User manual

User Manual Page 11 of 74
(PVI-6000-OUTD-UK-W Rev.1.0)
2 SYSTEM DESCRIPTION
The AURORA inverter is capable of feeding power to the grid converting the power
generated by a wind turbine. The wind turbine (using a generator) converts the
mechanical energy from wind into the 3-phase AC voltage. The voltage and frequency
of the AC generated by the wind turbine are variable and depend on the wind speed.
To be exported to the utility grid the power need to be converted to the frequency and
voltage level of the grid.
When used in parallel with the grid, the alternate current generated by the inverter is
directly fed into the distribution circuit, which is also connected to the public power
distribution grid.
The wind energy system can thus powers all the connected users, such as lighting
devices, household appliances, etc.
When the wind turbine is not generating enough energy, the power required by the
connected users is provided by the public power grid. If the energy produced by the
wind turbine exceeds the quantity required by the user’s loads, then extra power is
directly fed to the grid, becoming available to other users.
According to national and local standards and regulations the energy produced can be
sold to the electrical utility or credited to the user against future consumption, thus
providing financial savings.
2.1 Key elements of a wind energy system: “WIND TURBINE” and
“GENERATOR”
Two elements are necessary in order to harvest the wind energy: a wind turbine that
will spin based on the wind speed and a generator.
The turbine forces the generator to rotate thus producing energy that can be exported
to the grid.
The most common turbine design has a horizontal rotor with 2 or 3 vertical fiberglass
blades forming the propeller which may have a fixed or a variable tilt.
The generator is fixed on the rotor. Usually for the small wind system a synchronous
permanent magnet generator is used. The current generated by this type of generators
has variable voltage and frequency depending on the turbine speed. To be exported to
the grid this needs to be is converted to current.
The conversion is done in 2 steps:
A) The 3-phase AC voltage from the generator is filtered and converted to the
DC voltage. This conversion can be done inside the turbine or using an
interface box between the generator and the inverter.