Electrical device

Abstract

The invention relates to an electrical device (100) which has a generator unit (1) for generating an electrical current in a power line (2) having a plurality of phases, a frequency converter unit (3) based on SiC technology, and a filter unit (4) between the generator unit (1) and the frequency converter unit (3), which filter unit is designed for current limitation and voltage increase damping and has precisely one inductive element (41), which is designed as a current limiting element and which forms a voltage increase damping element together with a capacitive element (42) which has at least one capacitor per phase.

Description

[0001] Description

[0002] Electrical device

[0003] An electrical device is specified. The electrical device may, in particular, be part of a system designed for generating electricity.

[0004] Power generating plants typically feature three-phase inverters, which are modularly constructed with frequency converter modules to be adapted to the respective plant output by connecting internal modules in parallel. Limiting the current at a frequency converter module in the event of a short circuit in a module requires a suitable inductor in the form of a current-limiting choke.

[0005] High-performance frequency converters are increasingly based on SiC technology, which is characterized by very rapid voltage rises. This necessitates limiting the voltage rise for connected systems, so that at the output of a current-limiting choke, an additional voltage rise limitation of typically at least 60% is required for downstream sensitive components.

[0006] At least one function of certain implementation forms is to specify an electrical device, in particular an electrical device with a filter unit.

[0007] 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.

[0008] According to at least one embodiment, an electrical device includes a filter unit designed for current limiting and voltage rise damping. The electrical device can, in particular, be part of a power-generating system. For example, the electrical device can be part of a wind turbine. Similarly, the generator unit can be part of a wind power plant, such as a wind turbine. Furthermore, other power-generating systems are also possible.

[0009] According to another embodiment, the electrical device includes a generator unit for generating an electric current. In particular, the generator unit can be configured to generate an electric current in a power line with a plurality of phases. The power line preferably has three phases. Alternatively, the power line can also have two phases or more than three phases.

[0010] According to another embodiment, the electrical device includes a frequency converter unit. The frequency converter unit can, in particular, be a frequency converter unit based on SiC technology. In other words, the frequency converter unit can include transistors, for example MOSFETs (metal-oxide-semiconductor field-effect transistors), based on SiC. Compared to silicon or other materials used in power electronics, for example, SiC offers a higher breakdown field strength, thus enabling components with higher usable field strength and / or thinner semiconductor layers, the latter of which can reduce the forward voltage and thus improve the switching characteristics.Inverters with SiC components are therefore typically low-loss and allow high switching frequencies. At the same power output, they can be more compact, lighter, and more efficient than inverters based on conventional semiconductor materials. However, due to these properties, SiC-based components such as transistors, compared to conventional power electronics components based on silicon, for example, exhibit voltage rises with very fast rise times, which must be limited with regard to other components of the power-generating system. Therefore, the electrical device incorporates the aforementioned filter unit for current limiting and voltage rise damping.

[0011] According to another embodiment, the filter unit is arranged between the generator unit and the frequency converter unit. In other words, the filter unit can have an input side that is connected to the generator unit. Furthermore, the filter unit can have an output side that is connected to the frequency converter unit. Particularly preferably, the filter unit can be directly connected to the generator unit and / or directly connected to the frequency converter unit. "Directly connected" can, in particular, mean that there are no electrical and electronic components at all, or at least no electrical and electronic components, in the circuit between the generator unit and the filter unit and / or between the filter unit and the frequency converter unit that could be used for this purpose.

[0012] Filtering is provided.

[0013] According to another embodiment, the filter unit has exactly one inductive element, which is configured as a current-limiting element and which, together with a capacitive element, forms a voltage rise damping element. This means, in particular, that the filter unit has no other inductive element, but only precisely this one inductive element, which simultaneously serves as a current-limiting element and, together with the capacitive element, as a voltage rise damping element.

[0014] According to another embodiment, the capacitive element has at least one capacitor per phase of the power line. Accordingly, the capacitive element can, for example, have exactly n capacitors in the case of a power line with n phases. Furthermore, the capacitive element can, for example, have one resistor per phase, so that the capacitive element can have an RC circuit for each phase.

[0015] For example, the capacitive element can be connected upstream of the inductive element, viewed from the generator unit. The capacitive element can thus be located at the input side of the filter unit, while the inductive element can be located at the output side. The capacitors can be connected in a star configuration, for example, so that each phase can be connected to a capacitor, and the phases can be connected in parallel via the capacitors. Alternatively, the capacitors can be connected in a delta configuration, so that any two phases of the power line can always be connected together via an intermediate capacitor. As an alternative to having the capacitive element upstream of the inductive element, viewed from the generator unit, the capacitive element can also be connected downstream of the inductive element.In this case, the inductive element can be arranged on the input side of the filter unit, while the capacitive element can be arranged on the output side of the filter unit. Particularly preferred in this case is that each of the capacitors is connected between a phase and ground, so that the capacitors can be connected downstream of the inductive element from the generator unit and to ground.

