Fractional Order Pole Placement for a buck converter based on commensurable transfer function

• Published in: ISA transactions Vol. 107; pp. 370 - 384
• Main Authors: Ayres, Florindo A. de C., Bessa, Iury, Pereira, Vinicius Matheus Batista, da Silva Farias, Nei Junior, de Menezes, Alessandra Ribeiro, de Medeiros, Renan L.P., Chaves, João Edgar, Lenzi, Marcelo K., da Costa, Carlos Tavares
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2020
• Subjects: Commensurable Order Transfer Functions; DC/DC power converter; Fractional order control; Fractional Order Pole Placement; Fractional order three terms transfer function; Pseudo damping factor; Fractional Order Pole Placement; Fractional order three terms transfer function; Fractional order control; DC/DC power converter; Pseudo damping factor; Commensurable Order Transfer Functions
• ISSN: 0019-0578; 1879-2022; 1879-2022
• DOI: 10.1016/j.isatra.2020.07.034

In this work, a novel methodology for tuning fractional order controller, so-called fractional order pole placement (FOPP) is proposed. The proposed methodology extends classical (integer order) pole placement technique, using commensurable transfer functions for representing fractional order controllers and placing the fractional dominant poles within an extended stability region based on three terms fractional transfer functions. The designed fractional order controller can be digitally implemented by using the Oustaloup integer approximation of the fractional order dynamics with Hankel model reduction. The proposed FOPP is used to design fractional order controllers for a DC/DC buck converter. The experimental tests include comparisons between the proposed FOPP and other tuning methodologies for integer and fractional order controllers for the DC/DC buck converter that is subject to load, parametric, and load variations. Integral indices are computed to aid the assessment of the control strategies with respect to the robustness, performance specification compliance, and control effort. The results show that the proposed method outperforms the other approaches when occurs the variations. •A novel methodology for fractional order pole placement (FOPP) is proposed.•The fractional damping and order are chosen to ensure the desired performance.•The FOPP extends the stability region relaxing the design conditions.•The methodology is applied to a buck converter under parameter variations.•The FOPP is outperforms other integer and fractional order approaches.