DE102019133954A1 - Arrangement for filtering disturbances - Google Patents

Abstract

The invention, which relates to an arrangement (1) for filtering interference, is based on the object of specifying an arrangement (1) with which interference caused by a switching operation of a power semiconductor switch (5) is reduced, thus reducing electromagnetic interference (EMC). and switching losses of the power semiconductor switches (5) are reduced. This object is achieved in that at least one filter element (3) is arranged on an additional circuit board (10) that spring elements (13) are arranged on the additional circuit board (10), which is electrically conductively connected to the filter element (3), that the additional circuit board (10) with the spring elements (13) is arranged opposite the connecting wires (7) of at least two power semiconductor switches (5) in such a way that the at least one filter element (3) via the spring elements (13) has at least one connecting wire (7) each power semiconductor switch (5) contacted.

Description

The invention relates to an arrangement for filtering interference, which has at least one filter element, the filter element being connected to at least one connecting wire of a power semiconductor switch.

It is known from the prior art to use electrical switches or semiconductor switches in electrical devices in order, for example, to switch on or switch off voltages for components or assemblies. Such an electrical device can be, for example, an inverter for an electrical refrigerant compressor in a vehicle. If such electrical devices are supplied with larger currents, for example in the range of more than 1.00 amperes, power semiconductor switches are used.

So-called parasitic inductances of such power semiconductor switches, such as, for example, IGBTs or MOSFETs, cause disruptive oscillations when a power semiconductor switch is switched, in particular in conjunction with parasitic capacitances. Such inductances are formed by the connecting wires of the power semiconductor switches if they are implemented, for example, in a TO-247 housing.

Measurements show that voltages are induced, in particular during switching operations of the power semiconductor switches, and such disturbances are caused. Such disturbances have an effect, for example, on what is known as electromagnetic compatibility (EMC), which describes the property of a device or assembly to disrupt other devices through undesired electrical or electromagnetic effects, such as the vibrations that occur during a switching process. Switching processes are meant here which lead to a current that changes over time.

The basic task is therefore to filter out such interference in order to improve the electromagnetic compatibility.

In addition, due to the occurrence of such disturbances and overvoltages, a breakdown voltage must be selected for the power semiconductor switches which is sufficiently large to ensure that the power semiconductor switches function reliably.

To reduce such overvoltages, it can be provided that the switching process of the power semiconductor switch takes place more slowly. However, this results in higher losses, with the efficiency of the device or the assembly falling and a greater amount of heat being generated. This greater heat development causes an increased need for suitable cooling of the power semiconductor switches.

It is therefore known to arrange filter elements such as capacitors or RC filters, for example on a circuit board on which the power semiconductor switches are arranged, in order to reduce the disturbing vibrations that arise.

From WO 2010/136257 an overvoltage protection device for inverters with an input-side EMC filter is known. The object is to provide an overvoltage protection device for an inverter for feeding electrical energy from a direct voltage source into an alternating current network, with which all electronic and electrical components of the inverter are effectively and cost-effectively protected from transient overvoltages and their consequences.

To solve this, it is provided that in the disclosed overvoltage protection device, the overvoltage arresters for diverting overvoltages relative to earth are connected to the current-carrying lines of the inverter behind the EMC filter, as seen from the DC voltage source. The surge arresters can also divert surge voltages that are caused by stimuli from the EMC filter as a result of transient surge voltages and also protect the inverter from these surge voltages.

A disadvantage of such solutions, however, is that due to the length of the connecting wires of the power semiconductor switches, for example in a TO-247 housing form, the formation of the parasitic inductance cannot be sufficiently prevented.

There is thus a need to improve the solutions known from the prior art for filtering such disturbances during a switching operation of a power semiconductor switch.

The object of the invention is to provide an arrangement for filtering interference, with which interference caused by a switching operation of a power semiconductor switch is reduced, with the result that electromagnetic interference (EMC) and switching losses of the power semiconductor switch are reduced.

In addition, the improved arrangement for filtering interference is intended to enable the power semiconductor switches to be switched more quickly and performance losses due to slow switching operations can be avoided.

The object is achieved by an object with the features according to claim 1 of the independent claims. Further developments are given in the dependent claims.

In the solution of the inventive arrangement for filtering interference, provision is made for an additional circuit board with filter elements, such as capacitors, to be placed as close as possible to the housing of one or more power semiconductor switches. Such a placement takes place, for example, in a TO 247 housing of a power semiconductor switch with three connecting wires in such a way that contact with the filter elements arranged on the additional circuit board is made directly on the connecting wire emerging from the TO 247 housing.

