This paper presents research results of voltage gain number control methods of a power electronic resonant zero-current switching (ZCS) dc-dc switched-capacitor (SC) voltage multiplier (SCVM) in a topology with fault tolerance capability (FSCVM). The converters operated under the basic switching patterns are constant-voltage-gain dc-dc series-parallel resonant SC converters. However, this paper presents a method for the output voltage regulation by a special switching strategy. A variable voltage gain is made possible by selecting the number of active switching cells, using an appropriate control method. This creates a set of voltage ratio ranges. In addition, the proposed topology and method of control enable a fault-tolerant operation of the FSCVM under various failures of the device. The paper presents an analysis of the concept, simulation results and an experimental verification in a three-cell FSCVM dc-dc resonant boost converter operating at a 200 watt charge. Issues regarding the selection of components related to the problem of inrush currents which can occur during the voltage ratio increase are also analyzed in this paper, and the design for low inrush currents is demonstrated.

A coupled-inductor dc-dc converter has several modes of operation in continuous-conduction mode (CCM) and discontinuous-conduction mode (DCM), and is quite complex. This paper presents the derivation of the complete small-signal model of a two-phase interleaved dc-dc boost converter utilizing a single-core coupled-inductor operating in both CCM and DCM. Several small-signal models are required to fully model the converter due to the complexity of the converter operating in DCM. The transfer functions are then derived from these small-signal models. The theoretical analysis is validated experimentally using frequency sweeps from a 1-kW prototype.

This article presents a novel concept of switch-mode dc–dc boost converters with reduced switching losses. The converters use an auxiliary switching cell to achieve zero voltage switching during the turn- off of a transistor. The novel concept facilitates an increase in the efficiency or switching frequency of an IGBT-based boost converter. This article discusses the converters topology, the principle of operation, and issues related to the reduction of power losses, the range of optimal operation, and selection of components. The concept of the converter was verified through simulation and a series of experiments that demonstrate the process of zero-voltage turn- off and the efficiency of the converter.

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.

This paper presents a concept for the operation of a resonant DC–DC switched-capacitor converter with very high efficiency and output voltage regulation. In its basic concept, such a converter operates as a switched-capacitor voltage doubler (SCVD) in the Zero Current Switching (ZCS) mode with a constant output voltage. The proposed methods of switching allow for the switched-capacitor (SC) converter output voltage regulation, and improve its efficiency by the operation with Zero Voltage Switching (ZVS). In this paper, various switching patterns are proposed to achieve high efficiency and the output voltage control by frequency or duty cycle regulation. Some examples of the application of the proposed switching patterns are presented: in current control at the start-up of the converter, in a bi-directional converter, and in a modular cascaded system. The paper also presents an analytical model as well as the relationships between the switching frequency, voltage ratio and efficiency. Further, it demonstrates the experimental verification of the waveforms, voltage ratios, as well as efficiency. The proposed experimental setup achieved a maximum efficiency of 99.228%. The implementation of the proposed switching patterns with the ZVS operation along with the GaN-based (Gallium Nitride) design, with a planar choke, leads to a high-efficiency and low-volume solution for the SCVD converter and is competitive with the switch-mode step-up converters.

This article presents the results of research on a new topology of a DC-DC converter in which switching losses are reduced by an auxiliary switching circuit (ASC). The proposed ASC can work as a passive or active circuit depending on the voltage gain of the converter. In both cases, this does not affect the operation of the main circuit and is analogous to a classic boost converter, which allows the use of the same control circuits and methods. The operation of the ASC is synchronized with the control of the main converter transistor. The reduction of transistor turn-off losses over a wide range of converter gain is a unique advantage of the proposed auxiliary circuit. This is evidenced by the comparison of the loss reduction with the classic boost converter and the reference converter with soft turn off. This article presents an in-depth analytical discussion related to the reduction of power losses, supported by simulation results, and verified experimentally.