Analysis and control of electronic power transformer with star‐configuration under unbalanced conditions

Abstract

The active power adjustment capabilities of zero‐sequence and negative‐sequence voltages are mathematically compared in this study. Based on the comparison, the input currents and operating range of the electronic power transformer (EPT) using negative‐sequence voltages under unbalanced grid voltage conditions have been analysed, which can provide theoretical guidance on the design and control of the EPT. A novel reference current in the input stage is proposed for balancing three‐phase dc voltages. The proposed reference current can be rapidly adjusted to improve the dynamic response of the system and reduce the dc‐link voltage deviations when unbalanced grid voltage happens. These analysis and control schemes are supported by both simulation and experimental validation.