为研究光伏电池及阵列老化故障原因,建立故障辨识模型。单晶硅(砷化镓)电池老化前后理论拟合与实验数据全局均方根误差均小于0.11 mA (0.59 mA),表明了模型的可靠性。以此为依据,研究了二极管理想因子n、串联电阻R_(s)和并联电阻R_(sh)...为研究光伏电池及阵列老化故障原因,建立故障辨识模型。单晶硅(砷化镓)电池老化前后理论拟合与实验数据全局均方根误差均小于0.11 mA (0.59 mA),表明了模型的可靠性。以此为依据,研究了二极管理想因子n、串联电阻R_(s)和并联电阻R_(sh)对单晶硅(砷化镓)电池最大输出功率P_(max)影响,发现两种电池P_(max)随n和R_(s)增加而下降,随着R_(sh)增加而增加;n对两电池影响很小且基本一致;R_(s)和R_(sh)对硅电池影响大,原因在于砷化镓电池抗老化能力强。研究了4×4 BL、HC、TCT、NS硅阵列P_(max)与其中单电池n、R_(s)、R_(sh)的关系,发现P_(max)与n、R_(s)、R_(sh)的变化趋势与上述一致;R_(s)影响下阵列P_(max)的降序为BL>HC>TCT=NS。研究结果对于光伏电池及阵列的老化故障判断提供了理论指导。展开更多
The current impedance spectroscopy measurement techniques face difficulties in diagnosing solar cell faults due to issues such as cost,complexity,and accuracy.Therefore,a novel system was developed for precise broadba...The current impedance spectroscopy measurement techniques face difficulties in diagnosing solar cell faults due to issues such as cost,complexity,and accuracy.Therefore,a novel system was developed for precise broadband impedance spectrum measurement of solar cells,which was composed of an oscilloscope,a signal generator,and a sampling resistor.The results demonstrate concurrent accurate measurement of the impedance spectrum(50 Hz-0.1 MHz)and direct current voltametric characteristics.Comparative analysis with Keithley 2450 data yields a global relative error of approximately 6.70%,affirming the accuracy.Among excitation signals(sine,square,triangle,pulse waves),sine wave input yields the most accurate data,with a root mean square error of approximately 13.3016 and a global relative error of approximately 4.25%compared to theoretical data.Elevating reference resistance expands the half circle in the impedance spectrum.Proximity of reference resistance to that of the solar cell enhances the accuracy by mitigating line resistance influence.Measurement error is lower in high-frequency regions due to a higher signal-to-noise ratio.展开更多
目的探讨Oracle数据库系统跨版本跨平台升级实现的可行性方案。方法从制订方案、方案实施、数据验证方面,详细介绍了Oracle数据库升级的具体实施方法与技术要点。结果实现Oracle数据库从10g for Windows到19c RAC for Linux的跨多版本...目的探讨Oracle数据库系统跨版本跨平台升级实现的可行性方案。方法从制订方案、方案实施、数据验证方面,详细介绍了Oracle数据库升级的具体实施方法与技术要点。结果实现Oracle数据库从10g for Windows到19c RAC for Linux的跨多版本系统升级,系统稳定运行。结论采用数据泵(expdp/im‐pdp)工具,通过建立中间库的方式升级,安全可靠,可操作性强,对相同功能需求具有参考借鉴价值。展开更多
为了更有效的提高光纤电流互感器FOCT(Fiber-Optical Current Transformer)的信噪比,在分析FOCT输出信号特性的基础上,结合变步长自适应算法和小波变换理论,提出一种针对处理FOCT输出信号的改进多尺度域变步长自适应滤波算法,并设计了...为了更有效的提高光纤电流互感器FOCT(Fiber-Optical Current Transformer)的信噪比,在分析FOCT输出信号特性的基础上,结合变步长自适应算法和小波变换理论,提出一种针对处理FOCT输出信号的改进多尺度域变步长自适应滤波算法,并设计了一种基于Active X技术的变步长自适应滤波系统,通过该系统将改进算法与现有的变步长自适应算法进行了对比,结果表明此算法的收敛速度和稳态精度都得到了很大的改善。然后将此算法在FOCT中进行了应用测试,测试结果反映了该算法能有效提高FOCT的检测信噪比和抗噪声干扰能力。展开更多