Thus, the contact is made much earlier than in the prior art, which makes contact with a filter element only on a main circuit board or a main circuit board, which leads to a significant reduction in the line length between the semiconductor chip in the power semiconductor switch and the filter element. This reduction in the line length effectively reduces the formation of parasitic inductances in the connecting wires. As is known, according to the state of the art, the entire line length from the semiconductor chip in the power semiconductor switch is available, starting over the connecting wire and ending with a contact point, such as a soldering point, on the motherboard for the formation of parasitic inductances.

It is intended to establish contact between the connecting wire emerging from the housing of the semiconductor switch and the additional circuit board containing the filter elements by means of a clamp connection. For this purpose, the additional board is provided, for example, with resilient connections or spring elements. The additional circuit board is arranged in such a way that the spring elements are in contact with at least one connecting wire of the power semiconductor switch. For this purpose, the additional circuit board is arranged in such a way that the spring element makes contact with the connection wire while being slightly under spring tension and in this way secure contact is ensured between the spring element and the connection wire.

It is provided that at least one connecting wire of the power semiconductor switch is contacted via the spring element with the filter element arranged on the additional circuit board. In one embodiment, this can be the emitter of the power semiconductor switch. In an alternative embodiment, this can be the collector of the power semiconductor switch. Furthermore, it is also possible for both the emitter and the collector of a power semiconductor switch to be contacted. In a special embodiment it is provided that the emitter of a first power semiconductor switch and the collector of a second power semiconductor switch or the collector of a first power semiconductor switch and the emitter of a second power semiconductor switch are contacted.

In a special embodiment, two or more connecting wires of the power semiconductor switch can be contacted via the spring elements with the filter elements arranged on the additional circuit board. For example, the emitter and the collector of the power semiconductor switch can be contacted by means of spring elements.

The filter elements arranged on the additional circuit board can be, for example, a capacitance or a damping element consisting of a resistor and a capacitance.

In terms of circuitry, these filter elements can be arranged in such a way that they act between two connections of the power semiconductor switch, such as the emitter and the collector. Alternatively, the filter elements can also act between a connection of the power semiconductor switch and a positive operating voltage U +, a negative operating voltage U- or a ground potential GND.

It is also provided that connecting wires of two or more power semiconductor switches are connected to filter elements on an additional circuit board via spring elements. A simultaneous connection of connections of several power semiconductor switches enables the use of the additional board in assemblies in which several power semiconductor switches are arranged. An inverter for an electric refrigerant compressor in a vehicle can be cited as an example of such an assembly. In such an assembly, for example, a high-side power semiconductor switch and a low-side power semiconductor switch, that is to say a total of six power semiconductor switches, can be arranged in three so-called half bridges.

If, for example, two power semiconductor switches are arranged so that they are aligned on a surface, such as a cooling surface, that the connecting wires of two power semiconductor switches are aligned at least relative to one another, a single additional circuit board can corresponding spring elements a contact can be made to connecting wires of both power semiconductor switches. The additional board is thus located in an area between the two power semiconductor switches.

An offset such that the additional board is arranged in a plane, for example above the power semiconductor switches, can be provided, the spring elements being designed such that they protrude into the plane of the connections of the power semiconductor switches.

If, for example, three pairs of these two power semiconductor switches described are arranged so that they are aligned on a surface, such as a cooling surface, that the connecting wires are aligned in pairs, it is possible to use the spring elements of an additional circuit board to contact the desired connecting wires of all six power semiconductor switches .

In any case, an offset of the power semiconductor switches to one another or a rotation of the power semiconductor switches deviating from a common center line is permissible within certain tolerances and sometimes also necessary in order to be able to arrange all spring elements on an additional circuit board. An offset of the power semiconductor switches to each other also helps to maintain the prescribed and necessary isolation distances between the components.

This special design of the arrangement for filtering interference with an additional circuit board with appropriate spring elements and filter elements significantly reduces EMC interference through shorter cable lengths and also leads to a reduction in overvoltages caused by parasitic inductance of the connecting wires of the power semiconductor switches. The line length means the path between the semiconductor chip in the housing of the power semiconductor and the filter element.

