Multi-time Scale Life Assessment Method for Energy Storage Inverters

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.