Power losses in photovoltaic inverter components due to reactive power injection

The grid power stability is significantly affected as a result of the net impact of many small photovoltaic (PV) generators, since there is an increase of PV systems connected to distribution systems. There are many ways to improve the system stability, regarding voltage regulation. Some work proposes to use the PV inverter idle capacity to support reactive power to the grid. The main drawback of this solution is the increase of losses in the converter during this additional functionality. Therefore, this paper analyzes the power losses in the PV inverter components (IGBTs, diodes, a dc-link capacitor and damping resistance) during both active and reactive power injection. Simulations considering a 5kW three-phase PV inverter are performed with focus in conduction and switching losses, besides, the temperature in the semiconductor devices.