Switching system for power switching of electrical currents

Abstract

The present invention relates to a switching system (1) for switching electrical currents, comprising a first circuit breaker (4a), a second circuit breaker (4b), and a driver switching system (38, 38a, 38b), wherein the first circuit breaker (4a) and the second circuit breaker (4b) are configured to switch electrical currents in an electrical circuit (6), wherein the driver switching system (38, 38a, 38b) is configured to place the first circuit breaker (4a) and the second circuit breaker (4b) in a switched-on and switched-off state, wherein the driver switching system (38, 38a) is configured to switch the first circuit breaker (4a) and the second circuit breaker (4b) on and off, wherein the driver switching system (38, 38a, 38b) is configured to apply a first intermediate voltage (9) to the first circuit breaker (4b) before switching off the second circuit breaker (4b),so that the first intermediate voltage (9) is applied to the first circuit breaker (4a) when the second breaking voltage (11) is applied to the second circuit breaker (4b) and / or to apply a second intermediate voltage (12) to the second circuit breaker (4b) before switching off the first circuit breaker (4a), so that the second intermediate voltage (12) is applied to the second circuit breaker (4b) when the first breaking voltage (8) is applied to the first circuit breaker (4a).

Description

State of the art

[0001] The present invention relates to a switching system for power switching of electrical currents.

[0002] To switch high currents, power switches are required that can withstand the high electrical and thermal loads of high currents. Such power switches can be switched off as mechanical switches or as semiconductor switches. Power switches designed as semiconductor switches, when operated correctly, have a longer service life and are more compact in design than power switches designed as mechanical switches. In more complex electrical circuits in which at least two semiconductor switches are connected in series, for example half-bridge circuits, the switching-on process of a first semiconductor switch results in an electrical load on the second semiconductor switch. By applying a switching-off voltage to a switched-on first semiconductor switch, the first semiconductor switch changes from the switched-on state to the switched-off state.Here, by means of capacitive coupling, the switching-off process of the first semiconductor switch influences a voltage applied to the second semiconductor switch and reduces this voltage applied to the second semiconductor switch. Disclosure of the invention

[0003] The switching system according to the invention reduces an inadmissible electrical load on the components of the switching system and increases the service life of the components of the switching system by reducing the voltage loads occurring in the components.

[0004] The switching system for switching electrical currents comprises a first power switch, a second power switch, and a driver switching system. The first power switch and the second power switch are configured to switch electrical currents to the electrical circuit. The driver switching system is configured to place the first power switch and the second power switch into an on and off state. The driver switching system is configured to switch the first power switch on by applying a first switch-on voltage and to switch it off by applying a first switch-off voltage. The driver switching system is configured to switch the second power switch on by applying a second switch-on voltage and to switch it off by applying a second switch-off voltage.The driver switching system is configured to apply a first intermediate voltage to the first circuit breaker before the second circuit breaker is turned off, such that the first intermediate voltage is present at the first circuit breaker when the second breaking voltage is applied to the second circuit breaker. Alternatively or additionally, the driver switching system is configured to apply a second intermediate voltage to the second circuit breaker before the first circuit breaker is turned off, such that the second intermediate voltage is present at the second circuit breaker when the first breaking voltage is applied to the first circuit breaker. The first intermediate voltage is greater than the first breaking voltage and leaves the first circuit breaker in a turned off state. The second intermediate voltage is greater than the second breaking voltage and leaves the second circuit breaker in a turned off state.

[0005] By reducing the first make voltage to the first break voltage at the first circuit breaker, the voltage applied to the second circuit breaker drops in the second circuit breaker. If the voltage applied to the second circuit breaker drops below a critical voltage value, the second circuit breaker will be damaged. The same applies in the opposite case, in which the second make voltage is reduced to the second break voltage at the second circuit breaker, for the first circuit breaker. In this latter case, if the voltage drops below a critical value, the voltage applied to the first circuit breaker will drop and the first circuit breaker will be damaged.