文摘为研究光伏电池及阵列老化故障原因,建立故障辨识模型。单晶硅(砷化镓)电池老化前后理论拟合与实验数据全局均方根误差均小于0.11 mA (0.59 mA),表明了模型的可靠性。以此为依据,研究了二极管理想因子n、串联电阻R_(s)和并联电阻R_(sh)对单晶硅(砷化镓)电池最大输出功率P_(max)影响,发现两种电池P_(max)随n和R_(s)增加而下降,随着R_(sh)增加而增加;n对两电池影响很小且基本一致;R_(s)和R_(sh)对硅电池影响大,原因在于砷化镓电池抗老化能力强。研究了4×4 BL、HC、TCT、NS硅阵列P_(max)与其中单电池n、R_(s)、R_(sh)的关系,发现P_(max)与n、R_(s)、R_(sh)的变化趋势与上述一致;R_(s)影响下阵列P_(max)的降序为BL>HC>TCT=NS。研究结果对于光伏电池及阵列的老化故障判断提供了理论指导。
基金supported by National Natural Science Foundation of China(Nos.12064027,62065014,12464010)2022 Jiangxi Province Highlevel and High-skilled Leading Talent Training Project Selected(No.63)+1 种基金Jiujiang“Xuncheng Talents”(No.JJXC2023032)Nanchang Hangkong University Education Reform Project(No.JY21069).
文摘The current impedance spectroscopy measurement techniques face difficulties in diagnosing solar cell faults due to issues such as cost,complexity,and accuracy.Therefore,a novel system was developed for precise broadband impedance spectrum measurement of solar cells,which was composed of an oscilloscope,a signal generator,and a sampling resistor.The results demonstrate concurrent accurate measurement of the impedance spectrum(50 Hz-0.1 MHz)and direct current voltametric characteristics.Comparative analysis with Keithley 2450 data yields a global relative error of approximately 6.70%,affirming the accuracy.Among excitation signals(sine,square,triangle,pulse waves),sine wave input yields the most accurate data,with a root mean square error of approximately 13.3016 and a global relative error of approximately 4.25%compared to theoretical data.Elevating reference resistance expands the half circle in the impedance spectrum.Proximity of reference resistance to that of the solar cell enhances the accuracy by mitigating line resistance influence.Measurement error is lower in high-frequency regions due to a higher signal-to-noise ratio.
文摘目的探讨Oracle数据库系统跨版本跨平台升级实现的可行性方案。方法从制订方案、方案实施、数据验证方面,详细介绍了Oracle数据库升级的具体实施方法与技术要点。结果实现Oracle数据库从10g for Windows到19c RAC for Linux的跨多版本系统升级,系统稳定运行。结论采用数据泵(expdp/im‐pdp)工具,通过建立中间库的方式升级,安全可靠,可操作性强,对相同功能需求具有参考借鉴价值。
文摘为了更有效的提高光纤电流互感器FOCT(Fiber-Optical Current Transformer)的信噪比,在分析FOCT输出信号特性的基础上,结合变步长自适应算法和小波变换理论,提出一种针对处理FOCT输出信号的改进多尺度域变步长自适应滤波算法,并设计了一种基于Active X技术的变步长自适应滤波系统,通过该系统将改进算法与现有的变步长自适应算法进行了对比,结果表明此算法的收敛速度和稳态精度都得到了很大的改善。然后将此算法在FOCT中进行了应用测试,测试结果反映了该算法能有效提高FOCT的检测信噪比和抗噪声干扰能力。
