DE102007029889A1 - Network filter i.e. radio interference filter, for e.g. power converter, has low-pass circuit enclosed by sealing compound such that only network-and current-inverter-sided connections are projected - Google Patents

Abstract

The filter has x and y-capacitors, bar-core chokes, current-compensated choke, where filter units are interconnected as low-pass circuit that is enclosed by a sealing compound in such a manner that only network-and current-inverter-sided connections are projected. The sealing compound is covered with an electrically conductive layer, which is covered with a sealant. The sealing compound is arbitrarily formed. An electrical layer is provided by an electromagnetic compatibility (EMV) spray.

Description

The The invention relates to a line filter according to the preamble of claim 1.

From the manual of Georg Durcansky with the title "EMC-compliant device design - basics and design of low-interference electronics" from 1991, especially pages 340 to 346 , it is known that a filter is to be provided for the suppression of disturbing influences. A widely used filter is the line filter. The filter elements of such a network filter are interconnected as a low-pass filter. As filter elements, transverse capacitances (X or Y capacitors) and longitudinal inductors (rod or toroidal core chokes) are used. For the suppression of symmetrical interference components usually non-compensating connected rod capacitors are used. The suppression of asymmetric interference components is usually done by means of current-compensated chokes.

From the publication titled "Radio interference suppression of electronic devices", published in the German journal "antriebstechnik", Volume 36, 1997, No. 11, pages 64 to 66 , is a filter configuration for a power electronic device such. As converter or switching power supply, known. This filter, which is also referred to as a radio interference filter, in addition to a current-compensated choke also rod core chokes. Between each output line of this filter and a conductor, which is linked to ground potential, a Y-capacitor is connected. In addition, each output line and each power line are connected to an X-capacitor, these power and output side capacitors are each electrically connected in a star. The two star points are each connected to ground potential by means of a Y capacitor.

From the device manual "SINAMICS S120 AC Drive", Edition 03/2006, in particular the chapter "Mains Power Components" It is known that a line filter or a radio interference suppression filter is connected on the output side to inputs of an inverter or to inputs of a line reactor whose outputs are linked to inputs of an inverter. The circuit of the mains filter is housed in a metal housing, for example made of sheet steel or aluminum sheet, this circuit is cast in this metal housing. The metal housing is cuboid and has, for example in the size A following dimensions 200 × 73 × 44 mm. On this metal housing of the mains filter, the housing of a converter is mounted such that these two housings are electrically connected to each other.

Should the metal housing of a mains filter has a high degree of protection, For example, IP 56, so the cost increases for this metal case. An inverter with associated Line filters, as shown in the device manual, for example housed in a control cabinet. Due to the increasingly dense Cabinets are not always possible provided with a rear-mounted line filter To accommodate frequency converter in such a cabinet.

Of the The invention is therefore based on the object of specifying a line filter, which has a high degree of protection and in an existing space is customizable.

These The object is achieved with the characterizing features of claim 1 according to the invention.

Thereby, that the potting compound of the low-pass circuit of the line filter with an electrically conductive layer is coated, in turn Covered with a seal is used for the low pass circuit no metal housing needed anymore. That is, the potting compound can be any three-dimensional Taking form. This allows any desired sign for the filter can be implemented inexpensively. It also shows that Net filter according to the invention a high degree of protection on, because the low-pass circuit surrounded in such a way with a potting compound is that only the mains and power converter side connections sticking out of this. The outer surface of this Potting compound is coated with an electrically conductive layer. For this purpose, an EMC spray or an EMC varnish can be used. After this This EMC layer is dried, protects against mechanical Stress sealed this EMC layer. For sealing, for example Resin used, the layer thickness is not fixed. Around giving the potting compound a predetermined design becomes a shape in particular a silicone mold, with the desired design created in which the low-pass circuit is shed. after the Curing compound is cured, the silicone mold can be easy subtracted from.

By receives the embodiment of the invention a mains filter or an EMC filter that provides a high degree of protection and has an arbitrary design. This can one such a net filter without much effort on Adapt the device design of a converter. There is also the possibility of a remaining To be able to use space within a control cabinet thereby. By omitting the metal housing also decreases the weight of this net filter. As the numbers of a Net filters are rather small, the price of a network filter according to the invention is reduced opposite a commercially available line filter, However, the degree of protection has increased significantly.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited non-patent literature

• - Georg Durcansky with the title "EMC-compliant device design - basics and design of low-interference electronics" from 1991, especially pages 340 to 346 [0002]
• - "Radio interference suppression of power electronic devices", published in the German journal "antriebstechnik", Volume 36, 1997, No. 11, pages 64 to 66 [0003]
• - "SINAMICS S120 AC Drive", Edition 03/2006, in particular the chapter "Mains Power Components" [0004]

Claims (5)

Line filter with X and Y capacitors, rod core chokes and a current-compensated choke, these filter elements are connected as a low-pass filter, and wherein this low-pass circuit is surrounded with a potting compound such that their connections protrude, characterized in that this potting compound with an electrically conductive layer coated, which in turn is coated with a seal. Line filter according to Claim 1, characterized that the potting compound is arbitrarily shaped. Line filter according to Claim 1, characterized that the electrical layer is created by means of an EMC spray. Line filter according to Claim 1 or 2, characterized that the electrical layer is created by means of an EMC varnish. Line filter according to one of the preceding claims, characterized in that as a seal resin is provided.