In this research,a modified fractional order proportional integral derivate(FOPID)control method is proposed for the photovoltaic(PV)and thermoelectric generator(TEG)combined hybrid renewable energy system.The faster ...In this research,a modified fractional order proportional integral derivate(FOPID)control method is proposed for the photovoltaic(PV)and thermoelectric generator(TEG)combined hybrid renewable energy system.The faster tracking and steady-state output are aimed at the suggested maximum power point tracking(MPPT)control technique.The derivative order number(μ)value in the improved FOPID(also known as PIλDμ)control structure will be dynamically updated utilizing the value of change in PV array voltage output.During the transient,the value ofμis changeable;it’s one at the start and after reaching the maximum power point(MPP),allowing for strong tracking characteristics.TEG will use the freely available waste thermal energy created surrounding the PVarray for additional power generation,increasing the system’s energy conversion efficiency.A high-gain DC-DC converter circuit is included in the system to maintain a high amplitude DC input voltage to the inverter circuit.The proposed approach’s performance was investigated using an extensive MATLAB software simulation and validated by comparing findings with the perturbation and observation(P&O)type MPPT control method.The study results demonstrate that the FOPID controller-based MPPT control outperforms the P&O method in harvesting the maximum power achievable from the PV-TEG hybrid source.There is also a better control action and a faster response.展开更多
Adaptive broadband beamforraing is a key issue in array applications. The adaptive broadband beamformer with tapped delay line （TDL） structure for nonuniform linear array （NLA） is designed according to the rule of...Adaptive broadband beamforraing is a key issue in array applications. The adaptive broadband beamformer with tapped delay line （TDL） structure for nonuniform linear array （NLA） is designed according to the rule of minimizing the beamformer＇s output power while keeping the distortionless response （DR） in the direction of desired signal and keeping the constant beamwidth （CB） with the prescribed sidelobe level over the whole operating band. This kind of beamforming problem can be solved with the interior-point method after being converted to the form of standard second order cone programming （SOCP）. The computer simulations are presented which illustrate the effectiveness of our beamformer.展开更多
The finite element method （FEM） is employed to analyze the resonant oscillations of the liquid confined within multiple or an array of floating bodies with fully nonlinear boundary conditions on the free surface and...The finite element method （FEM） is employed to analyze the resonant oscillations of the liquid confined within multiple or an array of floating bodies with fully nonlinear boundary conditions on the free surface and the body surface in two dimensions. The velocity potentials at each time step are obtained through the FEM with 8-node quadratic shape functions. The finite element linear system is solved by the conjugate gradient （CG） method with a symmetric successive overelaxlation （SSOR） preconditioner. The waves at the open boundary are absorbed by the combination of the damping zone method and the Sommerfeld-Orlanski equation. Numerical examples are given by an array of floating wedge- shaped cylinders and rectangular cylinders. Results are provided for heave motions including wave elevations, profiles and hydrodynamic forces. Comparisons are made in several cases with the results obtained from the second order solution in the time domain. It is found that the wave amplitude in the middle region of the array is larger than those in other places, and the hydrodynamic force on a cylinder increases with the cylinder closing to the middle of the array.展开更多
Nonuniform linear arrays,such as coprime array and nested array,have received great attentions because of the increased degrees of freedom(DOFs)and weakened mutual coupling.In this paper,inspired by the existing copri...Nonuniform linear arrays,such as coprime array and nested array,have received great attentions because of the increased degrees of freedom(DOFs)and weakened mutual coupling.In this paper,inspired by the existing coprime array,we propose a high-order extended coprime array(HoECA)for improved direction of arrival(DOA)estimation.We first derive the closed-form expressions for the range of consecutive lags.Then,by changing the inter-element spacing of a uniform linear array(ULA),three cases are proposed and discussed.It is indicated that the HoECA can obtain the largest number of consecutive lags when the spacing takes the maximum value.Finally,by comparing it with the other sparse arrays,the optimized HoECA enjoys a larger number of consecutive lags with mitigating mutual coupling.Simulation results are shown to evaluate the superiority of HoECA over the others in terms of DOF,mutual coupling leakage and estimation accuracy.展开更多
