Failure mechanism and life estimate of metallized film capacitor under high temperature and humidity

Tai, Yunxiao; Chen, Pengqi; Yang, Jian; Fang, Qing‐Qing; Xu, Dan; Jiaan, Cheng

doi:10.1016/j.microrel.2022.114755

Cited by 13 publications

(12 citation statements)

References 23 publications

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“…(2) Calculating the activation energy E ak , E aD , and humidity coefficient n according to k 1 and D under different temperature and humidity conditions. (3) Calculating the RC according to Equation (17).…”

Section: Lists the Rc Of Ep-a And Ep-bmentioning

confidence: 99%

“…For epoxy resin with a thickness of 0.5–2.5 mm, it takes at least 1300 h for the moisture diffusion to reach Stage III [23]. However, for the encapsulated FCs used to suppress electromagnetic interference, the accelerated aging test duration is commonly within 1000 h [17], which corresponds to Stage I and Stage II shown in Figure 2. Since the moisture diffusion in Stage I is significantly faster than that in Stage II, this paper focuses on Stage I of the moisture diffusion in FC epoxy resins, and assumes that the epoxy resin is structurally intact, that is, the effect of defects is neglected.…”

Section: Moisture Diffusionmentioning

confidence: 99%

“…RC is usually set as a fixed value according to: (1) the load requirements, which are independent of the FC degradation. For suppressors in series to the main, the RC is set as a 10% capacitance loss of the initial capacitance [2,17]; (2) the change value of the characteristic parameter when the FC aging accelerates. For pulse capacitors, the RC is set as a 5% capacitance loss of the initial capacitance; for power electronic capacitors, the RC is defined by tanδ increasing to a certain value or insulation resistance decreasing by 50% [17,18].…”

Section: Introductionmentioning

confidence: 99%

“…For suppressors in series to the main, the RC is set as a 10% capacitance loss of the initial capacitance [2,17]; (2) the change value of the characteristic parameter when the FC aging accelerates. For pulse capacitors, the RC is set as a 5% capacitance loss of the initial capacitance; for power electronic capacitors, the RC is defined by tanδ increasing to a certain value or insulation resistance decreasing by 50% [17,18]. Since the FC aging process is highly dependent on the operating environment, FCs may not reach the expected lifetime under higher temperature and/or humidity conditions.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Reliability criterion of film capacitor based on moisture diffusion in encapsulation

Qiu

et al. 2023

High Voltage

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The current reliability criterion (RC) of the film capacitor (FC) is usually a fixed value, which does not consider the staged capacitance loss caused by moisture diffusion under high temperature and/or high humidity. The expected lifetime of capacitors would deviate far from the actual one. The moisture diffusion process of the encapsulated FC is analysed based on Fick's second law. In order to investigate the capacitance loss and moisture diffusion characteristics, 4 types of film capacitors are stressed with AC voltage under different temperatures and humidities. Based on the staged analysis of the capacitance and weight gain curves, the effect of moisture diffusion on capacitance loss is revealed. Results indicate that the linear stage of capacitance loss corresponds to the Fickian moisture diffusion stage of weight gain. The effect of voltage on FC aging is the most significant. The capacitance loss rate increases by 301% when the voltage rises by 30%. An RC calculation method of the FC is further proposed, which could also screen the encapsulation quality and shorten the aging test duration by at least 80%.

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Section: Lists the Rc Of Ep-a And Ep-bmentioning

confidence: 99%

Section: Moisture Diffusionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Reliability criterion of film capacitor based on moisture diffusion in encapsulation

Qiu

et al. 2023

High Voltage

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show abstract

“…An organic sealed package will be ultimately intruded by water vapor or gases due to the permeability of organic materials [1]. Active devices in harsh environments are preferentially recommended in a metal or ceramic hermetic package [2][3][4]. Sealing a package with a lid, usually the final process in packaging, allows an integrated circuit assembled inside in an isolated environment to prevent aggression of contaminants.…”

Section: Introductionmentioning

confidence: 99%

A new method for preventing stress cracking in repairable ceramic packages by changing the sealing ring shape

Yao,

Tian,

Fang

et al. 2023

Mater. Res. Express

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High-reliable ceramic packages are impressionable to the parallel seam welding (PSW) parameters leading to low yield and reliability. In this study, the structure of the ceramic package was modified by changing the sealing ring to improve weldability and high-temperature reliability. Three types of ceramic packages with different-shaped sealing rings, which are conventional rectangular rings, notch inward rings, and notch outward rings, were fabricated by Au-Sn soldering and a follow-up PSW process. The packages with the rectangular ring failed in the subsequent high-temperature aging test. The packages with the notch inward ring exhibited an early failure after PSW. Cracks were generated in the Au-Sn solder and propagated into the ceramic substrate. The packages with the notch outward ring exhibited remarkable weldability and reliability. Sequential thermo-structural coupling was used to simulate the temperature and stress distribution in the packages. The maximum principal stress in the aforementioned ceramic substrates rapidly increased to approximately 170.0 MPa, 168.5 MPa and 101.4 MPa in the PSW process. Stress concentration existed at the outside corner around the rectangular and notch inward-shaped sealing rings. The maximum temperature at the local position in the ceramic was raised to 250.3 °C, 238.6 °C and 157.2 °C depending on the shape of the sealing ring. The extra transmission path in the notch outward ring relieved thermal mismatch and deformation at the Au-Sn/ceramic interface during PSW. The packages with notch outward rings were recommended especially in the repairable ceramic packaging.

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Detuning analysis and power tracking of dual‐ended resonant circuit based on improved variable‐step perturbation observation for wireless power transfer system

Li,

Luo,

Wang

et al. 2024

Circuit Theory & Apps

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A power tracking method based on improved variable‐step perturbation observation approach has been proposed in this paper. This method is aimed at addressing the detuning issues caused by capacitor parameter drift in MCR‐WPT systems based on S‐S compensation circuits. Compared with traditional tuning methods, the proposed method has fast response, high accuracy, low complexity, and less prone to over‐tracking. Firstly, a mathematical model of the system based on the detuning factor has been established. Secondly, the impact of different detuning conditions on the system at the initial resonant frequency has been studied. Thirdly, the response characteristics of the system to different frequencies under different detuning conditions have been studied. Fourthly, based on the above researches, an improved variable‐step perturbation observation method based on the single‐step power drop factor has been proposed. Finally, an experimental platform was constructed, and relevant experiments were conducted. Experimental results validate the effectiveness of power tracking under different detuning conditions, with the lowest transmission efficiency being 81.51%.

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Failure mechanism and life estimate of metallized film capacitor under high temperature and humidity

Cited by 13 publications

References 23 publications

Reliability criterion of film capacitor based on moisture diffusion in encapsulation

Reliability criterion of film capacitor based on moisture diffusion in encapsulation

A new method for preventing stress cracking in repairable ceramic packages by changing the sealing ring shape

Detuning analysis and power tracking of dual‐ended resonant circuit based on improved variable‐step perturbation observation for wireless power transfer system

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