[0016] According to another embodiment, the inductive element is designed as a so-called "sharing reactor" and has an inductive section for each phase. In particular, the inductive element for each phase can have a coil element comprising a magnetic core and an electrical conductor passing through the magnetic core. Preferably, the inductive element for each phase can have an electrical conductor comprising, or more preferably, being formed by, a first conductor element, a second conductor element, and a third conductor element. Each of the electrical conductors can, for example, be formed by one or more metal sheets. The first conductor element and the third conductor element can each pass through the magnetic core and be connected to each other by the second conductor element, which is arranged outside the magnetic core.In particular, the first conductor element can have a first connection element and the third conductor element a second connection element, wherein for each phase the first connection element forms an input-side connection of the inductive element and the second connection element forms an output-side connection of the inductive element. For each phase, the first connection element can, for example, be directly connected to the capacitive element, while the second connection element can be directly connected to the frequency converter unit. Alternatively, for each phase the first connection element can also be, for example, directly connected to the generator unit, while the second connection element can be directly connected to the capacitive element.

[0017] The first conductor element preferably extends from the first terminal element at an input side of the magnetic core, through the magnetic core, to an output side of the magnetic core. The second conductor element leads back to the input side outside the magnetic core, and the third conductor element extends from the input side of the magnetic core, through the magnetic core, to the output side of the magnetic core and the second terminal element. Thus, the inductive element preferably comprises an electrical conductor for each phase, with two conductor elements inside the magnetic core and one conductor element outside the magnetic core. In particular, for each inductive part of the inductive element associated with a phase, no further part of the electrical conductor other than the first and second conductor elements may extend through the magnetic core.

[0018] In the electrical device with the filter unit described here, the electrical conductors and the magnetic cores for each phase can form conductor loops or coils with a suitable core made of magnetically active material, which can provide the saturation strength of the inductive element forming a choke up to a required peak current. The effect of the described conductor loop formed from the first, second, and third conductor elements for each phase can, for example, act as a low-pass filter in the high-frequency range with an RC network in a delta or star connection by reducing the voltage rise rate, whereby the respective magnetic core can be neglected.Thus, the filter unit described here, through its described design, can offer a defined simultaneous function in the low and high frequency range in order to fall below the required limits of short-circuit current and maximum voltage rise, without the need for two separate filter components as is usually the case.

[0019] Further advantages, advantageous implementation forms and further developments result from the exemplary implementations described below in conjunction with the figures.

[0020] Figure 1 shows a schematic representation of a power-generating plant with an electrical device according to an exemplary embodiment.

[0021] Figures 2 to 4 show schematic representations of an electrical device according to further exemplary embodiments.

[0022] Figure 5 shows a schematic representation of an inductive element according to a further embodiment. In the embodiments and figures, identical, similar, or similarly acting 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.

[0023] Figure 1 shows a power generating plant 1000 which has an electrical device 100 according to an exemplary embodiment.

[0024] The electrical device 100 comprises a generator unit 1 for generating an electric current. In particular, the generator unit 1 is configured to generate an electric current in a power line 2 with a plurality of phases. In the illustrated embodiment, the power line 2 has three phases. Alternatively, more or fewer phases are also possible. For the sake of clarity, the neutral and ground conductors, which are usually also present, are not shown in Figure 1 or in Figures 2 to 4.

[0025] For example, the electrical device 100 can be part of a wind turbine. In other words, the power-generating plant can be a wind turbine with one or more wind turbines in the form of windmills. Accordingly, the generator unit 1 can be part of a wind turbine, such as a windmill. Alternatively, other types of plants and generators are also possible, for example, in conjunction with hydropower. The power-generating plant 1000 serves to generate alternating current, which can be fed into an electrical grid 200.

[0026] Furthermore, the electrical device 100 includes a frequency converter unit 3, which can be configured, for example, as several switchable modules and is based on SiC technology. Accordingly, the frequency converter unit can include transistors such as MOSFETs based on SiC. For the frequency converter unit 3 indicated here, a module with a generator-side bridge 31 and a grid-side bridge 32 connected via a common-mode filter is shown as a purely exemplary example.

[0027] A filter unit 4 is arranged between the generator unit 1 and the frequency converter unit 3 for current limiting and voltage rise damping, in order to protect the components downstream of the generator unit 1 from overcurrents and excessively rapid voltage increases. Further features and properties of the filter unit 4 are described in conjunction with Figures 2 to 5 below.

[0028] Downstream of the electrical device 100, the power-generating system 1000, according to the present exemplary embodiment, has, for example, one or more transformers 201 to generate an alternating current that can be fed into the electrical network 200. Furthermore, the power-generating system 1000 downstream of the electrical device 100 may also have, for example, additional components, such as inductive filters 202, 203, a PWM filter 204 (PWM: pulse width modulation), and resistors 205. The additional components shown are purely exemplary and are not to be understood as limiting.

