PID, 2-DOF PID and Mixed Sensitivity Loop-Shaping Based Robust Voltage Control of Quadratic Buck DC-DC Converter

• Published in: Advances in electrical and electronic engineering Vol. 14; no. 5; pp. 551 - 561
• Main Authors: Ounis, Fateh, Golea, Noureddine
• Format: Journal Article
• Language: English
• Published: Ostrava Faculty of Electrical Engineering and Computer Science VSB - Technical University of Ostrava 01.12.2016; VSB-Technical University of Ostrava
• Subjects: dc-dc converters; Electric potential; loop-shaping; Matlab; mixed sensitivity; Noise; pid control; quadratic buck converter; Robust control; Robustness; Sensitivity; Sensors; Voltage
• ISSN: 1336-1376; 1804-3119
• DOI: 10.15598/aeee.v14i5.1821

DC-DC Quadratic Buck Converter (QBC) is largely used in applications where the high step-down conversion ratio is required. In the practical implementation, QBC is subject to uncertainties, disturbance, and sensor noise. To address the QBC control problems, a two-degree of freedom PID (2-DOF PID) is designed in the robust control framework. Further, for comparison purpose, a one-degree of freedom PID (1-DOF PID) and mixed sensitivity loop-shaping (MS-LS) controller are also proposed. Considering QBC parasitic components, the QBC small-signal transfer function is derived based on a practical approach. Sensitivity functions are used to specify the desired design requirements, and non-smooth optimization is used to tune both PID's parameters. The three control structures are implemented and tested in the Matlab/Simulink environment. As attested by simulation results, the 2-DOF PID exhibits a better regulation accuracy with enhanced robust stability and robust performance for a wide range of supply voltage/load variation and sensor noise effect.