[0006] By increasing the voltage applied to the second circuit breaker from the second breaking voltage to the second intermediate voltage, and maintaining the second intermediate voltage while reducing the first making voltage at the first circuit breaker to the first breaking voltage, the intermediate voltage applied to the second circuit breaker is prevented from falling below the critical voltage value at the second circuit breaker. The same applies accordingly in the reverse case.By raising the voltage applied to the first circuit breaker from the first breaking voltage to the first intermediate voltage and maintaining the first intermediate voltage at the first circuit breaker while reducing the second making voltage to the second breaking voltage at the second circuit breaker, the voltage applied to the first circuit breaker is prevented from falling below the critical voltage value. This prevents electrical stress on the first circuit breaker and / or the second circuit breaker and prevents damage to the first circuit breaker and / or the second circuit breaker without limiting the functionality of the first circuit breaker and / or the second circuit breaker. The reduced electrical stress increases the service life of the first circuit breaker and / or the second circuit breaker, respectively.

[0007] The subclaims show preferred developments of the invention.

[0008] The driver switching system preferably has a first driver circuit and a second driver circuit. The first power switch has a third control input. The second power switch has a fifth control input. The first driver circuit is connected to the third control input. The first driver circuit is configured to control the first power switch. The second driver circuit is connected to the fifth control input and configured to control the second power switch. An advantage of this embodiment can be that the first power switch and the second power switch can be controlled completely independently of one another by the first driver circuit and the second driver circuit.

[0009] Particularly preferably, the first driver circuit comprises a first switching unit and a second switching unit. The first switching unit and the second switching unit are connected to the third control input. The first switching unit is configured to place the first circuit breaker in an on state. The second switching unit is configured to place the first circuit breaker in an off state. An advantage of this embodiment may be that the state of the first circuit breaker can be controlled in a controlled manner by the first switching unit and the second switching unit.

[0010] Advantageously, the second driver circuit comprises a fourth switching unit and a fifth switching unit. The fourth switching unit and the fifth switching unit are connected to the fifth control input. The fourth switching unit is configured to place the second circuit breaker in an on state. The fifth switching unit is configured to place the second circuit breaker in an off state. An advantage of this embodiment may be that the state of the second circuit breaker can be specifically controlled by the fourth switching unit and the fifth switching unit.

[0011] Particularly advantageously, the first switching unit has a first supply input, a first supply output, and a first control input. The second switching unit has a second supply input, a second supply output, and a second control input. The first switching unit can be switched on and off using the first control input, and the second switching unit can be switched on and off using the second control input. The third control input, the first supply input, and the second supply output are electrically connected to one another via a first connection point. One advantage of this embodiment can be that a space-saving design for implementing the driver circuit can be realized.

[0012] The fourth switching unit preferably has a fourth supply input, a fourth supply output, and a fourth control input. The fifth switching unit has a fifth supply input, a fifth supply output, and a fifth control input. The fourth switching unit can be switched on and off using the fifth control input. The fifth switching unit can be switched on and off using the fifth control input. The fifth control input, the fourth supply input, and the fifth supply output are electrically connected to one another via a second connection point. An advantage of this embodiment can be that this configuration enables a particularly space-saving design for implementing the driver circuit.

[0013] Preferably, a first electrical resistor is connected in series between the first supply input and the first connection point. Alternatively and / or additionally, a second electrical resistor is connected in series between the second supply output and the first connection point. An advantage of this embodiment may be that damage to the first circuit breaker is prevented by means of the first electrical resistor and / or the second electrical resistor.

[0014] Preferably, a fourth electrical resistor is connected in series between the fourth supply input and the second connection point. Alternatively or additionally, a fifth electrical resistor is connected in series between the fifth supply output and the fourth and second connection points. An advantage of this embodiment may be that the fourth electrical resistor and the fifth electrical resistor prevent overloading of the second circuit breaker.

