An Optimal Control Scheme to Suppress the Current Zero-Crossing Distortion in Critical Mode Single-Phase Inverter

作者：Kunqi Han, Zhongshu Zheng, Li Zhang · 发表于：2022 IEEE 5th International Electrical and Energy Conference (CIEEC) · 年份：2022 · DOI：10.1109/cieec54735.2022.9846326 · 研究领域：Advanced DC-DC Converters、Multilevel Inverters and Converters、Microgrid Control and Optimization

Employing fully digital control to achieve a critical conduction mode (CRM) inverter is considered a cost-effective solution to obtain both high efficiency and high density. However, the distortion of the output current at the zero-crossing makes the inverter unable to provide high-quality power. This paper reveals the reasons for the distortion of fully-digital controlled CRM inverters. First, the generation of fundamental frequency driving signals is not synchronized with that of high-frequency driving signals, resulting in a current overshoot at the beginning of each half fundamental period. Second, there will be no driving signals region at the end of each half fundamental period. This paper proposes a quasi-close-loop control scheme and an improved driving signal generation logic, which combine to form an optimized control scheme to suppress the distortion of the output current. A fully-digital controlled CRM inverter with a rated power of 1kW is built. The effectiveness of the proposed control schemes is verified by experiments.