Overvoltage protection circuit

Abstract

The invention relates to an overvoltage protection circuit (100) for a DC network having a phase conductor (P), a neutral conductor (N) and a ground conductor (M), which overvoltage protection circuit has a first protection element (1) with a main arrester element (10), a first additional arrester element (11) and a second additional arrester element (12), wherein the main arrester element (10) can be connected to the phase conductor (P) and, via the first additional arrester element (11), to the neutral conductor (N) and, via the second additional arrester element (12), to the ground conductor (M), such that, in the connected state, the main arrester element (10) and the first additional arrester element (11) connect the phase conductor (P) to the neutral conductor (N), and the main arrester element (10) and the second additional arrester element (12) connect the phase conductor (P) to the ground conductor (M).

Description

[0001] P2024, 0998 WO N 29. September 2025

[0002] Description

[0003] Overvoltage protection circuit

[0004] A surge protection circuit is specified. The surge protection circuit can be specifically designed and configured to protect a DC network in the event of overvoltage events.

[0005] Typically, DC power supply lines are protected with surge arresters and / or semiconductor components such as varistors or diodes, with separate protection circuits used between pairs of conductors, thus creating multiple separate protection paths. However, duplicating these protection paths is quite expensive.

[0006] At least one function of certain implementation forms is to specify an overvoltage protection circuit.

[0007] This problem is solved by an article according to the independent patent claim. Advantageous

[0008] The various forms and further developments of the subject matter are characterized in the dependent claims and are further shown in the following description and drawings.

[0009] According to at least one embodiment, a surge protection circuit for a DC network is specified. The DC network may, in particular, have a phase conductor, a neutral conductor, and a ground conductor. For example, the DC network may be a low-voltage network and, for instance, part of a mobile radio application. Preferably, the DC network may be P2024, 0998 WO N 29. September 2025

[0010] 2. have a mains voltage of less than or equal to 120 V or less than or equal to 100 V and preferably of 48 V or 60 V or 72 V.

[0011] The surge protection circuit can be connected to the DC network, which can mean, in particular, that the surge protection circuit is intended to be connected to the DC network. In other words, the surge protection circuit can have at least one connection that can be connected to the phase conductor, at least one further connection that can be connected to the neutral conductor, and at least one further connection that can be connected to the ground conductor. In the installed state, and thus in the state connected to the DC network, these connections are linked to the conductors of the DC network. Whenever the following description states that a connection or element of the surge protection circuit is "connected" to a conductor of the DC network, this refers to the installed state of the surge protection circuit, and thus to the state connected to the DC network.Accordingly, such information is to be understood as meaning that the said “connected” connection or the said “connected” element of the surge protection circuit can be “connected” to the corresponding conductor if the surge protection circuit is not yet connected to the DC network.

[0012] According to another embodiment, the surge protection circuit has at least one surge arrester that can be connected simultaneously between the phase conductor and the neutral conductor as well as between the phase conductor and the ground conductor, and in the state connected to the DC network (P2024, 0998 WO N 29. September 2025), is simultaneously connected between the phase conductor and the neutral conductor as well as between the phase conductor and the ground conductor. Thus, the surge protection circuit can form a protective path between the phase conductor and the neutral conductor and between the phase conductor and the ground conductor, and both protective paths can have the same surge arrester.

[0013] According to another embodiment, the surge protection circuit comprises a first protection element with a main arrester element, which forms the common surge arrester. Furthermore, the first protection element can include a first auxiliary arrester element and a second auxiliary arrester element. The main arrester element can be connected to the phase conductor and, via the first auxiliary arrester element, to the neutral conductor. The main arrester element can also be connected to the ground conductor via the second auxiliary arrester element. Thus, the main arrester element and the first auxiliary arrester element can connect the phase conductor to the neutral conductor, and the main arrester element and the second auxiliary arrester element can connect the phase conductor to the ground conductor.In other words, the main arrester element and the first auxiliary arrester element can form a protective path, or at least part of it, between the phase conductor and the neutral conductor, while the main arrester element and the second auxiliary arrester element form another protective path, or at least part of it, between the phase conductor and the neutral conductor.