[0015] Preferably, the first electrical resistance is selected to be as low as possible without causing damage to the first circuit breaker when a voltage applied to the third control input builds up. The second electrical resistance is selected to be as low as possible without causing damage to the first circuit breaker when the voltage applied to the third control input drops. An advantage of this embodiment can be that damage to the first circuit breaker is prevented and, at the same time, the fastest possible build-up and reduction of the voltage at the first circuit breaker, and thus the fastest possible switching on and off of the first circuit breaker, is achieved.

[0016] Particularly preferably, the fourth electrical resistance is selected to be so low that the reduction of a voltage applied to the fifth control input does not cause damage to the second circuit breaker. The fifth electrical resistance is selected to be as low as possible without the reduction of the voltage applied to the fifth control input causing damage to the second circuit breaker. An advantage of this embodiment can be that the second circuit breaker can thus switch to an on state and an off state as quickly as possible without endangering the second circuit breaker.

[0017] The switching system preferably comprises a first reference switching unit. The first reference switching unit has a first reference supply input, a first reference supply output, and a first reference control input. The first reference supply output is electrically connected to the first connection point via a third electrical resistor. The first control unit is configured to switch the first reference switching unit on and / or off using the first reference control input. An advantage of this embodiment may be that a precise first intermediate voltage can be applied using the first reference switching unit.

[0018] Advantageously, the switching system comprises a second reference switching unit. The second reference switching unit comprises a second reference supply input, a second reference supply output, and a second reference control input. The second reference supply output is electrically connected to the second connection point via a sixth electrical resistor. A second control unit is configured to switch the second reference switching unit on and / or off using the second reference control input. An advantage of this embodiment may be that a precise second intermediate voltage can be applied to the second power switch using the second reference switching unit.

[0019] Preferably, the first control unit is configured to switch on the first reference switching unit to apply the first intermediate voltage to the first circuit breaker before switching off the second circuit breaker.

[0020] Particularly preferably, the second control unit is configured to switch on the second reference switching unit to apply the second intermediate voltage to the second circuit breaker before the first circuit breaker is switched off. An advantage of this embodiment may be that the first intermediate voltage and / or the second intermediate voltage can thus be applied precisely.

[0021] Preferably, the first switching unit and / or the second switching unit and / or the first reference switching unit and / or the third switching unit and / or the fourth switching unit and / or the second reference switching unit and / or the first power switch and / or the second power switch are designed as semiconductor switches. An advantage of this embodiment is a cost-effective and space-saving design of the units just listed.

[0022] Particularly preferably, the first switching unit and / or the second switching unit and / or the first reference switching unit and / or the third switching unit and / or the fourth switching unit are configured as MOSFETs, in particular as normally-off MOSFETs. An advantage of this embodiment may be that no electrical energy needs to be consumed to maintain a blocking state in the above units. Thus, the switching system is more energy-efficient.

[0023] Preferably, the first supply output is connected to a first electrical voltage level, and the second supply output is connected to a second electrical voltage level. The first supply reference input is connected to a first reference voltage level. The first voltage level is not equal to, in particular greater than, the second voltage level, and the first voltage level and the second voltage level are related to the reference voltage level.

[0024] Particularly preferably, the third supply output is connected to the first electrical voltage level, and the fifth supply input is connected to the second electrical voltage level. The second reference supply input is connected to the reference voltage level.

[0025] Particularly preferably, the first power switch has a first power switch input and a first power switch output. The first power switch has a first transistor, in particular a normally-off MOSFET. The first transistor is electrically connected to the third control input, the first power switch input, and the first power switch output. A first diode is connected in antiparallel to the first transistor, to the first power switch input and the first power switch output.

[0026] Particularly preferably, the second power switch has a second power switch input and a second power switch output. The second power switch has a second transistor, in particular a normally-off MOSFET. The second transistor is electrically connected to the fifth control input, the second power switch input, and the second power switch output. A second diode is connected in antiparallel to the second transistor, to the second power switch input and the second power switch output.

