Variable Gain Continuous Sliding Mode Control for Grid-Side Inverters in Wind Power Generation Systems with Parameter Uncertainties

Existing wind power generation systems (WPGSs) with the grid-side inverters (GSIs) are mostly composed of the PI controller, which is sensitive to the internal/external parameter uncertainties of the system and hard to obtain suitable control gains. This paper proposes a robust control strategy for WPGSs with GSIs connected between variable speed PMSGs and grid-side based on continuous higher-order sliding mode (HOSM) theory. Firstly, the GSI model combining the current outer loop and voltage inner loop are built, which considers internal component parameter uncertainties. Next, three novel integral-type super-twisting sliding mode (STSMC) controllers are proposed to better control the time-varying powers exchanged between the GSI and the grid. Further, the predictable control gain and time-varying control gain in different STSMC are constructed to reduce control energy wastage and avoid over-calculation of uncertainty boundary after the system is disturbed. Finally, the multi-condition simulations considering parameter perturbations are designed to validate the proposed method.