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.