power conversion station (PCS)
The term grid injection device (NEG) is used in photovoltaics( PV). It is a device that couples the photovoltaically generated direct current into the low- voltage grid.
Depending on the concept of the photovoltaic system - a distinction is made between stand-alone systems and grid-connected photovoltaic systems - in the case of a stand-alone system, the grid-feeding device performs the function of a DC/DC converter or an inverter. In the case of a grid-connected PV system, the grid-feeding device must perform the functions of phase coupling and transformation in addition to the function of the inverter.
The grid feed-in unit generates a voltage-correct, frequency-correct and phase-correct AC voltage of 230 V and 50 Hz from the PV direct current for feeding into the low-voltage grid. In addition, the inverter of the grid-feeding device controls the PV system by means of Maximum Power Point Tracking( MPPT), so that it always operates at the optimal operating point, the Maximum Power Point( MPP). And as another function, there is the transformation of the PV direct current to single-phase low-voltage grids and three-phase three-phase grids.