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

作　　者：李劲晖 贲洪奇[1] 朱俊函 宁继超 LI Jinhui;BEN Hongqi;ZHU Junhan;NING Jichao(School of Electrical Engineering and Automation,Harbin Institute of Technology,Harbin 150001,China;Huawei Technologies Co.,Ltd.,Dongguan 523000,China)

机构地区：[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

出　　处：《电机与控制学报》2024年第3期13-23,共11页Electric Machines and Control

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。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 circuit.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 converter were analyzed in detail,and the efficiency characteristics were compared with the cascaded converter composed of the same circuit.According to the topology and working characteristics of the combined 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 combined 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 

分 类 号：TM46[电气工程—电器]