Backstepping sliding mode control of doubly-fed variable-speed pumped storage units

Abstract

[Objective] Doubly-fed variable-speed pumped storage units have significant value in enhancing the consumption capacity of renewable energy and improving grid stability. However, their complex electromechanical coupling characteristics still pose notable technical challenges. To effectively mitigate power fluctuations from wind and solar power generation, it is necessary to develop a variable-speed pumped storage system that integrates electromechanical dynamic analysis, power decoupling mechanisms, and fast-response control. [Methods] Sliding mode control, as an effective control method for time-varying nonlinear systems, exhibits good control performance in variable-speed pumped storage systems, but its inherent chattering issue still affects system regulation accuracy. To address the issue, a backstepping sliding mode control strategy was proposed, which effectively suppressed system chattering and achieved power decoupling control by regulating power transmission between the grid-side and rotor-side converters of the doubly-fed induction generator. Compared with conventional sliding mode control, the proposed approach was validated through simulations under four scenarios: typical steady-state condition, rapid power variation, parameter variation, and wind power-pumped storage hybrid system. [Results] The result showed that under the three scenarios of rapid power variation, parameter variation, and wind power-pumped storage hybrid systems, backstepping sliding mode control could stably track power variations, while traditional sliding mode control lost power tracking capability after 51.154 7 s, 38.438 4 s, and 10 s, respectively. [Conclusion] Compared with traditional sliding mode control, backstepping sliding mode control demonstrates faster power response speed, stronger robustness, and better stability.

Keywords

variable-speed pumped storage / doubly-fed induction generator / backstepping sliding mode control / influencing factors / grid stability / consumption capacity of renewable energy / wind power generation