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This paper presents a novel concept of a high-voltage-gain DC-DC converter. The converter is made up of switched capacitors and passive resonant branches. A significant reduction in the count of switches and low voltage stress on the switches is achieved in this proposed converter topology, in comparison to that of a classical SC series-parallel converter. It is essential from the cost, volume, and efficiency of the converter standpoint. The reduction in the count of switches is threefold. The highest voltage stress on the switches depends on the output voltage and is decreased in the proposed converter as well, as the output voltage is divided into two series-connected capacitors. The presented results demonstrate the operation of the converter with the use of resonant branches, its switching strategies, voltage stresses of switches, efficiency, voltage gain, and output voltage regulation as well as the zero-voltage switching (ZVS) operation. The paper also presents novel issues related to analytical loss modeling, extended concepts of topology, converter start-up, and operation during transient states. The demonstrated concept of the converter, the analytical discussion and its design, as well as the experimental setup and results clearly demonstrate the optimization achievements.INDEX TERMS Boost converters, DC-DC converters, High voltage gain converter, Switched-capacitor converter.

This paper presents the overall concept of a wideband and cost-effective current sensor. The sensor consists of a paralleled Hall-based current sensor (LEM) and a wideband current transformer (CT). A significant improvement of the band range and the moderate cost of the proposed sensor enable it to be used both to measure the instantaneous value in order to precisely plot the current and to obtain signals for a closed-loop control system of high-frequency power electronic converters. The sensor should be considered as an Augmented LEM Current Sensor (ALCS), which allows it to measure low- and high-frequency current signals. Finally, it allows for the measurement of a bipolar current up to 40 A. The overall cost of the sensor, along with the previously mentioned benefits, is an important feature of the proposed sensor. The present paper presents the analytical concept of the sensor (ALCS), a theoretical approach using simulation analysis, and the experimental results, which clearly demonstrate the wide range of the sensor in dynamic and static measurements.

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High-frequency current transformers (HFCT) are widely used to measure fast transient current. Their advantages are simple structure and relatively moderate price. Their lower and upper bandwidth are limited, but the HFCT can be easily applied to many measuring applications in power electronics. The disadvantages of HFCT are substantial dimensions and a large weight. The paper proposes a system of a cascade connection of two transformers, which allows us to reduce these disadvantages. The properties of such an HFCT combination were investigated and described. In the article, the expression for double current transformer transmittances is derived. The frequency response of the sensor was determined, and the results were verified in a practical arrangement. An experimental setup of a cascade CT connection was made and tested, allowing for fast-changing signals in transients to be measured. This paper presents the theoretical basis and results of laboratory work on a wide range of static and dynamic tests of the proposed sensor.