关于多峰值最大功率点跟踪(maximum power point tracking,MPPT)算法的研究例如粒子群MPPT算法和全局扫描法以及其改进算法,往往只关注其静态搜索能力和辐照度突变情况下的扫描过程。但外界环境改变造成的特性曲线持续变化过程中的动态...关于多峰值最大功率点跟踪(maximum power point tracking,MPPT)算法的研究例如粒子群MPPT算法和全局扫描法以及其改进算法,往往只关注其静态搜索能力和辐照度突变情况下的扫描过程。但外界环境改变造成的特性曲线持续变化过程中的动态性能研究有些欠缺。为了提升多峰值MPPT算法的动态性能,文中提出一种基于功率闭环法的改进动态多峰值MPPT算法。该算法结合三点法和粒子群算法,快速搜索出全局最大功率点,动态响应能力好,具有较好的实际应用价值。通过实验室和实际电站测试验证了该算法的正确性和有效性。展开更多
局部阴影条件下,光伏发电系统中P-U曲线会呈现多峰现象,传统的最大功率点跟踪(Maximum Power Point Tracking,MPPT)算法易失效,粒子群(PSO)算法适用于复杂多极值系统的寻优,因而在多峰全局MPPT中得到应用。针对寻优过程中传统PSO算法搜...局部阴影条件下,光伏发电系统中P-U曲线会呈现多峰现象,传统的最大功率点跟踪(Maximum Power Point Tracking,MPPT)算法易失效,粒子群(PSO)算法适用于复杂多极值系统的寻优,因而在多峰全局MPPT中得到应用。针对寻优过程中传统PSO算法搜索精度低以及易出现早熟现象的缺点,文中提出了自适应惯性权重粒子群(APSO)算法,在PSO算法中引入非线性惯性权重,以提高多峰全局寻优的精度与速度。最后利用MATLAB/Simulink对系统进行仿真,仿真结果表明:在均匀光照和可变阴影条件下,APSO算法能有效提高系统寻优的收敛速度与精度。展开更多
In this study, a hybrid algorithm combining genetic algorithm （GA） with back propagation （BP） neural network （GA-BP） was proposed for extracting the characteristics of multi-peak Brillouin scattering spectrum. S...In this study, a hybrid algorithm combining genetic algorithm （GA） with back propagation （BP） neural network （GA-BP） was proposed for extracting the characteristics of multi-peak Brillouin scattering spectrum. Simulations and experimental results show that the GA-BP hybrid algorithm can accurately identify the position and amount of peaks in multi-peak Brillouin scattering spectrum. Moreover, the proposed algorithm obtains a fitting degree of 0.9923 and a mean square error of 0.0094. Therefore, the GA-BP hybrid algorithm possesses a good fitting precision and is suitable for extracting the characteristics of multi-peak Brillouin scattering spectrum.展开更多
传统的最大功率点跟踪(maximum power point tracking,MPPT)方法在均匀辐射条件下效率较高,但由于光伏阵列与辐射、温度之间的强非线性特性,在局部遮荫条件下阵列的多峰特性易使传统的MPPT方法陷入局部极值,无法有效追踪最大功率。建立...传统的最大功率点跟踪(maximum power point tracking,MPPT)方法在均匀辐射条件下效率较高,但由于光伏阵列与辐射、温度之间的强非线性特性,在局部遮荫条件下阵列的多峰特性易使传统的MPPT方法陷入局部极值,无法有效追踪最大功率。建立了局部遮荫条件下的光伏阵列模型,针对局部遮荫产生的多峰情况,采用电压扫描比较的方法确定最大功率点附近的电压,并以此电压值作为变步长电导增量法的初始值进行搜索,最终确定最大功率点的位置。该方法避免了在多峰条件下最大功率点跟踪陷入局部极值,实现了有效跟踪。展开更多
A new method for quantitative phase analysis is proposed by using X-ray diffraction multi-peak match intensity ratio. This method can obtain the multi-peak match intensity ratio among each phase in the mixture sample ...A new method for quantitative phase analysis is proposed by using X-ray diffraction multi-peak match intensity ratio. This method can obtain the multi-peak match intensity ratio among each phase in the mixture sample by using all diffraction peak data in the mixture sample X-ray diffraction spectrum and combining the relative intensity distribution data of each phase standard peak in JCPDS card to carry on the least square method regression analysis. It is benefit to improve the precision of quantitative phase analysis that the given single line ratio which is usually adopted is taken the place of the multi-peak match intensity ratio and is used in X-ray diffraction quantitative phase analysis of the mixture sample. By analyzing four-group mixture sample, adopting multi-peak match intensity ratio and X-ray diffraction quantitative phase analysis principle of combining the adiabatic and matrix flushing method, it is tested that the experimental results are identical with theory.展开更多
Until now, a high-efficiency demodulation method for fiber Bragg grating(FBG) sensors has been a challenge.In this Letter, by employing multi-peak FBGs, an FBG sensor with a partial wavelength scan is proposed and ini...Until now, a high-efficiency demodulation method for fiber Bragg grating(FBG) sensors has been a challenge.In this Letter, by employing multi-peak FBGs, an FBG sensor with a partial wavelength scan is proposed and initially demonstrated. By demodulating a near-symmetrical multi-peak FBG and an asymmetrical multi-peak FBG in the strain experiment, sensor sensitivities of 1.02 pm/με and 1.01 pm/με are measured for the interrogation system, respectively. The average demodulation deviations for the two sensors are 1.81% and 0.4%,respectively. The proposed method is expected to realize high-efficiency and low-cost FBG interrogators.展开更多
In the present paper,we consider the nonlocal Kirchhoff problem-(ε^2a+εb∫|■u|^2)Δu+u=Q(x)u^p,u>0 in R^3,,where a,b>0,1<p<5 andε>0 is a parameter.Under some assumptions on Q(x),we show the existenc...In the present paper,we consider the nonlocal Kirchhoff problem-(ε^2a+εb∫|■u|^2)Δu+u=Q(x)u^p,u>0 in R^3,,where a,b>0,1<p<5 andε>0 is a parameter.Under some assumptions on Q(x),we show the existence and local uniqueness of positive multi-peak solutions by LyapunovSchmidt reduction method and the local Pohozaev identity method,respectly.展开更多