[0014] Can form ground conductors. P2024, 0998 WO N 29. September 2025

[0015] 4

[0016] The main surge arrester element can, in particular, have a first terminal and a second terminal. The first terminal can be connected to the phase conductor. Particularly preferably, the first terminal can be connected directly to the phase conductor, i.e., without any further intermediate component. The first auxiliary surge arrester element and the second auxiliary surge arrester element can be connected to the second terminal of the main surge arrester element. Particularly preferably, the first auxiliary surge arrester element and the second auxiliary surge arrester element can be directly connected to the second terminal of the main surge arrester element. Furthermore, the first auxiliary surge arrester element can be directly connected to the neutral conductor. The second auxiliary surge arrester element can be directly connected to the earth conductor. The first protective element can thus have a terminal for the phase conductor, which is the first terminal of the main surge arrester element.Furthermore, the first protective element can have a connection for the neutral conductor, which is a connection of the first auxiliary arrester element. Furthermore, the first protective element can have a connection for the ground conductor, which is a connection of the second auxiliary arrester element.

[0017] According to another embodiment, the main surge arrester element is preferably a multi-section arrester with at least two sections or preferably with at least three sections. Typical surge arresters have a firing voltage of up to 15 V. Therefore, single-section arresters alone cannot be used at the preferred mains voltages mentioned above, as they would not extinguish after tripping. To extinguish the current, a varistor, for example, would have to be connected in series. By using a multi-section arrester, it is possible to avoid the additional need for P2024, 0998 WO N 29. September 2025

[0018] For example, a varistor must be used for surge arrester suppression, as this can significantly impair the current-carrying capacity of the protection. The more surge arrester sections the main surge arrester element has, the more surge arrester sections can be used simultaneously for the two protection sections of the first protection element described above.

[0019] Furthermore, the first auxiliary arrester element can be a single-section arrester or a multi-section arrester with at least two sections. The second auxiliary arrester element can also be a single-section arrester or a multi-section arrester with at least two sections. The first and second auxiliary arrester elements can have the same number of sections. This allows identical components to be used for both the first and second auxiliary arrester elements, and the two protective sections described above can be identical, at least with regard to their respective sections. Alternatively, the first and second auxiliary arrester elements can have a different number of sections. This allows the protective sections between the phase conductor and the neutral conductor, and between the phase conductor and the ground conductor, to be individually adapted.

[0020] Furthermore, the discharge tubes of the main discharge tube element, the first auxiliary discharge tube element, and the second auxiliary discharge tube element can all have the same firing voltage, for example, 10 V, 12 V, or 15 V. This allows for adjustments to the respective number of discharge tubes of the main discharge tube element, the first auxiliary discharge tube element, and the second auxiliary discharge tube element (P2024, 0998 WO N 29 September 2025).

[0021] 6. Simple scalability with respect to the electrical mains voltage of the DC network is enabled. Furthermore, the arrester sections of the main arrester element, the first auxiliary arrester element, and the second auxiliary arrester element can each be connected with capacitors in parallel as triggering aids. The capacitors can be present as external components in addition to the arresters or can be integrated into the arresters.

[0022] According to another embodiment, the surge protection circuit has a second protective element. An inductive element, particularly in the form of a choke or other coil, may be present in the phase conductor between the first and second protective elements to allow separation between them.

[0023] According to another embodiment, the second protective element comprises a semiconductor unit and a separating element. The semiconductor unit can particularly preferably be connected to the phase conductor. In particular, the semiconductor unit can be directly connected to the phase conductor. Furthermore, the semiconductor unit can be connected to the neutral conductor and the ground conductor via the separating element. The neutral conductor and the ground conductor can be directly connected to the separating element. Accordingly, the second protective element can have two protective zones, with the semiconductor unit being a common element of both protective zones. The second protective element can thus have a connection for the phase conductor, formed by a connection of the semiconductor unit, as well as a P2024, 0998 WO N 29. September 2025

[0024] 7

[0025] The connection for the neutral conductor and the ground conductor, each formed by a connection of the separating element, must be present.

[0026] The semiconductor unit can comprise at least one varistor and / or at least one TVS diode. In particular, the semiconductor unit can comprise a plurality of varistors and / or a plurality of TVS diodes connected in parallel. Furthermore, the semiconductor unit can comprise at least one varistor in series with a surge arrester in the form of a single-line arrester or a multi-line arrester.

