Overvoltage protection circuit

Abstract

A surge protection circuit (100) for a DC network with a phase conductor (P), a neutral conductor (N) and a ground conductor (M) is specified, which has a first protection element (1) with a main arrester element (10), a first auxiliary arrester element (11) and a second auxiliary arrester element (12), wherein the main arrester element (10) can be connected to the phase conductor (P) and via the first auxiliary arrester element (11) to the neutral conductor (N) and via the second auxiliary arrester element (12) to the ground conductor (M), so that in the connected state the main arrester element (10) and the first auxiliary arrester element (11) connect the phase conductor (P) to the neutral conductor (N) and the main arrester element (10) and the second auxiliary arrester element (12) connect the phase conductor (P) to the ground conductor (M).

Description

[0001] 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.

[0002] 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.

[0003] At least one function of certain embodiments is to specify an overvoltage protection circuit.

[0004] This problem is solved by an object according to the independent patent claim. Advantageous embodiments and further developments of the object are characterized in the dependent claims and are further described in the following description and drawings.

[0005] According to at least one embodiment, an overvoltage protection circuit for a DC network is specified. The DC network can, in particular, have a phase conductor, a neutral conductor, and a ground conductor. For example, the DC network can be a low-voltage network and, for instance, be part of a mobile communication application. Preferably, the DC network can have a network voltage of less than or equal to 120 V or less than or equal to 100 V, and more preferably 48 V, 60 V, or 72 V.

[0006] 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 its installed state, and thus in its connected state 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 its connection 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.

[0007] According to a further 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 which, when connected to the DC network, is simultaneously connected between both 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 utilize the same surge arrester.

[0008] According to a further embodiment, the surge protection circuit comprises a first protection element with a main surge arrester element, which forms the common surge arrester. Furthermore, the first protection element can comprise a first auxiliary surge arrester element and a second auxiliary surge arrester element. The main surge arrester element can, in particular, be connected to the phase conductor and, via the first auxiliary surge arrester element, to the neutral conductor. Furthermore, the main surge arrester element can be connected to the ground conductor via the second auxiliary surge arrester element. Thus, the main surge arrester element and the first auxiliary surge arrester element can connect the phase conductor to the neutral conductor, and the main surge arrester element and the second auxiliary surge 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 can form another protective path, or at least part of it, between the phase conductor and the ground conductor.

[0009] 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. 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. Preferably, the first auxiliary surge arrester element and the second auxiliary surge arrester element can be connected directly to the second terminal of the main surge arrester element. Furthermore, the first auxiliary surge arrester element can be connected directly to the neutral conductor. The second auxiliary surge arrester element can be connected directly to the ground 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 surge arrester. Furthermore, the first protective element can have a connection for the ground conductor, which is a connection of the second auxiliary surge arrester.

[0010] According to another embodiment, the main surge arrester is preferably a multi-section arrester with at least two sections or, more preferably, with at least three sections. Conventional surge arresters typically have a firing voltage of up to 15 V. Therefore, single-section arresters cannot be used alone at the preferred mains voltages mentioned above, as they would not extinguish after tripping. To extinguish the surge, a varistor, for example, would have to be connected in series. By using a multi-section arrester, the need for an additional varistor for extinguishing the surge can be avoided, as this can significantly impair the current-carrying capacity of the protection. The more sections the main surge arrester has, the more sections can be used simultaneously for the two protective sections of the first protective element described above.

[0011] Furthermore, the first auxiliary arrester element can be a single-line arrester or a multi-line arrester with at least two arrester sections. The second auxiliary arrester element can also be a single-line arrester or a multi-line arrester with at least two arrester sections. The first auxiliary arrester element and the second auxiliary arrester element can have the same number of arrester sections. This allows identical components to be used for both the first and second auxiliary arrester elements, and the two protective paths described above can be identical, at least with regard to their respective arrester sections. Alternatively, the first auxiliary arrester element and the second auxiliary arrester element can have a different number of arrester sections. This allows the protective paths between the phase conductor and the neutral conductor, and between the phase conductor and the ground conductor, to be individually adapted.