[0027] Preferably, the first electrical resistance and the second electrical resistance and / or the third electrical resistance are of equal magnitude. An advantage of this embodiment may be that it reduces the complexity of the switching system.

[0028] Particularly preferably, a fourth electrical resistor and a fifth electrical resistor and / or the sixth electrical resistor are of equal size. An advantage of this embodiment may be that the complexity of the switching system is reduced.

[0029] Particularly preferably, a further electrical resistor is connected in series between the first connection point and the third control input, or between the second connection point and the fifth control input. An advantage of this embodiment may be that, regardless of the selection of the first, second, and third electrical resistors, or the fourth, fifth, and sixth electrical resistors, a maximum speed and thus a maximum load on the first or second half-circuit breaker for voltage build-up and voltage reduction can be controlled.

[0030] Particularly preferably, in this embodiment, a first electrical resistor, a second electrical resistor, and a third electrical resistor, or a fourth electrical resistor, a fifth electrical resistor, and a sixth electrical resistor, can be omitted. One advantage of this embodiment may be that it reduces the number of components of the switching system. Short description of the drawings

[0031] Embodiments of the invention are described in detail below with reference to the accompanying drawings. In the drawing: Fig. 1 is a schematic representation of a switching system according to a first embodiment of the invention, Fig. 2 a schematic representation of a second subsystem of the switching system according to the first embodiment of the invention, Fig. 3 a schematic representation of voltage curves applied by a control unit to a first circuit breaker and a second circuit breaker, Fig. 4 a schematic representation of a second subsystem of the switching system according to a second embodiment of the invention, and Fig. 5 a schematic representation of a switching system according to the second embodiment of the invention. Embodiments of the invention

[0032] Fig. 1 shows a schematic representation of a switching system 1 according to a first exemplary embodiment of the invention. The switching system 1 for switching electrical currents has a first power switch 4a, a second power switch 4b, and a driver switching system 38, 38a, 38b. The first power switch 4a and the second power switch 4b are configured to switch electrical currents in an electrical circuit 6. The driver switching system 38, 38a, 38b is configured to place the first power switch 4a and the second power switch 4b in a switched-on and switched-off state. The driver switching system 38, 38a is configured to switch the first power switch 4a on by applying the first switch-on voltage 7 and to switch it off by applying a first switch-off voltage 8.The driver switching system 38, 38b is configured to switch on the second circuit breaker 4b by applying a second switch-on voltage 10 and to switch it off by applying a second switch-off voltage 11. The driver switching system 38, 38a, 38b is configured to apply a first intermediate voltage 9 to the first circuit breaker 4a before switching off the second circuit breaker 4b, such that the first intermediate voltage 9 is present at the first circuit breaker 4a when the second switch-off voltage 11 is present at the second circuit breaker 4b. Alternatively or additionally, the driver system is configured to apply a second intermediate voltage 12 to the second circuit breaker 4b before switching off the first circuit breaker 4a, such that the intermediate voltage 12 is present at the second circuit breaker 4b when the switch-off voltage 8 is present at the first circuit breaker 4a. The first intermediate voltage 9 is greater than the first switch-off voltage 8.The first intermediate voltage leaves the first circuit breaker in an open state. The second intermediate voltage 12 is greater than the second break voltage 11. The second intermediate voltage 12 leaves the second circuit breaker 4b in an open state.

[0033] Fig. Figure 2 shows a schematic representation of a second subsystem 1b of the switching system 1 according to the first embodiment of the invention. The driver switching system 38, 38a, 38b has a first driver circuit 38a and a second driver circuit 38b. The first power switch 4a has a third control input 13a, and the second power switch 4b has a fifth control input 13b. The first driver circuit 38a is connected to the third control input 13a and is configured to control the first power switch 4a. The second driver circuit 38b is connected to the fifth control input 13b and is configured to control the second power switch 4b.

