Adaptive fuzzy fractional-order sliding-mode control of LCL-interfaced grid-connected converter with reduced-order

Bo Long; PengJie Lu; Danny Zhan; Xin Lu; José Rodríguez; Josep M Guerrero; Kil To Chong

doi:10.1016/j.isatra.2022.06.022

Adaptive fuzzy fractional-order sliding-mode control of LCL-interfaced grid-connected converter with reduced-order

ISA Trans. 2023 Jan:132:557-572. doi: 10.1016/j.isatra.2022.06.022. Epub 2022 Jun 20.

Authors

Bo Long¹, PengJie Lu², Danny Zhan³, Xin Lu⁴, José Rodríguez⁵, Josep M Guerrero⁶, Kil To Chong⁷

Affiliations

¹ Yangtze Delta Region Institute (Huzhou) & School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Huzhou 313001, China. Electronic address: longbouestc1980@126.com.
² Yangtze Delta Region Institute (Huzhou) & School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Huzhou 313001, China. Electronic address: lpjuestc@126.com.
³ School of ENSEA, Institute for Electric Vehicle Driving System and Safety Technology, University of Electronic Science and Technology of China, Chengdu, China. Electronic address: danny.zhan@ensea.fr.
⁴ School of Automation Engineering, Institute for Electric Vehicle Driving System and Safety Technology, University of Electronic Science and Technology of China, Chengdu, China. Electronic address: 1187875086@qq.com.
⁵ Faculty of Engineering, Universidad Andres Bello, Santiago 8370146, Chile. Electronic address: jose.rodriguez@unab.cl.
⁶ Department of Energy Technology, Aalborg University, DK-9220 Aalborg, Denmark. Electronic address: joz@et.aau.dk.
⁷ Department of Electronics & Information Engineering, Chonbuk National University, Jeonju 567, Republic of Korea. Electronic address: kitchong@jbnu.ac.kr.

PMID: 35778111
DOI: 10.1016/j.isatra.2022.06.022

Abstract

This paper proposes a discrete-time fuzzy fractional-order sliding-mode control (Fuzzy-FOSMC) dual loop current controller for a three-phase LCL-type grid-connected converter (GCC) with reduced order. Conventional sliding-mode control (SMC) has been widely used in GCC due to its robustness to disturbances. However, the chattering in SMC may reduce the tracking performance of the controller, and even lead to system instability. To solve this problem, a Fuzzy-FOSMC controller is proposed in this paper. The introduced fractional-order term can suppress the chattering, and the fractional-order of FOSMC is further adjusted by the fuzzy controller to improve the overall system performance. In addition, the inner loop is implemented by a Fuzzy-FOSMC controller to ensure the tracking of the converter-side current, making the LCL-GCC converter behave like a controllable current source converter with a capacitive-inductive filter, the grid current control problem falls from a third-order to a reduced order system, which solves some difficulties on the design of most controller types. The stability of the two-stage PV system is analyzed. Finally, the effectiveness of the proposed controller is verified by experiments.

Keywords: Active damping; Discrete-time fuzzy fractional-order sliding mode control (Fuzzy-FOSMC); LCL filter; QPR controller.