电网频率特性是电力系统运行机理分析和控制策略研究的基础,主要研究微电网中涉及双向储能设备的频率特性分析问题。首先,对变流器的功频特性和调频原理进行总结和分析。在此基础之上,针对传统频率特性分析法存在的参考值问题、单电源...电网频率特性是电力系统运行机理分析和控制策略研究的基础,主要研究微电网中涉及双向储能设备的频率特性分析问题。首先,对变流器的功频特性和调频原理进行总结和分析。在此基础之上,针对传统频率特性分析法存在的参考值问题、单电源问题和单维度问题,提出双象限频率特性(dual quadrant frequency characteristic,DQFC)分析方法。该方法构建统一的功率参考体系,不但能实现传统分析方法的功能,而且可对双向储能设备和复杂多电源系统的一次调频、二次调频机理进行定性和定量分析。该多电源系统可由发电机组、无穷大电网、实际电网和多种控制策略下发电机模式/电动机模式运行的双向储能设备组合而成。最后,基于Matlab/Simulink仿真平台验证DQFC分析方法的正确性和可行性。展开更多
In order to maintain vibration performances within the limits of the design, a vibration-based feature extraction method for dynamic characteristic using empirical mode decomposition （EMD） and wavelet analysis was p...In order to maintain vibration performances within the limits of the design, a vibration-based feature extraction method for dynamic characteristic using empirical mode decomposition （EMD） and wavelet analysis was proposed. The proposed method was verified experimentally and numerically by implementing the scheme on engine block. In the implementation process, the following steps were identified to be important： 1） EMD technique in order to solve the feature extraction of vibration signals; 2） Vibration measurement for the purpose of confirming the structural weak regions of engine block in experiment; 3） Finite element modeling for the purpose of determining dynamic characteristic in time region and frequency region to affirm the comparability of response character corresponding to improvement schemes; 4） Adopting a feature index oflMF for structural improvement based on EMD and wavelet analysis. The obtained results show that IMF of signal is more sensitive to response character corresponding to improvement schemes. Finally, examination of the results confirms that the proposed vibration-based feature extraction method is very robust, and focuses on the relative merits of modification and full-scale structural optimization of engine, together with the creation of new low-vibration designs.展开更多
文摘电网频率特性是电力系统运行机理分析和控制策略研究的基础,主要研究微电网中涉及双向储能设备的频率特性分析问题。首先,对变流器的功频特性和调频原理进行总结和分析。在此基础之上,针对传统频率特性分析法存在的参考值问题、单电源问题和单维度问题,提出双象限频率特性(dual quadrant frequency characteristic,DQFC)分析方法。该方法构建统一的功率参考体系,不但能实现传统分析方法的功能,而且可对双向储能设备和复杂多电源系统的一次调频、二次调频机理进行定性和定量分析。该多电源系统可由发电机组、无穷大电网、实际电网和多种控制策略下发电机模式/电动机模式运行的双向储能设备组合而成。最后,基于Matlab/Simulink仿真平台验证DQFC分析方法的正确性和可行性。
基金Project(50975192) supported by the National Natural Science Foundation of ChinaProject(10YFJZJC14100) supported by Tianjin Municipal Natural Science Foundation of China
文摘In order to maintain vibration performances within the limits of the design, a vibration-based feature extraction method for dynamic characteristic using empirical mode decomposition （EMD） and wavelet analysis was proposed. The proposed method was verified experimentally and numerically by implementing the scheme on engine block. In the implementation process, the following steps were identified to be important： 1） EMD technique in order to solve the feature extraction of vibration signals; 2） Vibration measurement for the purpose of confirming the structural weak regions of engine block in experiment; 3） Finite element modeling for the purpose of determining dynamic characteristic in time region and frequency region to affirm the comparability of response character corresponding to improvement schemes; 4） Adopting a feature index oflMF for structural improvement based on EMD and wavelet analysis. The obtained results show that IMF of signal is more sensitive to response character corresponding to improvement schemes. Finally, examination of the results confirms that the proposed vibration-based feature extraction method is very robust, and focuses on the relative merits of modification and full-scale structural optimization of engine, together with the creation of new low-vibration designs.
