Fig 2 - uploaded by Bo Sun
Content may be subject to copyright.
![Foil Structure of Aluminum Electrolytic Capacitors [10]](profile/Bo-Sun-28/publication/281447856/figure/fig2/AS:391506063052801@1470353727230/Foil-Structure-of-Aluminum-Electrolytic-Capacitors-10.png)
Source publication
![Fig. 1. Construction of Aluminum Electrolytic Capacitors [10]](profile/Bo-Sun-28/publication/281447856/figure/fig1/AS:391506063052800@1470353727201/Construction-of-Aluminum-Electrolytic-Capacitors-10_Q320.jpg)
![Fig. 2. Foil Structure of Aluminum Electrolytic Capacitors [10]](profile/Bo-Sun-28/publication/281447856/figure/fig2/AS:391506063052801@1470353727230/Foil-Structure-of-Aluminum-Electrolytic-Capacitors-10_Q320.jpg)
The failure of aluminum electrolytic capacitors is considered as one of major failure modes of the LED drivers. This paper propose a degradation model of aluminum electrolytic capacitors considers impacts of operation time and temperature.
Similar publications
On the 2nd generation of PPB-Led [1], Figure 1,2, the electrodes and the foil capacitor are more solidly attached. Here, this is analysed since found to start-up by low-cycles input mechanical oscillations. Another feature was that the glow continues in an entire dry pot. Also, purely electric amplifiers were tested and found to provide a more stab...
http://dx.doi.org/10.5007/2175-7941.2015v32n3p824
Neste artigo nós apresentamos um método experimental para a determinação da constante de Planck, baseado na medição da corrente de descarga de um capacitor sobre um LED, sem o uso de resistores. Para tanto, utilizamos um capacitor ligado em paralelo a um LED e observamos a tensão no capacitor duran...
We present a wafer trimming technique for producing superconducting micro-resonator arrays with highly uniform frequency spacing. With the light-emitting diode (LED) mapper technique demonstrated previously, we first map the measured resonance frequencies to the physical resonators. Then, we fine-tune each resonator's frequency by lithographically...
Citations
... The aging of Al-caps is specifically manifested by the decrease of capacitance and the increase of ESR caused by the evaporation of electrolyte. Hence many scholars estimate the remaining lifetime of capacitors by monitoring the aging parameter (Sun et al., 2015;Agarwal et al., 2018). However, the capacitance is not easy to measure and the offset of ESR is affected by the ambient temperature during the aging process. ...
The charging modules of Electric vehicles (EVs) always run in a complex and variable state. As the weakness in the reliable operation of charging modules, the accurate lifetime prediction of aluminum electrolytic capacitors (Al-caps) is important for the later maintenance and reliability design. The hotspot temperature calculation method and lifetime model limit the accuracy of aluminum electrolytic capacitors lifetime prediction methods, which cannot meet the increasing requirements for reliability. In order to solve the problems above, this paper has proposed a hotspot temperature calculation method based on the ripple current with frequency characteristics and the cooling conditions on the heat generation and thermal conductivity of the capacitors. Furthermore, the lifetime model under reference voltage has been constructed with 3D surface fitting toolbox, which describes the trends of capacitor lifetime with ambient temperature and hotspot temperature under the constant voltage condition. Considering the variation of voltage, the multiple lifetime model of capacitor is established with a voltage correction coefficient. With the proposed method, it can be realized about the real-time lifetime prediction of capacitors under multiple operating profiles such as ripple current, thermal dissipation conditions, ambient temperature and operating voltage. Finally, the effectiveness of the proposed method is verified with the annual profiles of a 30 kW EV charging module.
... In the case of capacitors, it is found that the TCCDM is subject to the Arrhenius model between 339 K and 399 K ( Figure 6 in [32]), is linear between 253 K and 333 K ( Figure 12 in [33]), and exponential between 293 K and 353 K (Figure 7 in [34]). In other words, the Arrhenius model is only applicable within specific temperature ranges, whereas the relationship between the degradation parameter and temperature (i.e., the degradation rate) takes different shapes over different temperature ranges. ...
