Device for low-voltage circuits

Abstract

This invention relates to an apparatus for a low-voltage circuit, comprising: - a four-pole input terminal for a three-phase AC circuit having a neutral conductor (N), having first, second, and third input phase poles and an input neutral conductor pole; - a two-pole output terminal having a first output phase pole and an output neutral conductor pole; - a first connecting line between the input neutral conductor pole and the output neutral conductor pole; - first, second, and third electronic switching units that perform semiconductor-based closing and opening of electrical connections, wherein the first electronic switching unit is connected to the first input phase pole on the input side, and the second electronic switching unit is connected to the second input phase pole on the input side. - A phase connection and a third electronic switching unit connected to the third input phase on the input side; - First, second, and third electronic switching units connected to the first output phase on the output side; - A voltage sensor for determining the voltage magnitudes of the first, second, and third input phases; - A control unit connected to the voltage sensor, the first, second, and third electronic switching units, and designed to connect the first, second, or third input phase to the first output phase via the corresponding electronic switching unit based on the voltage magnitudes of the first, second, and third input phases, wherein the first output phase is connected to the input phase having the highest voltage.

Description

Technical Field

[0001] The present invention relates to an apparatus for a low-voltage circuit, a method for a three-phase low-voltage circuit having a neutral conductor and three phase conductors, and a system for a three-phase low-voltage circuit having a neutral conductor and three phase conductors. Background Technology

[0002] Low voltage refers to voltages up to 1000 volts of AC or 1500 volts of DC. More specifically, low voltage specifically refers to voltages greater than a value of 50 volts of AC or 120 volts of DC.

[0003] Low-voltage circuits refer to circuits with the voltage mentioned, used for currents from 10 to 6300 amperes. The current mentioned specifically refers to the circuit's rated current or conventional maximum current.

[0004] Therefore, as is common in Europe, a three-phase low-voltage circuit is, for example, a 400-volt (phase-to-phase) or 230-volt (phase-to-neutral) circuit or power grid with three phase conductors and one neutral conductor.

[0005] Typically, three-phase power grids are asymmetrically loaded with single-phase energy sinks or power consumers, such as operating components, storage devices, and / or generators. In recent years, asymmetrical loads have emerged, particularly from electric vehicles or high-power charging equipment for electric vehicles. These asymmetrical loads are expected to increase in the future, increasingly leading to unbalanced loads (asymmetrical loads) in circuits or (electrical) grids. Due to the statistical distribution of the charging process, even evenly distributing single-phase charging terminals across the phases will not result in equilibrium. Similar problems exist in the case of battery storage, for example in private homes that typically operate only on a single phase, or in the case of photovoltaic equipment (in this case, generators). Three-phase AC circuits are generally designed for (approximately) symmetrical loads. Asymmetrical loads result in high compensation currents in the neutral conductor (or neutral wire), which should be avoided.

[0006] Furthermore, CN 106 300 396A discloses a charging switchgear and method for three-phase load compensation in electric vehicles. Additionally, WO 2014 / 191692 A1 discloses phase selection for multiphase devices. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a device for improving the symmetry of a three-phase AC power grid with a neutral conductor, which operates particularly quickly.

[0008] This technical problem is solved by means of an apparatus having features according to the invention, a method having features according to the invention, or a system according to the invention.

[0009] According to the present invention, an apparatus is provided capable of switching the phase of a power consumer to a phase with a smaller load, or associating the phase of a power consumer with a phase of a low-voltage circuit, such that the phases (phase conductors) are loaded as uniformly as possible. According to the present invention, this is performed by an electronic switching unit. According to the present invention, an electronic switching unit refers to a semiconductor-based unit that performs the closing and opening of electrical connections, and not an electromechanical switching unit, i.e., an electromechanical switching unit with mechanical contacts.

[0010] According to the present invention, one criterion for switching a power consumer to a phase can be the magnitude of the voltage. The phase with the highest voltage (the effective value of the voltage) is typically the phase with the lowest load. That is, the power consumer is associated with the phase having the highest voltage.

[0011] According to the present invention, another aspect of the criterion for switching a power consumer to a phase can be the magnitude of the current. The phase with the minimum current (the effective value of the current) is the phase with the minimum load. That is, the power consumer is associated with the phase with the minimum current.

