【作者】 王亚东；

【导师】 张千帆；

【作者基本信息】 哈尔滨工业大学 ， 电气工程（专业学位）， 2023， 硕士

【摘要】 电动汽车的普及越来越广泛,随着功率器件的不断升级,更加小型化、轻量化、高功率密度、高效率的DC/DC变换器成为决定电动车充电性能好坏的主要因素之一,在实现基本功能的前提下满足更高的效率指标、更高的功率密度成为电动车充电领域的热点话题。本文针对电动汽车充电领域提出了一种新型三端口DC/DC变换器,集成市面上广为流行的原OBC及DC/DC变压器为一体,增加了磁性元件利用率的同时减少了开关器件的使用,大幅降低了成本要求。该变换器可以满足传统OBC的高压动力电池充电模式、低压辅助电池充电模式、高压电池回馈电网模式,还可以实现高压动力电池与低压辅助电池的同步充电。同时针对现有研究是否添加低压侧母线电容进行了理论上的分析,得出了省略母线电容同时能改进低压侧充电的方法。本文首先针对各模式下三端口DC/DC工作原理进行了详细描述,推导了电流关键点方程、输出功率方程及输出电压方程,并从开关器件应力及低压侧母线输出能力分析了低压侧母线电容的作用,提出了新的同步控制方案。在满足原母线电容优势的前提下,改进了低压侧的调压方式。其次对三端口变压器、高压侧谐振电感及低压侧滤波电感进行设计,以满足所有模式的工作需求。提出了磁性元件的集成方法使得功率密度进一步加大,并对所设计的磁性元件组件在各模式下进行损耗及温升的仿真,保证磁性元件组件可以正常工作。然后分别对G2V模式、H2L模式进行小信号建模及闭环回路的设计,G2V模式采用恒压、恒流、及恒功率的控制方式,H2L模式采用峰值电流控制,并将峰值电流控制的思想运用到G2V与G2L同步工作模式当中,优化了低压侧充电的设计。给出了各模式下PLECS仿真结果。最后对整个系统的硬件电路进行了设计,从削弱直流母线杂散电感、提高PCB电流承载能力、增强电路可靠性等方面逐步描述设计思路,给出了Maxwell涡流场杂散电感仿真结果及Icepack温升仿真结果,并搭建实物样机对所提三端口DC/DC变换器进行实物验证,验证了各模式下的输出性能。更多还原

【Abstract】 The popularity of electric vehicles is becoming increasingly widespread.With the continuous upgrading of power devices,more miniaturized,lightweight,high-power density,and high-efficiency DC/DC converters have become one of the main factors determining the charging performance of electric vehicles.Meeting higher efficiency indicators and power density while achieving basic functions has become a hot topic in the field of electric vehicle charging.This article proposes a new three ports DC/DC converter for the field of electric vehicle charging,which integrates the widely popular original OBC and DC/DC transformers on the market,increasing the utilization rate of magnetic components while reducing the use of switching devices,greatly reducing cost requirements.This converter can meet the traditional OBC’s high-voltage power battery charging mode,low-voltage auxiliary battery charging mode,high-voltage battery feedback grid mode,and can also achieve synchronous charging of high-voltage power batteries and low-voltage auxiliary batteries.At the same time,a theoretical analysis was conducted on whether to add lowvoltage side bus capacitors in existing research,and a method was proposed to improve low-voltage side charging by omitting bus capacitors.This article first provides a detailed description of the working principle of three port DC/DC in each mode,deducing the current key point equation,output power equation,and output voltage equation.It also analyzes the role of low-voltage side bus capacitance from the perspective of switch device stress and low-voltage side bus output capacity,and proposes a new synchronous control scheme.On the premise of meeting the advantages of the original busbar capacitance,the voltage regulation method on the low-voltage side has been improved.Secondly,design a three-port transformer,high-voltage side resonant inductance,and low-voltage side filtering inductance to meet the working requirements of all modes.A method for integrating magnetic components has been proposed to further increase power density,and simulation of loss and temperature rise of the designed magnetic component components in various modes has been carried out to ensure that the magnetic component components can work normally.Then,small signal modeling and closed-loop circuit design were carried out for G2 V mode and H2 L mode respectively.G2 V mode adopts constant voltage,constant current,and constant power control methods,while H2 L mode adopts peak current control.The idea of peak current control was applied to the synchronous working modes of G2 V and G2 L,optimizing the design of low-voltage side charging.The PLECS simulation results for each mode are provided.Finally,the hardware circuit of the entire system was designed,gradually describing the design ideas from aspects such as weakening the stray inductance of the DC bus,improving the current carrying capacity of the PCB,and enhancing circuit reliability.The Maxwell eddy current field stray inductance simulation results and Icepack temperature rise simulation results were provided,and a physical prototype was built to verify the output performance of the proposed three ports DC/DC converter in each mode.更多还原