A Three-Level Dual-Active-Bridge Converter With Blocking Capacitors for Bidirectional Electric Vehicle Charger

Abstract

In order to solve the considerable issues of air pollution, climate warming and fossil energy shortage, many governments around the world have formulated policies to encourage the development of electric vehicles over the past decade. This paper proposes a three-level dual-active-bridge (DAB) converter with blocking capacitors for bidirectional electric vehicle charger. In the proposed three-level DAB converter, two blocking capacitors are placed in series with the two windings of the transformer, respectively. Both of the two three-level bridges can operate in four modes, and generate square waves with four kinds of amplitude. Therefore, the proposed three-level DAB converter can adapt to the wide voltage range of electric vehicle. A working mode selection algorithm is developed to minimize the transformer RMS current of the three-level DAB converter. The optimal working mode can be selected in real time according to the voltage ratio and the active power. Finally, experimental results are presented to verify the feasibility and the advantage of the proposed three-level DAB converter.INDEX TERMS Asymmetric, blocking capacitor, dual-active-bridge, three-level.

A Comprehensive Review of Power Converter Topologies and Control Methods for Electric Vehicle Fast Charging Applications

“…For the voltage-fed DAB converter, when the input voltage, V dc is equal to nV bat , ZVS can be achieved for all switches, while in other cases, ZVS range is limited. The work in [136], introduces a three-level DAB converter that generates square wave of four different amplitudes and thus, allows adaptation to a wide voltage range. In a similar study presented in [137], a five-level DAB converter is employed to achieve wide voltage gain.…”

“…In a similar study presented in [137], a five-level DAB converter is employed to achieve wide voltage gain. Both [136] and [138] optimize transformer RMS current to enhance efficiency. Moreover, wide voltage gain can be achieved with a novel circuit architecture based on dual transformer in DAB [139].…”

“…In study [136], operation modes based on minimum transformer RMS current are selected for the three-level DAB converter with blocking capacitors. Generally, DAB converter suffers from conduction and copper losses due to high transformer RMS current.…”

Power Converter Topologies for Grid-Tied Solar Photovoltaic (PV) Powered Electric Vehicles (EVs)—A Comprehensive Review

“…Because of the lower installation cost, better power density, and improved reliability, an HF transformer is preferred in the bidirectional DC-DC power stage. The LLC resonant converter [55,56,[119][120][121][122][123][124][125], dual-active bridge (DAB) converter [57][58][59][60][61][62], DAB resonant converter [63][64][65][66][67][68][69][70][71][72], and phase-shifted full-bridge (PSFB) converter [73][74][75][76] are examples of isolated DC-DC converters proposed in publications. Modulation techniques and control methods for isolated DC-DC converters can be complicated.…”

Multibattery Charger System Based on a Three-Level Dual-Active-Bridge Power Converter

“…Furthermore, within these works, it is difficult to find a complete description of the BC topology and control, including the battery current control, the dc-link voltage balance control, and the dc-link control. For instance, in [5], a BC is implemented with an ac-dc ML converter in cascade with a dc-dc stage based on a hybrid NPC dual-active-bridge converter (DAB) and flying capacitor converter. However, no information about the acdc converter topology and control is reported.…”