What is VFD (VFD kya hai)/Drive (veriable Frequency Drive)

1.                        Drive    

  Drive is an electrical device  which produces an output of adjustable voltage and adjustable frequency.

                           Ns=120f/p

P number of Pole, f=50Hz for AC 

  Note  

    Since.f= 0 in a dc motor .we have to very the adjustable voltage.   

Adjustable voltage should very in ac motor.   

Drive are two types 

1. DC Drive .    2.AC Drive 

1.DC Drive --

It is used to start /stop ,forwards /reverseds and  to very the speed of the dc motor.

The main component used to control the speed of the DC motor is CHOPER. 

CHOPER--

Choper is an electronic component which convert the fixed dc into variable dc. 

We can very the speed of the dc motor by varying the delay angle --

2 .AC Drive --

These are two types 

1-VFD ( variable Frequency Drive) 

2-VVD ( variable voltage Drive)

 

 V. F. D.  is used to start /stop ,Fwd /Rvs and to very the speed of the AC motor regarding energy saving concept. 

AC Drive generates an output of adjustable voltage and adjustable frequency. 

Energy Saving concept --

*VFDs use in induction motor 

*AC motors synchronous speed =120f/p rpm 

rpm = Rebulation per minute 

Ns=120f/p.              (f=50hz p=number of Pole) 

Ns =6000/2=3000rpm

Actual speed Less (2-5%)

V. F. D.  System ----

*3phase AC motor use in industrial area and train.

*voltage 650,750,1500 in DC link depend on system. 

* DC links change DC  in pure DC. 

Inverter --

*Inverter changes DC in AC 3phase AC .

*Inverters are make  IGBT base. 

*Inverter controlled frequency. Motors speed depend on frequency. 

Inverters are two work 

1-make a 3phase AC and 2- frequency controlled. 

IGBT --

Three terminal are in IGBT as- Gate,controller,Emitter.controlle unit works in inverter. These unit work as per set time.  Voltage label IGBT depend on,on time.

V. F. D. Controller --

These are two types

 1- scaler controller --voltage & frequency are  fixed .these are cheap these controllers used in small motor v/f=constant 

*Low performance 

*simple control 

*price is Low 

2-vector control--

*more future & more performance are in this control .

*This vectors can used without computer & scada. 

V. F. D. Benefits --

*high performance. 

*Energy saving. 

*very good transient respons. 

*high power factor (for IGBT) .

*soft starting.

* control torque ( Jab Jyada bat move karna  ho).

*very good stood responce.