[0027] The isolating element can, for example, comprise or be formed by a three-terminal arrester, wherein, for example, the semiconductor unit can be connected to a center contact of the three-terminal arrester, while the neutral conductor and the ground conductor can be connected to the two other terminals of the three-terminal arrester. Furthermore, the isolating element can comprise a multi-terminal arrester or at least two single-terminal arresters, wherein the semiconductor unit can preferably be connected between two of these arrester segments.

[0028] In the surge protection circuit described here, a common element in the form of the main surge arrester or semiconductor unit is used for each of the protection elements, thus saving components compared to duplicated protection circuits typically used in the prior art. The auxiliary surge arresters or the isolating element can function as isolators in the first or second protection element, respectively. This arrangement reduces the number of protection components and the complexity of the P2024, 0998 WO N 29 September 2025

[0029] 8

[0030] The protective circuitry can be reduced, thus lowering costs compared to conventional protective circuits. In addition to the first and second protective elements, the surge protection circuit may include further protective elements that incorporate components of the first and / or second protective elements.

[0031] Further advantages, advantageous implementation forms and further developments result from the exemplary implementations described below in conjunction with the figures.

[0032] Figure 1 shows a schematic representation of an overvoltage protection circuit according to an exemplary embodiment.

[0033] Figure 2 shows a schematic representation of an overvoltage protection circuit according to a further embodiment.

[0034] Figures 3A to 3C show schematic representations of isolating elements for the surge protection circuit according to further exemplary embodiments and

[0035] Figure 4 shows a schematic representation of an overvoltage protection circuit according to a further embodiment.

[0036] In the examples and figures, identical, similar, or similarly functioning elements may each be designated with the same reference symbols. The depicted elements and their relative sizes are not to be considered to scale; rather, individual elements, such as layers, components, building elements, and areas, may be exaggerated for clarity and / or better understanding. P2024, 0998 WO N 29 September 2025

[0037] - 9 -

[0038] Figure 1 shows a surge protection circuit 100 designed and configured to protect a DC network. The DC network has a phase conductor P, a neutral conductor N, and a ground conductor PE. For example, the DC network can be part of a mobile radio application. Preferably, the DC network can operate in the low-voltage range and have an electrical network voltage of less than or equal to 120 V or less than or equal to 100 V, and in particular, for example, 48 V, 60 V, or 72 V.

[0039] In the illustrated embodiment, the surge protection circuit 100 is shown connected to the DC network, so that the following description explains that the terminals and components of the surge protection circuit 100 are connected to conductors P, N, and M of the DC network. When the surge protection circuit 100 is not yet connected to the DC network, the corresponding terminals and components can be connected to the respective conductors P, N, and M.

[0040] The surge protection circuit 100 has a first protection element 1 with a main arrester element 10. Furthermore, the first protection element 1 has a first auxiliary arrester element 11 and a second auxiliary arrester element 12. The main arrester element 10 is connected to the phase conductor P. The main arrester element 10 is also connected via the first auxiliary arrester element.

[0041] 11 is connected to the neutral conductor N. Furthermore, the main arrester element 10 is connected via the second auxiliary arrester element.

[0042] 12 is connected to the PE conductor. Thus, P2024, 0998 WO N 29, September 2025, connects.

[0043] 10

[0044] Main arrester element 10 and the first auxiliary arrester element

[0045] 11 the phase conductor P with the neutral conductor N, while the main arrester element 10 and the second auxiliary arrester element

[0046] 12 connect the phase conductor P with the ground conductor PE, so that the main arrester element 10 and the first auxiliary arrester element 11 form a first protective distance S il between the phase conductor P and the neutral conductor N, while the main arrester element 10 and the second auxiliary arrester element 12 form a second protective distance S 12 between the phase conductor P and the ground conductor PE .

[0047] The main surge arrester element 10 has a first terminal 101 and a second terminal 102, wherein the first terminal 101 is preferably connected directly to the phase conductor P, as shown, and the second terminal 102 is preferably connected directly to the first auxiliary surge arrester element 11 and the second auxiliary surge arrester element 12. Particularly preferably, the first auxiliary surge arrester element 11 is connected directly to the neutral conductor N, and the second auxiliary surge arrester element 12 is connected directly to the earth conductor PE. The first surge arrester element 1 can thus have a terminal for the phase conductor P, which is the first terminal 101 of the main surge arrester element 10. Furthermore, the first surge arrester element 1 can have a terminal for the neutral conductor N, which is a terminal of the first auxiliary surge arrester element 11. Furthermore, the first surge arrester element 1 can have a terminal for the earth conductor PE, which is a terminal of the second auxiliary surge arrester element 12.