[0012] Furthermore, the device includes a frequency sensor to determine the frequency of the current at the first, second, and third input phase poles connected to the control unit. In one design, the frequency of the voltage at the corresponding input phase poles can also be determined. This has a particular advantage, for example, enabling phase transitions at zero current and / or voltage crossings. Using an electronic switching unit, very rapid phase transitions can also be achieved, making them virtually imperceptible. Thus, switching can be performed without power consumption, and a smooth transition can be achieved during phase transitions.

[0013] In an alternative design, the association can be implemented by a higher-level management system. That is, the device has a communication interface, which can be used, for example, by means of communication signals, to determine the association between the power consumer and the phase (or the association between the phase (phase conductor) on the power consumer side and the phase (phase conductor) on the energy source side).

[0014] This has the particular advantage of enabling a more even load distribution on a three-phase AC power grid, where electronic switching units can perform exceptionally fast (in the range of microseconds or single-digit milliseconds) and, for example, power-free switching, where the number of switching cycles is virtually unlimited in the case of power-free switching.

[0015] Advantageous design solutions are described in this invention.

[0016] In an advantageous design of the invention, the device is arranged within a housing. This has the particular advantage of providing a compact device that can be intermediately linked to connect branches for power consumption in order to achieve a nearly symmetrical load.

[0017] In an advantageous embodiment of the invention, an internal current sensor for determining the current magnitude of the first output phase and / or a voltage sensor for determining the voltage magnitudes of the first, second, and third input phases are provided. These are connected to the control unit. This has the particular advantage of providing an additional standard (additional current or voltage) for phase selection in addition to the standard of voltage or current. This allows for better phase selection or phase correlation.

[0018] In an advantageous embodiment of the invention, the electronic switching unit is implemented as a semiconductor switch, particularly having a power semiconductor based on silicon, silicon carbide, silicon-carbon (Silizium-Kohlenstoff), gallium, gallium nitride, or gallium-nitrogen (Galium-Stickstoff). This has the particular advantage that simple implementation of the semiconductor switch or electronic switching unit is possible, enabling low losses and high switching power.

[0019] In addition, protection is claimed for an advantageous method and system for phase transition in parallel.

[0020] All design options, whether relating in a dependent manner to embodiments of the invention or only to individual features or combinations thereof, result in an improvement in the symmetrical load of a three-phase AC circuit. Attached Figure Description

[0021] The features, characteristics, and advantages of the invention, and how they are implemented, will become clearer and more readily understood in conjunction with the following detailed description of embodiments set forth in conjunction with the accompanying drawings.

[0022] In the attached image:

[0023] Figures 1 to 9 A circuit for illustrating the present invention is shown. Detailed Implementation

[0024] Figure 1A circuit illustrating the present invention is shown, comprising a first phase conductor L1, a second phase conductor L2, a third phase conductor L3, and a neutral conductor N in a three-phase low-voltage circuit. The three-phase low-voltage circuit has branches in which a first power consumer V1 (energy sink) is connected to the first phase conductor L1 and the neutral conductor N, a second power consumer V2 is connected to the second phase conductor L2 and the neutral conductor N, and a third power consumer V3 is connected to the third phase conductor L3 and the neutral conductor N. The connections of the three power consumers V1, V2, and V3 to the phase conductors L1, L2, and L3 are controlled by a three-phase switch S1. If the resistances of the first, second, and third power consumers are equal, then the same power is converted in the power consumers V1, V2, and V3; that is, the first power P1 of the first power consumer V1, the second power P2 of the second power consumer V2, and the third power P3 of the third power consumer V3 are equal; P1 = P2 = P3. Therefore, the first current I1 of the first power consumer V1, the second current I2 of the second power consumer V2, and the third current I3 of the third power consumer V3 are equal in magnitude (referring to the phase conductor currents; the first current I1 flows in the branch from the first phase conductor L1 to the first power consumer V1, the second current I2 flows in the branch from the second phase conductor L2 to the second power consumer V2, and the third current I3 flows in the branch from the third phase conductor L3 to the third power consumer V3), I1 = I2 = I3. Therefore, the current in the neutral conductor N is zero. A symmetrical load exists in the three-phase AC circuit.

[0025] Figure 2 It shows that according to Figure 1 The circuit differs in that the resistances of the first, second, and third power consumers V1, V2, and V3 are different. Therefore, the first, second, and third powers P1, P2, and P3 of these power consumers are also different, with P1 ≠ P2 ≠ P3. Consequently, the first to third currents I1, I2, and I3 are also different, with I1 ≠ I2 ≠ I3. Therefore, the compensation current flows in the neutral conductor N, and In ≠ 0. An asymmetrical load exists in the three-phase AC circuit.

