基于PCB绕组磁集成变压器的双有源桥DC-DC变换器效率优化及控制研究

With the rapid development of electric vehicle related technologies, electric vehicle on-board chargers show a trend of bidirectional power flow, high efficiency and high power transmission. To solve the problems of limited conversion efficiency and power density caused by wide range voltage variation of the electric vehicle battery, this proposal is focused on dual active bridge DC-DC converter used for bidirectional electric vehicle charger, and proposes efficiency optimization and control methods for bidirectional dual active bridge DC-DC converter with PCB-Winding-Based integrated transformers. The researches will be conducted on three aspects including zero voltage switching (ZVS) of the converter, unified power control and PCB-Winding-Based integrated transformers. Firstly, in order to reduce the switching loss, a ZVS method is proposed through modification of the existing topology, studying the soft switching mechanism, and then extracting the common soft switching law. Secondly, to reduce the conduction loss, the unified power control aiming at achieving ZVS and low reactive power is studied based on the power transfer mechanism. Thirdly, to optimize the transformer loss, the PCB-winding-based magnetic integration and loss optimization methods are studied. Finally, it provides theoretical basis and technical solutions for the development of high-efficiency and high-power electric vehicle on-board chargers.

随着电动汽车相关技术的快速发展，电动汽车车载充电机呈现出高效率、高功率以及双向功率传输的趋势。针对蓄电池电压宽范围变化导致车载充电机转换效率、功率密度受限的问题，本项目以应用于双向车载电动汽车充电机的双有源桥DC-DC变换器为研究对象，从变换器的ZVS（Zero Voltage Switching）软开关实现、统一功率控制以及PCB绕组变压器磁集成三个方面开展研究，提出基于PCB绕组磁集成变压器的变换器效率优化及控制方法。为降低器件开关损耗，基于新型拓扑，研究软开关机理，凝练共性规律，提出软开关通用实现方法；为降低器件的导通损耗，从功率传递机理着手，提出实现ZVS和低无功功率的统一功率控制方法；为优化变压器损耗，从PCB绕组磁集成变压器角度，研究多磁性元件的PCB绕组变压器磁集成结构与损耗优化方法。最终，为高效率、高功率双向车载充电机的发展提供理论依据及技术解决方案。

传统的DC-DC变换器由于硬开关、多磁性元件等问题，致使效率和功率密度受限，影响了电动汽车的节能效果。为此，本项目以提高双有源桥DC-DC变换器效率和功率密度为目标，就其中的关键技术问题进行研究。主要的研究成果揭示了辅助电流注入网络对扩宽ZVS范围的有效性，针对传统方法导致ZVS丢失问题，建立了考虑多谐振网络的高精度ZVS模型。根据所提的辅助电感网络概念，提出了一系列新型变换器拓扑结构及其功率控制方法，包括基于辅助电流注入的电流型双有源桥变换器及其电压匹配控制全范围软开关参数设计方法，以及基于辅助电流注入的混合桥双有源桥变换器及其软开关实现方法。在功率控制研究上，为了实现高效率提出了以实现全工作范围ZVS为前提的低电流有效值控制方法，为了避免模式切换带来的系统鲁棒性降低问题，提出了基于电压匹配控制的全工作范围ZVS统一控制方法。为了进一步提升效率和功率密度，从磁路优化着手，分别研究了基于单路和多路耦合电路的双有源桥变换器拓扑的工作机理，并提出了一种基于模块间耦合的新型双有源桥变换器及其可调制电感技术。研究成果解决了传统双有源桥变换器效率低、工作范围受限、功率密度低等问题，拓展了其应用范围，对优化相关产品性能和提高可靠性提供重要的支撑，对节能减排具有重要的理论价值和借鉴意义。