Degradation models are central to the lifetime prediction of electromagnetic relays. Coefficients of degradation models under accelerated degradation test (ADTs) can be obtained experimentally, and it is customary to map these coefficients back to those describing the actual degradation by the so-called Arrhenius model. However, for some components, such as springs in electromagnetic relays, the Arrhenius model is only appropriate over a certain ADT temperature range, which implies inaccurate mapping outside that range. On this point, an error function model (EFM) is proposed to overcome the shortcomings of the Arrhenius model. EFM is derived from the average vibration energy of the crystal, which is further related to temperature alongside some constants. The empirical part of the paper compares the proposed EFM to the Arrhenius model for the ADT of 28-V–2-A electromagnetic relays. The results show that EFM is superior in describing the temperature characteristics of coefficients in the degradation model. Through mechanism consistency checking, EFM is also shown to be a better option than the Arrhenius model. Moving beyond the case of electromagnetic relays, EFM is thought to have better applicability in the degradation models of capacitors and rubbers.
... The moveable electronics devices industry demands the work of high-energy capable storage devices with power and high energy densities. The electrode materials of supercapacitors should have carrier mobility, smooth surface area, and good morphology that have the power to deliver high capacitance [52][53][54]. ...
Fabrication and characterizations of hybrid materials based on Polyaniline, metal oxide, and Graphene nano-platelets for Supercapacitor electrodes, Inorganic Chemistry Communications (2022), doi: https://doi. Abstract MnO 2 nanowires were synthesized through the hydrothermal method that is used to fabricate the nanocomposite of polyaniline, MnO 2 , and Graphene nanoplatelets. The nanocomposites MnO 2 /polyaniline/Graphene-nanoplatelets-1 (MPG-1) and MnO 2 /polyaniline/Graphene nano-platelets-2 (MPG-2) were synthesized by in-situ polymerization of aniline monomer in the presence of surfactants e.g., N-N-N-cetyltrimethylammonium bromide (CTAB) and ammonium persulfate (APS) under ice-cold conditions. A homogenous dispersion of graphene nanoplatelets within the polymer was achieved due to the good surfactants. Due to moderate reaction conditions, the structural and electrochemical properties of all materials e.g. nanowires and nanocomposites were well maintained. These chemical, thermal, electrical, and structural properties were studied through SEM, XRD, TGA, FTIR, and electrochemical characterizations. The nanocomposite electrode materials were used for supercapacitive characterizations and had shown a high specific capacitance of 160Fg-1 ,218Fg-1 , and 330Fg-1 at 5 mVs-1 current density with good cyclic stability. These synthesized electrode materials exhibited very good energy and power densities with the value of 5.63~ Wh/kg and 1417.34 W/kg respectively at different scan rates. 2
... On the other hand, according to the research results shown in Figure 1, AL-CAPs hold the maximum distribution of long-term possible failures, which is more than 50%, compared to other power electronic devices [1,2]. It is widely accepted that the life of a power electronics system is equal to the life of the used AL-CAPs [3]. For these reasons, the selection of AL-CAPs and its life estimation play a critical role on long-life system design. ...
... Thereafter, total 100 Hz equivalent rms current value should be calculated using equation (2). The ripple current factor, RCF, is then calculated using equation (3). B. Temperature Effect on AL-CAPs life According to the Arrhenius Law, the life of the aluminum electrolytic capacitor is calculated based on the assumption that it is doubled with every decrease of temperature by 10°C. ...
... B. Temperature Effect on AL-CAPs life According to the Arrhenius Law, the life of the aluminum electrolytic capacitor is calculated based on the assumption that it is doubled with every decrease of temperature by 10°C. [3]. In order to apply this assumption, the rms value of the current flowing through the capacitor in any operating conditions must be smaller than the ripple current rating. ...
Aluminum electrolytic capacitors (AL-CAPs) are widely used in two-level inverter applications with having prominent features such as high capacitance – high voltage ratings, energy storage capability and good voltage regulation performance at low-cost. Reports show that AL-CAPs play a critical role on determining a power electronics system’s life performance. With increasing safety concerns brought by standards, it is crucial to deeply analyze AL-CAPs life performance in advance. For this reason, this paper focuses on the life estimation of AL-CAPs used in two-level inverters. In order to do this, a prototype is implemented and a practical and easy to understand method is suggested for selection and life estimation of AL-CAPs based on measurements on prototype. Life improvement methods are also discussed in the scope of the work.
... Hao Ma proposed the failure prediction model and estimated ESR from the vaporization mechanism of electrolyte [11]. Bo Sun obtained capacitance and the trend of ESR to forecast the remaining useful life from Arrhenius' rule of thumb [12]. However, the method treats the failure rate as a function of temperature without considering the effect of degradation time. ...
