Circuit breaker and method for determining a sequence of electrical pulses for a circuit breaker

Abstract

A circuit breaker (1) for an electrical circuit is provided, including - a switching unit (2) comprising - a semiconductor switching module (5), and - a clamping device (6) connected in parallel to the semiconductor switching module (5), and - a capacitor (7) connected to the switching unit (2), wherein - the semiconductor switching module (5) is configured to break the electrical circuit, - the semiconductor switching module (5) is configured to pre-charge the capacitor (7) with a sequence of electrical pulses. Further, a method for operating a circuit breaker and a method for determining a sequence of electrical pulses for a circuit breaker are provided.

Description

[0001] Description

[0002] CIRCUIT BREAKER AND METHOD FOR DETERMINING A SEQUENCE OF ELECTRICAL PULSES FOR A CIRCUIT BREAKER

[0003] A circuit breaker is provided . In addition, a method for determining a sequence of electrical pulses for a circuit breaker, a computer program and a computer-readable storage medium are provided .

[0004] Generally, in a typical Hybrid Current Breaker, HCB , and a typical Solid-State Circuit Breaker, SSCB, the used typical semiconductor devices are operated with a typical gate driver being si zed to be able to turn of f the typical semiconductor device during short circuit events without leaving a safe operating region of the typical semiconductor device to avoid breakdown of the switch . Typically, to achieve an acceptable dl / dt and dV / dt during a turn-of f , the typical gate driver is configured to perform the turn-of f comparatively slowly .

[0005] An obj ect to be achieved is to provide a circuit breaker which has improved electrical functions . Furthermore, a method for determining a sequence of electrical pul ses for such a circuit breaker and a computer program which is able to perform such a method are provided . In addition, a computer-readable storage medium with such a computer program is provided .

[0006] This obj ect is achieved by the subj ect-matter of the independent claims . Advantageous embodiments , implementations and further developments are the subj ect-matter of the respective dependent claims . A circuit breaker is speci fied . In particular, the circuit breaker is configured to protect electrical circuits from damage , exemplarily resulting from a short circuit . The circuit breaker is configured to automatically interrupt or break a current flow when a fault occurs in the electrical circuit . The fault can be an overload current or a short current , particularly occurring in the electrical circuit .

[0007] According to at least one embodiment , the circuit breaker comprises a switching unit . The switching unit is , for example , configured to control a state of the circuit breaker . In particular, the state of the circuit breaker is characteristic of an opening or closing of the electrical circuit .

[0008] According to at least one embodiment , the switching unit comprises a semiconductor switching module . The semiconductor switching module comprises , for example , at least one transistor, at least one diode , and / or at least one thyristor, for controlling a flow of the electrical current in the electrical circuit . The semiconductor switching module is in particular configured to switch and / or to regulate the flow of the electrical current in the electrical circuit .

[0009] The semiconductor switching module comprises , for example , at least one insulated gate bipolar transistor, IGBT .

[0010] According to at least one embodiment , the switching unit comprises a clamping device connected in parallel to the semiconductor switching module . The clamping device is , for example , a surge arrester . The clamping device is , for example , configured to protect the electrical circuit , in particular devices thereof , from voltage spikes and / or transient currents in the electrical circuit . Additionally or alternatively, the clamping device is , for example , configured to have a clamping voltage greater than a source voltage so that the current can come to zero naturally .

[0011] Exemplarily, the clamping device comprises or is formed of a metal oxide varistor, MOV . The metal oxide varistor comprises , for example , a zinc oxide material which is arranged between two metal electrodes .

[0012] Alternatively, the clamping device comprises or is formed of a transient voltage suppressor, TVS . The transient voltage suppressor comprises , for example , a semiconductor material and a Zener diode or an avalanche diode connected to two terminals .

[0013] According to at least one embodiment , the circuit breaker comprises a capacitor connected to the switching unit . Exemplarily, the capacitor is configured to be a part of a load for the switching module . The capacitance is , for example , at least 0 . 1 pF or at least 1 pF .