[0026] Figure 3 It shows that according to Figure 1 or Figure 2 The circuit differs in that only the first power consumer V1 is connected to the three-phase AC circuit. This three-phase AC circuit has only a single-phase switch S2. Here, the first current I1 in the branch to the first power consumer V1 is equal to the current in the neutral conductor N, I1 = In. That is, the three-phase AC circuit is asymmetrically loaded by the single-phase power consumer. An asymmetrical load exists in the three-phase AC circuit.

[0027] Figure 4 It shows that according to Figure 3The circuit differs in that, instead of the first power consumer V1, socket box 1 is connected as a branch to the first phase conductor L1 and the neutral conductor N. Second socket box 2 is connected as a branch to the second phase conductor L2 and the neutral conductor N. Third socket box 3 is connected as a branch to the third phase conductor L3 and the neutral conductor N. Similarly, other socket boxes 4…box N can be connected as branches to the phase conductors. Electric vehicles 1, 2, 3, 4, and N can, for example, be connected to the sockets as power consumers.

[0028] Figure 5 The circuit shown is based on the previous figure, except that the socket is implemented as a three-phase circuit, such that the socket is connected as a branch to the three phase conductors L1, L2, L3 and the neutral conductor N.

[0029] Figure 6 A circuit according to the previous figures is shown, the difference being that a device EA according to the invention is provided. This device has:

[0030] - A four-pole input connector for a three-phase AC circuit with a neutral conductor, the four-pole input connector having first, second and third input phase poles E1, E2, E3 and an input neutral conductor pole EN;

[0031] -A two-pole output connector with a first output phase pole AP1 and an output neutral conductor pole AN;

[0032] - The first connection line VN1 between the input neutral conductor EN and the output neutral conductor AN;

[0033] - First, second and third electronic switching units SE1, SE2 and SE3, which perform semiconductor-based closing and opening of electrical connections, wherein the first electronic switching unit SE1 is connected to the first input phase E1 on the input side, the second electronic switching unit SE2 is connected to the second input phase E2 on the input side and the third electronic switching unit SE3 is connected to the third input phase E3 on the input side.

[0034] - The first, second, and third electronic switch units SE1, SE2, and SE3 are connected to the first output phase AP1 on the output side;

[0035] - Voltage sensor A1 or U is used to determine the magnitude of the voltages on the first, second, and third input phases E1, E2, and E3, i.e., the magnitude of the three individual voltages;

[0036] Control unit A4, connected to voltage sensor A1 and first, second, and third electronic switching units SE1, SE2, and SE3, is designed to connect the first, second, or third input phases E1, E2, and E3 to the first output phase AP1 via the corresponding electronic switching units based on the voltage magnitudes of the first, second, and third input phases, wherein the first output phase AP1 is connected to the input phase with the highest voltage. To determine the voltage magnitude, voltage sensor A1 can be connected to the neutral conductor / input neutral conductor EN. That is, for example, if the first input phase E1 has a voltage of 228 volts, the second input phase E2 has a voltage of 230 volts, and the third input phase E3 has a voltage of 232 volts, then the third input phase E3 is connected to the first output phase AP1 via the third electronic switching unit SE3.

[0037] During operation, the correlation can be periodically changed at regular time intervals based on changes in the voltage level. Voltage refers to the effective value of the voltage. That is, for example, the correlation change should only be made after at least several cycles of a sinusoidal oscillation of the AC voltage. For instance, if the voltage level changes, the correlation change should only be made after at least 10 sinusoidal oscillations. This avoids device oscillations and constant correlation changes, allowing a stable state to be established.

[0038] Device EA is arranged, for example, in housing GEH.

[0039] The device EA may also have an internal current sensor A3 or I, for example, inside the housing GEH, which is used to determine the magnitude of the current in the first output phase AP1 and is connected to the control unit A4.

[0040] The electronic switching units SE1, SE2, and SE3 can be implemented as semiconductor switches, particularly those having power semiconductors based on silicon, silicon carbide, silicon carbide, gallium, gallium nitride, or gallium nitride.

[0041] The device EA may have a frequency sensor A2 or f, which is used to determine the frequency of the current and / or voltage of the first, second, and third input phase poles E1, E2, E3, and is connected to the control unit A4. Therefore, a phase transition can be performed, for example, at a zero-crossing.

