Active front ends

Active front ends are grid interface converters that have two main functions:

• transfer power from an energy source to the utility grid,
• transfer power from the utility grid to a load.
  

In renewable energy production, the power converter transform the energy in a form that allows to carry and/or use it. It also allows to optimize the energetic efficiency of the energy source. Photovoltaic solar panels and fuel cells produce a DC voltage that needs to be converted to an AC voltage to be injected on the AC utility grid. Current drawn from the photovoltaic solar panels must be controlled in order to obtain the highest possible energy production and thus the highest energetic efficiency. Wind turbine rotation speed varies with the wind speed and a power converter is necessary to allow energy transfer from the AC generator to the grid.

When energy is flowing from the grid to the load, diode rectifiers are replaced by active front ends when a unity power factor, high power quality and/or a regenerative capability is desired.