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开关电源作为核电厂分布式控制系统(DCS)卡件的关键部分,其故障可能造成卡件的失效,甚至破坏核电厂的经济、可靠和安全运行。铝电解电容是开关电源最易受损的短寿命元器件之一。此处提出了一种基于链式支持向量回归(Chained-SVR)的铝电解电容老化预测方法,以实现对多个电容的同时预测。为验证该方法可行性,首先通过所设计的加速寿命试验(ALT)获取4组不同系列电容老化过程中等效串联电阻(ESR)和电容,以构建所需数据集;进而建立基于Chained-SVR的预测模型,以初始健康状态作为输入变量,实现对电容的老化预测。试验结果表明,Chained-SVR模型具有良好的泛化能力且对同系列电容老化预测表现出较高准确性。 相似文献
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在开关电源中,铝电解电容广泛应用于各种滤波网络。据统计,铝电解电容是开关电源中故障率最高、最为薄弱的环节。铝电解电容的等效串联电阻(ESR)是反映电容寿命的重要指标。应用一种基于改进EMD和Hilbert变换的新方法,实现ESR值实时估测。该方法对采集的信号进行经验模态分解(EMD),得到一系列本征模函数(IMFs),对所需的IMF进行希尔伯特变换计算ESR,从而得到ESR实时估测值。以Buck电路为例,基于Saber进行仿真实验,结果表明本方法对ESR估测相对误差小于5%,从而为铝电解电容故障与劣化分析提供了新的理论依据和方法。 相似文献
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《电源世界》2006,(3):55-55
滤波电容在开关电源中起着非常重要的作用,如何正确选择滤波电容,尤其是输出滤波电容的选择则是每个工程技术人员都十分关心的问题。 50Hz工频电路中使用的普通电解电容器,其脉动电压频率仅为100Hz,充放电时间是毫秒数量级。为获得更小的脉动系数,所需的电容量高达数十万μF,因此普通低频铝电解电容器的目标是以提高电容量为主,电容器的电容量、损耗角正切值以及漏电流是鉴别其优劣的主要参数。而开关电源中的输出滤波电解电容器,其锯齿波电压频率高达数十kHz, 甚至是数十MHz,这时电容量并不是其主要指标,衡量高频铝电解电容优劣的标准是"阻抗-频率"特性,要求在开关电 相似文献
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本文提出了LED的长寿命与相对短寿命电解电容器之间的矛盾、影响LED灯及驱动电路寿命的因素。简单介绍了解决LED寿命与电容器寿命的解决方案,提出了超长寿命电解电容器是解决LED灯及LED驱动电路寿命的最适用的解决方案。介绍了国内外长寿命LED用电解电容器的现状。提出了小体积是高压电解电容器的技术关键,长寿命、低阻抗是长寿命低压电解电容器的技术关键。介绍了可以替代国外长寿命LED电解电容器的我国具有自主知识产权电解电容器。 相似文献
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铝电解电容器是电力电子系统中的核心组件,也是最容易失效的电力电子元器件之一,其运行状态直接影响电力电子系统的稳定性。为了及时发现并更换存在问题的铝电解电容器,提出了一种基于铝电解电容器放电规律的等效串联电阻(ESR)和电容的监测方法。通过对铝电解电容器放电过程中的电压曲线实时采样,并结合其放电过程中电压和电流之间的关系式,建立ESR和电容的计算模型。最后,设计一套可以监测铝电解电容器ESR值和电容值变化的系统,并进行实验验证。实验结果表明,该方法可以准确测量铝电解电容器的ESR值和电容值,从而验证了所提方法的可行性。 相似文献
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《Industry Applications, IEEE Transactions on》2005,41(6):1430-1435
Aluminum electrolytic capacitors are the leading choice for ac variable-frequency drive (VFD) bus filters. Predicting the expected life of these components in this application is complicated by four factors. First, the electrical impedance of aluminum electrolytic capacitors is nonlinear with both frequency and temperature. Second, motor drives produce a spectrally rich ripple current waveform that makes energy loss difficult to compute. Third, the heat transfer characteristic of capacitor banks is dependent on design geometry. Fourth, the expected life of aluminum electrolytic capacitors is extremely sensitive to operating temperature. This paper describes a method for predicting bus capacitor life that addresses these problems by using a multiple component model for capacitor impedance, a motor drive simulation to create ripple current waveforms, a heat transfer model based on bank geometry, and a capacitor life model derived from the device physics of failure. An example is given showing the effect of ac line impedance on the relative expected life. 相似文献
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LED作为第4代光源具有其他光源所无法比拟的优势:高效,节能,长寿命等,但传统的LED电源驱动中因普遍使用电解电容,大大缩短了整体LED照明的寿命。为提高LED电源的寿命,针对路灯等大功率照明应用提出了一种三相无电解电容的LED驱动电源的设计方案。三相交流电作为输入,利用三相电之间的相位差,通过驱动电路并行向LED供电,使LED获得恒定的电流从而得到恒定光通量。根据叠加定理,给出了详细的理论推导和证明,并使用Matlab/simulink软件对于所提出的方法进行了仿真,仿真结果验证了该设计方案在无电解电容的情况下能够有效地驱动LED输出恒定光通量。 相似文献