[0042] In alternative designs that can be arbitrarily combined with the aforementioned design schemes, an external current sensor C is provided, for example, located outside the housing GEH. This external current sensor is used to determine the current magnitude of the phase conductors L1, L2, L3 on the first, second, and third energy source sides of the low-voltage circuit, and, if necessary, the neutral conductor N. These phase conductors L1, L2, L3, and the neutral conductor N are connected via branches to the first, second, and third input phase poles E1, E2, E3, and EN. Typically, additional branches are connected to the power consumption devices at the phase conductors L1, L2, L3, and the neutral conductor N. Figure 6 (Not shown in the image).

[0043] In this design, the control unit A4 is connected, for example, to an external current sensor C, and first, second, and third electronic switch units SE1, SE2, and SE3. It is designed to connect, or has already connected, the first, second, or third input phases E1, E2, and E3 to the first output phase AP1 via the corresponding electronic switch units SE1, SE2, and SE3, based on the current magnitudes of the first, second, and third energy source side phase conductors L1, L2, and L3. The first output phase AP1 is connected to the input phases E1, E2, and E3 of its energy source side phase conductors L1, L2, and L3 that have the minimum current magnitude. That is, for example, if the first phase conductor L1 has a current of 70 amps, the second phase conductor L2 has a current of 40 amps, and the third phase conductor L3 has a current of 60 amps, then the second input phase E2 is connected to the first output phase AP1 via the second electronic switch unit SE2.

[0044] In the example according to the accompanying drawings, the energy source (not shown) is located at the left end of the phase conductors L1, L2, L3 or the neutral conductor N, where the reference numerals L1, L2, L3 or N are drawn.

[0045] In a design scheme that can be arbitrarily combined with the aforementioned design schemes, for example, a communication interface KS is provided on the housing GEH for communication signals that can be communicated via it. In this case, the control unit A4, which is connected to the communication unit, the first, second, and third electronic switch units, can be designed to connect, or has already connected, the first, second, or third input phases E1, E2, and E3 to the first output phase AP1 via the corresponding electronic switch units SE1, SE2, and SE3 according to the communication signals.

[0046] According to the present invention, Figure 6 A device EA is shown, incorporating all these design options, which can be used individually, selectively, or in combination. According to... Figure 6 In the example, the management system D is connected to the communication interface KS, for example. The power consumers or energy sinks B of electric vehicles such as vehicle 1, ..., vehicle N are connected to the first output phase AP1 and the output neutral conductor AN, for example.

[0047] Figure 7 It shows that according to Figure 6 The arrangement differs in that it features a four-pole output connector with first, second, and third output phases AP1, AP2, and AP3, and an output neutral conductor AN. Furthermore, a tenth electronic switch unit SEA is provided, connected to the second input phase E2 on the input side and to the second output phase AP2 on the output side. An eleventh electronic switch unit SEB is also provided, connected to the third input phase E3 on the input side and to the third output phase AP3 on the output side. In this design, only one output phase, in this example the first output phase AP1, can undergo a phase change. This is particularly advantageous for electric vehicle sockets, as charging can be performed in single-phase or three-phase configurations. Therefore, in the case of an approximately symmetrical three-phase load / charging configuration of an electric vehicle, a phase change is not required; in the case of a single-phase load, a phase change can be performed.

[0048] Figure 8 It shows that according to Figure 7 A variation of a portion of the circuit, differing in that:

[0049] - Fourth, fifth, and sixth electronic switch units SE4, SE5, and SE6 are provided. The fourth electronic switch unit SE4 is connected to the first input phase E1 on the input side; the fifth electronic switch unit SE5 is connected to the second input phase E2 on the input side; and the sixth electronic switch unit SE6 is connected to the third input phase E3 on the input side. The fourth, fifth, and sixth electronic switch units SE4, SE5, and SE6 are connected to the second output phase AP2 on the output side.

[0050] - Seventh, eighth, and ninth electronic switch units SE7, SE8, and SE9 are provided. The seventh electronic switch unit SE7 is connected to the first input phase E1 on the input side, the eighth electronic switch unit SE8 is connected to the second input phase E2 on the input side, and the ninth electronic switch unit SE9 is connected to the third input phase E3 on the input side. The seventh, eighth, and ninth electronic switch units SE7, SE8, and SE9 are connected to the third output phase AP3 on the output side.

