A three‐level isolated dc‐dc SEPIC converter with parallel‐connected output

Abstract

This paper presents a comprehensive theoretical analysis and experimental results for three-level isolated dc-dc converter based on the single-ended primary-inductance converter (SEPIC) topology. The main advantage of this structure is the reduction of voltage stress on semiconductors comparing it to the conventional SEPIC converter. Voltage stress is the major challenge associated with the conventional SEPIC structure, and contributions in this area can extend the range of applications for the family of SEPIC converters. The analyzed structure contains two switches, and their commands can be either equal or phase-shifted by 180 . This provides four different modes of operation in discontinuous conduction mode (DCM), which have different operating stages, waveforms, and design equations. In this paper, the topology with parallelconnected output and the static and dynamic theoretical analysis in DCM, for the four command signal profiles, are presented. The advantages and disadvantages, control strategy, experimental results, and a comparative analysis with the conventional SEPIC converter are discussed. The dc-dc SEPIC converter was verified by experimental results from a proof-of-concept prototype with 500 W rated power, 400 V input voltage, 120 V output voltage, and 50 kHz switching frequency. The converter achieved 94.72% efficiency at rated power.

Topologies and Design Characteristics of Isolated High Step-Up DC–DC Converters for Photovoltaic Systems

“…In order to prevent the two switching devices from operating simultaneously, the duty cycle for each was set to less than 50% [59]. Switching between the two power devices (Q 1 ) and (Q 2 ) in the push-pull converter is accomplished by a 180°phase difference between the two signals [45,60]. Due to their simplicity, push-pull converters are ideal for medium-to-low power applications [61].…”

Adaptive droop control strategy of parallel LLC converters

“…In some high-power industrial applications, such as electric vehicle charging piles and server base station power supply systems, the technology of parallel expansion of power supply has been widely used. [1][2][3][4][5][6] The power parallel system composed of N power modules has the advantages of N + 1 flexible backup, easy to repair, and replacement of faulty parts. 7,8 Figure 1 shows the composition of a modular DC power supply system.…”

“…With the development of the economy, the demand for electricity in human society is increasing. In some high‐power industrial applications, such as electric vehicle charging piles and server base station power supply systems, the technology of parallel expansion of power supply has been widely used 1–6 . The power parallel system composed of N power modules has the advantages of N + 1 flexible backup, easy to repair, and replacement of faulty parts 7,8 .…”