Highly Efficient dc–dc Transformer Based on Multicell Converter Topology for Next Generation dc Distribution System

Abstract

A multicell dc-dc transformer (DCX) with an efficiency of 98.0% is developed for a next generation dc distribution system. Input series output parallel (ISOP) and input parallel output series (IPOS) connection topologies of highly efficient dc-dc cell converters have been applied to realize DCXs that have arbitrary I/O voltages and a high transfer factor. The behavior of a DCX based on multicell topology using nonregulated dc-dc converters is analyzed, and the voltage stress in each cell converter is discussed quantitatively considering the variation in converter circuit parameters. Further, the availability of the applied topology and the validity of the analysis are confirmed by fabricating a prototype of a 384 V to 12 V 2400 W DCX. The multicell topology contributes to realizing a low-carbon society pushing the promotion of highly efficient, space-saving, and low cost dc power supplies with standardized, highly efficient cell converter modules. C⃝ 2016 Wiley Periodicals, Inc. Electr Eng Jpn, 198(4): 98-110, 2017; Published online in Wiley Online Library (wileyonlinelibrary.com).

Design Consideration for High Step-Up Nonisolated Multicellular dc-dc Converter for PV Micro Converters

“…In (16), the resistances in the cell converter are bundled to to simplify the calculation. Here, the parasitic resistance of 0.5 Ω and the output resistance of 205 Ω were applied to calculate the voltage transformation ratio, assuming the cell converter with the output voltage of 128 V (=384 V/3) and the output power of 80 W (240 W/3).…”

“…In the 380 V dc distribution system, the power factor correction (PFC) converters, the dc-dc transformers (DCX), and pointof-load (POL) converters are introduced to supply the electric power from ac 200 V to ICT (information and communication technology) equipment. Intensive studies have been conducted to realize highly efficient PFCs, DCXs, and POLs [15][16][17][18], and the potential to improve the total conversion efficiency in the dc distribution system from 80% to 94% has been discussed [9,16]. In the dc distribution system for the environmentally aware data center, the environmental impact will be also minimized by installing the renewable energy sources such as solar PV power generations.…”