This paper presents a concept and the results of an investigation of a DC–DC boost converter with high voltage gain and a reduced number of switches. The novel concept assumes that the converter operates in a topology composed of series connection switched- capacitor-based multiplier (SCVM) sections. Furthermore, the structure of the sections has significant impact on parameters of the converter which is discussed in this paper. The paper demonstrates the basic benefit such a multisection SCVM idea in the converter, which is the significant reduction in the number of switches and diodes for high voltage gain in comparison to an SCVM converter. Aside from the number of switches and diodes, such parameters as efficiency and volume of passive components in the multisection converter are analyzed in this paper. In figures, the analysis is demonstrated using the example of 100 kW thyristor-based converters. All the characteristics of the converter are compared between various configurations of switching cells in the particular sections, thus the paper can be useful for a design approach for a high voltage gain multicell converter.

The paper presents investigation results of the natural balancing phenomena in the flying-capacitor SEPIC converters. The SEPIC converters topologies can be reconfigured to the flying-capacitor topology. Owing to this modification the advantageous increase of frequency of the current in the chokes and the decrease of semiconductors voltages can be achieved which is shown in this paper. Similarly to other multilevel flying capacitor topologies the adequate voltage sharing of the flying capacitors is an important issue for safe operation of the converter. The paper focuses on the analysis of the flying capacitor voltages balancing in the converter by natural currents as well as by the application of the additional RLC balancing booster. The paper proves that the natural balancing can be achieved by the specific application of the balancing circuit in the flying-capacitor SEPIC topology and proves the specific differences in the balancing process by natural currents of converter and with the usage of the balancing circuit. An operation of the converter with the balancing circuit and the natural balancing ability is studied here.

In the paper results of the operation and efficiency of a DC-DC resonant converter with a switched capacitor topology, equipped with GaN transistors and SiC diodes are presented. Investigated problems are related to the optimization of the DC- DC power electronic converter in order to achieve miniaturization, a simplified design and high efficiency. The proposed system operates at a high frequency with low switching losses. The proposed design helps to achieve uniform heating of the transistors and diodes, as demonstrated by the results of the thermal imaging measurements. The GaN transistors are integrated in one package with dedicated gate drivers and used to simplify the drivers circuitry and increase the power density factor of the proposed device. In the high-frequency design presented in the paper, the converter is implemented without electrolytic capacitors. The results included in the paper contain waveforms recorded in the power circuit at ZVS operation when switching on the transistors. It occurs when the system operates above the frequency of current oscillations in the resonant circuit of the switched capacitor. Efficiency characteristics and a voltage gain curve of the converter versus its output power are presented as well. Results of efficiency and quality of waveforms are important because they allow to characterize the tested system for the implementation using WBG devices. The use of integrated GaN modules to minimize elements in the physical system is also unique to this model and it allows for very short dead-time use, operation in ZVS mode at low reverse-conduction losses.