At the heart of any photovoltaic (PV) system is the inverter,
also referred to as the power conversion unit (PCU) or power
conversion system (PCS). Its primary function is to convert the
direct current (DC) output of the PV array to alternating
current (AC) that can be used to power conventional building
loads. This means that the inverter must take the DC power
provided by the PV array—which varies with sky conditions, time
of day, season, temperature—and provide sufficient AC power of
the right voltage and frequency to drive the load. In addition,
unless the building loads served by the PV system are isolated
from the rest of the building distribution system or the
building is off the grid and powered solely by PV and other
alternative energy sources, the inverter must be capable of
interfacing with the utility system. Further, if the PV system
is a standalone system with batteries or a hybrid system with
both a utility connection and batteries, the inverter must be
able to charge the batteries when there i