电力系统实测信号在传输的过程中可能出现异常数据,且包含大量的高斯白噪声和高斯有色噪声,对功率振荡检测结果的精确性产生了较大的影响。为实现功率振荡信号的准确检测,对信号预处理方法进行了改进,采用七点二阶算法前推差分公式对异...电力系统实测信号在传输的过程中可能出现异常数据,且包含大量的高斯白噪声和高斯有色噪声,对功率振荡检测结果的精确性产生了较大的影响。为实现功率振荡信号的准确检测,对信号预处理方法进行了改进,采用七点二阶算法前推差分公式对异常数据进行识别,并进行了补正、滤波和去直流处理。进一步地,将原始信号用四阶累积量代替,并使用旋转不变技术信号参数估计(Estimating Signal Parameter via Rotational Invariance Techniques,ESPRIT)算法进行辨识,实现对功率振荡信号的精准检测。仿真结果表明,相比于直接使用ESPRIT算法,所提出的改进检测方法可以有效地消除异常数据、高斯白噪声和有色噪声对信号分析的影响,从而更为准确地辨识出系统中的振荡信息。展开更多
电力负荷具有一定的周期相似性,为此,提出一种基于子空间旋转矢量不变技术(E S P R I T)的综合负荷预测方法。对电力负荷数据进行移位平移处理构造出满足子空间不变性的数据矩阵,利用最小二乘法E S P R I T原理进行谐波检测,提取出各主...电力负荷具有一定的周期相似性,为此,提出一种基于子空间旋转矢量不变技术(E S P R I T)的综合负荷预测方法。对电力负荷数据进行移位平移处理构造出满足子空间不变性的数据矩阵,利用最小二乘法E S P R I T原理进行谐波检测,提取出各主要频率分量成分。利用K均值聚类法把提取的分量根据频率特点分为不同类型,之后建立不同预测模型对各部分进行独立负荷预测,最终得到综合的预测负荷值。E S P R I T算法具有较高的频谱分辨率,可降低原数据维数,且综合预测法能针对不同成分有更好的预测。最后仿真也证明了该方法预测的准确性及有效性。展开更多
One of the greatest challenges in the design of a gun is to balance muzzle velocity and recoil,especially for guns on aircrafts and deployable vehicles.To resolve the conflict between gun power and recoil force,a conc...One of the greatest challenges in the design of a gun is to balance muzzle velocity and recoil,especially for guns on aircrafts and deployable vehicles.To resolve the conflict between gun power and recoil force,a concept of rarefaction wave gun(RAVEN)was proposed to significantly reduce the weapon recoil and the heat in barrel,while minimally reducing the muzzle velocity.The main principle of RAVEN is that the rarefaction wave will not reach the projectile base until the muzzle by delaying the venting time of an expansion nozzle at the breech.Developed on the RAVEN principle,the purpose of this paper is to provide an engineering method for predicting the performance of a low-recoil gun with front nozzle.First,a two-dimensional two-phase flow model of interior ballistic during the RAVEN firing cycle was established.Numerical simulation results were compared with the published data to validate the reliability and accuracy.Next,the effects of the vent opening times and locations were investigated to determine the influence rules on the performance of the RAVEN with front nozzle.Then according to the results above,simple nonlinear fitting formulas were provided to explain how the muzzle velocity and the recoil force change with the vent opening time and location.Finally,a better vent venting opening time corresponding to the vent location was proposed.The findings should make an important contribution to the field of engineering applications of the RAVEN.展开更多
采用二维离散复镜像法(discrete complex image method,DCIM)计算分层媒质中场点和源点不在同一层时的格林函数。运用二维旋转子空间不变法(estimation of signal parameters via rotational invariant tech-nique,ESPRIT)将谱域核函数...采用二维离散复镜像法(discrete complex image method,DCIM)计算分层媒质中场点和源点不在同一层时的格林函数。运用二维旋转子空间不变法(estimation of signal parameters via rotational invariant tech-nique,ESPRIT)将谱域核函数表示成二维指数级数的形式,利用Sommerfeld恒等式得到场源点不同层情况下空域内的闭式格林函数,避免了插值方法的繁琐运算。数值仿真结果证明了其正确性和有效性。展开更多
