In order to improve tracking accuracy when initial estimate is inaccurate or outliers exist,a bearings-only tracking approach called the robust range-parameterized cubature Kalman filter(RRPCKF)was proposed.Firstly,th...In order to improve tracking accuracy when initial estimate is inaccurate or outliers exist,a bearings-only tracking approach called the robust range-parameterized cubature Kalman filter(RRPCKF)was proposed.Firstly,the robust extremal rule based on the pollution distribution was introduced to the cubature Kalman filter(CKF)framework.The improved Turkey weight function was subsequently constructed to identify the outliers whose weights were reduced by establishing equivalent innovation covariance matrix in the CKF.Furthermore,the improved range-parameterize(RP)strategy which divides the filter into some weighted robust CKFs each with a different initial estimate was utilized to solve the fuzzy initial estimation problem efficiently.Simulations show that the result of the RRPCKF is more accurate and more robust whether outliers exist or not,whereas that of the conventional algorithms becomes distorted seriously when outliers appear.展开更多
针对无线电能传输(wireless power transfer,WPT)系统处于不同负载、耦合系数和频率的运行状况进行分析,基于T型等效电路和二端口网络,得到了SS、LCL和LCC3种谐振网络的传递函数模型。将3种谐振网络的传输特性进行分析,实验结果表明3种...针对无线电能传输(wireless power transfer,WPT)系统处于不同负载、耦合系数和频率的运行状况进行分析,基于T型等效电路和二端口网络,得到了SS、LCL和LCC3种谐振网络的传递函数模型。将3种谐振网络的传输特性进行分析,实验结果表明3种谐振网络均为恒流输出,其中LCC网络具有随负载和耦合系数变化呈单调增的关系,有效地解决SS和LCL网络中存在传输功率过小等问题,并抑制系统处于偏谐振或低耦合状态下出现功率过载的情况。最后搭建了一台基于移相全桥(phase shift full bridge, PSFB)控制的LCC型WPT实验样机,能适应宽负载变化范围,当逆变器处于不同的移相角下均能保持零相角(zero phase angle, ZPA)的条件,使得系统具有较高的传输效率。展开更多
The Herz type Besov and Triebel-Lizorkin spaces with variable exponent are introduced. Then characterizations of these new spaces by maximal functions are given.
在地震动过程中,土介质中的剪切波速往往出现显著的降低现象,体现出强烈的非线性性质。本文将随机振动的虚拟激励原理、土非线性分析的等效线性化方法与工程波动理论散射问题的求解方法相结合,建立了开放系统中一致激励条件下考虑岩土...在地震动过程中,土介质中的剪切波速往往出现显著的降低现象,体现出强烈的非线性性质。本文将随机振动的虚拟激励原理、土非线性分析的等效线性化方法与工程波动理论散射问题的求解方法相结合,建立了开放系统中一致激励条件下考虑岩土介质非线性的工程场地地震动随机场数值模拟方法。该方法将随机输入下的波动分析问题转换为虚拟激励下的确定性波动分析问题,非线性土体峰值剪应变的统计特征可通过剪应变均方差和峰值因子获得。结合具体算例及M on te—C arlo模拟方法对所提出方法的合理性进行了验证,在此基础上应用该方法对一致激励下实际工程场地的地震动相干性进行分析,结果表明场地的局部条件对地震动相干性有重要影响。展开更多
To effectively study the dynamics of power systems with large-scale wind farms(WFs), an equivalent model needs to be developed. It is well known that back-toback converters and their controllers are important for the ...To effectively study the dynamics of power systems with large-scale wind farms(WFs), an equivalent model needs to be developed. It is well known that back-toback converters and their controllers are important for the dynamic responses of the wind turbine(WT) under disturbances. However, the detailed structure and parameters of the back-to-back converters and their controllers are usually unknown to power grid operators. Hence, it is difficult to build an accurate equivalent model for the WF using the component model-based equivalent modeling method. In this paper, a transfer function based equivalent modeling method for the WF is proposed. During modeling, the detailed structure and parameters of the WF are not required. The objective of the method is reproducing the output dynamics of the WF under the variation of the wind speed and power grid faults. A decoupled parameter-estimation strategy is also developed to estimate the parameters of the equivalent model. A WF that consists of 16 WTs is used to test the proposed equivalent model. Additionally,the proposed equivalent modeling method is applied to build the equivalent model for a real WF in Northwest China. The effectiveness of the proposed method is validated by the real measurement data.展开更多
基金Projects(51377172,51577191) supported by the National Natural Science Foundation of China
文摘In order to improve tracking accuracy when initial estimate is inaccurate or outliers exist,a bearings-only tracking approach called the robust range-parameterized cubature Kalman filter(RRPCKF)was proposed.Firstly,the robust extremal rule based on the pollution distribution was introduced to the cubature Kalman filter(CKF)framework.The improved Turkey weight function was subsequently constructed to identify the outliers whose weights were reduced by establishing equivalent innovation covariance matrix in the CKF.Furthermore,the improved range-parameterize(RP)strategy which divides the filter into some weighted robust CKFs each with a different initial estimate was utilized to solve the fuzzy initial estimation problem efficiently.Simulations show that the result of the RRPCKF is more accurate and more robust whether outliers exist or not,whereas that of the conventional algorithms becomes distorted seriously when outliers appear.
