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2011
Conference Paper
Titel
A new EMC DC line impedance stabilization network
Abstract
EMC emission measurements on photovoltaic inverters are carried out according to the generic standard IEC61000-6-3. Since edition 2.0 published in 2006, changes have been made in the test setup for conducted radiofrequency measurements. The DC-side of the inverter shall be connected with a CISPR AC-Line Impedance Stabilization Network (LISN). In the first edition, a 150 Ohm LISN according to IEC50022 has been prescribed. Many AC-LISN available on the EMC market include large earth capacities between the lines and PE. For many transformerless inverters, these large capacities in the range of several microfarads will lead to malfunctions or saturation effects in the EMC filters which will never occur if the inverter is connected to a photovoltaic generator whose earth capacity is orders of magnitude lower. Because of these facts, an EMC test according to the actual edition of EN 61000-6-3 on transformerless photovoltaic Inverters is not possible anymore. This disadvantage of the standardization has been discovered in 2007 by Fraunhofer IWES. The investigation results have been discussed with members of national and international standardization organizations. As an overcoming of this disadvantage, a new test setup and a special PV-LISN will be included in the next edition of CISPR11/IEC55011.