A 98.7% Efficient Composite Converter Architecture With Application-Tailored Efficiency Characteristic

Abstract

A DC-DC boost composite converter architecture is introduced that can lead to optimized efficiency over a range of operating points dictated by the application requirements. The composite converter system employs dissimilar modules to minimize the ac power losses in the indirect power conversion paths. It is composed of three converter modules: buck converter, boost converter, and a dual active bridge converter that operates as a DC Transformer (DCX). Each module processes partial power, with reduced voltage rating. With the same semiconductor area and same magnetics volume, substantial efficiency improvements and reductions in capacitor size are achieved relative to a conventional boost architecture. It is possible to design each module to optimize efficiency over a wide operating range, including pass-through modes that exhibit very low loss. A 10 kW boost composite converter is experimentally demonstrated having 98.7% efficiency at a critical partial power point, with similar very high efficiencies achieved over a wide operating range.

Perspectives of Convertors and Communication Aspects in Automated Vehicles, Part 1: Convertors and Condition Monitoring

“…It directly impacts the vehicle efficiency in terms of miles per gallons equivalent (MPGe) and improves the power density and reduces the size and the cost of the thermal management system. Chen et al [36] proposed a 30 kW boost composite converter with a peak efficiency of 98.5%, which is called a composite converter topology (D). Other variants are also proposed, such as boost composite converter (A), composite boost converter (B), and composite converter topology (C), out of which composite converter (D) is most suitable for electric vehicle powertrain.…”

“…The present article, i.e., Part 1, discusses several useful bidirectional DC-DC power con-verters for electric vehicle applications. The details of which are as follows: conventional bidirectional converters [6][7][8][9][10][11]; isolated bidirectional converters [12][13][14][15][16][17][18]; soft-switching converters [19][20][21][22][23]; coupled inductor approaches [24][25][26]; fly-back converter [27,28]; three-level converter [29]; dual active bridge converter approaches [30][31][32][33][34]; and composite converter approaches [35,36]. From the state of the art, it has been observed that the composite converter is the most efficient power converter in which different sets of modules are connected in series or parallel to control the power flow.…”

A Composite DC–DC Converter Based on the Versatile Buck–Boost Topology for Electric Vehicle Applications

“…Despite all the advantages of incorporating a dc–dc converter in the powertrain and the wide use in the EV market [ 15 ], there are still challenges where the improvement of power conversion efficiency stands out. In this application, the traditional dc–dc boost converter’s efficiency is poor when operating with high voltage-conversion ratios due to the high capacitor RMS current and the large semiconductor voltage and current stress [ 16 ]. This converter has low efficiency and power density at light load power, as with urban driving [ 17 ].…”

“…However, the previously proposed efficiency improvement approaches do not seek to enhance specific operating ranges’ efficiency. They have limited improvements in size, cost, and efficiency trade-offs, unlike the composite converter shown in Figure 3 [ 16 ]. In a composite converter, dissimilar smaller converter modules (switching converter(s) and an unregulated “dc transformer” DCX) are combined to process the total system power, with effective utilization of the semiconductor and reactive elements in each module to achieve superior performance of the whole system [ 25 ].…”

“…A composite converter architecture was proposed for the first time in [ 16 ] to improve the electric vehicle powertrain efficiency over a wide range of operating conditions. Furthermore, four different composite architectures were proposed in [ 4 ], and this paper focuses on the named topology A (see Figure 3 ) as the initial work.…”