[0034] The first driver circuit 38a has a first switching unit 2a and a second switching unit 3a. The first switching unit 2a and the second switching unit 3a are connected to the third control input 13a. The first switching unit 2a is configured to put the first power switch 4a into an on state. The second switching unit 3a is configured to put the first power switch 4a into an off state. The second driver circuit 38b has a fourth switching unit 2b and a fifth switching unit 3b. The fourth switching unit 2b and the fifth switching unit 3b are connected to the fifth control input 13b. The fourth switching unit 2b is configured to put the second power switch 4b into an on state. The fifth switching unit 3b is configured to put the second power switch 4b into an off state.

[0035] The first switching unit 2a has a first supply input 15a and a first supply output 14a and a first control input 16a. The second switching unit 3a has a second supply input 15a and a second supply output 17a and a second supply input 19a. The first switching unit 2a can be switched on and off using the first control input 16a. The second switching unit 3a can be switched on and off using the second control input 19a. The third control input 13a, the first supply input 15a and the second supply output 17a are electrically connected to one another via a first connection point 20a. The fourth switching unit 2b has a fourth supply input 15b, a first supply output 14b and a first control input 16b. The fifth switching unit 3b has a fifth supply input 18b, a fifth supply output 17b and a fifth control input 19b.The fourth switching unit 2b can be switched on and off via the fourth control input 16b. The fifth switching unit 3b can be switched on and off via the fifth control input 19b. The fifth control input 13b, the fourth supply input 14b, and the fifth supply output 17b are electrically connected to one another via a second connection point 20b.

[0036] A first electrical resistor 21a is connected in series between the first supply input 15a and the first connection point 20a. A second electrical resistor 22a is connected in series between the second supply output 17a and the first connection point 20a. A fourth electrical resistor 21b is connected in series between the fourth supply input 15b and the second connection point 20b. A fifth electrical resistor 22b is connected in series between the fifth supply output 17b and the second connection point 20b.

[0037] The first electrical resistance 21a is selected to be as low as possible without causing damage to the first circuit breaker 4a when a voltage is applied to the third control input 13a. The second electrical resistance 22a is selected to be as low as possible without causing damage to the first circuit breaker 4a when the voltage applied to the third control input 13a is reduced. The fourth electrical resistance 21b is selected to be as low as possible without causing damage to the second circuit breaker 4b when a voltage is applied to the fifth control input 13b is increased. The fifth electrical resistance 22b is selected to be as low as possible without causing damage to the second circuit breaker 4b when the voltage applied to the fifth control input 13a is reduced.

[0038] Fig. 3 shows a schematic representation of voltage waveforms 39, 40 applied by the first driver circuit 38a to the first power switch 4a and by the second driver circuit 38b to the second power switch 4b. The first turn-on voltage 7 and the second turn-on voltage 10 have a positive magnitude. The first turn-off voltage 8 and the second turn-off voltage 11 are identical. The first turn-off voltage 8 and the second turn-off voltage 11 have a negative magnitude. The first intermediate voltage 9 and the second intermediate voltage 12 are identical. The first intermediate voltage 9 and the second intermediate voltage 12 have a zero magnitude.

[0039] Initially, a first turn-on voltage 7 is applied to the first circuit breaker 4a and a second turn-off voltage 11 is applied to the second circuit breaker 4b. The first circuit breaker 4a is therefore in a turned-on state. The second circuit breaker 4b is in a turned-off state. At a first point in time 23, the voltage 40 applied to the second circuit breaker 4b is raised from the second turn-off voltage 11 to the second intermediate voltage 12. The first turn-on voltage 7 continues to be applied to the first circuit breaker 4a. The second circuit breaker 4b remains in a turned-off state and the first circuit breaker 4a remains in a turned-on state. At a second point in time 24, a voltage 39 applied to the first circuit breaker 4a is reduced from the first turn-on voltage 7 to the first turn-off voltage 8.In this case, the second intermediate voltage 12 continues to be applied to the second power switch 4b. At a third time 25, a voltage 40 applied to the second power switch 4b is increased from the second intermediate voltage 12 to the second switch-on voltage 10.