[0048] The surge protection circuit 100 shown thus has a common surge arrester in the form of the main arrester element 10, which simultaneously serves both P2024 , 0998 WO N 29 . September 2025

[0049] 11 is connected between the phase conductor P and the neutral conductor N, as well as between the phase conductor P and the ground conductor PE. Thus, the first protective path S 11 between the phase conductor P and the neutral conductor N and the second protective path S 12 between the phase conductor P and the ground conductor PE have the same surge arrester, formed by the main arrester element 10. In Figure 1, the current path of the first protective path S 11 between the neutral conductor N and the phase conductor P is indicated by dotted lines for a surge event such as a distant lightning strike, and the current path of the second protective path S 12 between the phase conductor P and the ground conductor PE is indicated by dashed lines.

[0050] The main arrester element 10 is a multi-section arrester with at least two arrester sections 103 and preferably at least three arrester sections 103. The main arrester element 10 with three arrester sections 103 is shown by way of example only. Furthermore, the first auxiliary arrester element 11 is a single-section arrester with one arrester section 113 or a multi-section arrester with at least two arrester sections 113, and the second auxiliary arrester element 12 is a single-section arrester with one arrester section 123 or a multi-section arrester with at least two arrester sections 123. The first and second auxiliary arrester elements 11 and 12 are each shown by way of example only as multi-section arresters with two arrester sections 113 and 123, respectively.

[0051] The first auxiliary arrester element 11 and the second auxiliary arrester element 12 can have the same number of arrester sections 113, 123 as shown, so that identical components are used for the first auxiliary arrester element 11 and the second auxiliary arrester element 12 and P2024, 0998 WO N 29 September 2025

[0052] 12. The two protective sections Sil, S12 described above can be configured identically, at least with regard to their respective arrester sections. Alternatively, the first auxiliary arrester element 11 and the second auxiliary arrester element 12 can have a different number of arrester sections 113, 123. This allows the protective sections Sil, S12 between the phase conductor P and the neutral conductor N and between the phase conductor P and the ground conductor PE to be individually adapted.

[0053] In the illustrated embodiment, the main arrester element 10 and each of the two auxiliary arrester elements 11, 12 effectively form a multi-section arrester with five arrester sections 103, 113, 123 for each of the two protective sections Sil, S12. Instead of two separate multi-section arresters, each with five arrester sections, and thus instead of a total of ten arrester sections as is common in the prior art, only seven arrester sections 103, 113, 123 are used in the illustrated embodiment. The individual arrester sections 103, 113, 123 have, for example, an arcing voltage of 12 V, so that each protective section Sil, S12 effectively has an arcing voltage of 60 V, which may be suitable, for example, for a mains voltage of 48 V in the DC network shown.A discharge voltage of 60 V ensures reliable extinguishing of a surge event, such as a distant lightning strike, or prevents a follow current in lines with a mains voltage of up to 60 V, after the event has subsided. For higher mains voltages, a correspondingly larger number of surge arrester sections can be provided, for example, for the main arrester element 10. P2024, 0998 WO N 29 September 2025.

[0054] For example, the following combinations of a number m of surge arrester sections 103 in Hae 10, a number k of surge arrester sections 113 in the first auxiliary surge arrester element 11, and a number n of surge arrester sections 123 in the second auxiliary surge arrester element 12 for a mains voltage up to 60 V may be particularly preferred (k:m:n): 2:3:2, 1:4:1, 1:5:2, 2:6:2, 3:6:3. Particularly preferably, k and n may each take the values ​​from 1 to 3, and m the values ​​from 3 to 6, where n and k may be the same or different.

[0055] Figure 2 shows a further embodiment of the overvoltage protection circuit 100, which is a modification of the previous embodiment and which, in addition to the first protective element 1, which can be configured as in the previous embodiment and which is only indicated in Figure 2, has a second protective element 2. An inductive element 3, in particular in the form of a choke or other coil, can be present in the phase conductor P between the first protective element 1 and the second protective element 2 to enable separation of the first and second protective elements 1, 2.