... The LED light source often has a lifetime as long as 25,000-100,000 h [1][2][3]. However, the LED driver has a much shorter life, in particular, when electrolytic capacitors are utilized [4][5][6]. Many studies have focused on the degradation analysis of LEDs only, without taking consideration of the LED driver's degradation [2,[7][8][9][10][11]. ...
In this paper, an integrated LED lamp with an electrolytic capacitor-free driver is considered to study the coupling effects of both LED and driver’s degradations on lamp’s lifetime. An electrolytic capacitor-less buck-boost driver is used. The physics of failure (PoF) based electronic thermal simulation is carried out to simulate the lamp’s lifetime in three different scenarios: Scenario 1 considers LED degradation only, Scenario 2 considers the driver degradation only, and Scenario 3 considers both degradations from LED and driver simultaneously. When these two degradations are both considered, the lamp’s lifetime is reduced by about 22% compared to the initial target of 25,000 hours. The results of Scenario 1 and 3 are close to each other. Scenario 2 gives erroneous results in terms of luminous flux as the LED’s degradation over time is not taken into consideration. This implies that LED’s degradation must be taken into considerations when LED and driver’s lifetimes are comparable.
... The high junction temperature not only degrades the LED devices, but also immensely affects the electronic driver, mechanical housing (including assembly parts, such as thermal dissipation, electronic isolation, and final installation), and optical lens [23,24]. For configuring switch mode driver, the effects of high temperature degradation of electrolytic capacitors on the driver have been investigated [25], as they play an important role in the dimming and color control technologies [23,[26][27][28]. In the linear mode high power LED driver, the hot carrier injection (HCI) has been found to be the main mechanism of degradation [29]. ...
With emerging market for multi-chip module (MCM)-based high power LED systems, the demand for advanced thermal management techniques has been steadily growing. This paper presents a model developed by the authors for thermal coupling matrix (TCM) that can calculate temperature distribution at a given heat power of each chip. The model significantly simplifies the task of measuring thermal coupling effect on multi-chip LEDs with symmetrical structure, while simultaneously preserving temperature accuracy. The modeling technique was validated experimentally on three-, four-, and six-chip rectangular modules, and a ten-chip circular module, by infrared thermography and transient thermal measuring system respectively. The modeling technique was found to be more efficient especially for large systems. The model offers a rapid way to predict thermal coupling behaviors of multi-chip LED systems.
... The linear-mode driver uses an error amplifier to control the output current linearly, while the switch-mode driver controls the output current by using a voltage-controlled switch with a feedback circuit. In the switch-mode driver's configuration, the electrolytic capacitors (E-cap) serve as the energy storage part and play a more significant role in device failure [46]. Whereas in the linear-mode driver, the output current of the driver is maintained by adjusting the gate voltage of the output transistor through the feedback circuit. ...
... For example, Han et al. [167] predicted the useful life of an LED driver by using the ALT method, in which the electrolytic capacitor was considered as the weakest link. Bo et al. [46] considered the failure of aluminum electrolytic capacitors as one of the major failure modes of the LED drivers and proposed a degradation model by considering the impacts of operation time and temperature. Lall et al. [168]- [170] conducted an accelerated aging test in order to assess the reliability of the LED drivers, in which the electrical drivers were exposed to a standard wet hot-temperature operating life of 85% RH and 85 °C. ...
High-power white light-emitting diodes (LEDs) have attracted much attention due to their versatility in a variety of applications and growing demand in markets such as general lighting, automotive lamps, communications devices, and medical devices. In particular, the need for high reliability and long lifetime poses new challenges for the research and development, production, and application of LED lighting. Accurate and effective prediction of the lifetime or reliability of LED lighting has emerged as one of the key issues in the solid-state lighting field. Prognostic is an engineering technology that predicts the future reliability or determines the remaining useful lifetime of a product by assessing the extent of deviation or degradation of a product from its expected normal operating conditions. Prognostics bring benefits to both LED developers and users, such as optimizing system design, shortening qualification test times, enabling condition-based maintenance for LED-based systems, and providing information for return-on-investment analysis. This paper provides an overview of the prognostic methods and models that have been applied to both LED devices and LED systems, especially for use in long-term operational conditions. These methods include statistical regression, static Bayesian network, Kalman filtering, particle filtering, artificial neural network, and physics-based methods. The general concepts and main features of these methods, the advantages and disadvantages of applying these methods, as well as LED application case studies, are discussed. The fundamental issues of prognostics and photoelectrothermal theory for LED systems are also discussed for clear understanding of the reliability and lifetime concepts for LEDs. Finally, the challenges and opportunities in developing effective prognostic techniques are addressed.