An array extension method in a noisy environment was proposed to improve angular resolution and array gain. The proposed method combines the FOC （fourth-order cumulants） technique with the ETAM （extended towed arra...An array extension method in a noisy environment was proposed to improve angular resolution and array gain. The proposed method combines the FOC （fourth-order cumulants） technique with the ETAM （extended towed array measurements） method to extend array aperture and suppress Gaussian noise, First, successive measurements of a virtual uniform linear array were constructed by applying lburth-order cumulants to measurements of uniform linear array; Gaussian noise in these measurements was also eliminated. Then, the array was extended by compensating phase differences using the ETAM method, Finally, the synthetic aperture was extended further by the fourth-order cumulants technique. The proposed FOC-ETAM-FOC method not only improves angular resolution and array gain, but also effectively suppresses Gaussian noise. Furthermore, it inherits the advantages of the ETAM method. Simulation results showed that the FOC-ETAM-FOC method achieved better angular resolution and array gain than the ETAM method. Furthermore this method outperforms the ETAM method in Gaussian noise environment.展开更多
局部放电是电力变压器绝缘劣化的主要原因,研究局部放电定位对提高电网的安全运行很有帮助。该文研制了一种用于电力变压器局部放电定位的复合传感器,并针对该传感器进行了定位仿真和实验。复合传感器由共形的13阵元十字形超声波传感器...局部放电是电力变压器绝缘劣化的主要原因,研究局部放电定位对提高电网的安全运行很有帮助。该文研制了一种用于电力变压器局部放电定位的复合传感器,并针对该传感器进行了定位仿真和实验。复合传感器由共形的13阵元十字形超声波传感器阵列和22阵元的超高频传感器阵列组成。应用高阶累积量处理技术对十字形超声阵列进行虚拟扩展,扩展后阵列具有61个阵元的阵列性能,提高了超声阵列的孔径和方向性锐度,这极大减少了后续硬件电路和成本。利用扩展超声阵列配合超高频阵列来仿真局部放电定位,结果表明扩展阵列具有很好的定位效果。在噪声背景下与多重信号分类(multiple signal classification,MUSIC)方法作了比较,结果表明高阶累积量处理技术能更好地抑制各种高斯色噪声的干扰。基于该十字形超声波阵列传感器进行了局部放电定位实验,结果表明扩展后的十字形超声阵列能精确地定位局部放电,定位的相对误差小于5%。对较少数目阵元的阵列实施虚拟扩展技术,为阵列技术在电力设备上的实用化提供了可能性。展开更多
针对MUSIC-LIKE方法能很好地扩展阵列孔径但计算量较大的问题,基于均匀线阵提出了一种快速提取阵列无冗余数据的新方法。该方法基于四阶累积量孔径扩展的原理,摒弃了原MUSIC-LIKE算法在均匀线阵DOA(direction of arrival)估计中的大量...针对MUSIC-LIKE方法能很好地扩展阵列孔径但计算量较大的问题,基于均匀线阵提出了一种快速提取阵列无冗余数据的新方法。该方法基于四阶累积量孔径扩展的原理,摒弃了原MUSIC-LIKE算法在均匀线阵DOA(direction of arrival)估计中的大量冗余数据,从而大大降低了矩阵运算的维数,降低了计算量。经过处理后的四阶累积量具有和二阶统计量类似的形式,因而可以将大多数业已成熟的基于信号二阶统计特性的阵列信号处理方法应用于四阶累积量中,计算机仿真证明了算法的有效性。展开更多
基金The authors extend their appreciation to the Deputyship for Research&Innovation,Ministry of Education in Saudi Arabia for funding this research work through the Project Number(IF-PSAU-2021/01/18128).
文摘In this research,a modified fractional order proportional integral derivate(FOPID)control method is proposed for the photovoltaic(PV)and thermoelectric generator(TEG)combined hybrid renewable energy system.The faster tracking and steady-state output are aimed at the suggested maximum power point tracking(MPPT)control technique.The derivative order number(μ)value in the improved FOPID(also known as PIλDμ)control structure will be dynamically updated utilizing the value of change in PV array voltage output.During the transient,the value ofμis changeable;it’s one at the start and after reaching the maximum power point(MPP),allowing for strong tracking characteristics.TEG will use the freely available waste thermal energy created surrounding the PVarray for additional power generation,increasing the system’s energy conversion efficiency.A high-gain DC-DC converter circuit is included in the system to maintain a high amplitude DC input voltage to the inverter circuit.The proposed approach’s performance was investigated using an extensive MATLAB software simulation and validated by comparing findings with the perturbation and observation(P&O)type MPPT control method.The study results demonstrate that the FOPID controller-based MPPT control outperforms the P&O method in harvesting the maximum power achievable from the PV-TEG hybrid source.There is also a better control action and a faster response.
基金supported by the National Nature Science Foundation of China (60472101)President Award of ChineseAcademy of Sciences(O729031511).
文摘Adaptive broadband beamforraing is a key issue in array applications. The adaptive broadband beamformer with tapped delay line （TDL） structure for nonuniform linear array （NLA） is designed according to the rule of minimizing the beamformer＇s output power while keeping the distortionless response （DR） in the direction of desired signal and keeping the constant beamwidth （CB） with the prescribed sidelobe level over the whole operating band. This kind of beamforming problem can be solved with the interior-point method after being converted to the form of standard second order cone programming （SOCP）. The computer simulations are presented which illustrate the effectiveness of our beamformer.
