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
模块化多电平技术(modular multilevel converter,MMC)因其电磁兼容性好、谐波含量低、开关损耗较小等优势已经在高压直流输电(high voltage direct current,HVDC)中得到了广泛的运用。在MMC-HVDC向无源网络供电的情况下,为了抑制不对...模块化多电平技术(modular multilevel converter,MMC)因其电磁兼容性好、谐波含量低、开关损耗较小等优势已经在高压直流输电(high voltage direct current,HVDC)中得到了广泛的运用。在MMC-HVDC向无源网络供电的情况下,为了抑制不对称故障对向无源网络供电的电能质量的影响,采用了将微分平坦理论应用于向无源网络供电的MMC-HVDC系统的方法,以提高发生不对称故障时MMC换流器的动态性能。首先分析了向无源网络供电的MMC-HVDC的系统结构和工作原理,针对MMC-HVDC整流级的MMC换流器建立了在不平衡电网电压时基于正负序系统的数学模型;其次针对不同输出变量,分别进行了平坦性分析;接着,对MMC系统进行稳定性分析,并根据微分平坦理论设计了MMC-HVDC换流站的内外环正负序控制器;最后,在Matlab/Simulink中建立一个对无源网络供电的MMC-HVDC系统,结果表明:在发生不对称故障的运行条件下,MMC-HVDC系统的控制策略具有较好的动态性能。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.
文摘模块化多电平技术(modular multilevel converter,MMC)因其电磁兼容性好、谐波含量低、开关损耗较小等优势已经在高压直流输电(high voltage direct current,HVDC)中得到了广泛的运用。在MMC-HVDC向无源网络供电的情况下,为了抑制不对称故障对向无源网络供电的电能质量的影响,采用了将微分平坦理论应用于向无源网络供电的MMC-HVDC系统的方法,以提高发生不对称故障时MMC换流器的动态性能。首先分析了向无源网络供电的MMC-HVDC的系统结构和工作原理,针对MMC-HVDC整流级的MMC换流器建立了在不平衡电网电压时基于正负序系统的数学模型;其次针对不同输出变量,分别进行了平坦性分析;接着,对MMC系统进行稳定性分析,并根据微分平坦理论设计了MMC-HVDC换流站的内外环正负序控制器;最后,在Matlab/Simulink中建立一个对无源网络供电的MMC-HVDC系统,结果表明:在发生不对称故障的运行条件下,MMC-HVDC系统的控制策略具有较好的动态性能。
