Reliability analysis of a solar inverter during reactive power injection

With the advancement in control of photovoltaic inverters, reactive power support is one of the advanced features which is expected from an inverter. Reactive power is injected into the grid during a faulty condition to regain stability. However, during the process of reactive power injection, the semiconductor switches and DC link capacitor witness additional power losses which lead to a rise in junction temperature and increasing strain. In this paper, the impact of reactive power injection on inverter components is studied. The thermal analysis of semiconductor switches and DC link capacitors on the base of the mission profile is performed. The lifetime analysis is performed on different components present in the inverter along with periodic reactive power injection. The result is further compared with inverter lifetime estimation without considering the reactive power injection to analyze the impact on inverter life due to reactive power injection.