The switched-capacitor-based cascaded multilevel inverters (CMI) have been emerging due to their voltage boosting capability. Unfortunately, they suffer from impulse charging current and nonuniform operation. This article presents a topology termed as dual-T-type five-level CMI to resolve these problems without compromising the desirable voltage boosting characteristic. The main idea is to integrate a half bridge and an inductor to soft charge a capacitor that is connected in series with the dc source. The capacitor enables the voltage gain boosted to two, while the control of eight power switches that constitutes a dual-T structure enables five voltage levels generation. In addition, uniform operation is achieved for cascaded extensions. The operating principle of the proposed topology is analyzed and elaborated. For validation, simulation, and experimental results of a prototype are presented.
Manuscript received November 15, 2019; revised December 26, 2019; accepted February 10, 2020. Date of publication February 13, 2020; date of current version May 1, 2020. This work was supported in part by the KEPCO Research Institute under the Project “Design of analysis model and optimal voltage for MVDC distribution system (R17DA10)” and in part by the Malaysian Ministry of Higher Education through Fundamental Research Grant Scheme under Grant FRGS/1/2018/TK04/USMC/02/1. Recommended for publication by Associate Editor E. Babaei. (Corresponding author: Sze Sing Lee.) Sze Sing Lee is with the Newcastle University in Singapore, 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 is an Associate Editor for the IEEE ACCESS.
