Single-source Switched-capacitor Boost Nine-level Inverter with Reduced Components

Abstract

Increasing demands for improvement in power quality and power capacity have contributed to development of switched-capacitor multilevel inverters (SCMLIs). Recently developed SCMLIs enable single-stage voltage boosting, as well as inversion resulting in step-up ac output. Towards reduction in number of components, this paper introduces a boost type single-source nine-level (9-level) SCMLI employing two capacitors and three diodes. Owing to the series-parallel connection process, capacitor voltages are inherently balanced and assist in quadruple voltage boosting from a single-source. Maximum voltage stress across semiconductor devices is limited to twice input voltage only. Using a minimum number of components, the proposed SCMLI can be extended to increase voltage levels without additional dc input. Each extension module adds two additional voltage steps in the output while maintaining maximum voltage stress the same as 9-level circuit. Followed by in-depth analysis of circuit operation and power losses, a thorough comparison of recently developed single-phase 9-level MLIs is carried out, which verifies design superiority. Extensive simulation and experimental results are presented to verify the prominent features of the 9-level SCMLI under dynamic operating conditions.