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Mitsuhiro Kadota Hiroyuki Shoji Atsushi Hatakeyama Keiji Wada 《Electrical Engineering in Japan》2019,209(3-4):26-34
This article proposes an LED driver that consists of a ceramic‐capacitor‐input rectifier and a buck‐boost converter. The LED driver has an advantage of long life because it does not contain any electrolytic capacitors. However, the issue with electrolytic capacitor‐less LED driver is that the ripple of the smoothed voltage becomes large due to insufficient capacitance of the smoothing capacitor. The proposed method, which uses the discontinuous current mode of a buck‐boost converter, reduces the output current ripple under such conditions. Experimental results using a 5.7 W LED driver prototype demonstrate that the proposed method reduces the output current ripple and that the percent flicker becomes 4.4%, which is smaller than the recommended upper limit of 8%. 相似文献
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Xiaohui Qu Siu‐Chung Wong Chi K. Tse 《International Journal of Circuit Theory and Applications》2012,40(8):759-775
To emit high‐quality LED light, one or a bin of LED lamp(s) is normally driven by a PWM‐controlled constant current source to minimize device variation and achieve accurate brightness control. Powered from offline AC mains, the front‐end power converters should provide a relatively low DC voltage bus for the inputs of post‐end LED current regulators. To match the long lifetime of LEDs, the whole LED driver (ballast) should work as durably as the LEDs. However, the lifetime of the driver is usually limited by the high‐voltage electrolytic charge storage capacitors used in conventional PFC pre‐regulators. In this paper, our previously proposed resonant current‐fed isolated PFC pre‐regulator is extended to operate in discontinuous conduction mode (DCM). It allows the use of the low‐voltage storage capacitors on the transformer secondary, and therefore extends the overall lifetime of the LED lighting system. A detailed procedure for finding the expected lifetime of the low‐voltage electrolytic capacitor is given. As before, the high‐voltage stress on the main switches, which is typical in current‐fed isolated converters, is reduced substantially by taking advantage of the transformer leakage inductance necessary for resonance. Additionally, high efficiency is ensured by the use of dual non‐cascading structures. Steady‐state state‐space averaging analysis is performed for designing the converter in DCM operation. A prototype converter is built to verify performance of the proposed PFC LED pre‐regulator. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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设计了一种采用LNK403EG为核心驱动芯片的带功率因数校正的LED驱动电源。该电源输入交流电压范围为90~265V,可以驱动输入电压为18V、电流为0.38A的大功率LED光源;电路中没有使用电解电容,延长了LED驱动器在高温下的工作寿命。 相似文献