[0040] After the third time 25, the first circuit breaker 4a is in an off state, and the second circuit breaker 4b is in an on state. During the second time 24, the voltage applied to the second circuit breaker 4b drops as a result of capacitive coupling between the first circuit breaker 4a and the second circuit breaker 4b. If the second breaking voltage 11b were applied to the second circuit breaker 4b, the voltage applied to the second circuit breaker 4b would drop below a critical voltage value. By applying the second intermediate voltage 12 to the second circuit breaker 4b, the voltage applied to the second circuit breaker 4b does not drop below the critical voltage value during a change from the first making voltage 7 applied to the first circuit breaker 4a to the first breaking voltage 8.This prevents damage to the second circuit breaker 4b.

[0041] At a fourth time 26, the voltage 39 applied to the first circuit breaker 4a is increased from the first breaking voltage 8 to the first intermediate voltage 9. The second closing voltage 10 continues to be applied to the second circuit breaker 4b. The first circuit breaker 4a remains in an off state. At a fifth time 27, the voltage 40 applied to the second circuit breaker 4b is reduced from the second closing voltage 10 to the second breaking voltage 11. The first intermediate voltage 9 continues to be applied to the first circuit breaker 4a. At a sixth time 28, the first intermediate voltage 9 applied to the first circuit breaker 4a is increased to the first closing voltage 7. After the sixth time 28, the second circuit breaker 4b is in an off state. The first circuit breaker 4a is in an on state.

[0042] During the fifth time 27, the voltage applied to the first circuit breaker 4a drops due to capacitive coupling between the second circuit breaker 4b and the first circuit breaker 4a. If the first output voltage were applied to the first circuit breaker 4a, the voltage applied to the first circuit breaker 4a would drop below the critical voltage value. By applying the first intermediate voltage 9 to the second circuit breaker 4b, the voltage applied to the second circuit breaker 4b does not drop below the critical voltage value during a change from the second switch-on voltage 10 applied to the second circuit breaker 4b to the second switch-off voltage 11. This prevents damage to the first circuit breaker 4a.

[0043] Fig. 4 shows a schematic representation of a second subunit 1b of a switching system 1 according to a second exemplary embodiment of the invention. The second exemplary embodiment has essentially the same features as the first exemplary embodiment. The switching system 1 according to the second exemplary embodiment additionally has a first reference switching unit 29a. The first reference switching unit 29a has a first reference supply input 30a, a first reference supply output 31a, and a first reference control input 32a. The first reference supply output 31a is electrically connected to the first connection point 20a via a third electrical resistor 33a. A first control unit 5a is configured to switch the first reference switching unit 29a on and / or off using the first reference control input 32a. The switching system 1 has a second reference switching unit 29b.The second reference switching unit 29b has a second reference supply input 30b, a second reference supply output 31b, and a second reference control input 32b. The second reference supply output 31b is electrically connected to the second connection point 22b via a sixth electrical resistor 33b. The second control unit 5b is configured to switch the second reference switching unit 29b on and / or off using the second reference control input 32b.

[0044] The first control unit 5a is configured to switch on the first reference switching unit 29a to apply the first intermediate voltage 9a to the first circuit breaker 4a before switching off the second circuit breaker 4b. The second control unit 5b is configured to switch on the second reference switching unit 29b to apply the second intermediate voltage 9b to the second circuit breaker 4b before switching off the first circuit breaker 4a.

[0045] The first switching unit 2b and / or the second switching unit 3a and / or the first reference switching unit 29b are configured as MOSFETs, in particular as normally-off MOSFETs. The third switching unit 2b and the fourth switching unit 3b and / or the second reference switching unit 29b are configured in particular as normally-off MOSFETs.