• 1: eine Anordnung zur Filterung von Störungen aus dem Stand der Technik,
• 2: eine beispielhafte erfindungsgemäße Anordnung zur Filterung von Störungen mit einer zusätzlichen Platine,
• 3: eine Anordnung einer zusätzlichen Platine mit entsprechenden Federelementen und Federelementen sowie zugehörigen Leistungs-Halbleiterschaltern auf einer Oberfläche eines Gehäuses eines elektrischen Kältemittelverdichters in einer Draufsicht,
• 4: eine Anordnung einer zusätzlichen Platine mit entsprechenden Federelementen und Federelementen sowie zugehörigen Leistungs-Halbleiterschaltern auf einer Oberfläche eines Gehäuses eines elektrischen Kältemittelverdichters in einer Seitenansicht und
• 5: ein Diagramm eines messtechnischen Vergleichs der erfindungsgemäßen Anordnung zur Filterung von Störungen mit einer Stand-der-Technik-Anordnung.

Further details, features and advantages of embodiments of the invention emerge from the following description of exemplary embodiments with reference to the associated drawings. Show it:

• 1 : an arrangement for filtering interferences from the state of the art,
• 2 : an exemplary arrangement according to the invention for filtering interference with an additional circuit board,
• 3 : an arrangement of an additional board with corresponding spring elements and spring elements and associated power semiconductor switches on a surface of a housing of an electric refrigerant compressor in a plan view,
• 4th : an arrangement of an additional board with corresponding spring elements and spring elements and associated power semiconductor switches on a surface of a housing of an electric refrigerant compressor in a side view and
• 5 : a diagram of a metrological comparison of the arrangement according to the invention for filtering interference with a prior-art arrangement.

1 shows an arrangement 1 'for filtering interference from the prior art. On a motherboard 2 are the filter elements provided for filtering interference 3 arranged. In addition to these filter elements 3 are on the motherboard 2 further components 4th arranged. These other components 4th are for the functionality of the motherboard 2 are important, but have no relevance to the present invention. For this reason, this is another component 4th not entered further. Such a motherboard 2 can, for example, be associated with an inverter in an electric refrigerant compressor and thus provide functionalities of an inverter.

In the 1 are below the motherboard 2 for example two power semiconductor switches 5 shown. These power semiconductor switches 5 have a cuboid TO 247 housing, which has a semiconductor chip arranged in the interior 6th of the power semiconductor switch 5 includes.

Such a power semiconductor switch 5 has, for example, three connecting wires 7th on which starting from the power semiconductor switch 5 in the example of 1 bent at an angle of 90 degrees to the motherboard 2 run away. Usually the connecting wires are 7th on the motherboard 2 by means of a solder connection with on the motherboard 2 arranged conductor runs, not shown, electrically connected.

An electrical connection between the semiconductor chip 6th of the power semiconductor switch 5 and the connecting wires 7th can for example by means of appropriate bonding wires inside the power semiconductor switch 5 be made, but is not shown in the figures.

Thus, the prior art has one line length 8th on which from the semiconductor chip 6th of the power semiconductor switch 5 to the motherboard 2 with the filter elements 3 runs. This relatively long line length 8th leads to relatively large parasitic inductances, which are the cause of the a switching operation of the power semiconductor switch 5 resulting disturbances.

In the example of the 1 become two of the connecting wires 7th of the left power semiconductor switch 5 partly by a fastening screw 9 covered, which is used to attach the motherboard 2 serves for example on a housing of a refrigerant compressor, not shown.

In the 2 is an exemplary arrangement according to the invention 1 to filter interference with an additional circuit board 10 shown. The motherboard shown 2 has further components 4th on which one is responsible for the functionality of the motherboard 2 are important.

Below the motherboard 2 are again two power semiconductor switches 5 shown. These power semiconductor switches 5 have a cuboid TO 247 housing, which has a semiconductor chip arranged in the interior 6th of the power semiconductor switch 5 includes.

The power semiconductor switches 5 again have three connecting wires 7th on which starting from the power semiconductor switch 5 bent at an angle of 90 degrees to the motherboard 2 run away.

The connecting wires 7th of the two power semiconductor switches 5 are aligned with each other. The connecting wires 7th both from the power semiconductor switch 5 each run starting from the power semiconductor switch 5 in a first area 11 almost parallel to the motherboard in front of your bend 2 and towards each other while the connecting wires 7th in a second area 12th parallel to each other after their bend and almost perpendicular to the motherboard 2 run until the connecting wires 7th the motherboard 2 reach, on which they are soldered, for example, to a corresponding conductor run.

It is planned to use an additional circuit board 10 to arrange on which one or more filter elements 3 are arranged. The additional board 10 has spring elements 13th on, by means of which an electrical contact between the connecting wires 7th and the one on the additional board 10 arranged filter elements 3 will be produced. In the example of the 2 is the additional board 10 almost parallel to the motherboard 2 aligned. Only one filter element is exemplary 3 on the additional board 10 shown. Of course, more filter elements can also be used as required 3 on the additional board 10 to be ordered. Such filter elements 3 can for example be a capacitance or a damping element consisting of a resistor and a capacitance.

