how to correct harmonics in power supply when we use a lot of non linera devices

1. CORRECTION IN POWER
SUPPLIES FEEDING
NON-LINEAR LOADS
GUIDED BY:-MS.BINODINEE SWAIN
PRESENTATED BY:-
SOURAV SAHOO(1601105336)
SHUBHAM MOHANTY(1601105324)
RAHUL BEHERA(1721105011)
CHINMAYA MAHARANA(1721105043)

2. LITERATURE OVERVIEW
Harmonic Correction in Power Supplies
Feeding Non- Linear Loads
Panagiotis Dimitriadis,Brunel University,
London panosdimel@gmail.com &
Mohamed Darwish,Brunel University, London
Mohamed.Darwish@brunel.ac.uk
978-1-4799-6557-1/14 ©2014 IEEE
This paper focuses on the design of an
electronic circuit which can be used in
conjunction with the power supplies used
at the input of non-linear loads
(computers, TV sets, etc.) in order to filter
out the input current harmonics in such
loads.
A New Phase Shift Full Bridge LLC Resonant
Converter with Auxiliary Circuit
Li-Ting Chou and Chih-Chiang Hua
Electrical Engineering Department, National
Yunlin University of Science and Technology,
Yunlin, Taiwan
Email: {m10712001, huacc}@yuntech.edu.tw
A new Phase-Shift Full-Bridge LLC auxiliary
circuit converter (PSFBLLC) controlled by
phase-shift pulse width modulation and
LLC resonance is proposed in this paper.
Design and Implementation of Cosine
Control
Firing Scheme for Single Phase Fully
Controlled
Present paper deals with design and
implementation of cosine control firing
scheme for single phase fully controlled
rectifier with desired results simulated in

3. CONTENTS
Introduction
Current Distortion Caused By Non-linear Load
Harmonics Sources and Effects
Harmonic Compensation Schemes
Shunt Active Power Filter
Comparative Analysis
Conclusion
References

4. INTRODUCTION
The Use Of The Nonlinear Load Creates Harmonics In Current
Waveform. This Degrades The Power Quality And Thus Mitigation Is
Needed.
 Total Harmonic Distortion Need To Be Maintained With In The
Power Quality Guide Lines. Hence, Presently A Harmonic Correction
Mechanism Is Designed To Reduce The Effect Created By The
Nonlinear Loads.
The Proposed Method Is Based On The Active Power Filter
Mechanism, And The Performances Are Validated Using The Thd
Waveforms.

5. CURRENT DISTORTION CAUSED BY NON-
LINEAR LOADThis Circuit Is A Typical Bridge Rectifier Circuit.
Small Distributed Loads With Switched –Mode Power Supplies At Their Inputs
Add Up To A Large Increase Amount Harmonic Current Injected In Distribution
SYSTEM.

6.  A smoothing
capacitor is usually
used to filter out
the output voltage.
However this causes the
input current to be
discontinuous and full of
odd order harmonics

7. HARMONICS SOURCES AND EFFECTS
Sources Effects
1. Non-Linear Power electronic
Devices
2. Saturated Core Transformer
3. Uninterrupted Power
Supply(UPS)
4. Adjustable Speed Drives etc.
1. Overheating of transformer
2. Excessive neutral Current
3. Low power factor and
excessive copper and core
losses
4. Malfunction of sensitive
Equipment

8. Harmonic Compensation Schemes
Due to wide range of semiconductor and other non-linear devices,
power quality has come down in the source.
Also called Harmonics pollution.
Two type of Harmonics are present which are:
Characteristic
Harmonic
Non-Characteristic
Harmonic
i. These are always present in
the system even the system
is purely ideal and balanced
ii. Their magnitude decrease
with increase in order of
harmonic
iii. Usually even harmonics are
ignored because of their
dying nature due to
i. Harmonic of the order other
than characteristic harmonics
are termed as non-
characteristic harmonic
ii. Occur due to unbalance and
distortion in AC voltages and
unequal transformer leakage
impedances
iii. Also called residual

9. Shunt Active Power
Filter
 It consist of a voltage source
inverter (VSI) shunted with capacitor
 Voltage across capacitor is termed
as dc-link voltage and needs to be
constant for proper operation of
filter
 The filter, non-linear load and the
source are connected at point of
common coupling (PCC)
Basic diagram of shunt APF for current harmonic compensation

10. Contd..
The firing pulses are provided to the inverter which is generated
using the control block
The dc-link voltage, source and filter current are sensed and passed
to the control block for generating the firing pulses
The basic idea of operation is that when any nonlinear load demands
non-linear current from source, it has to supply that current when
filter is not used
But when filter scheme like shunt active power filter is being used in
the system, it supply the harmonic of the current where as supply
provides the sinusoidal current.

11. Contd..
Fig : APF non-linear

12. Comparative Analysis
THD linear load THD non-linear load

13. Contd..
THD compensated non-linear load

14. Comparison Of Voltage And Current
Linear voltage_ current
Non-linear voltage _current
Compensated voltage_ current

15. Conclusion
The application of the semiconductors in the switching mode
power manipulation, like diode rectifier power supply with filtering
capacitance, results to the distortion of the supply-source current
In the case where there is high power distribution systems like
buildings with many non-linear loads, as tv’s, computers, printers,
ups’s etc. One compensator circuit located between mains supply
and input of the ac/dc converter is enough, after controlling -
adjusting the complementary source current related to the final
distorted one

16. REFERENCE
JOURNALS REFERRED:
Harmonic Correction In Power Supplies Feeding Non- Linear Loads
Panagiotis Dimitriadis,brunel University, London Panosdimel@gmail.Com &
Mohamed Darwish,brunel University, London
Mohamed.Darwish@brunel.Ac.Uk 978-1-4799-6557-1/14 ©2014 IEEE
Design And Implementation Of Cosine Control Firing Scheme For Single Phase Fully
Controlled Bridge Rectifier
Mukesh Gupta, Sachin Kumar And Vagicharla Karthik
Darwish, “Harmonic Filters - Passive & Active Filters And Future
Developments”, Brunel Unmohamediversity WEST LONDON, School Of
Engineering And Design, 2012.
S.G.; Kianinezhad, R.; Ghasemi, A.; Monadi. , "Quality Improvement
Of Shunt Active Power Filter, Using Optimized Tuned Harmonic
Passive Filters," Power Electronics,electrical Drives, Automation And

17. Contd..
Vic Gosbell. “Harmonic Distortion In The Electrical Supply
System,” PQC Tech Note No. 3 (Power Quality Centre), Elliot Sound
Products. Http://Sound.Westhost.Com/Lamps/Technote3.Pdf
Rachid Belaidi, “Shunt Active Power Filter Connected To A
Photovoltaic Array For Compensating Harmonics And Reactive
Power Simultaneously” 4th International Conference On Power
Engineering, Energy And Electrical Drives Istanbul, 13-17 May
2013 IEEE, Turkey