[0046] The first supply output 14a is connected to a first electrical voltage level. The second supply input 18a is connected to a second electrical voltage level. The first reference supply input 30a is connected to a reference voltage level. The first voltage level is not equal to, in particular greater than, the second voltage level. The first voltage level and the second voltage level refer to the reference voltage level. The third supply input 14b is connected to the first electrical voltage level. The fourth supply input 18b is connected to the second electrical voltage level. The second reference supply input 30a is connected to the reference voltage level.

[0047] Fig.5 shows a schematic representation of a switching system 1 according to the second exemplary embodiment of the invention. The first power switch 4a has a first power switch input 35a and a first power switch output 34a. The first power switch 4a further comprises a transistor 36a. The first transistor 36a is designed as a normally-off MOSFET. The first transistor 36a is electrically connected to the third control input 13a, the first power switch input 35a, and the first power switch output 34a. A first diode 37a is connected antiparallel to the first transistor 36a to the first power switch input 35a and the first power switch output 34a. The second power switch 4b has a second power switch input 35b and a second power switch output 34b. The second power switch 4b further comprises a second transistor 36b, which is designed as a normally-off MOSFET.The second transistor 36b is electrically connected to the fifth control input 13b, the second power switch input 35b, and the second power switch output 34b. A second diode 37b is connected in antiparallel to the second transistor 36b, the second power switch input 35b, and the second power switch output 34b.

