System Identification of a DC-DC Buck Converter Based on Two-Channel Relay Method

This work presents a system identification approach based on a two-channel relay applied to a DC-DC buck converter operating in closed-loop with a PI controller to regulate its output voltage. The implemented two-relay method allows system identification while the system is running online. Moreover, the algorithm works in a closed-loop configuration while introducing a minimal perturbation in the converter's operation. The presented algorithm was used to identify the frequency response of the converter with no-prior knowledge about the system structure. Furthermore, the identified transfer function parameters has a good agreement with the mathematical model of the converter. Simulation results of the comparison between the switching model, mathematical model and the identified model are provided to validate the theoretical analysis.. Authors: AlZawaideh, Ayman [North Carolina State University, Raleigh, NC (United States); NCSU]; Tu, Hao [North Carolina State University, Raleigh, NC (United States)]; Lukic, Srdjan [North Carolina State University, Raleigh, NC (United States)]. DOE Contract: AR0001580. Subjects: 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; DC-DC converters; Describing function; two-channel relay