VFD with Active Front end

[easyser]

 

Hi All !

 

What is an active front end ? How is it superior to 'normal' front end ?

When is the used of a VFD with an active front end jusitified ?

 

Thanks,

easyser

[kens]

Hi easyser, basically a drive with an active front end has IGBTs rather than the standard rectifier section. If you imagine using the output components of the drive on the input side also. This has several advantages such as very low harmonic disturbance, improved power factor and also the abilitiy to disipate regenerative energy back into the supply instead of onto a braking resistor or via linked DC busses. Unfortunatly it is also an added cost to the drive.

Ken

 

sorry just re-read the second part of your question, I would say that the biggest advantage is the Harmonic performance so the justification could be if you have a requirement for very low Harmonic interference. Also if there is a need for a lot of regeneration from the system and not an opportunity for load-sharing then the energy savings can help justify the additional costs.

Ken