[0051] Based on the fact that it can be combined with other design schemes Figure 8 (refer to Figure 7In one design, a voltage sensor A1 is provided to determine the voltage magnitudes of the first, second, and third input phases E1, E2, and E3. Additionally, an internal current sensor A3 is provided to determine the current magnitudes of the first, second, and third output phases AP1, AP2, and AP3. A control unit A4 is connected to the voltage sensor A1, the internal current sensor A3, and the first to ninth electronic switch units SE1 to SE9. It is designed to connect the input and output phases based on the voltage magnitudes of the first, second, and third input phases and the current magnitudes of the first, second, and third output phases using corresponding electronic switch units. Specifically, the output phase with the largest current is connected to the input phase with the highest voltage; the output phase with the second largest current is connected to the input phase with the second highest voltage; and the output phase with the third largest current is connected to the input phase with the third highest voltage.

[0052] For example, if the voltage of the first input phase is 228 volts, the voltage of the second input phase is 230 volts, and the voltage of the third input phase is 232 volts; the current of the first output phase is 42 amperes, the current of the second output phase is 44 amperes, and the current of the third output phase is 38 amperes; then connect the second output phase to the third input phase, connect the first output phase to the second input phase, and connect the third output phase to the first input phase.

[0053] Based on the fact that it can be combined with other design schemes Figure 8 (refer to Figure 7 In another design scheme, an external current sensor C, located externally, for example outside the housing GEH, is provided to determine the current magnitudes IP1, IP2, IP3, and INN of the first, second, and third energy source side phase conductors L1, L2, L3 and the neutral conductor N (which is connected to the first, second, and third input phases in the form of a branch). Additionally, an internal current sensor A3 is provided to determine the current magnitudes of the first, second, and third output phases AP1, AP2, and AP3. The control unit A4 is connected to the external current sensor C, the internal current sensor A3, and the first to ninth electronic switch units SE1 to SE9, and is designed to connect the input and output phases based on the current magnitudes IP1, IP2, IP3 of the first, second, and third energy source side phase conductors (and, if necessary, the neutral conductor), and, if necessary, INN, and based on the current magnitudes of the first, second, and third output phases (AP1, AP2, AP3), using the corresponding electronic switch units SE1 to SE9. Wherein:

[0054] The output phase with the largest current is connected to the input phase with the smallest current on its energy source side conductor; the output phase with the second largest current is connected to the input phase with the second smallest current on its energy source side conductor; and the output phase with the third largest current is connected to the input phase with the third smallest current on its energy source side conductor. For example, if the current IP1 of the first phase conductor L1 is 500 amps, the current IP2 of the second phase conductor L2 is 400 amps, and the current IP3 of the third phase conductor L3 is 250 amps; if the current of the first output phase is 42 amps, the current of the second output phase is 44 amps, and the current of the third output phase is 38 amps; then the second output phase is connected to the third input phase, the first output phase is connected to the second input phase, and the third output phase is connected to the first input phase.

[0055] Based on the fact that it can be combined with other design schemes Figure 8 (refer to Figure 7 In one design, only a communication interface KS for communication signals is provided. The control unit, connected to the communication interface KS and the first to ninth electronic switching units SE1 to SE9, is designed to connect at least one input phase to an output phase via corresponding electronic switching units according to the communication signal. Specifically, two input phases are connected to two output phases via corresponding electronic switching units, or three input phases are connected to three output phases via corresponding electronic switching units. In this configuration, one phase is connected from the input phase to the output phase, ensuring that two different phases never connect to each other.

[0056] Figure 9 It shows that according to Figure 5 The circuit differs in that, in at least one or all of the socket boxes 1 to N, a circuit based on... Figure 6 , 7 Or the device EA according to the invention of 8.

[0057] The invention, including its advantages, will now be described again in other forms.

[0058] Based on power semiconductors (silicon, silicon carbide / SiC, or gallium nitride / GaN), phase selection can be performed without mechanical switching elements. For example, the integrated measurement and control technologies of the electronic switching unit can independently identify which phase should be switched to, using determined current and / or voltage values. This can be done continuously before or during operation, or adjusted or switched before or during operation. The electronic switching unit can also be selected and controlled by an external system, such as a network control technology or a (charging) management system.

[0059] This has the following advantages:

[0060] - The semiconductor-based electronic switching unit that performs the closing and opening of electrical connections, i.e., switching, is not subject to mechanical wear, and therefore can perform more repeated switching.

[0061] - The phase selection (commutation) can be changed without problems and with minimal disruption during operation.

[0062] - By using wide-bandgap power semiconductors (based on SiC, based on GaN), unnecessary power losses caused by coils and drives for electromechanical switching elements are eliminated.

[0063] - External / upper-level systems can provide further services from the data and information provided, and act "from the outside" on the electronic switching unit (based on semiconductors).

[0064] - Sensors can provide real-time measurements to control the electronic switching unit.

