This Ph.D. Thesis is about the design and implementation of an electronic
photovoltaic (PV) power converter working in a microgrid environment.
Microgrids based on renewable energies have raised a great interest in the
last years. Thus, improving the microgrids capabilities becomes a crucial point.
The microgrids are composed by clusters of micro generation power sources,
storage elements, loads and power distribution managed autonomously, which
can operate either connected to the public electric grid or isolated from it.
This work shows a PV power electronic converter with battery backup which
is able to operate in both situations, i.e., in grid connection operation mode or
isolated from the grid. It is shown that the converter can switch between both
operation modes undergoing smooth transitions that do not affect the loads
connected to the microgrid. The system adapts its control configuration to each
operation mode, being able to work in parallel with other power conversion
equipments with no communication links among converters.
The backup energy storage based on batteries provides a secure supply of
power for the loads when the microgrid is isolated and the PV source doesn´t
provide enough energy. The energy storage is done in direct current through a
DC/DC converter connected to the DC link of the inverter. When the generated
PV power is higher than the load demand, the excess of energy can be stored in
the batteries.
The presented simulation and experimental results carried out on a 3 kW
prototype confirm that the system works properly in various situations.