[0029] In conjunction with Figures 2 to 4, exemplary embodiments of the electrical device 100 of the power-generating plant 1000 shown in Figure 1, and in particular of the filter unit 4, which is arranged between the generator unit 1 and the frequency converter unit 3, are described. Unless otherwise stated, the following description applies equally to Figures 2 to 4.

[0030] The filter unit 4 has an input side that is connected to the generator unit 1. Furthermore, the filter unit 4 has an output side that is connected to the frequency converter unit 3. Preferably, the filter unit 4 is directly connected to the generator unit 1 or directly to the frequency converter unit 3, or, more preferably, as shown in Figures 1 to 4, directly to both the generator unit 1 and the frequency converter unit 3, so that no further electrical and electronic components, in particular no further filter elements, are present in the circuit between the generator unit 1 and the filter unit 4, and between the filter unit 4 and the frequency converter unit 3.

[0031] The filter unit 4 has exactly one inductive element 41, which is configured as a current-limiting element and which, together with a capacitive element 42, forms a voltage rise damping element. Thus, in addition to the inductive element 41, the filter unit 4 has no further inductive element, but only exactly the one inductive element 41, which simultaneously serves as a current-limiting element and, together with the capacitive element 42, as a voltage rise damping element.

[0032] The capacitive element 42 comprises at least one capacitor 420 per phase of the current line 2. Accordingly, in the illustrated embodiments, the capacitive element 42 comprises exactly three capacitors 420. Furthermore, the capacitive element 42 can, for example, comprise a resistive element (not shown) per phase, so that the capacitive element 42 can also comprise an RC circuit for each phase. Particularly preferably, the filter unit 4 comprises no further filter components other than the described components in the form of the inductive element 41 and the capacitive element 42. Furthermore, the capacitive element 42 particularly preferably comprises no further filter components other than the described capacitors 420 or other than the described capacitors 420 and resistive elements. The filter unit 4 can thus be formed from the inductive element 41 and the capacitive element 42 without further filter components such as additional capacitors and inductors.

[0033] As shown in Figures 2 and 3, the capacitive element 42 can be connected upstream of the inductive element 41, viewed from the generator unit 1. The capacitive element 42 is thus arranged at the input side of the filter unit 4, which is connected to the generator unit 1, while the inductive element 41 is arranged at the output side of the filter unit 4, which is connected to the frequency converter unit 3. The capacitors 420 can be connected in a star configuration, as shown in Figure 2, so that each phase is connected to a capacitor 420 and the phases are connected in parallel via the capacitors 420. Alternatively, the capacitors 420 can be connected in a delta configuration, as shown in Figure 3, so that two phases of the power line 2 are always connected to each other via an intermediate capacitor 420.

[0034] Figure 4 shows an example in which the capacitive element 42 is connected downstream of the inductive element 41. In this case, the inductive element 41 is arranged at the input side of the filter unit 4, while the capacitive element 42 is arranged at the output side of the filter unit 4. Particularly preferably, in this case, each of the capacitors 420 is connected between a phase and ground, so that the capacitors 420 are thus connected downstream of the inductive element 41 from the generator unit 1 and are connected to ground.

[0035] The inductive element 41 fulfills a dual function in the filter unit 4 as described, namely current limiting and, together with the capacitive element 4, voltage rise limiting. In particular, the inductive element is designed as a so-called "sharing reactor" and has an inductive part formed by a coil element 411 for each phase, as shown in Figure 5. The inductive element 41 has, in particular, a coil element 411 for each phase, which comprises a magnetic core 412 and an electrical conductor 413 passing through the magnetic core 412, and which is formed, in particular, by the respective magnetic core 412 and the respective electrical conductor 413.The inductive parts of the inductive element 41 are configured identically for each phase, such that the inductive element 41 has an electrical conductor 413 for each phase, comprising a first conductor element 4131, a second conductor element 4132, and a third conductor element 4133, and is particularly preferably formed by these. In particular, each of the electrical conductors 413 is formed by one or more metal sheets, for example, made of or containing copper. The magnetic core 412, which comprises or is formed from a magnetically active material such as a ferromagnetic material, can be formed in one piece and, for example, be wound, pressed, or stacked from shaped sheets.

[0036] The first conductor element 4131 and the third conductor element 4133 each pass through the magnetic core 412. Furthermore, the second conductor element 4132, which is arranged outside the magnetic core 412, connects the first conductor element 4131 and the third conductor element 4133. As can be seen in Figure 5, the first conductor element 4131 and the third conductor element 4133 are designed as parallel strips of sheet metal. The second conductor element 4132 is also designed as a strip of sheet metal, which is oriented perpendicular to the first and third conductor elements 4131 and 4133.