[0065] Semiconductor-based electronic switching units can switch between two phases in less than a millisecond, thereby commutating power.

[0066] Semiconductor-based electronic switching units are capable of performing millions of switching operations, and therefore, unlike electromechanical switching devices, they are also capable of performing switching operations that meet operational requirements.

[0067] - The series resistance of the electronic switch unit in the ON state is approximately equal to the contact resistance of the mechanical contacts. This eliminates power losses in the contactor coil and heat losses in the bimetallic component of the thermally detonating trip unit.

[0068] - Using communication interfaces, such as TCP / IP, Modbus, etc., IP-based communication can be carried out with the upper-level system.

[0069] Although the invention has been shown and described in more detail by way of examples, the invention is not limited to the disclosed examples, and those skilled in the art can derive other modifications therefrom without departing from the scope of protection of the invention.

Claims

1. A device (EA) for a low-voltage circuit, the device comprising: - A four-pole input connector for a three-phase AC circuit with a neutral conductor (N), the four-pole input connector having a first input phase pole, a second input phase pole, and a third input phase pole (E1, E2, E3) and an input neutral conductor pole (EN). - A two-pole output connector, wherein the two-pole output connector has a first output phase pole (AP1) and an output neutral conductor pole (AN). - The first connection line (VN1) between the input neutral conductor and the output neutral conductor. - A first electronic switching unit, a second electronic switching unit, and a third electronic switching unit (SE1, SE2, SE3) that perform semiconductor-based closing and opening of electrical connections, wherein, The first electronic switch unit (SE1) is connected to the first input phase (E1) on the input side, the second electronic switch unit (SE2) is connected to the second input phase (E2) on the input side, and the third electronic switch unit (SE3) is connected to the third input phase (E3) on the input side. - The first electronic switch unit, the second electronic switch unit, and the third electronic switch unit (SE1, SE2, SE3) are connected to the first output phase (AP1) on the output side. - Voltage sensor (A1), the voltage sensor being used to determine the voltage magnitudes of the first input phase, the second input phase, and the third input phase (E1, E2, E3), - A control unit (A4), which is connected to the voltage sensor (A1), the first electronic switch unit, the second electronic switch unit, and the third electronic switch unit (SE1, SE2, SE3), and the control unit is designed to... Based on the voltage magnitudes of the first, second, and third input phases (E1, E2, E3), the first, second, or third input phase (E1, E2, E3) is connected to the first output phase (AP1) using corresponding electronic switching units. The first output phase (AP1) is connected to the input phase with the highest voltage. The electronic switching units (SE1, SE2, SE3) are implemented as semiconductor switches. A frequency sensor (A2) is included to determine the frequency of the current at the first, second, and third input phase poles (E1, E2, E3). This frequency sensor is connected to the control unit (A4) to enable phase transition when the current crosses zero. During operation, the correlation is periodically changed at certain time intervals according to changes in voltage level, with the change occurring at least after several cycles of sinusoidal oscillation of the AC voltage.

2. The apparatus (EA) according to claim 1, Its features are, An internal current sensor (A3) is provided to determine the magnitude of the current in the first output phase (AP1), and the internal current sensor is connected to the control unit (A4).

3. The apparatus (EA) according to claim 1 or 2, characterized in that, The electronic switching units (SE1, SE2, SE3) include power semiconductors based on silicon, silicon carbide, silicon carbide, gallium, gallium nitride, or gallium nitride.

