Modified Instantaneous Power Control with Phase Compensation and Current-limited Function under Unbalanced Grid Faults

In distributed generation systems, power quality is one of the main concerns during short-term unbalanced grid voltage faults. However, for the most common three-phase three-wire grid-connected inverter-based power systems, there may be a tradeoff between power oscillations and current harmonics during the unbalanced grid fault ride-through control, which has a crucial impact on the installed inverters for different applications. In this article, a modified instantaneous power control-based voltage phase compensation control strategy is proposed to enhance the inverter current quality, while, at the same time, mitigating the active/reactive instantaneous power oscillations. Moreover, a simplified peak current-limited control strategy is developed to improve the reliability of the grid-connected system, and it does not need the extraction of the grid voltage and/or current fundamental positive/negative sequence components, which significantly reduce the computation burden. Finally, the experimental tests based on dSPACE-DS1007 and MATLAB/Simulink are carried out to verify the effectiveness of the proposed strategy.