Sun Xiao-Wu, Qiao Ying, Li Yin-Da, Cao Chong-Feng, Guo Xiang-Ming
Wuxi Power Filter Co., Ltd., Wuxi, 214112, Jiangsu, China.
Department of Electrical Engineering, Tsinghua University, Beijing, 100084, China.
Sci Rep. 2025 Feb 1;15(1):3968. doi: 10.1038/s41598-025-88522-2.
Thermal stress is an important factor affecting the life of a DC link capacitor (DCLC). However, relevant studies on thermal stress mechanism directly influencing the lifetime of the capacitor are rarely reported. In this paper, the heat setting and thermal stress of DCLC has been analyzed, and the relevant experimental platforms have been developed to evaluate the breakdown strength of DCLC at two heat setting temperatures (HSTs). Simultaneously, the life aging analysis of DCLC at different HSTs and the life aging tests at various temperatures were also executed to attain insights into the influence of thermal stress on the lifetime of DCLC. The results showed that the stress caused by heat setting and operating temperature influenced the breakdown voltage capability and the lifetime of DCLC. With an increase in HST by 5 °C, a step-increase in the withstand voltage capability of DCLC from 7,000 V to 7,200 V was observed that demonstrated an enhancement of 2.86% in the breakdown strength performance. Correspondingly, the lifetime of DCLC with a capacitance change rate of -3% enhanced from 1,500 h to 1,700 h. However, severe deterioration in the life span of DCLC from 4,200 h to 500 h was observed with an increasing operating temperature from 55 °C to 85 °C, respectively. The lifetime could be enhanced by increasing the HST as well as reducing the operating temperature. The presented results could be termed a harbinger for industrial production of high-performance DCLC with enhanced lifetime that augers well for high-power applications.
热应力是影响直流链路电容器（DCLC）寿命的一个重要因素。然而，关于直接影响电容器寿命的热应力机制的相关研究鲜有报道。本文分析了DCLC的热定型和热应力，并搭建了相关实验平台，以评估DCLC在两个热定型温度（HST）下的击穿强度。同时，还对不同HST下DCLC的寿命老化进行了分析，并在不同温度下进行了寿命老化测试，以深入了解热应力对DCLC寿命的影响。结果表明，热定型和工作温度引起的应力影响了DCLC的击穿电压能力和寿命。随着HST升高5°C，观察到DCLC的耐受电压能力从7000V逐步提高到7200V，击穿强度性能提高了2.86%。相应地，电容变化率为-3%的DCLC的寿命从1500小时提高到1700小时。然而，随着工作温度分别从55°C升高到85°C，DCLC的寿命从4200小时严重缩短至500小时。提高HST以及降低工作温度可以延长寿命。所呈现的结果可被视为工业生产具有更长寿命的高性能DCLC的先兆，这对高功率应用来说是个好兆头。