[0037] In particular, the first conductor element 4131 has a first connection element 414 and the third conductor element 4133 has a second connection element 415, such that for each phase the first connection element 414 forms an input-side electrical connection of the inductive element 41 and the second connection element 415 forms an output-side electrical connection of the inductive element 41. For each phase, the first connection element 414 is preferably connected directly to the capacitive element 42 according to the embodiments shown in Figures 2 and 3, while the second connection element 415 is connected directly to the frequency converter unit 3. Alternatively, the first connection element 414 for each phase can also be connected directly to the generator unit 1 according to the embodiment shown in Figure 4, while the second connection element 415 is connected directly to the capacitive element 42.

[0038] As can be seen in Figure 5, the first conductor element 4131 extends from the first terminal element 414 at an input side of the magnetic core 412 through the magnetic core 412 to an output side of the magnetic core 412, the second conductor element 4132 leads back to the input side outside the magnetic core 412, and the third conductor element 4131 extends from the input side of the magnetic core 412 through the magnetic core 412 to the output side of the magnetic core 412 to the second terminal element 415. Thus, the inductive element 41 preferably has an electrical conductor 413 for each phase, with two conductor elements 4131, 4133 inside the magnetic core 412 and one conductor element 4132 outside the magnetic core 4132. In particular, for each inductive part of the inductive element 41, apart from the first and second conductor elements 4131, 4133, no further part of the electrical conductor 413 can be passed through the magnetic core 412.

[0039] 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 part. The invention is not limited to the embodiments described. Rather, the invention encompasses every new feature and 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.

[0040] Reference character list

[0041] 1 generator unit

[0042] 2 Power lines

[0043] 3 Frequency converter unit

[0044] 4 filter units

[0045] 31 generator-side bridge

[0046] 32 network-side bridge

[0047] 41 inductive element

[0048] 42 capacitive element

[0049] 200 electrical network

[0050] 201 Transformer

[0051] 202, 203, 204 Filter

[0052] 205 Resistance element

[0053] 411 Coil element

[0054] 412 Magnetic core

[0055] 413 electrical conductor

[0056] 414 first connection element

[0057] 415 second connection element

[0058] 420 Capacitor

[0059] 100 electrical devices

[0060] 1000 electricity-generating plant

[0061] 4131 first conductor element

[0062] 4132 second conductor element

[0063] 4133 third conductor element

Claims

Patent claims 1. Electrical device (100) , comprising - a generator unit (1) for generating an electrical current in a power line (2) with multiple phases, - a frequency converter unit (3) based on SiC- Technology and - a filter unit (4) between the generator unit (1) and the frequency converter unit (3) which is configured for current limiting and voltage rise damping and which has exactly one inductive element (41) configured as a current limiting element and which together with a capacitive element (42) with at least one capacitor per phase forms a voltage rise damping element.

2. Electrical device (100) according to claim 1, wherein the capacitive element (42) is connected upstream of the inductive element (41) as seen from the generator unit (1) and the capacitors are connected in a star configuration.

3. Electrical device (100) according to claim 1, wherein the capacitive element (42) is connected upstream of the inductive element (41) as seen from the generator unit (100) and the capacitors are connected in a delta connection.

4. Electrical device (100) according to one of the preceding claims, wherein the generator unit (1) is part of a power generating plant (1000).

5. Electrical device (100) according to one of the preceding claims, wherein the power line (2) has three phases.

6. Electrical device (100) according to one of the preceding claims, wherein the inductive element (41) has a coil element (411) for each phase, comprising a magnetic core (412) and an electrical conductor (413), a first conductor element (4131), a second conductor element (4132) and a third conductor element (4133), the first conductor element (4131) and the third conductor element (4133) each passing through the magnetic core (412) and being connected to each other by the second conductor element (4132), which is arranged outside the magnetic core (412).

7. Electrical device (100) according to claim 6, wherein for each phase the electrical conductor (413) is formed by one or more metal sheets.

8. Electrical device (100) according to claim 6 or 7, wherein the first conductor element (4131) and the third conductor element (4133) are formed by sheet metal strips aligned parallel to each other and the second conductor element (4132) is formed by a sheet metal strip aligned perpendicular to the first conductor element (4131) and to the third conductor element (4133).

9. Electrical device (100) according to one of claims 6 to 8, wherein for each phase, apart from the first and second conductor elements (4131, 4133), no further part of the electrical conductor (413) passes through the magnetic core (412).

10. Electrical device (100) according to one of claims 6 to 9, wherein for each phase the first conductor element (4131) forms a first connection element (414) which forms an input-side connection of the inductive element (41), and the third conductor element (4133) forms a second Connection element (415) which forms an output-side connection of the inductive element (41).

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