A New ZVS-CV Bridgeless PFC Dual Boost Converter for Pure Electric Vehicle Battery Charger

In the next future pure electric vehicles will be more and more adopted as the unique viable city-car solution. The battery charger is a fundamental component for this type of vehicle. Generally it is composed by a front-end ac-dc power factor corrected converter and a dc-dc isolated converter. The front-end ac-dc converter is a key component of the charger system. High efficiency, low cost, low encumbrance and high reliability are the main requirements for such type of device. In addition to the front-end ac-dc converter is required to meet strictly the EN 61000-3-2 standard as high power factor correction (PFC) and adequate amplitudes of the main harmonics. In the paper a new zero-voltage switching clamped-voltage bridgeless PFC dual boost converter for pure electric vehicle battery charger is proposed. The soft-switching capability is achieved adding a simple auxiliary active clamping circuit for each leg of a classical bridgeless dual boost configuration. Such auxiliary circuit, operating in soft-switching mode, guarantees active clamped voltage and zero voltage switching operations of the main switches and of the slow diodes without interesting the main power path. High efficiency in continue current mode operations and reduced size are assured. In the paper the operating principle, soft-switching conditions and steady state analysis have been presented. A 2000 W prototype, suitable for automotive residential charger applications is built and experimental set-up to verify the theoretical analysis has been provided. The experimental results demonstrate unitary power factor (99.96%), full achievement of EN 61000-3-2 standard, peak efficiency of 98.9 % and THD less than 3 %. Copyright (C) 2011 Praise Worthy Prize S.r.L - All rights reserved.