共查询到20条相似文献,搜索用时 218 毫秒
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《机械制造与自动化》2017,(5):198-201
针对立方星体积小、成本低、能源有限等特点,设计了基于最大功率点跟踪的立方星电源系统。该系统采用三结砷化镓太阳能电池和比容量高的锂离子电池构成太阳能电池阵联合供电系统,电源转换和功率分配电路采用商用集成器件,在降低成本的同时能够提升功率转换与传输效率,降低系统功耗,提高负载供电可靠性。利用变步长扰动观察法实现了MPPT功能,试验表明该电源系统MPPT模块功率跟踪误差在2%以内,动态响应速度和稳定性较高。 相似文献
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本文提出一种便携式的太阳能双向变换器,并分析了其工作原理.对双向变换器中的太阳能电池、外供电源、蓄电池以及便携式负载之间进行能量管理,以高效地应用能量.同时进行最大功率跟踪与电池充电曲线控制,以提高装置的性能与使用寿命.实验结果验证了该便携式太阳能双向变换器的可行性.这种太阳能变换器可作为充电器广泛应用于便携式电子产品. 相似文献
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TDI-CCD图像传感器的噪声分析与处理 总被引:8,自引:2,他引:6
为提高TDI-CCD的工作性能,根据TDI-CCD器件的工作原理,较完整地分析了TDI-CCD图像的噪声组成,给出了其噪声的详细分类。TDI-CCD 的噪声主要来自两个方面,一个是TDI-CCD器件本身所固有的噪声,如霰粒噪声、非均匀性噪声、暗电流噪声、固定图形噪声、转移噪声等,另一个是TDI-CCD工作过程中的各种噪声干扰,如复位噪声和1/f噪声等。根据各种噪声的特点,提出了相应的噪声处理技术,并针对KTC噪声,给出了双相关采样电路处理方式,提高了器件的信噪比,输出信噪比达到53.8 dB。 相似文献
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基于AVR单片机设计了全数字化便携式太阳能光伏电站控制系统。并且太阳能电池安装部分结构可折叠,介绍了系统的硬件构成,分析了主要部件和器件的选型原则,描述了系统的软件框架。在AVP.单片机系统控制下,可将太阳能电池获取的直流电进行有效存储和合理转换,提供给用户使用.并且总标称功率可以选择配置。整个系统充分利用了AVR单片机的软件资源.最大程度地简化了硬件电路,使系统具有较高的性价比和可靠性。 相似文献
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高精度太阳辐射测量系统台站试验与初步资料分析 总被引:1,自引:0,他引:1
在原高精度太阳辐射测量系统研究的基础上,改进太阳跟踪装置,提高其运行稳定性与可靠性,使其达到业务运行的要求.将总辐射表、散射辐射表和大气长波辐射表放在跟踪太阳的装置上,利用太阳自动跟踪和遮光装置,可准确地测量太阳散射辐射.采用两短、两长波辐射测量方法,获得净全辐射测量值,改变净全辐射测量方法,提高了净全辐射测量的准确度.通过丽江和漠河气象站的比对观测,对试验资料进行了初步分析和比较,验证了高精度太阳辐射测量系统辐射测量方法的正确性. 相似文献
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Water level is a critical component for observation and management of water resources. Since video surveillance is becoming a standard configuration of gauging stations, more attentions have been paid on the image-based water level measurement techniques in recent years. Instead of human eyes, images of staff gauge can be captured by a camera and automatically processed to detect the readings of water line. However, it is quite unreliable to identify the readings on staff gauges due to low imaging resolution, tilt viewing angle and complex illumination in field conditions. For that reason, most of the existing methods failed to make effective automatic measurements in practice. To resolve difficulties of poor visibility, image distortions and ambient noises in in-situ water level measurement with standard bicolor staff gauges, an all-weather, real-time and automatic flow measurement system using single near infrared (NIR)-imaging video camera is developed. Lab and in-situ experiments demonstrate that NIR-imaging is efficient to enhance image contrast and suppress reflection noises on the water surface, which successfully overcomes the limitation of water line detection with current visible light (VIS)-imaging systems in clear water and low velocity conditions. The proposed water level conversion method is based on image ortho-rectification. It requires no on-site calibration by utilizing natural corresponding points to build the perspective transformation between the staff gauge Region of Interest (ROI) and an orthographic template image. The measurement resolution of water level (1 mm) is controlled by the physical resolution (1 mm/pixel) of the template. The proposed water line detection approach is integrated by a series of algorithms: the Order-Statistic Filtering for adaptive thresholding, the Morphological Opening Operation for local noise suppression, the Multi-points Continuity Criterion for water line locating and the Median Filtering for random noise elimination. It overcomes the deficiency of traditional Otsu method for images with uneven illumination. The reliability of system under various weather and illumination conditions is proved with water level accuracy up to 1 cm and Effective Data Ratios up to 95%. 相似文献
