This paper presents a new concept and research results of DC-DC high-voltage-gain, high-frequency step-up resonant converters. The proposed topologies are optimized towards minimizing the number of switches and improvements in efficiency. Another relevant advantage of such type of converters is that they have a common input and output negative point. The proposed converters are based on the resonant switched-capacitor voltage multiplier circuit, and that is why they are compared with a classic converter from this family. The included results show the operating principle, possible switching methods with the consideration of their impact on the voltage gain level, as well as the voltage and current ripples. The operating concepts and analytical calculations are confirmed by simulation and experimental results.

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This paper presents the concept and results of a novel resonant DC-DC converter which achieves high voltage gain at a low number of utilized switches, low voltage stress on transistors, ZVS and ZCS operation, high efficiency and variable voltage gain. The converter uses resonant switched-capacitors (SC) circuits with five switches which allows it to reach a six-fold voltage gain. By the application of adequate switching patterns, seven levels of voltage adjustment can be achieved. The basic operation mode of the converter is at zero current switching (ZCS) but a part of the existing transitions can be switched-on at a zero drain-source voltage. Zero voltage switching (ZVS) allows for a reduction of Coss losses and a decrease in disturbances of voltages and currents. In the proposed converter, voltage stress on switches are noticeably lower than the output voltage which is beneficial from viewpoint the cost reduction and switching quality improvement. The converter output stage consists of two series connected capacitors which allows for a supply of 3-level NPC inverters. Resonant inductors, used in the proposed topology, store very low amount of energy and their volume is significantly lower than in case of chokes typically used in switch-mode converters. Qualities of the converter such as low switch count, efficiency, ZCS and ZVS operation as well as voltage gain variation are demonstrated in this paper. Furthermore, an impact of MOSFET transistors type on the efficiency of the converter is investigated. The design based on low Coss superjunction (SJ) MOSFETs is compared with the implementation where R ds(on) of switches is minimized. Due to low voltage stress, application of Schottky rectifiers is also demonstrated in the converter. The concept of the topology and switching patterns is verified by the results of analysis, simulations and experiments.INDEX TERMS Boost converters, DC-DC converters, high voltage gain converter, switched-capacitor circuit.

This paper presents research results related to the concept of a high-voltage-gain DC-DC converter with a low input current ripple. In the proposed topology, a low-volume DC-DC switch-mode boost converter operates in parallel with a switched-capacitor voltage multiplier (SCVM). The overall converter achieves a four-fold voltage gain, but the voltage stress of the transistor and the diode of the boost converter is only half of the output voltage. This is achieved by applying the specific topology of the proposed converter. Furthermore, the boost part uses a low-volume choke as it operates in the discontinuous conduction mode (DCM). The parallel operation of the boost converter with the SCVM decreases the current stress in some components of the multiplier. This paper presents a concept of the hybrid converter, an analytical model for the selection of components and switching parameters, an efficiency model, and the verification of the converter operation through simulation tests and experiments.

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.

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This paper presents a novel high step-down DC-DC converter based on a switched-capacitor resonant topology. It is presented in a 48/8 V version, which was verified by simulations and experiments. The most notable features specific to this converter are an almost non-iductive design and relatively low voltage stress across switching devices. The proposed topology allows for zero-current-switching (ZCS) and zero-voltage-switching (ZVS). Experimental tests confirm that ZVS operation brings a significant increase in the efficiency of the proposed device. Taking into account all the advantages of the suggested converter, it can be concluded that this device is suitable for any application where a high step-down voltage conversion is required. In a prospective application, the proposed converter can be utilized as a part of the power supply unit for data centers.INDEX TERMS Buck converters, DC-DC converters, high voltage step-down gain converter, switchedcapacitor circuit.