[0014] According to at least one embodiment of the circuit breaker, the semiconductor switching module is configured to break the electrical circuit . Exemplarily, ' to break the electrical circuit ' means here and in the following that the semiconductor switching module is configured to control a flow of electrical current in the electrical circuit, that the flow is interrupted in a switched-of f state , and that the flow is not interrupted in a switched-on state .

[0015] In particular, when breaking the electrical circuit , the semiconductor switching module is switched from the switched- on state, i.e. a conducting state, to the switched-off state, i.e. a non-conducting state. This transition effectively interrupts the flow within the electrical circuit.

[0016] Exemplarily, the breaking of the electrical current is performed dependent on an overload current or a short circuit current .

[0017] According to at least one embodiment of the circuit breaker, the semiconductor switching module is configured to precharge the capacitor with a sequence of electrical pulses.

[0018] The capacitor can be part of a capacitive load comprising the capacitor and a resistor connected in series. The semiconductor switching module is exemplarily controlled by means of a pulse width modulation, PWM, technique. In particular, the sequence of electrical pulses is generated by the semiconductor switching module by the pulse width modulation technique. For example, the semiconductor switching module is turned on and off at a comparatively high frequency for generating the sequence of electrical pulses.

[0019] For example, a ratio of a first time interval where the semiconductor switching module is switched on to a second time interval where the semiconductor switching module is switched off, within each cycle, is known as a duty cycle. An effective power provided to the capacitor, i.e. the precharging, is controlled dependent on the duty cycle.

[0020] An idea of the circuit breaker described herein is to employ a semiconductor switching module which is capable of circuit breaking as well as of pre-charging the capacitor. Advantageously, by switching the semiconductor switching module on and off, the capacitor can be additionally charged. According to at least one embodiment , the circuit breaker comprises a mechanical switch connected to the switching unit . The mechanical switch particularly is configured to conduct the electrical current , e . g . in a switched-on state , or to block the electrical current , e . g . in a switched-of f state .

[0021] According to at least one embodiment of the circuit breaker, the mechanical switch is arranged between the switching unit and the capacitor . Exemplarily, the mechanical switch is configured to provide a safe galvanic separation of the switching module and the load in the switched-of f state .

[0022] According to at least one embodiment , the circuit breaker comprises a mechanical bypass switch connected in parallel to the semiconductor switching module and the clamping device . Exemplarily, the mechanical bypass switch is compri sed by the semiconductor switching module . The mechanical bypass switch particularly is configured to trans fer the electrical current to the semiconductor switching module . In particular, the mechanical bypass switch is configured to conduct current in the switched on-state and is configured to trans fer current to the semiconductor switching module during a switching of f event .

[0023] According to at least one embodiment , the circuit breaker comprises a short-circuit choke connected in series to the switching unit . The short-circuit choke is , for example an inductance . Exemplarily, in a HCB embodiment , there is the inductance and a stray inductance of a cable . For example , in a SSCB embodiment there is exclusively the stray inductance of the cable and exemplary an additional inductor o f approximately 2 % of the inductance in the HCB embodiment . According to at least one embodiment of the circuit breaker, the semiconductor switching module comprises at least two power semiconductor switches connected in series to one another . Each of the power semiconductor switches comprises or is formed of at least one of an insulated gate bipolar transistor, a metal-oxide-semiconductor field-ef fect transistor, MOSFET and j unction field-ef fect transi stor, JFET , inter alia .

[0024] According to at least one embodiment of the circuit breaker, amplitudes of an electrical current of the sequence of electrical pulses are smaller than an amplitude of a predefined instantaneous trip current . In particular, each amplitude of the electrical current of the sequence of electrical pulses is characteristic for a maximum current value of a corresponding electrical pulse . Exemplarily, all amplitudes of the electrical current of the sequence of electrical pulses are smaller than the amplitude of the predefined instantaneous trip current . The instantaneous trip current is characteristic for a current at which the breaker trips to open circuit .

[0025] According to at least one embodiment of the circuit breaker, an amplitude of an electrical current of the electrical pulses decreases for consecutive electrical pulses while a load voltage increases .

