Sliding Mode Control of a Three-Phase AC/DC Voltage Source Converter Under Unknown Load Conditions: Industry Applications

• Published in: IEEE transactions on systems, man, and cybernetics. Systems Vol. 48; no. 10; pp. 1771 - 1780
• Main Authors: Liu, Jianxing, Yin, Yunfei, Luo, Wensheng, Vazquez, Sergio, Franquelo, Leopoldo G., Wu, Ligang
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.10.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Capacitors; Control; Disturbance observer; Electric converters; Electric potential; Industrial applications; Load resistance; Observers; Power converters; Power factor; Reactive power; Robustness; Sliding mode control; sliding mode control (SMC); State observers; Switches; Tracking; Tracking loops; unity power factor; Voltage control
• ISSN: 2168-2216; 2168-2232
• DOI: 10.1109/TSMC.2017.2758598

A new approach to the control of three-phase two-level grid-connected power converters is proposed in this paper. The proposed control is an extended state observer (ESO)-based second order sliding mode (SOSM), which comprises two control loops: the outer loop is a voltage regulation loop, as well as inner loop is an instantaneous power tracking loop. The outer loop is accomplished by an <inline-formula> <tex-math notation="LaTeX">{H}_{\infty } </tex-math></inline-formula> controller plus an ESO, which is designed to regulate dc-link capacitor voltage of the converter and asymptotically reject external disturbances and parameter perturbations. The SOSM strategy is employed in the inner loop to drive the active and reactive power convergence to their desired values. Control objectives of nearly unity power factor and dc-link capacitor voltage regulation are simultaneously satisfied. Availability of the ESO-based SOSM is compared with the classic proportional-integral control in simulations, and the comparison implies that the proposed strategy not merely achieves an almost perfect tracking performance, but also provides a complete robustness against resistance load variation.