基金supported by the Fundamental Research Funds for the Central Universities and NPRP 08-691-2-289 grant from Qatar National Research Fund (QNRF)
文摘The finite element method （FEM） is employed to analyze the resonant oscillations of the liquid confined within multiple or an array of floating bodies with fully nonlinear boundary conditions on the free surface and the body surface in two dimensions. The velocity potentials at each time step are obtained through the FEM with 8-node quadratic shape functions. The finite element linear system is solved by the conjugate gradient （CG） method with a symmetric successive overelaxlation （SSOR） preconditioner. The waves at the open boundary are absorbed by the combination of the damping zone method and the Sommerfeld-Orlanski equation. Numerical examples are given by an array of floating wedge- shaped cylinders and rectangular cylinders. Results are provided for heave motions including wave elevations, profiles and hydrodynamic forces. Comparisons are made in several cases with the results obtained from the second order solution in the time domain. It is found that the wave amplitude in the middle region of the array is larger than those in other places, and the hydrodynamic force on a cylinder increases with the cylinder closing to the middle of the array.
基金supported by the National Natural Science Foundation of China(62071476,62022091,61801488,61921001)the China Postdoctoral Science Foundation(2021T140788,2020M683728)+1 种基金the Science and Technology Innovation Program of Hunan Province(2020RC2041)the Research Program of National University of Defense Technology(ZK19-10,ZK20-33).
文摘Nonuniform linear arrays,such as coprime array and nested array,have received great attentions because of the increased degrees of freedom(DOFs)and weakened mutual coupling.In this paper,inspired by the existing coprime array,we propose a high-order extended coprime array(HoECA)for improved direction of arrival(DOA)estimation.We first derive the closed-form expressions for the range of consecutive lags.Then,by changing the inter-element spacing of a uniform linear array(ULA),three cases are proposed and discussed.It is indicated that the HoECA can obtain the largest number of consecutive lags when the spacing takes the maximum value.Finally,by comparing it with the other sparse arrays,the optimized HoECA enjoys a larger number of consecutive lags with mitigating mutual coupling.Simulation results are shown to evaluate the superiority of HoECA over the others in terms of DOF,mutual coupling leakage and estimation accuracy.
基金Supported by the National Science Foundation of China (No.60872146)
文摘An array extension method in a noisy environment was proposed to improve angular resolution and array gain. The proposed method combines the FOC （fourth-order cumulants） technique with the ETAM （extended towed array measurements） method to extend array aperture and suppress Gaussian noise, First, successive measurements of a virtual uniform linear array were constructed by applying lburth-order cumulants to measurements of uniform linear array; Gaussian noise in these measurements was also eliminated. Then, the array was extended by compensating phase differences using the ETAM method, Finally, the synthetic aperture was extended further by the fourth-order cumulants technique. The proposed FOC-ETAM-FOC method not only improves angular resolution and array gain, but also effectively suppresses Gaussian noise. Furthermore, it inherits the advantages of the ETAM method. Simulation results showed that the FOC-ETAM-FOC method achieved better angular resolution and array gain than the ETAM method. Furthermore this method outperforms the ETAM method in Gaussian noise environment.
文摘局部放电是电力变压器绝缘劣化的主要原因,研究局部放电定位对提高电网的安全运行很有帮助。该文研制了一种用于电力变压器局部放电定位的复合传感器,并针对该传感器进行了定位仿真和实验。复合传感器由共形的13阵元十字形超声波传感器阵列和22阵元的超高频传感器阵列组成。应用高阶累积量处理技术对十字形超声阵列进行虚拟扩展,扩展后阵列具有61个阵元的阵列性能,提高了超声阵列的孔径和方向性锐度,这极大减少了后续硬件电路和成本。利用扩展超声阵列配合超高频阵列来仿真局部放电定位,结果表明扩展阵列具有很好的定位效果。在噪声背景下与多重信号分类(multiple signal classification,MUSIC)方法作了比较,结果表明高阶累积量处理技术能更好地抑制各种高斯色噪声的干扰。基于该十字形超声波阵列传感器进行了局部放电定位实验,结果表明扩展后的十字形超声阵列能精确地定位局部放电,定位的相对误差小于5%。对较少数目阵元的阵列实施虚拟扩展技术,为阵列技术在电力设备上的实用化提供了可能性。
文摘针对MUSIC-LIKE方法能很好地扩展阵列孔径但计算量较大的问题,基于均匀线阵提出了一种快速提取阵列无冗余数据的新方法。该方法基于四阶累积量孔径扩展的原理,摒弃了原MUSIC-LIKE算法在均匀线阵DOA(direction of arrival)估计中的大量冗余数据,从而大大降低了矩阵运算的维数,降低了计算量。经过处理后的四阶累积量具有和二阶统计量类似的形式,因而可以将大多数业已成熟的基于信号二阶统计特性的阵列信号处理方法应用于四阶累积量中,计算机仿真证明了算法的有效性。
