Single-Layer Decoupled Multiple-Order Generalized Integral Control for Single-Stage Solar Energy Grid Integrator With Maximum Power Extraction

Abstract

In this article, a novel single-layer decoupled multiple-order generalized integral-based control algorithm is used for a single-stage solar energy grid integrator (SEGI) with maximum power extraction. The single-layer decoupled structure is used to extract the fundamental component of load current. Moreover, the online grid frequency estimation is carried out for an accurate band-pass filtering. The single-layer architecture of the control for the three-phase load current estimation, reduces the control complexity, and improves the response time. Moreover, the single-stage system is operated with the maximum power point tracking based on the residual incremental conductance algorithm. Hence, the cost of a new conversion stage and additional control are saved. This system is operated under three operating modes. In “normal-mode,” it feeds power to the load and the grid. Wherein the “sharing mode,” SEGI and grid supply the load power. During the night, SEGI functions as an active filter, which is termed as “filter-mode.” The steady-state and dynamic performances of SEGI during each operating mode and transition between the modes due to irradiation variation as well as load fluctuation are verified experimentally on a developed prototype. Moreover, test results under dynamic load variations such as nonlinear and unbalanced load conditions are presented to validate the theoretical claims.