Freedom (1-DOF) discrete PID controller for the buck converter working in Continuous Conduction Mode (CCM) based on Field Programmable Gate Array (FPGA) device. The converter operates at a switching frequency of 500 KHz. The elaborated PID control algorithm takes advantage of the conjugation of Xilinx ISE digital designing environment with MATLAB/Simulink simulation and testing environment, through Xilinx System Generator toolbox. This results in a faster and efficient design flow. First the PID controller is designed using Simulink Control Design Toolbox or `sisotool´ from MATLAB to generate the required set of compensator coefficients to meet the start-up and the transients characteristics. The controller is then realized using Xilinx System Generator (XSG) Blockset. The design example certifies the validity of the classical discrete 1-DOF PID controller as an efficient, more compact and reliable control method for rapid system prototyping for designs developed using the MATLAB/Simulink environment.