Multi-converter system is mainly used in advanced automotive systems.Different converters and inverters are taking part in automotive systems to provide different voltage levels in a multi-converter system.It involves...Multi-converter system is mainly used in advanced automotive systems.Different converters and inverters are taking part in automotive systems to provide different voltage levels in a multi-converter system.It involves constant voltage load(CVL),constant power load(CPL)and other loads.The CPL in such systems offers negative impedance characteristic and it creates a destabilizing effect on the main converter.The effect of destabilization can be reduced by increasing the CVL or inserting parasitic components.Attempts have been made by authors to improve the stability by using parasitics of different components such as switch,diode and inductor.Influence of insertion of parasitics including the series equivalent resistance of the filter capacitor and variation in CVL on the performance of main converter is mathematically analyzed and conflicting behavior between system stability and efficiency is observed.The optimum solution between these two functions is obtained by using multi-objective decision making(MODM)by varying parasitics of different components and CVL.An attempt has been made to demonstrate the effect of CVL load and the parasitics on the stability and efficiency of the main converter,experimentally.展开更多
基于模块化多电平变流器(modular multi-level converter,MMC)的电池储能系统(battery energy storage system,BESS)适用于中高压交直流混合电网,有助于解决可再生能源大规模并网问题。针对电池容量利用率问题,该文分析了MMC-BESS中各...基于模块化多电平变流器(modular multi-level converter,MMC)的电池储能系统(battery energy storage system,BESS)适用于中高压交直流混合电网,有助于解决可再生能源大规模并网问题。针对电池容量利用率问题,该文分析了MMC-BESS中各端电源功率传递关系,提出了一种电池荷电状态(state of charge,SOC)均衡控制策略,通过三级均衡控制,实现相间、上下桥臂间、桥臂内子模块间电池模块的SOC均衡。同时为提高系统运行的可靠性,研究了故障容错运行工况下的SOC均衡控制策略。最后通过仿真和实验验证了所提控制策略的有效性。展开更多
文摘Multi-converter system is mainly used in advanced automotive systems.Different converters and inverters are taking part in automotive systems to provide different voltage levels in a multi-converter system.It involves constant voltage load(CVL),constant power load(CPL)and other loads.The CPL in such systems offers negative impedance characteristic and it creates a destabilizing effect on the main converter.The effect of destabilization can be reduced by increasing the CVL or inserting parasitic components.Attempts have been made by authors to improve the stability by using parasitics of different components such as switch,diode and inductor.Influence of insertion of parasitics including the series equivalent resistance of the filter capacitor and variation in CVL on the performance of main converter is mathematically analyzed and conflicting behavior between system stability and efficiency is observed.The optimum solution between these two functions is obtained by using multi-objective decision making(MODM)by varying parasitics of different components and CVL.An attempt has been made to demonstrate the effect of CVL load and the parasitics on the stability and efficiency of the main converter,experimentally.
文摘基于模块化多电平变流器(modular multi-level converter,MMC)的电池储能系统(battery energy storage system,BESS)适用于中高压交直流混合电网,有助于解决可再生能源大规模并网问题。针对电池容量利用率问题,该文分析了MMC-BESS中各端电源功率传递关系,提出了一种电池荷电状态(state of charge,SOC)均衡控制策略,通过三级均衡控制,实现相间、上下桥臂间、桥臂内子模块间电池模块的SOC均衡。同时为提高系统运行的可靠性,研究了故障容错运行工况下的SOC均衡控制策略。最后通过仿真和实验验证了所提控制策略的有效性。
文摘针对模块化多电平变流器多端直流配电系统,提出了一种改进协调控制策略。该控制策略是对下垂控制改进,改进的策略避免了直流网络在功率发生较大程度变化时出现过电压。在此背景下,设计了基于半桥型模块化多电平换流器(Half-bridge Modular Multi level ConverterHBMMC)的四端柔性柔性多端直流配电系统。本文首先分析了模块化多电平换流器的基本原理,然后在此基础上设计了四个模块化多电平换流器的控制和内部环流并在基础上改进了协调控制策略,最后用PSCAD/EMTDC平台搭建了21电平MMC验证仿真模型,最后仿真结果验证了:稳定时,各级控制器间的相互配合使得所构建模型可行性;系统在任意一端换流站故障退出后仍具备稳定运行的能力,可以最大限度地维持直流电压的稳定。