针对多输入多输出(Multi-Input Multi-Output,MIMO)阵列多目标定位,提出一种基于子空间特征分解的MIMO阵列旋转不变子空间算法(MIMO array estimation of signal parameters via rotational invariance techniques,简称MIMO-ESPRIT)。M...针对多输入多输出(Multi-Input Multi-Output,MIMO)阵列多目标定位,提出一种基于子空间特征分解的MIMO阵列旋转不变子空间算法(MIMO array estimation of signal parameters via rotational invariance techniques,简称MIMO-ESPRIT)。MIMO阵列各阵元发射彼此独立信号,因此阵列输出数据协方差矩阵不存在降秩以及信号子空间向噪声子空间扩散的现象,可直接应用子空间分解算法进行MIMO阵列目标方位估计。性能分析和仿真结果表明,随着发射阵元个数的增加和发射阵元间距的扩大,算法的多目标分辨能力和方位估计精度将得到明显改善。展开更多
文摘电力系统实测信号在传输的过程中可能出现异常数据,且包含大量的高斯白噪声和高斯有色噪声,对功率振荡检测结果的精确性产生了较大的影响。为实现功率振荡信号的准确检测,对信号预处理方法进行了改进,采用七点二阶算法前推差分公式对异常数据进行识别,并进行了补正、滤波和去直流处理。进一步地,将原始信号用四阶累积量代替,并使用旋转不变技术信号参数估计(Estimating Signal Parameter via Rotational Invariance Techniques,ESPRIT)算法进行辨识,实现对功率振荡信号的精准检测。仿真结果表明,相比于直接使用ESPRIT算法,所提出的改进检测方法可以有效地消除异常数据、高斯白噪声和有色噪声对信号分析的影响,从而更为准确地辨识出系统中的振荡信息。
文摘电力负荷具有一定的周期相似性,为此,提出一种基于子空间旋转矢量不变技术(E S P R I T)的综合负荷预测方法。对电力负荷数据进行移位平移处理构造出满足子空间不变性的数据矩阵,利用最小二乘法E S P R I T原理进行谐波检测,提取出各主要频率分量成分。利用K均值聚类法把提取的分量根据频率特点分为不同类型,之后建立不同预测模型对各部分进行独立负荷预测,最终得到综合的预测负荷值。E S P R I T算法具有较高的频谱分辨率,可降低原数据维数,且综合预测法能针对不同成分有更好的预测。最后仿真也证明了该方法预测的准确性及有效性。
基金supported by the National Natural Science Foundation of China(Grant No.11502114)the Fundamental Research Funds for the Central Universities(Grant No.30918011323)
文摘One of the greatest challenges in the design of a gun is to balance muzzle velocity and recoil,especially for guns on aircrafts and deployable vehicles.To resolve the conflict between gun power and recoil force,a concept of rarefaction wave gun(RAVEN)was proposed to significantly reduce the weapon recoil and the heat in barrel,while minimally reducing the muzzle velocity.The main principle of RAVEN is that the rarefaction wave will not reach the projectile base until the muzzle by delaying the venting time of an expansion nozzle at the breech.Developed on the RAVEN principle,the purpose of this paper is to provide an engineering method for predicting the performance of a low-recoil gun with front nozzle.First,a two-dimensional two-phase flow model of interior ballistic during the RAVEN firing cycle was established.Numerical simulation results were compared with the published data to validate the reliability and accuracy.Next,the effects of the vent opening times and locations were investigated to determine the influence rules on the performance of the RAVEN with front nozzle.Then according to the results above,simple nonlinear fitting formulas were provided to explain how the muzzle velocity and the recoil force change with the vent opening time and location.Finally,a better vent venting opening time corresponding to the vent location was proposed.The findings should make an important contribution to the field of engineering applications of the RAVEN.
文摘采用二维离散复镜像法(discrete complex image method,DCIM)计算分层媒质中场点和源点不在同一层时的格林函数。运用二维旋转子空间不变法(estimation of signal parameters via rotational invariant tech-nique,ESPRIT)将谱域核函数表示成二维指数级数的形式,利用Sommerfeld恒等式得到场源点不同层情况下空域内的闭式格林函数,避免了插值方法的繁琐运算。数值仿真结果证明了其正确性和有效性。
文摘针对多输入多输出(Multi-Input Multi-Output,MIMO)阵列多目标定位,提出一种基于子空间特征分解的MIMO阵列旋转不变子空间算法(MIMO array estimation of signal parameters via rotational invariance techniques,简称MIMO-ESPRIT)。MIMO阵列各阵元发射彼此独立信号,因此阵列输出数据协方差矩阵不存在降秩以及信号子空间向噪声子空间扩散的现象,可直接应用子空间分解算法进行MIMO阵列目标方位估计。性能分析和仿真结果表明,随着发射阵元个数的增加和发射阵元间距的扩大,算法的多目标分辨能力和方位估计精度将得到明显改善。
