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Cooperative Operation of R-SFCL and Online Current Limitation Strategy of GCPVS under Asymmetrical Faults
摘要： Grid-connected photovoltaic (GCPVS) should remain grid-connected and inject specified reactive current in accordance with fault-ride-through (FRT) requirements. To minimize voltage ripples on the DC link voltage and restrict the maximum phase currents, a modified online current limitation strategy (OCLS) is presented in this paper. Transient performance of GCPVS is enhanced as resistive-type superconducting fault current limiter (R-SFCL) is applied under severe asymmetrical faults. By introducing proper resistance selection process, the cooperative operation of OCLS and SFCL is proved to be effective.
关键词： reactive power control,transient performance,superconducting fault current limiters (FCL),online current limitation strategy (OCLS),photovoltaic systems,Fault ride-through (FRT) capability,symmetrical and asymmetrical faults
更新于2025-09-23 15:22:29
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Arrays of Si Field Emitter Individually Regulated by Si Nanowires High Breakdown Voltages and Enhanced Performance
摘要： We fabricate Si field emitter arrays (FEAs) with integrated Si nanowire current limiters and investigate a method to enable higher voltage operation, which can potentially increase achievable current densities. In this work, we focus on the dielectric breakdown occurring in the vicinity of the nanopillar. A deeper etch is shown to increase the breakdown voltage but at the expense of poorer field emission characteristics possibly due to the loss of mechanical support or increased surface states.
关键词： field emitter arrays,Silicon,breakdown voltage,current limiters
更新于2025-09-23 15:21:21
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Performance and Degradation Evaluation of PV Modules on the Substring Level by an In-Situ Electronic Device
摘要： We report silicon ?eld emitter arrays (FEAs) that demonstrate current densities >100 A/cm2 at gate–emitter voltages <75 V. These are the highest current densities reported for a semiconductor FEA, and approach the current densities of Spindt-type metal cathodes. We achieved these results using a new device structure that employs high-aspect-ratio silicon nanowire current limiters in series with each emitter tip to address the major failure mechanisms in FEAs. These current limiters mitigate emitter tip failure due to joule heating thus allowing for higher reliability. We employed a novel fabrication process to produce small gate apertures (≈350 nm) that are self-aligned to the ?eld emitter tip enabling device operation at >100 A/cm2 with gate-to-emitter voltages that are less than 75 V. These FEAs demonstrate performance that has the potential to enable smaller, more ef?cient, and high-power vacuum electronics.
关键词： FEAs,nanowires,Field emission arrays,silicon FEAs,silicon tips,silicon nanowire current limiters
更新于2025-09-19 17:13:59
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Grid-Connected Photovoltaic Power Plant without Phase Angle Synchronization Able to Address Fault Ride-Through Capability
摘要： This paper discusses the control of large-scale grid-connected photovoltaic power plants (GCPPPs) operating under unbalanced grid voltage sags. The positive and negative sequences of the output currents are controlled to achieve different targets: injecting constant power (i) to the grid, or (ii) to the ac side of the converter, i.e., including the filter and the grid. Traditionally, synchronization with the grid voltages is required, which is usually performed by a phase-locked-loop (PLL) technique. In this paper, the proposed control technique does not require any grid voltage synchronization. An arbitrary angle is used instead with the only requirement of having a frequency equal or close to the grid frequency. The fault-ride-through capability of the GCPPP during unbalanced voltage sags is addressed by proposing a current limiter. Simulation and experimental results verify the performance of the proposed GCPPP.
关键词： Power system faults,Phase locked loops,Photovoltaic systems,Fault current limiters
更新于2025-09-11 14:15:04