Grid-connected photovoltaic power system Solar energy gathered by photovoltaic solar panels, intended for delivery to a power grid, must be conditioned, or processed for use, by a grid-connected inverter. Fundamentally, an inverter changes the DC input voltage from the PV to AC voltage for the grid. This inverter sits between the solar array and the grid, draws energy from each, and may be a large stand-alone unit or may be a collection of small inverters, each physically attached to individual solar panels. See AC Module. The inverter must monitor grid voltage, waveform, and frequency. One reason for monitoring is if the grid is dead
Support of a module the word "support". Most properties of the support generalize from modules to quasicoherent sheaves word by word. For example, the support of a coherent sheaf (or more generally, a finite type sheaf) is a closed subspace of "X". If "M" is a module over a ring "A", then the support of "M" as a module coincides with the support of the associated quasicoherent sheaf formula_18 on the affine scheme Spec("R"). Moreover, if formula_19 is an affine cover of a scheme "X", then the support of a quasicoherent sheaf "F" is equal to the union of supports of the associated modules