Claims

[1] Switching system (1) for power switching of electrical currents comprising, - a first circuit breaker (4a), - a second circuit breaker (4b), and - a driver switching system (38, 38a, 38b), - wherein the first circuit breaker (4a) and the second circuit breaker (4b) are arranged to switch electrical currents in an electrical circuit (6), - wherein the driver switching system (38, 38a, 38b) is arranged to put the first circuit breaker (4a) and the second circuit breaker (4b) into an on and off state, - wherein the driver switching system (38, 38a) is arranged to switch on the first power switch (4a) by applying a first switch-on voltage (7) and to switch it off by applying a first switch-off voltage (8), - wherein the driver switching system (38, 38b) is arranged to switch on the second power switch (4b) by applying a second switch-on voltage (10) and to switch it off by applying a second switch-off voltage (11), - wherein the driver switching system (38, 38a, 38b) is configured to apply a first intermediate voltage (9) to the first circuit breaker (4b) before switching off the second circuit breaker (4b), so that the first intermediate voltage (9) is applied to the first circuit breaker (4a) when the second switching-off voltage (11) is applied to the second circuit breaker (4b) and / or to apply a second intermediate voltage (12) to the second circuit breaker (4b) before switching off the first circuit breaker (4a), so that the second intermediate voltage (12) is applied to the second circuit breaker (4b) when the first switching-off voltage (8) is applied to the first circuit breaker (4a), - wherein the first intermediate voltage (9) is greater than the first switching-off voltage (8) and leaves the first circuit breaker (4a) in a switched-off state, and - wherein the second intermediate voltage (12) is greater than the second switching-off voltage (11) and leaves the second power switch (4b) in a switched-off state. [2] Switching system (1) according to claim 1 characterized by , that - the driver circuit system (38, 38a, 38b) comprises a first driver circuit (38a) and a second driver circuit (38b), and - the first circuit breaker (4a) has a third control input (13a) and the second circuit breaker (4b) has a fifth control input (13b), - wherein the first driver circuit (38a) is connected to the third control input (13a) and is configured to control the first power switch (4a), and - wherein the second driver circuit (38b) is connected to the fifth control input (13b) and is configured to control the second power switch (4b). [3] Switching system (1) according to claim 2, characterized by , that - the first driver circuit (38a) comprises a first switching unit (2a) and a second switching unit (3a), - wherein the first switching unit (2a) and the second switching unit (3a) are connected to the third control input (13a), - wherein the first switching unit (2a) is arranged to put the first circuit breaker (4a) into a switched-on state, and - wherein the second switching unit (3a) is configured to put the first circuit breaker (4a) into a switched-off state, and / or - the second driver circuit (38b) has a fourth switching unit (2b) and a fifth switching unit (3b), - wherein the fourth switching unit (2b) and the fifth switching unit (3b) are connected to the fifth control input (13b), - wherein the fourth switching unit (2b) is arranged to put the second circuit breaker (4b) into a switched-on state, and - wherein the fifth switching unit (3a) is configured to put the second circuit breaker (4b) into a switched-off state. [4] Switching system (1) according to claim 3 characterized by , that - the first switching unit (2a) has a first supply input (15a), a first supply output (14a) and a first control input (16a), and - the second switching unit (3a) has a second supply input (15a), a second supply output (17a) and a second control input (19a), - wherein the first switching unit (2a) can be switched on and off by means of the first control input (16a) and the second switching unit (3a) can be switched on and off by means of the second control input (19a), and - wherein the third control input (13a), the first supply input (15a) and the second supply output (17a) are electrically connected to one another via a first connection point (20a). [5] Switching system (1) according to claim 4 characterized by , that - a first electrical resistor (21a) is connected in series between the first supply input (15a) and the first connection point (20a), and / or - a second electrical resistor (22a) is connected in series between the second supply output (17a) and the first connection point (20a). [6] Switching system (1) according to claim 5 characterized by , that - the first resistance (21a) is selected to be as low as possible without causing damage to the first power switch (4a) when a voltage is applied to the third control input (13a), and / or - the second resistance (22a) is selected to be as low as possible without causing damage to the first circuit breaker (4a) when the voltage applied to the third control input (13a) is reduced. [7] Switching system (1) according to one of claims 3 to 6 characterized by , - a first reference switching unit (29a), - wherein the first reference switching unit (29a) has a first reference supply input (30a), a first reference supply output (31a) and a first reference control input (32a), - wherein the first reference supply output (31a) is electrically connected to the first connection point (20a) via a third electrical resistor (33a), and - wherein the first control unit (5a) is configured to switch the first reference switching unit (29a) on and / or off by means of the first reference control input (32a). [8] Switching system (1) according to claim 7 characterized by in that the first control unit (5a) is configured to switch on the first reference switching unit (29a) in order to apply the first intermediate voltage (9a) to the first circuit breaker (4a) before switching off the second circuit breaker (4b) and / or to switch on the second reference switching unit (29b) in order to apply the second intermediate voltage (12) to the second circuit breaker (4b) before switching off the first circuit breaker (4a). [9] Switching system (1) according to one of the preceding claims, characterized bythat the first switching unit (2a) and / or the second switching unit (3a) and / or the first reference switching unit (29a) and / or the first power switch (4a) and / or the second power switch (4b) are designed as semiconductor switches. [10] Switching system (1) according to one of the preceding claims characterized by that the first switching unit (2a) and / or the second switching unit (3a) and / or the first reference switching unit (29a) are designed as a MOSFET, in particular as a self-blocking MOSFET. [11] Switching system (1) according to one of claims 7 to 10 characterized by , that - the first supply output (14a) is connected to a first electrical voltage level, - the second supply input (18a) is connected to a second electrical voltage level, and - the first reference supply input (30a) is connected to a reference voltage level, - wherein the first voltage level is unequal, in particular greater, than the second voltage level, and - where the first voltage level and the second voltage level refer to the reference voltage level. [12] Switching system (1) according to one of the preceding claims characterized by , that - the first circuit breaker (4a) has a first circuit breaker input (35a) and a first circuit breaker output (34a), and - the first power switch (4a) comprises a first transistor (36a), in particular a self-blocking MOSFET, - wherein the first transistor (36a) is electrically connected to the third control input (13a), the first power switch input (35a) and the first power switch output (34a), and - wherein a first diode (37a) is connected anti-parallel to the transistor (36a) to the first power switch input (35a) and the first power switch output (34a).

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