| Abstract |
This paper presents a self-synchronizing controller achieving a current tracking objective without knowledge of the grid parameters. An estimated rotating reference frame (_d -frame) is utilized. Within the control scheme, adaptive compensation terms facilitate the current tracking objective and, simultaneously, accounts for the unavailable grid voltage magnitude, grid frequency, and grid phase, hence eliminating the need for an additional measurement and feedback system for synchronization, such as a Phase-Locked Loop (PLL) which are sensitive to harmonics, to disturbances and to large frequency deviations causing unnecessary energy losses.A system frequency behavior study is developed through this article by comparing a PQ-PLL controller to the novel self-synchronizing design under the conditions of a variable inertia and renewable penetration ratio. Using the novel controller in a high-renewable (low-inertia) grid indicates that the monitored performance metrics are significantly improved when compared to PLL-controlled, inverter-dominated grid. When benchmarked to the PQ-PLL controller results, increasing the penetration ratio will have a positive impact on the self-synchronizing controller due to its adaptive nature which depends only on the current control errors signals. Lowering the grid's inertia shows that the self-synchronizing inverter reaches steady-state significantly faster than the PQ-PLL one due to the internal dynamics of the adaptive control by disrupting the need for a cascaded control scheme. |
