A SEMINAR ON

THREE PHASE FULL BRIDGE RECTIFIER

National Institute of Technical Teachers Training and Research Chandigarh-160019

Presented By:Vivek AhlawatM.E (Regular), EE (I&C)Roll No – 152521

Submitted To:Er. Shimi S.L(Asst. Professor)

Department of Electrical Engineering (Instrumentation & Control)

Power Electronics Devices

Power Electronics is an art of converting electrical energy from one form to another in an efficient, clean, compact & robust manner.

Types of Power Electronics Converters

Diode rectifiers (uncontrolled rectifiers) Ac to dc converters ( controlled rectifiers) Dc to ac converters (Inverters) Dc to dc converters (choppers) Ac to ac converters (cycloconverters) Static switches

Three Phase Full Bridge Rectifier

There are six diodes are used in three phase full bridge rectifier.

There are two groups:1)-Top group or Positive group (Diode 1,3 & 5)2)-Bottom group or Negative group (Diode 2,4 & 6)

Positive group diodes will conduct for positive half cycle. Negative group diodes will conduct for negative half cycle. Each diode will conduct for 120 degree in each pair.

Three Phase Full Bridge Rectifier

Three Phase Full Bridge Rectifier

We study two cases in three phase full bridge rectifier:Case 1:- When ac side inductance is zero (=0) The current flow through one diode from the top group &

one diode from bottom group. In top group one of the diode with its anode at the highest

potential will conduct & the other two became the reverse biased.

In bottom group one of the diode with its anode at the lowest potential will conduct & the other two became the reverse biased.

Three Phase Full Bridge Rectifier

so arbitrarily the time t=0

By integrating the , the volt second area A is given by

And therefore dividing by π/3 intervals yields = 1.35

The rms value of current- = 0.816

The fundamental frequency component- = 0.78

Phase voltage & current for one phase of three phase rectifier

Effect of on current commutation

Current Commutation process

Current Commutation process

Effect of Case2 :- when has a finite valueThe commutation voltage-

=2 =

The commutation interval can be obtained by multiplying both sides & integrating the above equation

This area is lost at every or interval, so the voltage drop due to comm.∆

So the output voltage-∆1.35

Distortion in line -current waveform

Three phase rectifier with a finite and a constant dc voltage

Equivalent ckt

Distortion in line -current waveform

Comparison B/w Single phase & Three phase RectifiersWhen 0 (Ideal case)

THD= 48.43% THD=31.08%

Where h= 1, 3, 5, 7, 9, 11,13…… Where h= 1, 5, 7, 11, 13……

When Finite ValueVolt radian area () = 2 Volt radian area () =

Area lost every half cycle Area lost after every

Voltage drop (∆V) = Voltage drop (∆V) =

Output voltage ( = - Output voltage ( = -

Recent Research A major area of research is to develop higher frequency

rectifiers, that can rectify to terahertz and light frequencies. These devices are used in optical heterodyne detection, which

has myriad applications in optical fiber communication and atomic clocks.

Another prospective application for such devices is to directly rectify light waves picked up by tiny antenna, called nantennas, to produce dc electric power.

Power Electronics; Author Dr. P.S.BhimbraPower Electronics; Author-Ned MohanPower Electronics; Author- M.H.Rashid

www.google.co.inwww.wikipdia.org

References

THANKS