This paper proposes the design of a novel DC current flow controller(CFC)and evaluates the control performance of balancing and regulating the DC branch currents using the DC CFC in a meshed multi-terminal HVDC(MTDC)g...This paper proposes the design of a novel DC current flow controller(CFC)and evaluates the control performance of balancing and regulating the DC branch currents using the DC CFC in a meshed multi-terminal HVDC(MTDC)grid.The DC CFC consists of two identical full bridge DC-DC converters with the capacitors of the two converters being connected in parallel.The scalability of the DC CFC is easily achievable due to the identical bridge converter topology;the cost of this DC CFC is also relatively low due to its simple physical structure and low voltage ratings.The control performance of the DC CFC is tested on a meshed 3-terminal(3-T)HVDC grid,which is based on modular multilevel converters(MMC).The DC branch current control in the meshed MTDC grid is achieved using the proposed control strategy of the DC CFC,and is verified through case studies on the real-time digital simulator(RTDS).展开更多
分析了由并联型有源电力滤波器(parallel active power filter,PAPF)和并联电容器组成的混合补偿系统的系统稳定性。分析表明采用传统的PAPF控制方式时,当PAPF检测的负载电流中不包含并联电容器的电流时,混合补偿系统稳定,并且有理想的...分析了由并联型有源电力滤波器(parallel active power filter,PAPF)和并联电容器组成的混合补偿系统的系统稳定性。分析表明采用传统的PAPF控制方式时,当PAPF检测的负载电流中不包含并联电容器的电流时,混合补偿系统稳定,并且有理想的谐波补偿效果;当PAPF检测的负载电流中包含并联电容器的电流时,此时混合系统存在稳定性和谐波抑制效果之间的矛盾。实际系统中检测的负载电流中包含并联电容器电流的情况有时是不可避免的,针对这种情况提出一种同时检测负载电流和电源电压来控制PAPF输出电流的控制方案,该控制方案可以使系统变稳定,并且具有理想的谐波补偿效果。最后给出了仿真和实验验证结果。展开更多
In the present scenario,modular multilevel converters(MMCs)are considered to be one of the most promising and effective topologies in the family of high-power converters because of their modular design and good scalab...In the present scenario,modular multilevel converters(MMCs)are considered to be one of the most promising and effective topologies in the family of high-power converters because of their modular design and good scalability;MMCs are extensively used in high-voltage and high-power applications.Based on their unique advantages,MMCs have attracted increasing attention from academic circles over the past years.Several studies have focused on different aspects of MMCs,including submodule topologies,modeling schemes,modulation strategies,control schemes for voltage balancing and circulating currents,fault diagnoses,and fault-tolerant control strategies.To summarize the current research status of MMCs,all the aforementioned research issues with representative research approaches,results and characteristics are systematically overviewed.In the final section,the current research status of MMCs and their future trends are emphasized.展开更多
基金supported by UK-China Smart Grid Project ERIFT via UK EPSRC,University of Birmingham SiGuang Li Scholarship and China Scholarship Council。
文摘This paper proposes the design of a novel DC current flow controller(CFC)and evaluates the control performance of balancing and regulating the DC branch currents using the DC CFC in a meshed multi-terminal HVDC(MTDC)grid.The DC CFC consists of two identical full bridge DC-DC converters with the capacitors of the two converters being connected in parallel.The scalability of the DC CFC is easily achievable due to the identical bridge converter topology;the cost of this DC CFC is also relatively low due to its simple physical structure and low voltage ratings.The control performance of the DC CFC is tested on a meshed 3-terminal(3-T)HVDC grid,which is based on modular multilevel converters(MMC).The DC branch current control in the meshed MTDC grid is achieved using the proposed control strategy of the DC CFC,and is verified through case studies on the real-time digital simulator(RTDS).
文摘分析了由并联型有源电力滤波器(parallel active power filter,PAPF)和并联电容器组成的混合补偿系统的系统稳定性。分析表明采用传统的PAPF控制方式时,当PAPF检测的负载电流中不包含并联电容器的电流时,混合补偿系统稳定,并且有理想的谐波补偿效果;当PAPF检测的负载电流中包含并联电容器的电流时,此时混合系统存在稳定性和谐波抑制效果之间的矛盾。实际系统中检测的负载电流中包含并联电容器电流的情况有时是不可避免的,针对这种情况提出一种同时检测负载电流和电源电压来控制PAPF输出电流的控制方案,该控制方案可以使系统变稳定,并且具有理想的谐波补偿效果。最后给出了仿真和实验验证结果。
基金Supported by the Science and Technology Program of State Grid Corporation of China(5100-201999330A-0-0-00)。
文摘In the present scenario,modular multilevel converters(MMCs)are considered to be one of the most promising and effective topologies in the family of high-power converters because of their modular design and good scalability;MMCs are extensively used in high-voltage and high-power applications.Based on their unique advantages,MMCs have attracted increasing attention from academic circles over the past years.Several studies have focused on different aspects of MMCs,including submodule topologies,modeling schemes,modulation strategies,control schemes for voltage balancing and circulating currents,fault diagnoses,and fault-tolerant control strategies.To summarize the current research status of MMCs,all the aforementioned research issues with representative research approaches,results and characteristics are systematically overviewed.In the final section,the current research status of MMCs and their future trends are emphasized.