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可靠性筛选试验是保证电子产品可靠性水平和质量的重要手段,高温老化是主要筛选方法之一。本文在阐述老化测试基本理论的基础上,系统介绍了电容器高温老化测试系统的设计原理。系统可同时对400工位各类电容器进行老化,并自动测试电容值和漏电流,实现失效工位的自动剔除。实际测试表明,系统精度优于5%,完全符合大多数产品对使用电容器的要求。 相似文献
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TYTUS BERNAS † DAVID BARNES# ELIKPLIMI K. ASEM‡ J. PAUL ROBINSON† & BARTEK RAJWA† 《Journal of microscopy》2007,226(2):163-174
Standardization and calibration of optical microscopy systems have become an important issue owing to the increasing role of biological imaging in high‐content screening technology. The proper interpretation of data from high‐content screening imaging experiments requires detailed information about the capabilities of the systems, including their available dynamic range, sensitivity and noise. Currently available techniques for calibration and standardization of digital microscopes commonly used in cell biology laboratories provide an estimation of stability and measurement precision (noise) of an imaging system at a single level of signal intensity. In addition, only the total noise level, not its characteristics (spectrum), is measured. We propose a novel technique for estimation of temporal variability of signal and noise in microscopic imaging. The method requires registration of a time series of images of any stationary biological specimen. The subsequent analysis involves a multi‐step process, which separates monotonic, periodic and random components of every pixel intensity change in time. The technique allows simultaneous determination of dark, photonic and multiplicative components of noise present in biological measurements. Consequently, a respective confidence interval (noise level) is obtained for each level of signal. The technique is validated using test sets of biological images with known signal and noise characteristics. The method is also applied to assess uncertainty of measurement obtained with two CCD cameras in a wide‐field microscope. 相似文献
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分析了三种不同类型的商业太阳电池片-P 型铸造多晶硅太阳电池,定边喂膜生长硅(EFG)太阳电池
和单晶硅太阳电池的光谱响应(外量子效率EQE),光束诱导电流(LBIC)和暗电流-电压(I-V),光照I-V
曲线。在I-V 特性测试中,利用太阳电池的二极管等效模型从测量数据中得出重要的电池参数,例如串联
电阻,并联电阻,二极管理想因子,暗饱和电流等。通过光谱响应和LBIC 测试,分析影响这些参数的可
能性缺陷。在铸造多晶硅、EGF 太阳电池中影响电池参数的主要缺陷是晶界以及位错以及材料中杂质,而
对于单晶硅来说,主要的却是存在于体内的金属杂质等。 相似文献
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自动电阻测量仪设计采用C8051F020单片机作为核心,采用高精度恒流源驱动的伏安法针对不同档位电阻进行测量,选用MAX1241高精度A/D转换器进行模数转换,具有100Ω1、kΩ、10 kΩ1、0 MΩ四个量程,电阻测量精度均达到0.4%。各档位之间均可以实现手动分档或自动档位切换,并能根据键盘输入的电阻值和误差值进行筛选,对于不合格的电阻能够给出语音提示,该系统同时可以自动测量连续变化的电阻值并实时显示及绘制变化的曲线。自动电阻测量仪体积小、精度高、运行稳定可靠,具有一定的实用价值。 相似文献
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太阳电池测试仪中数学模型的建立 总被引:6,自引:0,他引:6
对太阳电池测试仪中应用的单指数数学模型和双指数数学模型进行了较深入的研究。用参数可分离非线性最小二乘拟合方法,根据少量测量数据较准确地求得了太阳电池双指数数学模型。该数学模型的建立,对研究太阳电池特性,求解太阳电池等效数,完整绘出太阳电池伏安特性曲线有着重要意义。 相似文献