The one on the additional board 10 arranged spring elements 13th for contacting the connecting wires 7th the power semiconductor switch 5 show in the example of 2 in the direction of the motherboard 2 and contact the two front connecting wires 7th from below, so to speak. The additional board 10 is attached in such a way that the spring elements 13th are under a slight mechanical tension, while the spring elements 13th the connecting wires 7th to contact. A means of securing the additional board 10 is in the 2 not shown.

This type of contacting of the connecting wires 7th in their first area 11 by means of a spring element 13th allows to compensate for tolerances, which components such as the power semiconductor switch 5 or the spring elements 13th exhibit. In addition, manufacturing or assembly-related tolerances, such as tolerances when bending the connecting wires or during assembly, are also compensated. Furthermore, temperature-related changes in the dimensions can also be compensated for.

In the example of the 2 is made by means of an additional circuit board 10 with corresponding spring elements 13th one connection wire each 7th of the two power semiconductor switches that are at least relatively aligned with one another 5 contacted. However, there is no restriction to this version.

For example, one or both power semiconductor switches 5 two or more connecting wires 7th by means of appropriate spring elements 13th to be contacted.

In addition, the connecting wires 7th of more than two power semiconductor switches 5 to be contacted. For example, one or more semiconductor switches 5 in each case the emitter and / or the collector are contacted, with a filter element 3 on the additional board 10 is arranged such that it acts to reduce interference between the emitter and / or the collector.

In one example, the lead wires 7th of six power semiconductor switches 5 be contacted, which are associated with an inverter assembly of an electric refrigerant compressor in a vehicle. In this case, for example, the two in the 2 power semiconductor switch shown 5 each arranged multiple times one behind the other, with an alignment of the connecting wires 7th can be preserved in pairs to each other.

Like it in the 2 can be clearly seen, the cable length is shortened 14th of the present invention significantly compared to the line length 8th according to the prior art, as this in the 1 is shown. This reduction in line length 14th is achieved by having a single additional board 10 with corresponding spring elements 13th , which a contacting of the connecting wires 7th both power semiconductor switches 5 enable in an area between the two power semiconductor switches 5 is arranged. The connecting wires are advantageous here 7th two power semiconductor switches 5 arranged at least substantially aligned with one another and thus extend into the area of the additional circuit board 10 .

A shortening of the line length 14th means that the distance between the semiconductor chip 6th in the power semiconductor switch 5 and the filter element 3 has decreased. As a result, the parasitic inductances that form are reduced and the filtering of the during a switching process of a power semiconductor switch is improved 5 resulting disturbances reached.

The 3 shows an arrangement of an additional board 10 with appropriate filter elements 3 and spring elements 13th as well as associated power semiconductor switches 5 on a surface 15th a housing 16 of an electric refrigerant compressor in a plan view.

An example is a case 16 an electric refrigerant compressor, although this is not a limitation. On an at least partially flat surface 15th six power semiconductor switches are arranged opposite one another in pairs 5 shown. These six power semiconductor switches 5 are for example associated with an inverter of the electric refrigerant compressor.

In the example of the 3 are the power semiconductor switches 5 by means of clamps 17th on the surface 15th arranged and attached. These clamps 17th enable quick assembly, but are not mandatory. Alternative fastening methods are possible.

Two of the power semiconductor switches each 5 are with a slight lateral offset to each other on the surface 15th arranged, with their connecting wires 7th to each other, in the area of the additional board 10 pointing, are arranged. An offset of the power semiconductor switches 5 like in the 3 shown and also an alignment at an angle to each other are possible as long as it can be guaranteed that the connecting wires 7th through those on the additional board 10 arranged spring elements 13th can be contacted.

In the 3 are the spring elements 13th not to be seen, as this is under the connecting wires 7th the power semiconductor switch 5 are arranged. In the 3 is also just the course of the connecting wires 7th in their first area 11 to recognize, since the course in the second area 12th in the direction of the viewer 3 lies. In practice this would be above the power semiconductor switches 5 and the additional board 10 the main circuit board 2 to be ordered. For the sake of clarity, the main circuit board is 2 in the 3 not shown.

In the 4th is an arrangement 1 to filter interference with an additional circuit board 10 with appropriate filter elements 3 and spring elements 13th as well as associated power semiconductor switches 5 on a surface 15th a housing 16 an electric refrigerant compressor shown in a side view.

The two power semiconductor switches shown 5 be on the surface 15th a housing 16 using appropriate clamps 17th kept what at least in the right part of the 4th is shown in full.

