DESCRIPTION
The term FFE (Fundamental Front End) refers to a bidirectional AC-DC converter in which DC Voltage is not controlled.
It works as a diode bridge but with the recovery of energy to the grid. FFE only works on the fundamental component (50-60Hz) with no PWM modulation.

TECHNICAL DETAILS
The advantage is the reduction of the losses (no switching losses) with an improvement of current available; furthermore, the fact of not having PWM modulation allows to have a smaller inductance line side and no LC filter required.

DIFFERENCES BETWEEN FFE AND AFE

ADVANTAGES:

• SIZE: the dimensions are similar to AFE but the size can be increased. It depends on the size: from a 18% (OPDE90) to a 41% size increase (OPDE110) with 120% overload.
• CABINET COMPONENTS: the inductance is reduced and the LC filter is no longer needed. This is very important in terms of costs and space in the cabinet.

DISADVANTAGES:

• THD similar to diode bridge (AFE guarantees THD ≈ 4%)
• No bus regulation