The conventional hard-switching converters suffer from the limitations like the upper limit on switching frequency, high electromagnetic interference (EMI), more switching losses, large size, increased weight and low efficiency. To overcome these limitations, resonant converters are popularly used in chargers of electric vehicles (EVs). However, the detailed classification of resonant converters used in EVs is not sufficiently discussed in the literature. The guideline to select a resonant converter based topology required to charge an EV on the basis of its rating is not mentioned. To fill this gap, this paper presents a state-of-art literature survey of various resonant converter based topologies used in chargers of EVs. This paper focuses on a detailed classification of resonant converters used in the second stage of EV chargers. Further, it provides a guideline to designers to choose a converter topology used in the first stage and the second stage of EV charger required based on wattage, unidirectional and bidirectional power flow. Depending on the number of reactive elements present in a given resonant converter topology, these are classified as two-element, three-element, and multi-element resonant converters. Depending upon the connection of inductive (L) and capacitive (C) elements with respect to transformer winding, these converter topologies are further categorized as series, parallel (two-elements), inductor–inductor–capacitor (LLC) (three-element) and capacitor–inductor–inductor–capacitor (CLLC) (Multi-elements). However, the LLC type resonant converters offer high efficiency, zero-voltage switching (ZVS turn-on, turn-off) and low voltage stress on switches and high power density. Therefore, this paper mainly focuses on LLC type resonant converter topology. In addition, various modulation schemes and control schemes for LLC, CLLC resonant converter along with control of active power and reactive power are discussed for vehicle-2-grid (V2G) mode of operation.

中文翻译：

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电动汽车谐振变换器分类综述

传统的硬开关变换器存在开关频率上限、电磁干扰(EMI)高、开关损耗较多、尺寸大、重量增加和效率低等限制。为了克服这些限制，谐振转换器广泛用于电动汽车 (EV) 的充电器。然而，文献中没有充分讨论电动汽车中使用的谐振转换器的详细分类。没有提及根据电动汽车的额定值选择基于谐振转换器的拓扑来为电动汽车充电的指南。为了填补这一空白，本文对电动汽车充电器中使用的各种基于谐振转换器的拓扑进行了最新文献调查。本文重点介绍电动汽车充电器第二级中使用的谐振转换器的详细分类。此外，它还为设计人员根据瓦数、单向和双向功率流选择所需的电动汽车充电器第一级和第二级所使用的转换器拓扑提供了指导。根据给定谐振转换器拓扑中存在的电抗元件的数量，这些转换器被分类为二元件、三元件和多元件谐振转换器。根据变压器绕组中电感 (L) 和电容 (C) 元件的连接，这些转换器拓扑进一步分类为串联、并联（双元件）、电感器-电感器-电容器 (LLC)（三元件）和电容器-电感器-电感器-电容器 (CLLC)（多元件）。然而，LLC 型谐振转换器提供高效率、零电压开关（ZVS 开通、关断）、开关电压应力低以及功率密度高。因此，本文主要关注 LLC 型谐振转换器拓扑。此外，还讨论了针对车辆 2 电网 (V2G) 运行模式的 LLC、CLLC 谐振转换器的各种调制方案和控制方案以及有功功率和无功功率的控制。