power quality improvement in dc drives by suppressing
TRANSCRIPT
POWER QUALITY IMPROVEMENT IN DC DRIVES BY SUPPRESSING HARMONICS
Under the guidance ofProf. K.V.DEVADAS
Head of the Department, E&EKVGCE- Sullia.
Presented by,ARAVIND NARAGUND4th sem. M.Tech (CAID)
KVGCE- Sullia
ABSTRACT
This project presents various techniques like passive filter, shunt active
filter, sinusoidal pulse width modulation and selective harmonic elimination for
harmonic reduction. The power quality parameters such as “Total Harmonic
Distortion of voltage” (THDV) and “Total Harmonic Distortion of current”
(THDI) has determined in each case of above said techniques for different ratings
of DC motor and also extended the work to higher pulse converters (up to 96
pulse). By using MATLAB for simulation, the clear comparison of power quality
parameters has made between before and after application of above discussed
techniques.
1. INTRODUCTION
Figure : Three phase bridge rectifier circuit for speed control of DC motor
Power quality Current quality Voltage quality Total harmonic distortion
2. POWER QUALITY IMPROVEMENT TECHNIQUESThe following are types of the filters generally used. (a) Passive filters (b) Active filters and (c) Hybrid filters
2.1) Passive Filters
Passive implementations of linear filters are based on combinations of
resistors(R), inductors(L) and capacitors(C). These types are collectively known
as passive filters, because they do not depend upon an external power supply
and/or they do not contain active components such as transistors.
2.2) Shunt Active Filter
Figure : Basic Scheme of shunt active filter
Figure: Voltage source converter topology for active filters.
VOLTAGE SOURCE CONVERTERS
Multi-pulse systems result in two major accomplishments namely, 1. Reduction of ac input line current harmonics. 2. Reduction of DC output voltage ripple.
2.3) Multipulse Converters
2.3.1 12-PULSE CONVERTER
2.3.2 24-PULSE CONVERTER
Two twelve pulse converters phase shifted by 15 degrees from
each other, can provide a twenty four, obviously with much lower
harmonics on ac and DC side. Its ac output voltage would have order
harmonics i.e., 23rd, 25th, 47th , 49th harmonics with magnitudes of
1/23rd , 1/25th , 1/47th ,1/49th ,…respectively, of the phase shift.
2.3.3 36, 48 AND 96-PULSE CONVERTERHigher number of pulse converters can be
implemented by connecting appropriate number of six pulse converter either in series or parallel with proper degree of phase shift between them. The connection for 36, 48 and 96-pulse converter is shown in fig 3.8, 3.9 & 3.10 respectively.
3. MATLAB/SIMULINK MODELS AND RESULTS
3.1) 6 Pulse Converter
THDI before application of Filter = 15.32%
3.2) 6 Pulse Converter with Passive Filter
THDI after application of Passive Filter = 4.16
3.3 ) Application of Shunt Active Filter to 6 Pulse Converter.
After Application of Shunt Active Filter, THDV = 2.07, THDI = 0.91
3.4) 6 Pulse Controlled Converter
Before application of PWM Signals THDV = 1.462, THDI = 0.4179
3.5) After application of PWM Signals
After application of PWM Signals THDV = 0.60, THDI = 0.20
3.6) 12 Pulse Converter
For 12 Pulse Converter THDV = 1.37, THDI = 1.95
3.7) 24 Pulse Converter
For 24 Pulse Converter THDV =1.30, THDI = 1.93
3.8) 36 Pulse Converter
For 36 Pulse Converter THDV =1.26 ,THDI = 1.94
3.9) 48 Pulse Converter
For 48 Pulse Converter THDV =1.02,THDI =2.32
3.10) 96 Pulse Converter
For 96 Pulse Converter THDV =1.36,THDI =2.00
Table 1 Comparison of THDI for Multipulse convertersRating of Motor in
HP
4 pulse Converte
r
6 pulse Converte
r
12 pulse Converte
r
24 pulse Converte
r
36 pulse Converte
r
48 pulse Converte
r
96 pulse Converte
r
%THDI %THDI %THDI %THDI %THDI %THDI %THDI
5 37.16 3.11 2.46 2.40 2.31 2.47 2.3810 7.24 3.11 2.78 2.44 2.13 2.44 2.1920 6.42 1.67 2.22 2.20 2.03 2.38 2.0430 5.92 2.56 2.06 2.04 1.96 1.94 1.9840 6.26 2.41 1.95 1.93 1.92 2.35 1.98
Table 2 Comparison of THDV for Multipulse convertersRating of Motor in
HP
4 pulse Converte
r
6 pulse Converte
r
12 pulse Converte
r
24 pulse Converte
r
36 pulse Converte
r
48 pulse Converte
r
96 pulse Converte
r
%THDV %THDV %THDV %THDV %THDV %THDV %THDV
5 6.35 1.51 1.30 1.15 1.03 1.07 1.1110 6.33 1.51 2.07 1.46 1.07 1.07 1.1120 7.21 2.79 1.50 1.37 1.14 1.07 1.1630 6.34 1.60 1.43 1.34 1.2 1.20 1.2540 5.11 1.53 1.37 1.30 1.24 1.04 1.34
Plot of %THDI vs Different Rating(in HP) of DC Motor
Plot of %THDV vs Different Rating(in HP) of DC Motor
4. CONCLUSION
Power Quality related issues, and various harmonic suppression
techniques are discussed in detail. The reduction techniques such as passive filter,
shunt active filter and multipulse converters are simulated using Matlab/Simulink.
From the simulated results, it’s found that quality of power has improved after
application of filters. For multipulse converters with increase in number of pulses,
the total harmonic distortion has reduced and thus quality of power is improved. And
it’s also found that the power quality parameters such as THDV and THDI has
reduced for large DC motor loads.
REFERENCES
[1] John N. Chiasson, Leon M. Tolbert, Keith J. McKenzie, Zhong Du, A Complete Solution to the Harmonic Elimination Problem, IEEE Transactions on Power Electronics, vol. 19, no. 2, march 2004 (491-499).
[2] M.Izhar, C.M.Hadzer,S.Masri and S.Idris, A Study of the Fundamental Principles to Power System Harmonic, National Power and Energy Conference 2003 Proceedings, BangiMalaysia. (Page no: 225-231). [3] Tony Hoevenaars, Kurt LeDoux, Matt Colosino, Interpreting IEEE Std 519 and Meeting its Harmonic Limits in VFD Applications, Paper No. PCIC-2003-15. [4] Math H J Bollen, “Understanding Power Quality Problems; Voltage sags and interruptions”, Wiley India, 2011.
[5] Roger C Dugan, et.al, “Electrical power Systems Quality”,3rd Edition, TMH, 2012.
THANK YOU