http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Ma, Hui,Xie, Yunxiang,Sun, Biaoguang,Mo, Lingjun The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.1
This paper uses the switching function approach to present a simple state model of the Vienna-type rectifier. The approach introduces the relationship between the DC-link neutral point voltage and the AC side phase currents. A novel direct power control (DPC) strategy, which is based on the sliding mode control (SMC) for Vienna I rectifiers, is developed using the proposed power model in the stationary ${\alpha}-{\beta}$ reference frames. The SMC-based DPC methodology directly regulates instantaneous active and reactive powers without transforming to a synchronous rotating coordinate reference frame or a tracking phase angle of grid voltage. Moreover, the required rectifier control voltages are directly calculated by utilizing the non-linear SMC scheme. Theoretically, active and reactive power flows are controlled without ripple or cross coupling. Furthermore, the fixed-switching frequency is obtained by employing the simplified space vector modulation (SVM). SVM solves the complicated designing problem of the AC harmonic filter. The simplified SVM is based on the simplification of the space vector diagram of a three-level converter into that of a two-level converter. The dwelling time calculation and switching sequence selection are easily implemented like those in the conventional two-level rectifier. Replacing the current control loops with power control loops simplifies the system design and enhances the transient performance. The simulation models in MATLAB/Simulink and the digital signal processor-controlled 1.5 kW Vienna-type rectifier are used to verify the fast responses and robustness of the proposed control scheme.
Hui Ma,Yunxiang Xie,Biaoguang Sun,Lingjun Mo 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.1
This paper uses the switching function approach to present a simple state model of the Vienna-type rectifier. The approach introduces the relationship between the DC-link neutral point voltage and the AC side phase currents. A novel direct power control (DPC) strategy, which is based on the sliding mode control (SMC) for Vienna I rectifiers, is developed using the proposed power model in the stationary α-β reference frames. The SMC-based DPC methodology directly regulates instantaneous active and reactive powers without transforming to a synchronous rotating coordinate reference frame or a tracking phase angle of grid voltage. Moreover, the required rectifier control voltages are directly calculated by utilizing the non-linear SMC scheme. Theoretically, active and reactive power flows are controlled without ripple or cross coupling. Furthermore, the fixed-switching frequency is obtained by employing the simplified space vector modulation (SVM). SVM solves the complicated designing problem of the AC harmonic filter. The simplified SVM is based on the simplification of the space vector diagram of a three-level converter into that of a two-level converter. The dwelling time calculation and switching sequence selection are easily implemented like those in the conventional two-level rectifier. Replacing the current control loops with power control loops simplifies the system design and enhances the transient performance. The simulation models in MATLAB/Simulink and the digital signal processor-controlled 1.5 kW Vienna-type rectifier are used to verify the fast responses and robustness of the proposed control scheme.
Huijuan Qiu,Hongkang Wei,Shifeng Ren,Lingjun Sun,Jia Li,Zihan Wang,Lin Zhao,Chang-an Wang,Zhipeng Xie 한양대학교 청정에너지연구소 2024 Journal of Ceramic Processing Research Vol.25 No.2
Titanium carbide powders were synthesized under an argon atmosphere using titanium dioxide and pyrolysis carbon derivedfrom pyrolyzed phenolic resin as raw materials. The effects of synthesis temperature, holding time, and C/Ti molar ratio onthe phase composition and morphology of the synthesized powders were investigated. The results show that the pyrolyzedphenolic resin at 1000 ℃ is a carbon source composed of amorphous and crystalline carbon. Increasing the C/Ti molar ratio ofthe mixed powder can reduce the content of titanium oxide impurity, indicating the improvement in the purity of TiC powder. In addition, the C/Ti molar ratio can also significantly affect the morphology of the synthesized TiC powders. SEM and EDSresults exhibit that the atomic content on the surface of TiC particles is closely correlated with the atomic distribution on thesurface of the particles. TiC powder with a median particle size of 384 nm could be synthesized at 1500 ℃ for 30 min at the C/Ti molar ratio of 2.3:1. In addition, the sinterability of the synthesized TiC powder was preliminarily discussed. The hardnessand fracture toughness of the TiC ceramic sintered at 2000 ℃ under 40 MPa with a dwell time of 2 h are 15.92 GPa and 3.22MPa·m1/2, respectively.