Due to the large number of submodules(SMs),and modular multilevel converters(MMCs)in high-voltage applications,they are usually regulated by the nearest level modulation(NLM).Moreover,the large number of SMs causes a ...Due to the large number of submodules(SMs),and modular multilevel converters(MMCs)in high-voltage applications,they are usually regulated by the nearest level modulation(NLM).Moreover,the large number of SMs causes a challenge for the fault diagnosis strategy(FDS).This paper proposes a currentless FDS for MMC with NLM.In FDS,the voltage sensor is relocated to measure the output voltage of the SM.To acquire the capacitor voltage and avoid increasing extra sensors,a capacitor voltage calculation method is proposed.Based on the measurement of output voltages,the faults can be detected and the number of different-type switch open-circuit faults can be confirmed from the numerous SMs in an arm,which narrows the scope of fault localization.Then,the faulty SMs and faulty switches in these SMs are further located without arm current according to the sorting of capacitor voltages in the voltage balancing algorithm.The FDS is independent of the arm current,which can reduce the communication cost in the hierarchical control system of MMC.Furthermore,the proposed FDS not only simplifies the identification of switch open-circuit faults by confirming the scope of faults,but also detects and locates multiple different-type faults in an arm.The effectiveness of the proposed strategy is verified by the simulation results.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
基金supported by the State Key Laboratory of Advanced Power Transmission Technology(GEIRI-SKL-2020-011)。
文摘Due to the large number of submodules(SMs),and modular multilevel converters(MMCs)in high-voltage applications,they are usually regulated by the nearest level modulation(NLM).Moreover,the large number of SMs causes a challenge for the fault diagnosis strategy(FDS).This paper proposes a currentless FDS for MMC with NLM.In FDS,the voltage sensor is relocated to measure the output voltage of the SM.To acquire the capacitor voltage and avoid increasing extra sensors,a capacitor voltage calculation method is proposed.Based on the measurement of output voltages,the faults can be detected and the number of different-type switch open-circuit faults can be confirmed from the numerous SMs in an arm,which narrows the scope of fault localization.Then,the faulty SMs and faulty switches in these SMs are further located without arm current according to the sorting of capacitor voltages in the voltage balancing algorithm.The FDS is independent of the arm current,which can reduce the communication cost in the hierarchical control system of MMC.Furthermore,the proposed FDS not only simplifies the identification of switch open-circuit faults by confirming the scope of faults,but also detects and locates multiple different-type faults in an arm.The effectiveness of the proposed strategy is verified by the simulation results.
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.
