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A bidirectional DC-DC converter with high step-down and step-up voltage conversion ratio is proposed in this paper. Two capacitors series in the high-voltage side of proposed converter are used for voltage division. The divided voltages are then discharged to and charged from the low-voltage side by a modified two-phase interleaved buck-boost converter, respectively. Due to stacking architecture of the proposed converter, high bidirectional voltage conversion ratio with low voltage stresses on power switches can be achieved by the proposed converter with reasonable duty ratio. Besides, a smart phase-rotating control scheme can be integrated into the proposed converter to improve the conversion efficiency at light loads. A prototype circuit with a voltage of 200V in high-voltage side, a voltage of 24V in low-voltage side and a rated output power of 500W is implemented to verify the performance of proposed bidirectional DC-DC converter. Experimental results show that the maximum conversion efficiencies, about 93.40% and 93.86%, for step-down mode and step-up mode, respectively along with lower voltage stresses on power switches can be achieved. Besides, a conversion efficiency improvement of 5.42% can be accomplished for the proposed converter with smart phase-rotating control scheme under 25W.

To achieve the athermal mount of remote sensor reflectors,the calculation and controlling methods of the adhesive layer thickness for a reflector in athermal mount was researched.Firstly,the methods to calculate the adhesive layer thickness for athermal mount in engineering applications were introduced,the several kinds of controlling processes of layer thickness for the reflector was described and the advantages,disadvantages and limitations of each method were analyzed in detail.Based on the analysis of the problem of the layer thickness control process,the hollow glass beads with different diameter sizes were used to control the layer thickness.A tensile test was performed to prove that the optical epoxy glue added hollow glass beads has improved the mechanical properties by 20% than the pure optical epoxy glue.The experiment shows that the adhesive process method by using the hollow glass beads to ensure the layer thickness can provide a good surface figure for the reflector,which meets the requirements of lens stress-free mount.The method has been used in engineering projects.

Speckle filtering and edge detection are fundamental techniques for polarimetric synthetic aperture radar (PolSAR) image analysis. In this paper, based on complex Wishart distribution and the similarity test of the covariance matrix, a completely adaptive speckle filtering is proposed. Meanwhile, a new edge indicator named similar pixel number is developed. This indicator shows great sensitivity to determine the edge pixels and a new edge detection method is proposed. The novelty of this edge detector is that the edge can be detected without mono-edge assumption and the edge orientation can be extracted automatically without any window configurations and searching steps. The efficiency of the proposed speckle filter and edge detection scheme are demonstrated by ALOS/PALSAR data set., 形態: カラー図版あり, 形態: DVD-ROM1枚, Physical characteristics: Original contains color illustrations, Note: One DVD-ROM, 資料番号: AA0065135086, レポート番号: JAXA-SP-11-007E