Backstepping direct power control without phase‐locked loop of AC/DC converter under both balanced and unbalanced grid conditions

Abstract

This study presents a backstepping direct power control (BS-DPC) strategy for the grid-connected AC/DC converter under both balanced and unbalanced grid conditions. The proposed BS-DPC adopts the non-linear BS controller to the DPC strategy in the stationary reference frame, thus phase-locked loop is unnecessary. A generalised power compensation method is applied to the proposed BS-DPC under unbalanced grid condition to achieve multiple control targets. To validate the effectiveness of the proposed BS-DPC, comparative experimental studies are conducted under both balanced and unbalanced grid conditions. Experimental results verify that the proposed BS-DPC inherits the excellent dynamic performance of the traditional DPC and has excellent steady-state performance as well. In addition, flexible control targets can be achieved and dynamically adjusted under unbalanced grid condition according to the grid safety operation requirement.