Switched-capacitor-based multilevel inverters have been gaining increasing attention in recent years in view of their voltage-boosting capability and capacitor self-balancing properties. However, the existing topologies, which comprise frontend switched-capacitor cells and a backend H-bridge, result in longer discharging duration in some of their switched-capacitors. In addition, the adoption of backend H-bridge introduces common-mode voltage and necessitates multiple dc sources for voltage level extension. To resolve these problems, this article proposes a novel topology comprises a T-type inverter and n cascaded switched-capacitor cells. It requires only a single dc source and it manages to mitigate the common-mode voltage by connecting the neutral of ac output to the mid-point of dc link. All switched-capacitors in the proposed topology are ensured to be charged for at least half of the fundamental period to alleviate the capacitor voltage ripples and current spikes. The operation of the proposed topology is analyzed and experimental results are presented for validation.
Manuscript received January 18, 2020; revised March 16, 2020 and April 7, 2020; accepted April 25, 2020. Date of publication May 12, 2020; date of current version March 22, 2021. This work was supported in part by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and in part the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea under Grants 20194030202370 and 20182410105160. (Corresponding author: Sze Sing Lee.) Sze Sing Lee is with the Newcastle University in Singapore 567739, Singapore (e-mail: szesinglee@gmail.com).Dr. Lee was the recipient of the International Scholar Exchange Fellowship from Korea Foundation for Advanced Studies in 2018. He serves as an Associate Editor for the IEEE ACCESS.
