储能变流器多时间尺度寿命评估方法

Multi-time Scale Life Assessment Method for Energy Storage Inverters

储能变流器是蓄电池与电网进行电能交互的关键装备,然而由于新能源出力与电力系统负荷的随机性和波动性,储能变流器的可靠性低,亟需对其进行可靠性评估以降低储能变流器非计划停机带来的经济损失,提升电网供电的稳定性和可靠性。然而现有研究多集中在对光伏、风电等新能源出力侧变流器进行可靠性评估,很少有对储能变流器开展寿命评估的研究。基于上述背景,提出一种考虑长时间尺度电力系统负荷和新能源出力任务剖面的储能变流器可靠性评估方法。以3.5 MW光伏储能变流器为例,结合结温数值迭代算法和解析寿命模型,评估不同时间尺度热载荷导致的寿命消耗。结果表明,光伏储能变流器中IGBT的寿命消耗大于二极管的寿命消耗,并且低频寿命消耗大于基频寿命消耗,因此需要重点减轻低频热载荷引起的IGBT寿命消耗,以提高储能变流器预期使用寿命。

The energy storage converter can realize the rapid conversion of electric energy between supply and demand,and is a key component of the normal and efficient operation of the energy storage system.Its reliability is affected by the change of operating conditions,so the reliability evaluation of the energy storage converter should consider the impact of long-term task profile.However,most of the existing literature focuses on the life assessment of photovoltaic converters and wind power converters,and few studies on the reliability of energy storage converters.Therefore,based on the converter reliability evaluation method,a reliability evaluation method of energy storage converter considering load variation is proposed.Taking the 3.5 MW photovoltaic energy storage converter as an example,the long-term task profile of the converter is divided,and the base-frequency lifetime consumption and low-frequency lifetime consumption are evaluated.The research shows that the life consumption of the IGBT chip in the photovoltaic energy storage converter is greater than that of the diode chip,and the life consumption of the low frequency is greater than that of the fundamental frequency.