4. An apparatus (EA) for a low-voltage circuit, the apparatus comprising: - A four-pole input connector for a three-phase AC circuit with a neutral conductor (N), the four-pole input connector having a first input phase pole, a second input phase pole, and a third input phase pole (E1, E2, E3) and an input neutral conductor pole (EN). - A four-pole output connector, wherein the four-pole output connector has a first output phase pole, a second output phase pole, and a third output phase pole (AP1, AP2, AP3) and an output neutral conductor pole (AN). - The first connection line (VN1) between the input neutral conductor (EN) and the output neutral conductor (AN), - A first electronic switching unit, a second electronic switching unit, and a third electronic switching unit (SE1, SE2, SE3) that perform semiconductor-based closing and opening of electrical connections, wherein, The first electronic switch unit (SE1) is connected to the first input phase (E1) on the input side, the second electronic switch unit (SE2) is connected to the second input phase (E2) on the input side, and the third electronic switch unit (SE3) is connected to the third input phase (E3) on the input side. The first electronic switch unit, the second electronic switch unit, and the third electronic switch unit (SE1, SE2, SE3) are connected to the first output phase (AP1) on the output side. - A fourth, fifth, and sixth electronic switching unit (SE4, SE5, SE6) that perform semiconductor-based closing and opening of electrical connections, wherein the fourth electronic switching unit (SE4) is connected to the first input phase (E1) on its input side, the fifth electronic switching unit (SE5) is connected to the second input phase (E2) on its input side, and the sixth electronic switching unit (SE6) is connected to the third input phase (E3) on its input side. The fourth, fifth, and sixth electronic switch units (SE4, SE5, SE6) are connected to the second output phase (AP2) on the output side. - A seventh, eighth, and ninth electronic switch unit (SE7, SE8, SE9) that perform semiconductor-based closing and opening of electrical connections, wherein the seventh electronic switch unit (SE7) is connected to the first input phase (E1) on its input side, the eighth electronic switch unit (SE8) is connected to the second input phase (E2) on its input side, and the ninth electronic switch unit (SE9) is connected to the third input phase (E3) on its input side. The seventh, eighth, and ninth electronic switch units (SE7, SE8, SE9) are connected to the third output phase (AP3) on the output side. - Voltage sensor (A1), the voltage sensor being used to determine the voltage magnitudes of the first input phase, the second input phase, and the third input phase (E1, E2, E3), - An internal current sensor (A3) is used to determine the current magnitudes of the first output phase, the second output phase, and the third output phase (AP1, AP2, AP3). - A control unit (A4), which is connected to the voltage sensor (A1), the internal current sensor (A3), and the first to ninth electronic switching units (SE1, ..., SE9), and the control unit is designed to... Based on the voltage magnitudes of the first, second, and third input phases (E1, E2, E3) and the current magnitudes of the first, second, and third output phases (AP1, AP2, AP3), the input phases are connected to the output phases using corresponding electronic switching units, wherein: Connect the output phase with the maximum current to the input phase with the highest voltage. Connect the output phase with the second largest current to the input phase with the second highest voltage. Connect the output phase with the third largest current to the input phase with the third highest voltage. The electronic switching units (SE1, ..., SE9) are implemented as semiconductor switches. A frequency sensor (A2) is included to determine the frequency of the current at the first, second, and third input phase poles (E1, E2, E3). This frequency sensor is connected to the control unit (A4) to enable phase transition when the current crosses zero. During operation, the correlation is periodically changed at certain time intervals according to changes in voltage level, with the change occurring at least after several cycles of sinusoidal oscillation of the AC voltage.

5. The apparatus (EA) according to claim 4, characterized in that, The electronic switching unit (SE1, ..., SE9) includes a power semiconductor based on silicon, silicon carbide, silicon carbide, gallium, gallium nitride, or gallium nitride.

6. An apparatus (EA) for a low-voltage circuit, the apparatus comprising: - A four-pole input connector for a three-phase AC circuit with a neutral conductor (N), the four-pole input connector having a first input phase pole, a second input phase pole, and a third input phase pole (E1, E2, E3) and an input neutral conductor pole (EN). - A four-pole output connector, wherein the four-pole output connector has a first output phase pole, a second output phase pole, and a third output phase pole (AP1, AP2, AP3) and an output neutral conductor pole (AN). - The first connection line (VN1) between the input neutral conductor (EN) and the output neutral conductor (AN), - A first electronic switching unit, a second electronic switching unit, and a third electronic switching unit (SE1, SE2, SE3) that perform semiconductor-based closing and opening of electrical connections, wherein, The first electronic switch unit (SE1) is connected to the first input phase (E1) on the input side, the second electronic switch unit (SE2) is connected to the second input phase (E2) on the input side, and the third electronic switch unit (SE3) is connected to the third input phase (E3) on the input side. The first electronic switch unit, the second electronic switch unit, and the third electronic switch unit (SE1, SE2, SE3) are connected to the first output phase (AP1) on the output side. - A fourth, fifth, and sixth electronic switching unit (SE4, SE5, SE6) that perform semiconductor-based closing and opening of electrical connections, wherein the fourth electronic switching unit (SE4) is connected to the first input phase (E1) on its input side, the fifth electronic switching unit (SE5) is connected to the second input phase (E2) on its input side, and the sixth electronic switching unit (SE6) is connected to the third input phase (E3) on its input side. The fourth, fifth, and sixth electronic switch units (SE4, SE5, SE6) are connected to the second output phase (AP2) on the output side. - A seventh, eighth, and ninth electronic switch unit (SE7, SE8, SE9) that perform semiconductor-based closing and opening of electrical connections, wherein the seventh electronic switch unit (SE7) is connected to the first input phase (E1) on its input side, the eighth electronic switch unit (SE8) is connected to the second input phase (E2) on its input side, and the ninth electronic switch unit (SE9) is connected to the third input phase (E3) on its input side. The seventh, eighth, and ninth electronic switch units (SE7, SE8, SE9) are connected to the third output phase (AP3) on the output side. - Communication interface (KS) for communication signals, - A control unit (A4), which is connected to the communication interface (KS) and the first to ninth electronic switch units (SE1, ..., SE9), and the control unit is designed to... Based on the communication signal, at least one input phase is connected to the output phase using corresponding electronic switching units (SE1, ..., SE9). The electronic switching units (SE1, ..., SE9) are implemented as semiconductor switches. A frequency sensor (A2) is included to determine the frequency of the current at the first, second, and third input phase poles (E1, E2, E3). This frequency sensor is connected to the control unit (A4) to enable phase transition when the current crosses zero. During operation, the correlation is periodically changed at certain time intervals according to changes in voltage level, with the change occurring at least after several cycles of sinusoidal oscillation of the AC voltage.

