An advanced nonlinear robust control scheme is proposed for multi-machine power systems equipped with thyristor-controlled series compensation (TCSC). First, a decentralized nonlinear robust control approach based on ...An advanced nonlinear robust control scheme is proposed for multi-machine power systems equipped with thyristor-controlled series compensation (TCSC). First, a decentralized nonlinear robust control approach based on the feedback linearization and H∞ theory is introduced to eliminate the nonlinearities and interconnections of the studied system, and to attenuate the exogenous disturbances that enter die system. Then, a system model is built up, which has considered all the generators’ and TCSC’s dynamics, and the effects of uncertainties such as disturbances. Next, a decentralized nonlinear robust coordinated control law is developed based on this model. Simulation results on a six-machine power system show that the transient stability of the power system is obviously improved and die power transfer capacity of long distance transmission lines is enhanced regardless of fault locations and system operation points. In addition, the control law has engineering practicality since all the variables in the expression of he control strategy can be measured locally.展开更多
Results of an investigation on the application of STATCOM for damping subsynchronous resonance (SSR) in a multi-machine system is presented in this paper. For a multi-machine system which has a set of identical parall...Results of an investigation on the application of STATCOM for damping subsynchronous resonance (SSR) in a multi-machine system is presented in this paper. For a multi-machine system which has a set of identical parallel turbine-generators or non-identical turbine-generators having torsional modes of the same frequency, generators may suffer from the same mode of torsional interaction corresponding to a certain series compensation degrees. Generators in such system may have different oscillation behaviors when they are unequally loaded or have different shaft and electrical parameters. Serving as the grid-side equipment, the reactive power output of a STATCOM could have an impact on all generators electrical distance nearby. Thus a single STATCOM could be used to damp torsional interactions of multi-generators when additional proper control strategy is supplemented. In this paper, control strategy of using STATCOM to damp SSR in a multi-machine system is designed and its effectiveness is validated based on a modified IEEE second benchmark model.展开更多
To improve the performance of the short interleaved serial concatenated convolutional code(SCCC) with low decoding iterative times, the structure of Log MAP algorithm is introduced into the conventional SOVA decoder...To improve the performance of the short interleaved serial concatenated convolutional code(SCCC) with low decoding iterative times, the structure of Log MAP algorithm is introduced into the conventional SOVA decoder to improve its performance at short interleaving delay. The combination of Log MAP and SOVA avoids updating the matrices of the maximum path, and also makes a contribution to the requirement of short delay. The simulation results of several SCCCs show that the improved decoder can obtain satisfied performance with short frame interleaver and it is suitable to the high bit rate low delay communication systems.展开更多
A mine-used multi-function serial signal converter is introduced.This converter is based on Ethernet.The core of this design is embedded microprocessor STM32F107VCT6.Embedded operation system μC/OS-Ⅱ is transplanted...A mine-used multi-function serial signal converter is introduced.This converter is based on Ethernet.The core of this design is embedded microprocessor STM32F107VCT6.Embedded operation system μC/OS-Ⅱ is transplanted into this converter,and light-weight Internet protocal （LwIP） stack is also embedded to realize mutual conversion of serial signals such as meter bus （M-Bus） signal,RS485 signal,RS232 signal and Ethernet signal.Interconnection between all kinds of monitoring system interfaces under coal mine can be formed easily,which can solve compatibility problem between monitoring system and communication system and improve overall performance of safety monitoring system.The designed multi-function serial signal converter is of great value for application,which is worthy to be popularized in coal mine safety production.展开更多
The women of the 1930s in the Chinese TV serials deduct inspiring stories.They play different roles in the big wealthy families such as mothers-in-law,daughters-in-law,and maidservants.There are unceasing conflicts be...The women of the 1930s in the Chinese TV serials deduct inspiring stories.They play different roles in the big wealthy families such as mothers-in-law,daughters-in-law,and maidservants.There are unceasing conflicts between these women,because of their struggle for men's love,wealth or social position.The theme of their stories is always about fertility,love,kindness and evil,with the ending being either comic or tragic.The stories of various kinds of women of the 1930s in the Chinese TV serials decorate and enrich the lives of many of us latecomers and their names are passed on from generation to generation.展开更多
Empty categories,which lack phonological form and hence are not visible in the phonetic representation of the sentence,have both syntactic and semantic properties.Null subjects PRO and pro are base-generated empty cat...Empty categories,which lack phonological form and hence are not visible in the phonetic representation of the sentence,have both syntactic and semantic properties.Null subjects PRO and pro are base-generated empty categories.This thesis,based on Chomsky's theory about empty categories and research achievements made by Chinese scholars,attempts to analyze the liandong(Serial Verb) construction from Figure and Ground perspective.展开更多
基金This work was supported by Chinese National Natural Science Foundation(No.50377018)Chinese National Key Basic Research Fund(No.G1998020309)by New Energy and Industrial Technology Development Organization of Japan.