[0012] Furthermore, the surge arrester sections of the main surge arrester, the first auxiliary surge arrester, and the second auxiliary surge arrester can all have the same firing voltage, for example, 10 V, 12 V, or 15 V. This allows for simple scalability with respect to the DC mains voltage by adjusting the respective number of surge arrester sections of the main surge arrester, the first auxiliary surge arrester, and the second auxiliary surge arrester. In addition, the surge arrester sections of the main surge arrester, the first auxiliary surge arrester, and the second auxiliary surge arrester can each be connected with capacitors in parallel as ignition aids. The capacitors can be external components in addition to the surge arresters or can be integrated into the surge arresters.

[0013] According to another embodiment, the overvoltage protection circuit has a second protective element. An inductive element, in particular in the form of a choke or other coil, can be present in the phase conductor between the first and second protective elements to allow separation between them.

[0014] According to a further 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 connection each for the neutral conductor and the ground conductor, each formed by a connection of the separating element.

[0015] 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.

[0016] The isolating element can, for example, comprise or be formed by a three-terminal surge arrester, wherein, for instance, the semiconductor unit can be connected to a center contact of the three-terminal surge arrester, while the neutral conductor and the ground conductor can be connected to the two other terminals of the three-terminal surge arrester. Furthermore, the isolating element can comprise a multi-terminal surge arrester or at least two single-terminal surge arresters, wherein the semiconductor unit can preferably be connected between two of these surge arrester segments.

[0017] 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. This allows for component savings 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 and second protection elements, respectively. This arrangement reduces the number of protection components, decreases the complexity of the protection circuit, and lowers costs compared to conventional protection circuits. In addition to the first and second protection elements, the surge protection circuit can include further protection elements that may incorporate elements of the first and / or second protection elements.

[0018] Further advantages, advantageous embodiments and further developments result from the exemplary embodiments described below in conjunction with the figures. Fig. Figure 1 shows a schematic representation of an overvoltage protection circuit according to an exemplary embodiment. Fig. Figure 2 shows a schematic representation of an overvoltage protection circuit according to a further embodiment, Fig. Figures 3A to 3C show schematic representations of isolating elements for the overvoltage protection circuit according to further embodiments and Fig. Figure 4 shows a schematic representation of an overvoltage protection circuit according to a further embodiment.

[0019] In the exemplary embodiments and figures, identical, similar, or similarly functioning elements may be designated with the same reference numerals. 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.

[0020] In Fig. 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 communication 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.

[0021] 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, 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, M.

[0022] The surge protection circuit 100 comprises a first protection element 1 with a main arrester element 10. Furthermore, the first protection element 1 comprises 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 to the neutral conductor N via the first auxiliary arrester element 11. Finally, the main arrester element 10 is connected to the protective earth conductor PE via the second auxiliary arrester element 12.Thus, the main arrester element 10 and the first auxiliary arrester element 11 connect the phase conductor P to the neutral conductor N, while the main arrester element 10 and the second auxiliary arrester element 12 connect the phase conductor P to the ground conductor PE, so that the main arrester element 10 and the first auxiliary arrester element 11 form a first protective distance S11 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 S12 between the phase conductor P and the ground conductor PE.

[0023] The main surge arrester 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 11 and the second auxiliary surge arrester 12. Particularly preferably, the first auxiliary surge arrester 11 is connected directly to the neutral conductor N and the second auxiliary surge arrester 12 is connected directly to the ground conductor PE. The first protective element 1 can thus have a terminal for the phase conductor P, which is the first terminal 101 of the main surge arrester 10. Furthermore, the first protective element 1 can have a terminal for the neutral conductor N, which is a terminal of the first auxiliary surge arrester 11. Furthermore, the first protective element 1 can have a terminal for the ground conductor PE, which is a terminal of the second auxiliary surge arrester 12.

[0024] The surge protection circuit 100 shown thus has a common surge arrester in the form of the main arrester element 10, which is simultaneously connected between both the phase conductor P and the neutral conductor N and between the phase conductor P and the ground conductor PE. Therefore, the first protective path S11 between the phase conductor P and the neutral conductor N and the second protective path S12 between the phase conductor P and the ground conductor PE have the same surge arrester, formed by the main arrester element 10. Fig. 1. The current path of the first protective path S11 between the neutral conductor N and the phase conductor P is indicated by dots for an overvoltage event such as a distant lightning strike, and the current path of the second protective path S12 between the phase conductor P and the ground conductor PE is indicated by dashed lines.

