Enhanced control of a buck-boost DC-DC converter via a closed-form MPC reference governor scheme

• Published in: IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society Vol. 1; pp. 365 - 370
• Main Authors: Yfoulis, Christos, Papadopoulou, Simira, Voutetakis, Spyridon
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.10.2019
• Subjects: Buck-Boost DC-DC converters; DC-DC power converters; Inductors; Model predictive control; Observers; Optimization; PID type-III compensation; reference governor; State-space methods; Voltage control
• ISSN: 2577-1647
• DOI: 10.1109/IECON.2019.8927486

This paper considers the problem of enhancing the performance of buck-boost DC-DC converters that are already regulated in voltage-mode by a typical PID type-III primary controller. This need may arise in situations where a commercial power converter is not easily replaceable. In these cases improved performance may be obtained with the addition of a secondary controller/prefilter in the form of a reference governor. Recent results in the literature have justified this policy for buck or boost converters. It has been shown that such a complementary scheme, which adjusts the imposed voltage reference signal dynamically, can offer significant performance enhancement in a wide operating range, and without imposing extra requirements or limitations. This work has applied similar concepts to the case of a buck-boost converter topology. An optimal design using a closed-form model predictive control (MPC) methodology is adopted, which is computationally tractable for digital microprocessor implementation. Moreover, contrary to the buck or boost case, the MPC reference governor policy has been found more flexible when applied to buck-boost converters, i.e. offering a better constraints handling ability. These findings are supported by extensive simulation results.