文摘An advanced nonlinear robust control scheme is proposed for multi-machine power systems equipped with thyristor-controlled series compensation (TCSC). First, a decentralized nonlinear robust control approach based on the feedback linearization and H∞ theory is introduced to eliminate the nonlinearities and interconnections of the studied system, and to attenuate the exogenous disturbances that enter die system. Then, a system model is built up, which has considered all the generators’ and TCSC’s dynamics, and the effects of uncertainties such as disturbances. Next, a decentralized nonlinear robust coordinated control law is developed based on this model. Simulation results on a six-machine power system show that the transient stability of the power system is obviously improved and die power transfer capacity of long distance transmission lines is enhanced regardless of fault locations and system operation points. In addition, the control law has engineering practicality since all the variables in the expression of he control strategy can be measured locally.
文摘Results of an investigation on the application of STATCOM for damping subsynchronous resonance (SSR) in a multi-machine system is presented in this paper. For a multi-machine system which has a set of identical parallel turbine-generators or non-identical turbine-generators having torsional modes of the same frequency, generators may suffer from the same mode of torsional interaction corresponding to a certain series compensation degrees. Generators in such system may have different oscillation behaviors when they are unequally loaded or have different shaft and electrical parameters. Serving as the grid-side equipment, the reactive power output of a STATCOM could have an impact on all generators electrical distance nearby. Thus a single STATCOM could be used to damp torsional interactions of multi-generators when additional proper control strategy is supplemented. In this paper, control strategy of using STATCOM to damp SSR in a multi-machine system is designed and its effectiveness is validated based on a modified IEEE second benchmark model.
文摘To improve the performance of the short interleaved serial concatenated convolutional code(SCCC) with low decoding iterative times, the structure of Log MAP algorithm is introduced into the conventional SOVA decoder to improve its performance at short interleaving delay. The combination of Log MAP and SOVA avoids updating the matrices of the maximum path, and also makes a contribution to the requirement of short delay. The simulation results of several SCCCs show that the improved decoder can obtain satisfied performance with short frame interleaver and it is suitable to the high bit rate low delay communication systems.
文摘A mine-used multi-function serial signal converter is introduced.This converter is based on Ethernet.The core of this design is embedded microprocessor STM32F107VCT6.Embedded operation system μC/OS-Ⅱ is transplanted into this converter,and light-weight Internet protocal （LwIP） stack is also embedded to realize mutual conversion of serial signals such as meter bus （M-Bus） signal,RS485 signal,RS232 signal and Ethernet signal.Interconnection between all kinds of monitoring system interfaces under coal mine can be formed easily,which can solve compatibility problem between monitoring system and communication system and improve overall performance of safety monitoring system.The designed multi-function serial signal converter is of great value for application,which is worthy to be popularized in coal mine safety production.
文摘The women of the 1930s in the Chinese TV serials deduct inspiring stories.They play different roles in the big wealthy families such as mothers-in-law,daughters-in-law,and maidservants.There are unceasing conflicts between these women,because of their struggle for men's love,wealth or social position.The theme of their stories is always about fertility,love,kindness and evil,with the ending being either comic or tragic.The stories of various kinds of women of the 1930s in the Chinese TV serials decorate and enrich the lives of many of us latecomers and their names are passed on from generation to generation.
文摘Empty categories,which lack phonological form and hence are not visible in the phonetic representation of the sentence,have both syntactic and semantic properties.Null subjects PRO and pro are base-generated empty categories.This thesis,based on Chomsky's theory about empty categories and research achievements made by Chinese scholars,attempts to analyze the liandong(Serial Verb) construction from Figure and Ground perspective.
