基于电压自适应层叠式能效优化的宽增益范围AC/DC变换方法与关键技术研究

电动汽车充电、储能等直流侧电压宽幅变化的系统中，难以在全电压范围内实现高效率是影响两级式AC/DC变换器系统性能和经济性的主要难题。拟将变换器交流侧脉动功率根据交流电压瞬时大小分区处理，针对不同电压区间分别构建高效功率通路，提出基于多功率通路层叠式优化的多直流端口整流器；通过使多直流端口整流器的直流输出电压与负载侧电压自适应匹配，直接利用整流器实现负载电压的宽幅调节，大大减小后级直流变换器电压增益调节范围，实现宽直流电压范围高效电能变换。拟研究并提出：电压自适应匹配层叠式能效优化的AC/DC变换器电路结构；多直流端口整流器电路拓扑构造机理及其系统实现方法；兼顾高效率和端口功率约束的调制策略和关键参数设计准则；多直流端口整流器与直流变换器协同运行控制技术。项目成果将解决直流侧电压宽幅变化时变换器无法兼顾电压调节范围和变换效率的关键问题，为未来电动汽车、储能系统的规模化应用提供关键技术支撑。

Two-stage AC/DC power converters with wide voltage range on the DC-side are widely applied in various power systems, such as electric-vehicle chargers, energy storage system, renewable power systems and the like. It is difficult for the conventional two-stage AC/DC power converters to achieve high conversion efficiency within the entire operation range when the DC-side voltage varies in a wide range. The performance of the conventional two-stage AC/DC power converter is affected greatly by the DC-side voltage regulation range. According to the instantaneous value of the AC input voltage, the pulsating input power of the AC/DC converter will be divided into two parts and processed optimally by building multiple power flow paths. Novel multi-DC-port rectifiers with multiple power paths and stacked energy-efficiency optimization principles will be proposed. The DC output voltage of the multi-DC-port rectifier will be adaptively matched with the DC voltage on the load side. Hence the load-side DC voltage can be directly regulated by the front-end rectifier, rather than regulated only by the second-stage DC/DC converter. As a result, the voltage regulation range of the second-stage DC/DC converter can be narrowed significantly. With the proposed stacked energy-efficiency optimization and voltage adaptive matching methods, high efficiency AC/DC power conversion within wide DC voltage range will be achieved. This work will propose and study: (1) circuit architecture of novel two-stage AC/DC power converters based on voltage adaption and stacked energy efficiency optimization; (2) the mechanism and systematic realization methods for novel multi-DC-port rectifier topologies; (3) design criterion of key parameters and optimized modulation strategies considering high efficiency and power constraint of power ports simultaneously; (4) the coordinated operation and control methods of the multi-DC-port rectifiers and DC-DC converters. The research results will provide new methods and key technologies for AC/DC power converters with wide DC-side voltage range. Based on the above works, the issue that can't achieve high conversion efficiency within a wide DC voltage range will be solved. The research results will provide key technical support for the large-scale application of electric-vehicle and energy storage system in the future.