文摘关于多峰值最大功率点跟踪(maximum power point tracking,MPPT)算法的研究例如粒子群MPPT算法和全局扫描法以及其改进算法,往往只关注其静态搜索能力和辐照度突变情况下的扫描过程。但外界环境改变造成的特性曲线持续变化过程中的动态性能研究有些欠缺。为了提升多峰值MPPT算法的动态性能,文中提出一种基于功率闭环法的改进动态多峰值MPPT算法。该算法结合三点法和粒子群算法,快速搜索出全局最大功率点,动态响应能力好,具有较好的实际应用价值。通过实验室和实际电站测试验证了该算法的正确性和有效性。
文摘局部阴影条件下,光伏发电系统中P-U曲线会呈现多峰现象,传统的最大功率点跟踪(Maximum Power Point Tracking,MPPT)算法易失效,粒子群(PSO)算法适用于复杂多极值系统的寻优,因而在多峰全局MPPT中得到应用。针对寻优过程中传统PSO算法搜索精度低以及易出现早熟现象的缺点,文中提出了自适应惯性权重粒子群(APSO)算法,在PSO算法中引入非线性惯性权重,以提高多峰全局寻优的精度与速度。最后利用MATLAB/Simulink对系统进行仿真,仿真结果表明:在均匀光照和可变阴影条件下,APSO算法能有效提高系统寻优的收敛速度与精度。
文摘In this study, a hybrid algorithm combining genetic algorithm （GA） with back propagation （BP） neural network （GA-BP） was proposed for extracting the characteristics of multi-peak Brillouin scattering spectrum. Simulations and experimental results show that the GA-BP hybrid algorithm can accurately identify the position and amount of peaks in multi-peak Brillouin scattering spectrum. Moreover, the proposed algorithm obtains a fitting degree of 0.9923 and a mean square error of 0.0094. Therefore, the GA-BP hybrid algorithm possesses a good fitting precision and is suitable for extracting the characteristics of multi-peak Brillouin scattering spectrum.
基金Supported by the Fundamental Research Funds for the Central Universities(DL12DB03)National Natural Science Foundation of China(60871034)Program for New Century Excellent Talents in University(NCET-09-0279)
文摘传统的最大功率点跟踪(maximum power point tracking,MPPT)方法在均匀辐射条件下效率较高,但由于光伏阵列与辐射、温度之间的强非线性特性,在局部遮荫条件下阵列的多峰特性易使传统的MPPT方法陷入局部极值,无法有效追踪最大功率。建立了局部遮荫条件下的光伏阵列模型,针对局部遮荫产生的多峰情况,采用电压扫描比较的方法确定最大功率点附近的电压,并以此电压值作为变步长电导增量法的初始值进行搜索,最终确定最大功率点的位置。该方法避免了在多峰条件下最大功率点跟踪陷入局部极值,实现了有效跟踪。
文摘A new method for quantitative phase analysis is proposed by using X-ray diffraction multi-peak match intensity ratio. This method can obtain the multi-peak match intensity ratio among each phase in the mixture sample by using all diffraction peak data in the mixture sample X-ray diffraction spectrum and combining the relative intensity distribution data of each phase standard peak in JCPDS card to carry on the least square method regression analysis. It is benefit to improve the precision of quantitative phase analysis that the given single line ratio which is usually adopted is taken the place of the multi-peak match intensity ratio and is used in X-ray diffraction quantitative phase analysis of the mixture sample. By analyzing four-group mixture sample, adopting multi-peak match intensity ratio and X-ray diffraction quantitative phase analysis principle of combining the adiabatic and matrix flushing method, it is tested that the experimental results are identical with theory.
基金supported by the National Key R&D Program of China(Nos.2017YFA0206401 and 2018YFB2201801)the National Natural Science Foundation of China(No.61435014)+1 种基金the Key R&D Program of Jiangsu Province(No.BE2017003)the Natural Science Foundation of Jiangsu Province(No.BK20160907)
文摘Until now, a high-efficiency demodulation method for fiber Bragg grating(FBG) sensors has been a challenge.In this Letter, by employing multi-peak FBGs, an FBG sensor with a partial wavelength scan is proposed and initially demonstrated. By demodulating a near-symmetrical multi-peak FBG and an asymmetrical multi-peak FBG in the strain experiment, sensor sensitivities of 1.02 pm/με and 1.01 pm/με are measured for the interrogation system, respectively. The average demodulation deviations for the two sensors are 1.81% and 0.4%,respectively. The proposed method is expected to realize high-efficiency and low-cost FBG interrogators.
基金supported by Natural Science Foundation of China(11771166)Hubei Key Laboratory of Mathematical Sciences and Program for Changjiang Scholars and Innovative Research Team in University#IRT 17R46financially supported by funding for basic research business in Central Universities(innovative funding projects)(2018CXZZ090)。
文摘In the present paper,we consider the nonlocal Kirchhoff problem-(ε^2a+εb∫|■u|^2)Δu+u=Q(x)u^p,u>0 in R^3,,where a,b>0,1<p<5 andε>0 is a parameter.Under some assumptions on Q(x),we show the existence and local uniqueness of positive multi-peak solutions by LyapunovSchmidt reduction method and the local Pohozaev identity method,respectly.
