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
The multiphase multilevel motor drives are a promising solution for some high-power and high-reliability applications,since they have multiple power conversion routes,a large amount of redundant voltage vectors,higher...The multiphase multilevel motor drives are a promising solution for some high-power and high-reliability applications,since they have multiple power conversion routes,a large amount of redundant voltage vectors,higher equivalent switching frequencies and superior harmonic performance.It has great significance to exploit their remedial control strategies in depth to fully utilize their high fault tolerant capabilities.This paper will present an updated technical review of fault tolerant control schemes for multiphase multilevel motor drives.Based on exemplification of the diode neutral-point-clamping three-level(DNPC-3L)inverters and T-type NPC three-level(TNPC-3L)inverters fed asymmetric six-phase PMSM drives,the study is taken for both phase-leg faults and switch faults.Furthermore,the discussion on multiple-switch faults,short-circuit switch faults and switch and leg hybrid faulty conditions are discussed in this paper.展开更多
This paper presents an isolated DC/AC/DC converter using a middle frequency transformer coupling two modular multilevel converters(MMC),suitable for interconnecting DC transmission lines of different voltage levels in...This paper presents an isolated DC/AC/DC converter using a middle frequency transformer coupling two modular multilevel converters(MMC),suitable for interconnecting DC transmission lines of different voltage levels in high voltage direct current(HVDC)system.The basic operational principle of the isolated module multilevel DC/DC converter(IMMDCC)is analyzed.The dynamic model of IMMDCC is studied in detail and the transient relationship between DC side and AC side of IMMDCC is revealed,which is physically straightforward for understanding the power transfer in IMMDCC.The control strategy in D-Q coordinate system is put forward,and the fault characteristic and corresponding protection method is analyzed.Finally,computer simulation using Matlab/Simulink is performed to verify the dynamic model and the proposed control strategy.The simulation results show good performances and the quick response ability of the proposed control strategy.展开更多
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.
基金Supported by National Natural Science Foundation of China under Grant 51577027.
文摘The multiphase multilevel motor drives are a promising solution for some high-power and high-reliability applications,since they have multiple power conversion routes,a large amount of redundant voltage vectors,higher equivalent switching frequencies and superior harmonic performance.It has great significance to exploit their remedial control strategies in depth to fully utilize their high fault tolerant capabilities.This paper will present an updated technical review of fault tolerant control schemes for multiphase multilevel motor drives.Based on exemplification of the diode neutral-point-clamping three-level(DNPC-3L)inverters and T-type NPC three-level(TNPC-3L)inverters fed asymmetric six-phase PMSM drives,the study is taken for both phase-leg faults and switch faults.Furthermore,the discussion on multiple-switch faults,short-circuit switch faults and switch and leg hybrid faulty conditions are discussed in this paper.
文摘This paper presents an isolated DC/AC/DC converter using a middle frequency transformer coupling two modular multilevel converters(MMC),suitable for interconnecting DC transmission lines of different voltage levels in high voltage direct current(HVDC)system.The basic operational principle of the isolated module multilevel DC/DC converter(IMMDCC)is analyzed.The dynamic model of IMMDCC is studied in detail and the transient relationship between DC side and AC side of IMMDCC is revealed,which is physically straightforward for understanding the power transfer in IMMDCC.The control strategy in D-Q coordinate system is put forward,and the fault characteristic and corresponding protection method is analyzed.Finally,computer simulation using Matlab/Simulink is performed to verify the dynamic model and the proposed control strategy.The simulation results show good performances and the quick response ability of the proposed control strategy.
