Impact of Measurement Data Time Resolution on Predicted Lifetime of PV Inverters in Residential Solar Panel Systems

Abstract

The reliability of grid-tied PV inverters without integrated battery is compared with AC/DC-coupled PV- battery systems while varying the time resolution of the load and mission profiles (1 min – 60 min). Adding a battery increases self-consumption and can lower the needed grid power capacity in both DC- and AC-coupled configurations. A comparison between a battery-free PV system and a grid-tied PV-battery system shows that adding a battery to the system will not only improve the energy performance of the system but also increase the lifetime of the inverter (~15% in DC-coupled structure). The results have been extracted for two cases: (a) varying both mission profile and load profile resolutions, (b) varying the available load profile time resolution while keeping the mission profile time resolution constant at 1 min. The obtained results show that in our case, the influence of mission profile time resolution is greater than the input of load data. However, the expected PV inverter lifetime does not differ much for different time resolutions. This can highlight the importance of using measurement data with a resolution of even less than 1 minute because higher IGBT junction temperature swings can happen in a few seconds which cannot be seen in lower time resolutions.