[0056] The second protective element 2, which can provide additional protection to the first protective element 1 and which can be specifically designed and configured for fine-tuning the overall protective effect of the surge protection circuit 100, comprises a semiconductor unit 20 and a isolating element 21. The semiconductor unit 20 is directly connected to the phase conductor P via a first terminal 201. Furthermore, the semiconductor unit 20 is directly connected to the neutral conductor N and the ground conductor PE via the isolating element 21. The isolating element 21 is labeled P2024 , 0998 WO N 29 . September 2025

[0057] 14 connected to a terminal 201 directly to a second terminal 202 of the semiconductor unit 20 .

[0058] In particular, the second protective element 2, like the first protective element 1, has two protective sections S21 and S22, which are indicated in Figure 2 by dotted and dashed lines analogously to Figure 1, with the semiconductor unit 20 being a common element of both protective sections S21 and S22. The second protective element 2 thus has a connection for the phase conductor P, formed by the first connection 201 of the semiconductor unit 20, as well as a connection each for the neutral conductor N and the ground conductor PE, formed by a connection 212 and a connection 213, respectively, of the isolating element 21.

[0059] The semiconductor unit 20 can comprise at least one varistor and / or at least one TVS diode. In particular, the semiconductor unit 20 can comprise a plurality of varistors and / or a plurality of TVS diodes connected in parallel. Furthermore, the semiconductor unit 20 can comprise at least one varistor in series with a surge arrester in the form of a single-line arrester or a multi-line arrester.

[0060] The isolating element 21 can, for example, as indicated in Figure 3A, comprise or be a three-terminal arrester, wherein the semiconductor unit 20 is preferably connected to the central terminal of the three-terminal arrester forming terminal 211, while the neutral conductor N and the ground conductor PE are connected to the two other terminals 212, 213 of the three-terminal arrester. Furthermore, the isolating element 21 can, as indicated in Figure 3B, be a multi-path arrester or, as indicated in Figure 3C, at least two P2024, 0998 WO N 29. September 2025

[0061] 15

[0062] have or be single-section arresters, wherein the semiconductor unit is preferably connected to a terminal 211 between the respective two arrester sections.

[0063] Figure 4 shows a preferred embodiment of the surge protection circuit 100, in which the first protection element 1 comprises the main surge arrester element 10 and the two auxiliary surge arrester elements 11, 12 as described in conjunction with Figure 1. Furthermore, the arrester sections 103, 113, 123 of the main surge arrester element 10, the first auxiliary surge arrester element 11, and the second auxiliary surge arrester element 12 are each connected to capacitors 13 in parallel as triggers. The capacitors 13 can be present as external components in addition to the surge arresters 10, 11, 12, as indicated, or they can be integrated into the surge arresters 10, 11, 12. Typically, the capacitors 13 for the described arresters 10, 11, 12 have a capacitance in the range of 100 pF up to several 100 pF, for example 330 pF.

[0064] The second protective element 2, in the illustrated embodiment, comprises four parallel-connected varistors 203 in the form of MLVs (MLV: "multi-layer varistor") as a semiconductor unit 20. Alternatively, depending on the required level of protection, other and / or more or fewer varistors, or, as described above, TVS diodes and / or surge arresters, may be used.

[0065] The features and embodiments described in connection with the figures can be combined with one another according to further embodiments, even if not all combinations are explicitly described. Furthermore, the features and embodiments described in connection with figures P2024, 0998 WO N 29 September 2025

[0066] The embodiments described in Section 16 may alternatively or additionally have further features as described in the general part. The invention is not limited to the description provided in the embodiments. Rather, the invention encompasses every new feature as well as every combination of features, which in particular includes every combination of features in the claims, even if that feature or combination itself is not explicitly stated in the claims or embodiments.

