IGBT reliability analysis of photovoltaic inverter with reactive power output capability

When the PV power supply participates in reactive power regulation of distribution network, its output reactive power will affect the reliability of IGBT in the PV inverter. Aiming at this problem, this paper first qualitatively analyzed the influence of photovoltaic power supply participating in reactive power regulation of distribution network on the reliability of photovoltaic power supply. Then, a quantitative evaluation method of IGBT reliability based on data-driven was proposed. This method uses LightGBM machine learning model to replace the traditional thermoelectric coupling model, which effectively improves the calculation efficiency of IGBT junction temperature and reduces the dependence of IGBT reliability evaluation results on IGBT model parameters. Through this method, the reliability of core power electronic devices in photovoltaic inverters is quantitatively evaluated according to active power, reactive power, solar irradiance and ambient temperature. Finally, based on the IEEE 33 node distribution system, the reliability of IGBT in PV inverters participating in reactive power regulation of the distribution network was evaluated.