一种组合式宽输入高效率DC-DC变换器
Combined wide input and high efficiency DC-DC converter
李劲晖 1贲洪奇 1朱俊函 2宁继超1
作者信息
- 1. 哈尔滨工业大学 电气工程及自动化学院,黑龙江 哈尔滨 150001
- 2. 华为技术股份有限公司,广东 东莞 523000
- 折叠
摘要
针对车载 DC-DC 变换器输入电压变化范围大的问题,提出一种组合式宽输入高效率DC-DC变换器.该变换器包括飞跨电容(FC)型三电平Buck电路和LLC谐振电路两部分,FC三电平Buck电路输出端口与LLC谐振电路输入端口串联,通过控制FC三电平Buck电路占空比实现输出电压调节以适应宽输入电压范围,同时三电平结构降低了开关管电压应力、减小了损耗;LLC谐振电路传输负载所需全部功率,采用定频开环控制以获得高效率和稳定增益,同时实现了电气隔离.详细分析了组合式变换器的拓扑结构、直流增益以及工作效率,并与相同电路构成的级联式变换器进行了效率特性对比,根据组合式变换器的拓扑结构和工作特性,提出一种解耦控制策略,实现输出电压稳定和飞跨电容电压平衡,最后搭建了一个200～400 V输入、12 V/20 A输出的实验电路进行验证,实验结果表明所提组合式变换器的正确性和可行性.
Abstract
Aiming at the problem that the input voltage of the vehicle-mounted DC-DC converter varies widely,a combined wide-input high-efficiency DC-DC converter was proposed.The converter consists of two parts:a flying capacitor(FC)type three-level Buck circuit and an LLC resonant circuit.The output port of the FC three-level Buck circuit is connected in series with the input port of the LLC resonant cir-cuit.By controlling the duty cycle of the FC three-level Buck circuit,the output voltage was adjusted to adapt to a wide input voltage range.At the same time,the three-level structure reduces the voltage stress of the power switches and reduces the loss;the LLC resonant circuit transmits all the power required by the load.Using fixed-frequency and open-loop control,high efficiency and stable gain were achieved while achieving electrical isolation.The topology,DC gain and working efficiency of the combined con-verter were analyzed in detail,and the efficiency characteristics were compared with the cascaded con-verter composed of the same circuit.According to the topology and working characteristics of the com-bined converter,a decoupling control strategy was proposed to achieve output voltage stability and flying capacitor voltage balance.Finally,an experimental circuit with 200-400 V input and 12 V/20 A output was built for verification.The experimental results show correctness and feasibility of the proposed com-bined converter.
关键词
组合式变换器/飞跨电容型三电平Buck/LLC/宽输入电压范围/高效率/解耦控制Key words
combined converter/flying capacitor type three-level Buck/LLC/wide input voltage range/high efficiency/decoupling control引用本文复制引用
出版年
2024
NETL
NSTL
万方数据