Power Electronic

  • June 2020
  • PDF

This document was uploaded by user and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Report DMCA


Overview

Download & View Power Electronic as PDF for free.

More details

  • Words: 517
  • Pages: 7
FACULTY OF ELECTRICAL ENGINEERING UNIVERSITI TEKNOLOGI MARA

EPO642 POWER ELECTRONIC II

ASSIGNMENT 1

MUHAMMAD KHUDRI BIN HALIM BASHAH 2007270412 EEB7AP

DR. MOHAMMAD NAWAWI SEROJI

ASSIGNMENT 1: A full-bridge controlled rectifier produces a continuous and discontinuous (intermittent) output voltage waveform when feeding a purely resistive load. 1) Identify the range of firing angle that produces both waveforms

For continuous waveform condition; 0° ≤ α ≤ 60° At α = 30°,

Figure 1: For continuous waveform condition at α = 30°

For discontinuous waveform condition; 60°

α

120°

At α = 90°,

Figure 2: For discontinuous waveform condition at α = 30°

2) Derive the average output voltage equations for both operations (continuous and discontinuous, Vo)

For continuous waveform: 

VDC

=

6

1



3







V LL cos(t )d (t )

  6





1  6 = V LL sin(t )       3 6 

3V LL     = sin(   ) sin(   )    6 6  

3V LL       = (sin cos  cos sin  )  (sin cos   cos sin  )    6 6 6 6  

=

3V LL

=

3V LL



(0.5cos  0.866 sin  )  (0.5 cos   0.866 sin  )





cos 

For discontinuous waveform, 

VDC

=

2 

1



3

V

LL

cos(t )d (t )

  6



1  2 = V LL sin(t )      3 6 

3V LL     = sin sin(   )    2 6  

3V LL      = sin [sin( ) cos   cos( ) sin  )    2 6 6  

=

3V LL



1 0.5 cos   0.866 sin  )



3V LL    1  cos(  ) =    3  

=

3V LL



1  cos(  60)

3) Verify your answers using PSIM simulation. State any assumptions you have made i.e. values of V s, f, R etc.) Answer: Assume; 

VLL(rms) =415V



R load=100Ω



Frequency = 50Hz



Pulse width = 120

Figure 3: PSIM simulation circuit diagram of three phase full bridge controlled rectifier purely resistive load with 60 degree firing angle.

Let α = 30°

Figure 4: Firing angle at α = 30°. From simulation; VDC = 483.914V From formula for continuous current condition; 

VDC =

3V LL



cos 

= 415 x √2 =

 

3 2 (415)



cos 30

= 485.3613 V

Let α = 90°

Figure 5:Firing angle at α = 90°. From simulation; VDC = 73.7533V From formula for discontinuous current condition; 

VDC=

3V LL



1  cos(  60)

= 415 x √2 =

 

3 2 (415)



1  cos(90  60)

= 75.0856 V

Related Documents