Capacitor in intermediate circuit in VFD

[thyristor]

Hello All,I would like to understand how capacitor banks used in the intermediate circuit(located between rectifer and inverter section of VFD) help to smoothen the pulsating DC ouptut from rectifier output before feeding it to inverter.

 

[jraef]

Capacitors store and release energy. The rectifier diodes only conduct at the peaks of each sine wave, resulting in pulsating DC. As the pulses hit the capacitors they charge up, storing the energy. As the transistors send energy to the motor, that energy is drawn out of the capacitors.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[thyristor]

Understand that capacitors are used as storage device.But how is pulsating DC smoothened after capacitor?

 

[waross]

Try a basic text book. Look at simple rectifier circuits. You should be able to fine some showing pictures of basic capacitor filtering.
A picture may be worth 1000 words.
Link
Scroll down to Filtration.


Bill
--------------------
"Why not the best?"
Jimmy Carter