文摘针对无线电能传输(wireless power transfer,WPT)系统处于不同负载、耦合系数和频率的运行状况进行分析,基于T型等效电路和二端口网络,得到了SS、LCL和LCC3种谐振网络的传递函数模型。将3种谐振网络的传输特性进行分析,实验结果表明3种谐振网络均为恒流输出,其中LCC网络具有随负载和耦合系数变化呈单调增的关系,有效地解决SS和LCL网络中存在传输功率过小等问题,并抑制系统处于偏谐振或低耦合状态下出现功率过载的情况。最后搭建了一台基于移相全桥(phase shift full bridge, PSFB)控制的LCC型WPT实验样机,能适应宽负载变化范围,当逆变器处于不同的移相角下均能保持零相角(zero phase angle, ZPA)的条件,使得系统具有较高的传输效率。
基金This work was supported in part by the National Natural Science Foundation of China （Grant No. 11071064） and the Natural Science Foundation of Hainan Province （No. 111006）.
文摘The Herz type Besov and Triebel-Lizorkin spaces with variable exponent are introduced. Then characterizations of these new spaces by maximal functions are given.
文摘在地震动过程中,土介质中的剪切波速往往出现显著的降低现象,体现出强烈的非线性性质。本文将随机振动的虚拟激励原理、土非线性分析的等效线性化方法与工程波动理论散射问题的求解方法相结合,建立了开放系统中一致激励条件下考虑岩土介质非线性的工程场地地震动随机场数值模拟方法。该方法将随机输入下的波动分析问题转换为虚拟激励下的确定性波动分析问题,非线性土体峰值剪应变的统计特征可通过剪应变均方差和峰值因子获得。结合具体算例及M on te—C arlo模拟方法对所提出方法的合理性进行了验证,在此基础上应用该方法对一致激励下实际工程场地的地震动相干性进行分析,结果表明场地的局部条件对地震动相干性有重要影响。
基金supported by National Natural Science Foundation of China (No. 51422701)the support of Chinese National ‘‘111’’ Project of ‘‘Renewable Energy and Smart Grid’’ at Hohai University
文摘To effectively study the dynamics of power systems with large-scale wind farms(WFs), an equivalent model needs to be developed. It is well known that back-toback converters and their controllers are important for the dynamic responses of the wind turbine(WT) under disturbances. However, the detailed structure and parameters of the back-to-back converters and their controllers are usually unknown to power grid operators. Hence, it is difficult to build an accurate equivalent model for the WF using the component model-based equivalent modeling method. In this paper, a transfer function based equivalent modeling method for the WF is proposed. During modeling, the detailed structure and parameters of the WF are not required. The objective of the method is reproducing the output dynamics of the WF under the variation of the wind speed and power grid faults. A decoupled parameter-estimation strategy is also developed to estimate the parameters of the equivalent model. A WF that consists of 16 WTs is used to test the proposed equivalent model. Additionally,the proposed equivalent modeling method is applied to build the equivalent model for a real WF in Northwest China. The effectiveness of the proposed method is validated by the real measurement data.
