Conventional active-neutral-point-clamped (ANPC) inverters exhibit low voltage gain that inherently leads to a high dc-link voltage requirement. An improved ANPC inverter that is capable of generating five voltage levels has recently reduced the dc-link voltage twofold to achieve unity gain. This led to the development of a single-stage dc-ac power converter with no frontend boost dc-dc converter. This article proposes novel ANPC inverters capable of unity or boosted voltage gain while generating higher voltage levels. The first topology can provide a voltage gain of 1.5 and extends the number of levels to seven by incorporating only one additional switch. The topology can also be extended by adding three switches and one floating capacitor to generate nine levels with unity voltage gain, or 11 levels with a voltage gain of 2.5. The proposed ANPC inverters and their operations are comprehensively discussed. Experimental results are provided to validate the feasibility of the proposed ANPC inverters.
Manuscript received January 18, 2019; revised July 2, 2019 and September 4, 2019; accepted October 30, 2019. Date of publication November 3, 2019; date of current version February 20, 2020. This work was supported in part by the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT for “First-Mover Program for Accelerating Disruptive Technology Development” under Grant NRF-2018M3C1B9088457, in part by the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, South Korea, for “Human Resources Program in Energy Technology” under Grant 20194030202370, 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 J. Clare. (Corresponding author: Kyo-Beum Lee.) S. S. Lee is with the Newcastle University in Singapore, Singapore 609607 (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.
