“Before Learning about AC VFD Work. We need to understand What is AC VFD Systems.”
In this blog, we will cover the Internal Electronics of the AC VFD systems and how each electronics work in AC VFD.
What is AC VFD?
VFD stands for Variable Frequency Drive. So it is used to run an AC motor at a variable speed & time. VFD Drives are also called “Motor Controllers”.
These electronics systems are now becoming the major component in the Industrial Field. As they are not only controlling the Motor but also reducing the Power Consumption in the whole Industry.
Major Application of VFD System
- Textile Industries.
- Water Purification Plants.
- Power Plants.
- Solar Power Applications.
& many more…
Circuits Helping AC VFD Work :
- Rectifier Circuit
- Capacitor Bank
- IGBT
- Precharge Resistor
- Dynamic Breaking Resistor
- SMPS Circuit of VFD
POWER CARD AC VFD
INTERNAL CIRCUIT DIAGRAM AC VFD
1) RECTIFIER CIRCUIT
The rectifier converts AC to DC, here the rectifier will do the same as a normal rectifier Circuit.
In the above diagram, we can see two sections one is R, S, T & the second one is U, V, W where R, S, T are inputs for the VFD System. So the Input supply of VFD is AC which is then converted into DC using Rectifier Circuit.
So the Initial sector of VFD is a Rectifier Circuit that distributes the power to the whole other area of VFD (Control Card, IGBT, Capacitor bank, etc. )
In conclusion, we can say that Rectifier is the Power Source for the working of the VFD System.
2) Capacitor Bank
The DC output in the rectifier is not pure DC. but convert the pure DC we have to use Capacitor Bank. The portion you are looking at in the given diagram is known as Capacitor Bank.
3) IGBT
IGBT is an Insulated -Gate Bipolar Transistor. Most commonly IGBT Systems are used where the application is needing HIGH POWER i.e., voltage and current.
In an IGBT there are different combination of Gates that operates as per the requirement of power in a circuit. As it is designed to Turn on and Off very rapidly, So this is the reason it is vastly used in Switching amplifiers & Industrial Control Systems like AC VFD.