7. The apparatus (EA) according to claim 6, Its features are, Based on the communication signal, the two input phases are connected to the two output phases by means of corresponding electronic switching units (SE1, ..., SE9).

8. The apparatus (EA) according to claim 6 or 7, Its features are, Based on the communication signal, the three input phases are connected to the three output phases by means of corresponding electronic switching units (SE1, ..., SE9).

9. The apparatus (EA) according to claim 6, characterized in that, The electronic switching unit (SE1, ..., SE9) includes a power semiconductor based on silicon, silicon carbide, silicon carbide, gallium, gallium nitride, or gallium nitride.

10. A method for a three-phase low-voltage circuit having a neutral conductor (N) and first-phase conductors, a second-phase conductor, and a third-phase conductor (L1, L2, L3), - It has a first electronic switching unit, a second electronic switching unit, and a third electronic switching unit (SE1, SE2, SE3), which perform semiconductor-based closing and opening of electrical connections, wherein, The first electronic switch unit (SE1) is connected to the first phase conductor (L1) on the input side, the second electronic switch unit (SE2) is connected to the second phase conductor (L2) on the input side, and the third electronic switch unit (SE3) is connected to the third phase conductor (L3) on the input side. The first electronic switch unit, the second electronic switch unit, and the third electronic switch unit (SE1, SE2, SE3) are connected to the first output phase (AP1) on the output side. - Voltage sensor (A1), the voltage sensor being used to determine the voltage magnitudes of the first phase conductor, the second phase conductor, and the third phase conductor (L1, L2, L3), -Based on the voltage magnitudes of the first, second, and third phase conductors (L1, L2, L3), the first, second, or third phase conductor (L1, L2, L3) is connected to the first output phase (AP1) using corresponding electronic switching units (SE1, SE2, SE3), wherein the first output phase (AP1) is connected to the phase conductor with the highest voltage. The electronic switching units (SE1, SE2, SE3) are implemented as semiconductor switches. A frequency sensor (A2) is included to determine the frequency of the current at the first, second, and third input phase poles (E1, E2, E3). This frequency sensor is connected to a control unit (A4) to enable phase transition when the current crosses zero. During operation, the correlation is periodically changed at certain time intervals according to changes in voltage level, with the change occurring at least after several cycles of sinusoidal oscillation of the AC voltage.

11. The method according to claim 10, characterized in that, The electronic switching units (SE1, SE2, SE3) include power semiconductors based on silicon, silicon carbide, silicon carbide, gallium, gallium nitride, or gallium nitride.

12. A system for a three-phase low-voltage circuit having a neutral conductor (N) and a first phase conductor, a second phase conductor, and a third phase conductor (L1, L2, L3), wherein the first phase conductor, the second phase conductor, and the third phase conductor are connected to an energy source on one side, and on the other side, a plurality of single-phase and / or three-phase leads for power consumption are connected to the first phase conductor, the second phase conductor, and the third phase conductor. in, Each phase conductor (L1, L2, L3) has an external current sensor (C) on the energy source side, which is used to determine the current magnitude of the first phase conductor, the second phase conductor, and the third phase conductor (L1, L2, L3). The device (EA) according to any one of claims 1 to 9 has at least one lead wire. The external current sensor (C) is connected to at least one such device (EA).

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