低压直流高频隔离AC/DC变换器寿命评估

Low Voltage DC High Frequency Isolation AC/DC Converter Lifetime Estimation

AC/DC变换器是联系交流配电系统与直流用电系统的重要纽带,实现交直流配用电的功率交换,其寿命对末端连续可靠用电起主导作用。基于物理失效的方法,多方面地综合考虑了变换器的任务剖面、环境温度和承受的电热应力,量化地评估低压直流高频隔离AC/DC变换器的寿命。解析了变换器可靠性机理,探明了其薄弱环节,并分析了冗余配置对变换器寿命的影响。最后,算例分析表明,无冗余配置时VIENNA整流器中二极管D1是高频隔离AC/DC变换器的最薄弱位置;配置1个冗余AC/DC模块变换器的寿命能提高2.35倍,此时薄弱环节转移为高频隔离DC/DC变换器输出侧直流支撑电容。

AC/DC converter is an important link between AC power distribution system and DC power supply system.It can realize the power exchange of AC and DC power distribution.Its life plays a leading role in the continuous and reliable power supply at the end.Based on physical failure approach,the mission profile,ambient temperature and electro-thermal stress of the converter are considered comprehensively,the life of the low-voltage DC and high-frequency isolated AC/DC converter is evaluated quantitatively.The reliability mechanism of the converter is analyzed,its weak links are identified,and the influence of redundancy configuration on the life of the converter is analyzed.Finally,the analysis of numerical examples shows that diode D1 is the weakest position of high-frequency isolated AC/DC converter in Vienna rectifier without redundancy configuration.The lifetime of a redundant AC/DC module converter can be increased by 2.35 times.At this point,the weak link shifts to the DC support capacitor on the output side of the high-frequency isolated DC/DC converter.