To improve the harmonic suppression ability of multi-pulse rectifier,a 12-pulse rectifier based on zigzag autotransformer by DC side active compensation strategy is proposed.By controlling the small capacity current i...To improve the harmonic suppression ability of multi-pulse rectifier,a 12-pulse rectifier based on zigzag autotransformer by DC side active compensation strategy is proposed.By controlling the small capacity current inverter to generate compensating currents and injecting the currents directly into the DC side of the system,the grid-side currents of the rectifier can be approximated to sine wave.Using zigzag autotransformer as phase-shifting transformer can block the zero sequence current components and reduce the equivalent capacity of the rectifying system.The study on harmonic distortion rate of grid-side currents with the variation of the load shows that the harmonic content of the compensated rectifier decreases significantly under various load conditions.The harmonic content of the grid-side currents of the proposed active injection rectifier is only 1.17%,and the equivalent capacity of the rectifier is calculated.The results show that the rectifier can not only suppress the harmonic currents,but also have a lower equivalent capacity.展开更多
The emergence of a large quantity of digital resources in geometry, various geometric automated theorem proving systems, and kinds of dynamic geometry software systems has made geometric computation, reasoning, drawin...The emergence of a large quantity of digital resources in geometry, various geometric automated theorem proving systems, and kinds of dynamic geometry software systems has made geometric computation, reasoning, drawing, and knowledge management dynamic, automatic or interactive on computer. Integration of electronic contents and different systems is desired to enhance their accessibility and exploitability. This paper proposes an equivalent transformation framework for manipulating geometric statements available in the literature by using geometry software systems. Such a framework works based on a newly designed geometry description language(GDL), in which geometric statements can be represented naturally and easily. The author discusses and presents key procedures of automatically transforming GDL statements into target system-native representations for manipulation.The author also demonstrates the framework by illustrating equivalent transformation processes and interfaces for compiling the transformation results into executable formats that can be interpreted by the target geometry software systems for automated theorem proving and dynamic diagram drawing.展开更多
基金National Natural Science Foundation of China(No.51767013)Science and Technology Research and Development Plan of China Railway Corporation(No.2017J012-A)Lanzhou City Science and Technology Program for Innovation and Entrepreneurship of Talents(No.2017-RC-51)。
文摘To improve the harmonic suppression ability of multi-pulse rectifier,a 12-pulse rectifier based on zigzag autotransformer by DC side active compensation strategy is proposed.By controlling the small capacity current inverter to generate compensating currents and injecting the currents directly into the DC side of the system,the grid-side currents of the rectifier can be approximated to sine wave.Using zigzag autotransformer as phase-shifting transformer can block the zero sequence current components and reduce the equivalent capacity of the rectifying system.The study on harmonic distortion rate of grid-side currents with the variation of the load shows that the harmonic content of the compensated rectifier decreases significantly under various load conditions.The harmonic content of the grid-side currents of the proposed active injection rectifier is only 1.17%,and the equivalent capacity of the rectifier is calculated.The results show that the rectifier can not only suppress the harmonic currents,but also have a lower equivalent capacity.
基金supported partially by the SKLSDE Open Fund(SKLSDE-2011KF-02)the Natural Science Foundation of China under Grant No.61003139the MOE-Intel Joint Research Fund(MOE-INTEL-11-03)
文摘The emergence of a large quantity of digital resources in geometry, various geometric automated theorem proving systems, and kinds of dynamic geometry software systems has made geometric computation, reasoning, drawing, and knowledge management dynamic, automatic or interactive on computer. Integration of electronic contents and different systems is desired to enhance their accessibility and exploitability. This paper proposes an equivalent transformation framework for manipulating geometric statements available in the literature by using geometry software systems. Such a framework works based on a newly designed geometry description language(GDL), in which geometric statements can be represented naturally and easily. The author discusses and presents key procedures of automatically transforming GDL statements into target system-native representations for manipulation.The author also demonstrates the framework by illustrating equivalent transformation processes and interfaces for compiling the transformation results into executable formats that can be interpreted by the target geometry software systems for automated theorem proving and dynamic diagram drawing.
