面向V2G的双向电流型变换器拓扑结构和控制策略研究

本项目针对V2G应用中电网与电动汽车蓄电池能量交互问题，提出高功率密度、高效率、无污染和多功能的车载双向电流型变换器。针对变换器的拓扑结构，研究各种模式的工作原理、统一化数学模型、开关应力分布和损耗模型；综合考虑输出电流纹波、极限调制区域内变换器性能、能量转换效率和非理想工况条件等因素，研究其优化的调制策略；研究系统中恒功率负载的负阻抗特性、电网电压扰动、控制和系统参数等因素对V2G系统稳定性的影响规律，确定系统的稳定域；针对系统在不同模式下存在的稳定性差异问题，研究其差异性根源和稳定化方法。本项目的研究，为实现V2G中电网和电动汽车间的能量交互、优化、控制等关键技术提供有效途径，在实现蓄电池充放电基本功能的同时，能为电网提供无功补偿、谐波治理、平衡负载等辅助服务，为V2G系统安全可靠和经济高效运行奠定基础。

To meet the requirements of the energy-interaction between the grid and batteries of vehicle in grid (V2G) systems, this project proposes a high power density, high efficiency, pollution-free, multifunctional on-board bidirectional current source AC/DC converter. According to the topology, operating principle, unified mathematical model, switch stress distribution and switch loss model are studied under every operating mode. Taking output current ripple, the performance of the converter in the limited modulation region, energy conversion efficiency and non-ideal operating condition into account, the optimized modulation strategy will be presented. How the negative Impedance characteristic of the constant load, disturbs of the grid ,control and system parameters influence the stability of the V2G system is studied, and the stability regions are determined. Then the origin of the difference of stability between charging and discharging will be revealed, and stabilization methods will be introduced. This project is dedicated to provide a viable solution for the key technologies in V2G such as energy-interaction, optimization and modulation strategy, and provides auxiliary services such as reactive power regulation, harmonic control, load balancing, while realizing the basic function of charge-discharge. The final purpose is to ensure the safe operation, reliability and cost-effectiveness of V2G system.