http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Control Algorithm Design and Implementation of Solid State Transformer
Gedeon Niyitegeka,Juyoung Park,GyeongSig Cho,Gawoo Park,Jaeho Choi 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
In this paper, a design review and control algorithm of a solid state transformer (SST) model intended to replace the existing 60Hz power transformer for the railway application is presented. The proposed smart transformer is a high-frequency power electronic transformer. It is made of multiple cascade AC-DC converter modules, linked by a high voltage DC-link to the multiple parallel dual active bridges (DAB) DC-DC converters. This arrangement of modules is susceptible to the unbalanced voltage of the DC-link capacitors, and the voltages of modules as well. However, if the control system is well designed, the voltage balance can be maintained. The main advantage of the presented SST is that it is capable of controlling the instantaneous voltage and improving the power quality by compensating the harmonics. The proposed control algorithm includes the design analysis of the output DC voltage control, the voltage balancing capability across the DC-link capacitors and the cascaded modules. It guarantees the great performance during the verification process. The validity of the proposed algorithm is verified by PSIM simulation and scale-downed experimental results.
Nelson Luis Costa dos Santos Filho,Eden Santos Silva,Clodualdo Aranas Jr.,Fulvio Siciliano,Gedeon Silva Reis,Samuel Filgueiras Rodrigues 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11
The correlation between hardening and softening in an ASTM F-1586 stainless steel used as biomaterial was investigatedby means of hot torsion simulations. Multi-pass deformation under continuous cooling was employed to simulate industrialhot rolling. Samples were subjected to 17 deformation passes of strains of 0.20 and 0.30, strain rate of 1.0 s−1 in a temperaturerange of 1250 to 930 °C. Interpass times (tp) of 5.0, 10, 20, 40, and 80 s were used. The obtained results showed directdependence of the mean flow stress (MFS) and all applied thermomechanical parameters. The work hardening rate associatedwith the degree of stress accumulation (Δσ) inhibited the metadynamic recrystallization. This led to the variation ofthe non-recrystallization temperature (Tnr), associated with intense static recovery in the material. From the experimentaldata, a constitutive function of the mean flow stress (MFS) obtained through multiple nonlinear regression technique wasproposed. The study aimed to have a better understanding of the physical metallurgy behind the thermomechanical behaviorof the steel under a multi-pass process. The results allowed to monitor the recrystallized fraction (X) and the grain size (d)during the simulated conditions.