The power semiconductor switches 5 are aligned so that the connecting wires 7th in a first area 11 towards each other and parallel to the surface 15th run away. In the second area 12th the connecting wires run 7th the power semiconductor switch 5 parallel to each other and away from the surface 15th . Within the first area 11 become the connecting wires 7th by means of the illustrated s-shaped spring elements 13th contacted. About these spring elements 13th becomes an electrically conductive connection to the ones on the additional circuit board 10 arranged filter elements 3 produced. The one in the 4th motherboard shown only by means of a dash-dash line 2 becomes parallel to the additional board 10 and to the surface 15th and arranged at a distance from this.

5 shows a diagram of a metrological comparison of the arrangement according to the invention 1 for filtering interference with an arrangement known from the prior art 1' for filtering disturbances.

In the diagram of the 5 is the switching process of a power semiconductor 5 with the generated unwanted disturbances with its voltage amplitude in a time course. In this case, such a disruption according to the prior art is represented by means of a dot-dot line. When using the arrangement according to the invention 1 The switching process to be recorded with its fault is shown by a continuous line. Like it in the 5 can be clearly seen, the malfunction occurring with the arrangement according to the invention 1 much better attenuated. This means that the amplitude of the disturbance is significantly lower and, according to the invention, is only about half to a quarter of the value to be expected according to the prior art.

Thus, through the use of the arrangement according to the invention 1 to filter interference, the size of the EMC interference that occurs is significantly reduced. In addition, the interference is already close to its source in the area of the power semiconductor switches 5 attenuated and thus reach the motherboard 2 not to the extent known from the prior art.

Thanks to this improved damping of occurring disturbances, the power semiconductor switches can 5 can be switched quickly without any problems.

List of reference symbols

1, 1 '

Arrangement for filtering disturbances

2

Motherboard

3

Filter element

4th

further components

5

Power semiconductor switch

6th

Semiconductor chip in the power semiconductor switch

7th

Connecting wires

8th

State of the art line length

9

Fastening screw

10

additional board

11

first area

12th

second area

13th

Spring element

14th

Line length invention

15th

surface

16

Housing of a coolant compressor

17th

Clamp

Claims (9)

Arrangement (1) for filtering interference, which has at least one filter element (3), the filter element (3) being connected to at least one connecting wire (7) of a power semiconductor switch (5), characterized in that at least one filter element (3 ) is arranged on an additional board (10), that spring elements (13) are arranged on the additional board (10), electrically connected to the filter element (3), that the additional board (10) with the spring elements (13) is arranged opposite the connecting wires (7) of at least two power semiconductor switches (5) that the at least one filter element (3) contacts at least one connecting wire (7) of each power semiconductor switch (5) via the spring elements (13). Arrangement (1) according to Claim 1 , characterized in that the connection wires (7) are contacted by the spring elements (13) in a first area (11) of the connection wires (7). Arrangement (1) according to Claim 1 or 2 , characterized in that the first region (11) of the connecting wires (7), starting from a housing of the power semiconductor switch (5), comprises the first half of the connecting wires (7), in particular comprising a first third of the connecting wires (7). Arrangement (1) according to one of the Claims 1 to 3 , characterized in that the additional board (10) with the spring elements (13) is arranged opposite the connecting wires (7) of six power semiconductor switches (5), the power semiconductor switches (5) in pairs and with their connecting wires (7) are arranged aligned relative to one another. Arrangement (1) according to one of the Claims 1 to 4th , characterized in that the additional circuit board (10) is arranged on a surface (15) of a housing (16), that the spring elements (13) on the additional circuit board (10) between the additional circuit board (10) and connecting wires (7) the power semiconductor switches (5) are arranged and that the power semiconductor switches (5) are arranged on the surface (15) of a housing (16) and next to the additional circuit board (10). Arrangement (1) according to one of the Claims 1 to 5 , characterized in that the power semiconductor switches (5) are arranged fastened to the surface (15) of a housing (16) by means of clamps (17). Arrangement (1) according to one of the Claims 1 to 6th , characterized in that the connecting wires (7) of the power semiconductor switches (5) run in a first area (11) parallel to the surface (15) and that the connecting wires (7) of the power semiconductor switches (5) in a second area ( 12) run perpendicular to the surface (15) and away from it. Arrangement (1) according to one of the Claims 1 to 7th , characterized in that a main board (2) is arranged above the additional board (10) and the power semiconductor switches (5). Arrangement (1) according to one of the Claims 1 to 8th , characterized in that a capacitance or a damping element consisting of a resistor and a capacitance is arranged as the filter element (3).

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