外文翻譯--變速恒頻交流勵(lì)磁雙饋風(fēng)力發(fā)電系統(tǒng)及其控制技術(shù)研究-其他專業(yè)(文件)
【正文】 re studied based on the sub—project that is entitled as research on operation technology of VSWT with large capacity in an electrical power system and the full analysis on the references from domestic and aboard． The primary contents and original contributions of this dissertation are as follows： Firstly， a simply 3rd order dynamic model for DFIG is developed． The proposed model is adequate to describe dynamic behaviors and is easy to simulate by puter． Since control variables have taken place step changes and gradual changes， a detailed parison of dynamic behaviors is made between the proposed model and exact model in the dissertation． The results are shown that the proposed model has a favorable definition and can substitute the exact model in research on DFIG with high power factor and large range of rotor speed． Therefore， the 3rd model could be applied in study on VSWT with DFIG. Secondly， based on 3rd order dynamic model of DFIG， a linear model in state space formulation and transfer functions fitting for analysis on small disturbance stability of DFIG are presented． Moreover using open transfer function and eigenvalue locus for the first time， the relationship between original operation point and dynamic characteristics are discussed in the dissertation. Thirdly， a model of frequency converter that is expressed by four control parameters， that is， modulation ratio and phase difference of converter and inverter is originally presented in this dissertation Meanwhile， a aggregated dynamic model of VSWT is established based on the physical characteristics of posing ponents Then a simulation tool of VSWT is originally developed by using MATLAB． Fourthly， the operation characteristics of VSWT are discussed in this dissertation． At the aspects of steady characteristics， the active power， reactive power and PQ capacity limit are analyzed． At the aspects of dynamic characteristics， the dynamic behaviours are simulated contrastively between VWST and constant speed wind turbine (CSWT)． The results show that VSWT has more superior behaviors． Furthermore， taking the example of VS WT with DFIG connected straight with large grid． the
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