For internal use only / © Siemens AG 2010. All Rights Reserved.
Low Harmonics
Frequency Convertors
Patrick New, Siemens nv / SA
Product Manager Drive Technologies
© Siemens AG 2010. All Rights Reserved.Page 2 10/06/2010 Howest - Lemcko
Line harmonics
Definition
Electrical loads with non-linear characteristics connected to a line
power supply with sinusoidal voltage source (generator,
transformer) draws a non-sinusoidal current that distorts the
voltage at the line supply connection point - PCC (Point of
Common Coupling).
Harmonics cause a voltage drop at the transformer and
disturb other loads at the PCC
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Line harmonics
Definition
According to Fourier, a non-sinusoidal
signal can be decomposed in a sum of
some of its multiple in frequency called
harmonics
© Siemens AG 2010. All Rights Reserved.Page 4 10/06/2010 Howest - Lemcko
Line harmonics
International standard
IEEE 519 – 1992
Sets limits for voltage and current harmonics both for the
individual consumer and for the connection point (PCC)
Used in:
Europe
USA & Canada
Many parts of Asia
Isc/ILoad Vk < 11 11< h < 17 17 < h < 23 23 < h < 35 35 < h THD
< 20 >5% 4.0 2.0 1.5 0.6 0.3 5 %
20 < 50 5%-2% 7.0 3.5 2.5 1.0 0.5 8 %
> 50 <2% 10.0 4.5 4.0 1.5 0.7 12 %
IEEE 519-1992 Maximum Harmonic Current Distortion in Percent of ILoad
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Line harmonics
International standard
EN 61000-2-4
Compatibility Levels for Low-Frequency
Conducted Disturbances in Industrial Plants
EN 61000-2-4 does not define limits for harmonic currents.
Limits are specified only for harmonic voltages and the total
harmonic distortion of the voltage THD(V).
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Line harmonics
6-pulse frequency converter
Line side Converter side
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Line harmonics
6-pulse system
6-pulse rectifier circuits, only generate odd currents and harmonic
voltages that cannot be divided by 3:
h = n * 6 ± 1 where n = 1, 2, 3, ...
h = 5, 7, 11, 13, 17, 19, 23, 25, 29, 31, 35, 37, 41, ...
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Line harmonics
Improvement of a 6-pulse system
Insertion of a line reactor to improve the waveform
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Line harmonics
Relative short-circuit power on a 6-pulse system
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Line harmonics
12-pulse system
The 30° phase shift in the transformer compensates
h = 5, 7, 17, 19, 29, 31, ... , so that only odd harmonic currents and
voltages that cannot be divided by 3 remain:
h = n * 12 ± 1 where n = 1, 2, 3, ...
h = 11, 13, 23, 25, 35, 37, 47, 49, ...
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Line harmonics
Spectral harmonics representation of a12-pulse system
18-, 24-, 36-pulse systems reduce harmonics generation even
more
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Line harmonics
Active Front End system (AFE)
Main features:
Actively-pulsed feeding / regenerative supply (4Q)
Full IGBT inverter, with a constant & controlled DC link voltage
The clean power filter ensures an almost sinusoidal power
consumption and very few system perturbations
Power factor compensation (cos φ ≈ 1)
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Clean power frequency converter
Integration of an efficient Line Harmonic Filter (LHF)
LCM LHF
compact
Power
Module
+
SINAMICS G150
Clean PowerSINAMICS
G150LHF compact
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Integrated line harmonics filter
Design
The converter-side harmonic absorber is tuned to the 5th
current harmonic and filters it almost entirely. The 7th, 11th and
13th harmonics are also noticeably reduced.
The line-side harmonic absorber is tuned to the non-existent 3rd
harmonic so that the line is only partially filtered.
Line ReactorSupply
Inductance
Supply
PCC
U = 2% k
LHF Converter
Number n of the Harmonic Current
1 3 5 7 11 13
Line-side Filter
Characteristics Converter-side
Filter
Characteristics
The filter is made up of a line-side and a converter-side
harmonic absorber:
© Siemens AG 2010. All Rights Reserved.Page 15 10/06/2010 Howest - Lemcko
Integrated line harmonics filter
Harmonics rejection
0
20
40
60
80
100
1 3 5 7 9 11 13 15 17 19 21 23 250
20
40
60
80
100
1 3 5 7 9 11 13 15 17 19 21 23 25
Converter-side
Current
Harmonics
(THD(I) = 25% - 50%)
Filter
Line-side
Current
Harmonics
(THD(I) = 5% - 7.5%)
Significant reduction of harmonics according to IEEE519
© Siemens AG 2010. All Rights Reserved.Page 16 10/06/2010 Howest - Lemcko
Customer benefits
Energy savings with Line Harmonics Filter
Power losses (kW) 380...480V
0
10
20
30
40
50
110 132 160 200 250 315 400 630 900 kW
G150 Clean
Pow er
Avg AFE
Energy cost - Savings (€/a)(0,08€/kWh, 8.000 h/a)
0
2.000
4.000
6.000
8.000
10.000
110 132 160 200 250 315 400 630 900 kW
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Integrated line harmonics filter
Cost reduction
PCC
G130 / G150
with 6-pulse
rectifier
U = 2% k
Line
Harmonics
Filter
LHFLine
Reactor
Point of
Common
Coupling (PCC)
~~
External, Line-
side Fuse
Main
Contactor
Integration in the single cabinet = easy installation
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Integrated line harmonics filter
Additional benefits
Passive components, MTBF ≈ > 75% higher than an AFE
Higher efficiency compared to active filter technologies
An additional line reactor is eliminated
Less motor stress (voltage peaks, insulation, bearing currents)
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Line harmonics reduction systems
Performance overview
Complexity
Harm
onic
s
G150 Clean
Power
6-pulse
12-pulse
18-pulse
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Line harmonics reduction systems
General conditions using passive filters
Used in weak supplies with uk ≥ 5%
Line harmonics are reduced, however, the level specified by IEEE519 is
not achieved
Used in extremely weak line supplies with uk ≥ 10% (e.g. ships or a UPS)
The resonance frequency of the filter can be significantly detuned, so that
the basic fundamental of the input voltage increases significantly – and
goes outside the permissible tolerance limits.
cos φ is shifted into the partial load range
Capacitive reactive power is drawn in the partial load range.
HOWEVER: Line supplies are generally pre-loaded as a result of
inductive reactive power, which LHF partially compensate
If general conditions prevent the use of an LHF, then an AFE is always a solution!
© Siemens AG 2010. All Rights Reserved.Page 21 10/06/2010 Howest - Lemcko
Line harmonics reduction systems
Best of breed solution selection scheme
Converter with low line harmonics
SINAMICS S150 w. AFESINAMICS G150 Clean Power
Energy recovery required Weak supply line, cos φNo
Yes
For internal use only / © Siemens AG 2010. All Rights Reserved.
Thank you for your attention!
Siemens nv / SA
Patrick New
Product Manager Drive Technologies
Square Marie Curie, 30
B-1070 Brussels
Tel: +32 2 536 69 34
Mail: [email protected]