Improved second-order sliding mode control method for synchronous static compensator

Abstract

The invention relates to an improved second-order sliding-mode control method for a synchronous static compensator. According to the method, a reactive current controller and a DC side capacitor voltage controller are adopted, wherein the reactive current controller employs a sliding-mode controller designed based on a super-spiral algorithm, a linear compensation item is introduced into a low-order item to improve the reactive current controller, the DC side capacitor voltage controller adopts the sliding mode controller designed based on the super spiral algorithm, the designed sliding modesurface is S2=e2+ke<.>2, and a linear compensation term is respectively introduced into a low-order term and a high-order term to improve the DC side capacitor voltage controller. The method has the advantages that the reactive compensation current is accurately controlled, buffeting-free output is realized, the dynamic response capability of the reactive compensation current is improved, the dynamic response capability of the direct-current side capacitor voltage of the step compensator is improved, and output buffeting is reduced. When the two controllers are applied to a synchronous staticcompensator control system, the voltage at the common coupling position can be rapidly stabilized, the voltage overshoot is reduced, and the system robustness is enhanced.

Description

technical field [0001] The invention relates to an improved second-order sliding mode control method for a synchronous static compensator. Background technique [0002] Synchronous static compensator is a new type of reactive power compensation device with voltage or current three-phase bridge converter as the core. It has the functions of reactive power compensation, suppression of voltage flicker and three-phase unbalance, etc. Compared with the traditional static var compensation device, it has many advantages such as wide operating range, compact structure, rapid reactive power compensation, and less resonance, and has become a flexible power system. Hotspots in the field of AC transmission. [0003] Synchronous static compensator is a complex nonlinear strong coupling system, and the control system becomes the key to affect the operating characteristics of synchronous static compensator. The inverse system method can decouple the linearization of the original system, ...

AI Technical Summary

Problems solved by technology

The inverse system method can decouple the linearization of the original system, and introduce a PI controller to realize the decoupling of active current and reactive current. However, there are disadvantages of low control accuracy and poor anti-disturbance performance.

The sliding mode can realize the nonlinear control of the current and DC voltage of the synchronous static compensator. The traditional first-order sliding mode has the problems of control discontinuity and inherent chattering, which affects the control effect of the system.

Images