[0025] The main surge arrester element 10 is a multi-section arrester with at least two sections 103 and preferably at least three sections 103. The main surge arrester element 10 with three sections 103 is shown by way of example only. Furthermore, the first auxiliary surge arrester element 11 is a single-section arrester with one section 113 or a multi-section arrester with at least two sections 113, and the second auxiliary surge arrester element 12 is a single-section arrester with one section 123 or a multi-section arrester with at least two sections 123. The first and second auxiliary surge arrester elements 11 and 12 are each shown by way of example only as multi-section arresters with two sections 113 and 123, respectively.

[0026] 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 the two protective sections S11, S12 described above can be identical, at least with regard to the 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 S11, 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.

[0027] 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 protection sections S11, 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 protection section S11, 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 safe extinguishing or prevention of follow-through current in lines with a mains voltage of up to 60 V after the decay of an overvoltage event, such as a distant lightning strike. For higher mains voltages, correspondingly more surge arrester sections can be provided, for example, for the main surge arrester element 10.

[0028] 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 preferred are k and n each taking the values ​​from 1 to 3 and m the values ​​from 3 to 6, where n and k may be the same or different.

[0029] In Fig. 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 designed as in connection with the previous embodiment and which in Fig. 2 is only indicated, a second protective element 2 is present. Between the first protective element 1 and the second protective element 2, an inductive element 3, in particular in the form of a choke or another coil, may be present in the phase conductor P to enable separation of the first and second protective elements 1, 2.

[0030] 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 directly connected to a second terminal 202 of the semiconductor unit 20 via a terminal 201.

[0031] In particular, the second protective element 2, like the first protective element 1, has two protective distances S21, S22, which are located in Fig. 2 dotted and dashed lines analogous to Fig. 1 are indicated, where the semiconductor unit 20 is a common element of both protective sections S21, 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 one connection each for the neutral conductor N and the ground conductor PE, formed by one connection 212, 213 of the isolating element 21, respectively.

[0032] 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.

[0033] The separating element 21 can, for example, be shown in Fig. As indicated in 3A, a three-terminal arrester may be or have 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 be, as in Fig. 3B indicates a multi-path surge arrester or, as in Fig. 3C indicates that at least two single-line arresters have or are in existence, wherein the semiconductor unit is preferably connected to a terminal 211 between the respective two arrester lines.

[0034] In Fig. Figure 4 shows a preferred embodiment of the surge protection circuit 100, in which the first protection element 1 is the main arrester element 10 and the two auxiliary arrester elements 11, 12 as in conjunction with the Fig.as described in Figure 1. Furthermore, 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 are each connected to parallel-connected capacitors 13 as triggering aids. The capacitors 13 can be present as external components in addition to the arresters 10, 11, 12, as indicated, or they can be integrated into the arresters 10, 11, 12. Typically, the capacitors 13 for the described arresters 10, 11, 12 have a capacitance in the range of 100 pF to several hundred pF, for example, 330 pF.

[0035] 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.

[0036] 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 embodiments described in connection with the figures can alternatively or additionally include further features as described in the general section.

[0037] The invention is not limited to the description provided by means of the exemplary 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 exemplary embodiments. Reference symbol list 1 first protective element 2 second protective element 3 inductive element 10 Main discharge element 11 first additional surge arrester element 12 second additional surge arrester element 13 Capacitor 20 semiconductor units 21 Separating element 100 surge protection circuit 101 first connection 102 second connection 103 Diverter section 113 Diverter section 123 Diverter section 201 first connection 202 second connection 203 Varistor 211 connection 212 connection 213 connection N Neutral conductor M Ground conductor P Phase conductor S11, S12 Protection section S21, S22 Protection route

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) comprising a main arrester element (10), a first auxiliary arrester element (11) and a second auxiliary 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 surge arrester element (11) and the second additional surge arrester element (12) are directly connected to the second terminal (102). [3] Overvoltage protection circuit (100) according to one of the preceding claims, wherein - the first additional surge arrester element (11) can be directly connected to the neutral conductor (N) and - the second additional surge arrester element (12) can be directly connected to the ground conductor (M). [4] Overvoltage protection circuit (100) according to one of the preceding claims, wherein the main arrester element (10) is a multi-section arrester with at least two arrester sections (103). [5] Overvoltage 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). [6] Overvoltage 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). [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 arrester element (11) and the second 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), where - 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. [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-way arrester or at least two single-way arresters.

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