TDK Technologies & Products Press Conference 2014
LeaXield™ – active filter for leakage current
minimization
Andrew Tucker
Automotive & Power Conversion Solutions
Magnetics Business Group
In conventional converter-based power drive systems with long motor cables, very high earth
leakage currents can occur in standard three-phase industrial power grids. They are caused
by capacitive coupling between PE and the system components, which include the EMC
input filter, the frequency converter, the motor cable and the motor itself. In addition, the
leakage current has a broad range of spectral components, the aggregate of which can trip
the RCD (residual current device). The consequences may include expensive downtimes for
production machines.
LeaXield minimizes leakage currents
The EPCOS LeaXield™ is an innovative solution designed to minimize earth leakage
currents which avoids these problems. The add-on module is connected between the grid
and the EMC input filter. LeaXield detects the common-mode currents on the load-side via a
current sensing transformer. It then feeds an inverse of these currents via an amplifier and a
capacitor network to the power line to produce almost complete cancellation of the leakage
currents. LeaXield is suitable for all applications, in which converter-generated leakage
currents can trip the RCD, especially in the frequency range from 1 kHz to approximately
500 kHz.
LeaXield is now designed for rated currents of up to 150 A for 3-phase grids at frequencies of
50/60 Hz and a rated voltage of 520 V AC. The new active filter can be used in systems with
leakage currents of up to 1000 mA. LeaXield types for higher leakages currents and higher
rated currents are in development. LeaXield active filter modules do not need an additional
power supply.
LeaXield improves EMC
The reduction of the common-mode currents has a further positive effect: Conductive EMC,
which must be ensured at frequencies between 150 kHz to 30 MHz, can be improved
significantly in the range up to 500 kHz. Under typical test conditions LeaXield was thus able
to improve the EMC performance of a power drive system from category C2 to category C1
(EN 61800-3:2004+A1:2012). LeaXield is also effective in the range below 150 kHz,
achieving high attenuation of up to 30 dB at 4 kHz and up to 40 dB at 10 kHz.
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The EPCOS LeaXield module can be retrofitted to existing converter-based installations in
order to improve their EMC and the RCD compatibility of the power drive system. Moreover,
LeaXield circuits can be integrated into new EMC filter solutions in order to downsize the
expensive current-compensated filter chokes.
----You can download this text, the related presentation charts, and associated images from
www.epcos.com/tpc14.
For further information on the products contact Sales at www.epcos.com/inquiry.
Please forward reader inquiries to marketing.communications@epcos.com.
----Contacts for regional media
Region
Contact
Phone
Mail
+65 6597 0618
klaus.unterweger@epcos.com
ASEAN
Mr. K. UNTERWEGER
EPCOS PTE LTD
SINGAPORE
Greater
China
Ms. S. SUEN
EPCOS LTD
HONG KONG
+852 3669 8224
stella.suen@epcos.com
Europe
Mr. C. JEHLE
EPCOS
Munich, GERMANY
+49 89 54020 2441
christoph.jehle@epcos.com
India
Mr. G. DALVI
EPCOS India Private Ltd.
Mumbai, INDIA
+91 22 2575 0804
girish.dalvi@epcos.com
Japan
Ms. M. MIYAUCHI
TDK Corporation
Tokyo, Japan
+813 6852 7102
pr@jp.tdk.com
North
America
Ms. S. McSHEA
EPCOS Inc.
Greenville, SC, USA
+1 864 232 4240
mcsheacp4@aol.com
South
America
Mr. C. DALL’AGNOL
EPCOS do Brasil Ltda.
Gravataí, BRAZIL
+55 51 3484 7158
candido.dallagnol@epcos.com
TDK Corporation
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