[0067] P2024, 0998 WO N 29. September 2025

[0068] Reference character list

[0069] 1 first protective element

[0070] 2 second protective element

[0071] 3 inductive element

[0072] 10 Main discharge element

[0073] 11 first additional surge arrester element

[0074] 12 second additional surge arrester element

[0075] 13 Capacitor

[0076] 20 semiconductor units

[0077] 21 Separating element

[0078] 100 surge protection circuit

[0079] 101 first connection

[0080] 102 second connection

[0081] 103 Diverter section

[0082] 113 Diverter section

[0083] 123 Diverter section

[0084] 201 first connection

[0085] 202 second connection

[0086] 203 Varistor

[0087] 211 connection

[0088] 212 connection

[0089] 213 connection

[0090] N Neutral conductor

[0091] M Ground conductor

[0092] P Phase conductor

[0093] S il , S 12 protection section

[0094] S21, S22 Protection Route

Claims

P2024, 0998 WO N September 29, 2025 Patent claims 1. Overvoltage protection circuit (100) for a DC network comprising a phase conductor (P), a neutral conductor (N) and a ground conductor (M), comprising - a first protective element (1) with a main discharge element (10) , a first additional arrester element (11) and a second additional arrester element (12) , wherein - the main surge arrester element (10) can be connected to the phase conductor (P) and via the first auxiliary surge arrester element (11) to the neutral conductor (N) and via the second auxiliary surge arrester element (12) to the ground conductor (M), so that in the connected state the main surge arrester element (10) and the first auxiliary surge arrester element (11) connect the phase conductor (P) to the neutral conductor (N) and the main surge arrester element (10) and the second auxiliary surge arrester element (12) connect the phase conductor (P) to the ground conductor (M).

2. Overvoltage protection circuit (100) according to claim 1, wherein - the main discharge element (10) has a first terminal (101) and a second terminal (102), - the first connection (101) can be directly connected to the phase conductor (P) and - the first additional discharge element (11) and the second Additional surge arrester element (12) is directly connected to the second terminal (102).

3. Overvoltage protection circuit (100) according to one of the preceding claims, wherein P2024, 0998 WO N September 29, 2025 - the first additional surge arrester element (11) directly connected to the The neutral conductor (N) can be connected and - the second additional surge arrester element (12) directly connected to the The ground conductor (M) can be connected.

4. Overvoltage protection circuit (100) according to one of the preceding claims, wherein the main arrester element (10) is a multi-path arrester with at least two The conductor sections (103) are.

5. Surge protection circuit (100) according to one of the preceding claims, wherein the first additional arrester element (11) is a single-section arrester with one arrester section (113) or a multi-section arrester with at least two arrester sections (113) is.

6. Surge protection circuit (100) according to one of the preceding claims, wherein the second additional arrester element (12) is a single-section arrester with one arrester section (123) or a multi-section arrester with at least two arrester sections (123) is.

7. Overvoltage protection circuit (100) according to one of the preceding claims, wherein the first additional arrester element (11) and the second additional arrester element (12) have the same number of arrester sections (113, 123).

8. Overvoltage protection circuit (100) according to one of the preceding claims, wherein the first additional surge arrester element (11) and the second P2024, 0998 WO N September 29, 2025 20 Additional arrester element (12) have a different number of arrester sections (113, 123).

9. Overvoltage protection circuit (100) according to one of the preceding claims, wherein the arrester sections (103, 113, 123) of the main arrester element (10), the first auxiliary arrester element (11) and / or the second auxiliary arrester element (12) are each connected with parallel-connected capacitors (13) as ignition aids.

10. Overvoltage protection circuit (100) according to one of the preceding claims, wherein the arrester sections (103, 113, 123) of the main arrester element (10), the first auxiliary arrester element (11) and the second auxiliary arrester element (12) all have the same firing voltage.

11. Overvoltage protection circuit (100) according to one of the preceding claims, further comprising - a second protective element (2) with a semiconductor unit (20) and a separating element (21) , wherein - the semiconductor unit (20) can be connected to the phase conductor (P) and via the separating element (21) to the neutral conductor (N) and the ground conductor (M).

12. Overvoltage protection circuit (100) according to claim 11, wherein the semiconductor unit (20) comprises at least one varistor (203) and / or at least one TVS diode. P2024, 0998 WO N September 29, 2025 13. Overvoltage protection circuit (100) according to claim 11 or 12, wherein the semiconductor unit (20) comprises a plurality of varistors (203) connected in parallel and / or a plurality of TVS diodes connected in parallel.

14. Overvoltage protection circuit (100) according to one of claims 11 to 13, wherein the isolating element (21) comprises a three-pole arrester, a multi-line arrester or at least two single-line arresters.

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