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This paper proposes a single-stage direct AC to high-frequency (HF) AC resonant converter based on LLC configuration for induction heating (IH) systems or HF applications. Unlike conventional converters for IH systems, the proposed topology converts the utility frequency to HF AC in a single stage without using a DC link inductor and capacitors and takes the advantages of LLC configuration. Additionally, it improves the power factor to 0.9–1, lowers the THD (3.2% experimentally), and protects against the high-frequency components. An embedded control scheme was designed to keep the HF current oscillating at a resonant frequency, ensuring zero-voltage switching. The operating principle of the proposed topology was investigated using mathematical equations and equivalent circuits. Finally, it was verified using computer simulation, and an experimental prototype of 1.1 kW was developed to demonstrate the proposed topology's uniqueness. [ABSTRACT FROM AUTHOR]

In this article, basic cell (BC) of a novel swi-tched capacitor converter (SCC) has been proposed first. After that, the generalized structure of proposed SCC is developed. The developed SCC requires reduced number of switches, drivers, diodes, capacitors, and lower number of conducting switches in current flow paths and capacitor charging paths as compared to the other recently developed SCCs. A switched capacitor multilevel inverter (SCMLI) utilizing two numbers of generalized SCCs is developed next. Further, cascaded extension of proposed SCMLI is realized and analyzed for symmetric and asymmetric dc source configurations. A detail analysis of optimum selection of capacitance for switched capacitors of 13-level SCMLI is presented. An extensive comparison study shows that the proposed SCMLI requires lower number of components as compared to other SCMLIs. Further, the proposed structure has minimum cost function per level per boosting factor as compared to the other SCMLIs. Extensive experimental results considering fundamental switching frequency scheme are presented to validate the merits and effectiveness of the proposed structure. [ABSTRACT FROM AUTHOR]

In this paper, a novel structure of switched capacitor converter (SCC) is proposed. First, the basic unit of the proposed SCC is presented. After that, a generalized structure of the proposed SCC is discussed. The presented SCC uses one dc source, several switches, diodes, and capacitors to produce multistep dc boosted output voltage. The capacitors in the SCC can be charged in trinary asymmetrical pattern. A detailed comparative study between the proposed and other recently developed SCC structures is presented. It is shown that the proposed SCC can produce an output voltage level with lower total standing voltage and lower maximum switch stress voltage as compared to most of the suggested SCC structures. Further, a switched capacitor multilevel inverter (SCMLI) based on cross-switched multilevel inverter has been developed and analyzed for symmetric and asymmetric dc source configurations. For fair comparison with the existing SCMLI structures, the overall cost of the structures is compared based on a cost function (CF). The proposed SCMLI provides lower cost function/output voltage level (CF/NL) in comparison with most of the other SCMLI structures for both symmetric and asymmetric dc source configurations. Extensive experimental studies validate the operation and performance of the proposed SCMLI structure. [ABSTRACT FROM AUTHOR]