[0026] According to at least one embodiment of the circuit breaker, the semiconductor switching module is configured to be controlled with a first gate driver and a second gate driver di f ferent from the first gate driver . According to at least one embodiment of the circuit breaker, the first gate driver is characteristic of the pre-charging and the second gate driver is characteristic of breaking the electrical circuit . Exemplarily, the first gate driver is configured to switch the semiconductor switching module alternatingly from the switched-of f state to the switched-on state and from the switched-on state to the switched-of f state for generating the sequence of electrical pul ses . Exemplarily, the second gate driver is configured to switch the semiconductor switching module from the switched-on state to the switched-of f state for breaking the circuit if there is a current equal to or higher than the predefined instantaneous trip current .

[0027] In particular, the second gate driver is si zed to turn of f the semiconductor switching module comparatively slowly . In contrast to such a second gate driver, the first gate driver is configured to drive the semiconductor switching module in a fast mode , advantageously to limit the pre-charging current .

[0028] Moreover, a method for operating a circuit breaker is speci fied . The method is applied in particular to the circuit breaker described herein . Therefore , all features and embodiments disclosed in connection with the method are also disclosed in connection with the circuit breaker and vice versa .

[0029] According to at least one embodiment of the method, a first gate driver is applied to the semiconductor switching module for the pre-charging . According to at least one embodiment of the method, a second gate driver is applied to the semiconductor switching module for generating and breaking a corresponding circuit .

[0030] Furthermore , a method for determining a sequence of electrical pulses for a circuit breaker is speci fied . The method is applied in particular to the circuit breaker described herein . Therefore , all features and embodiments disclosed in connection with the method are also di sclosed in connection with the circuit breaker and vice versa .

[0031] According to at least one embodiment of the method, a capacitor information of a capacitor is provided . Particularly, the capacitor information comprises the capacitance of the capacitor .

[0032] According to at least one embodiment of the method, a first inductivity information of connections is provided .

[0033] Particularly, the first inductivity information comprises the inductivity of a neutral conductor line and an external conductor line at which the components of the circuit breaker are arranged and to which they are connected .

[0034] According to at least one embodiment of the method, a second inductivity information of a short-circuit choke is provided . Particularly, the second inductivity information comprises the inductivity of the short-circuit choke being the inductance .

[0035] According to at least one embodiment of the method, a duty cycle is determined dependent on the capacitor information, the first inductivity information and the second inductivity information . In addition, a computer program is speci fied, comprising instructions which, when the computer program is executed by a computer, cause the computer program to execute the method described herein .

[0036] Further, a computer-readable storage medium is specified, on which the computer program described herein is stored .

[0037] Exemplary embodiments of the method are explained in more detail below with reference to the Figures .

[0038] Figures 1 and 2 each show a circuit breaker according to an exemplary embodiment .

[0039] Figure 3 shows a flow diagram of the method according to an exemplary embodiment .

[0040] Elements of the same structure or function are marked with the same reference signs throughout the Figures .

[0041] The circuit breaker 1 according to Figure 1 comprises a switching unit 2 . The switching unit 2 comprises a semiconductor switching module 5 , and a clamping device 6 connected in parallel to the semiconductor switching module 5. The semiconductor switching module 5 comprises two bidirectional power semiconductor switches 3 , 4 , e . g . a first power semiconductor switch 3 and a second power semiconductor switch 4 , each comprising or being formed of an IGBT, for example . The clamping device 6 exemplarily comprises or is formed of an MVO or a TVS . A mechanical bypass switch 10 is connected in parallel to the semiconductor switching module 5 and the clamping device 6 . The switching unit 2 is arranged between a first external terminal 14, e.g. being an input, and a second external terminal 15, e.g. being an output.

[0042] Between the first external terminal 14 and the switching unit 2, a current measurement device 16 is arranged. The current measurement device 16 exemplarily comprises a shunt resistor and / or a current transformer.

[0043] Further, downstream of the first external terminal 14, the switching unit 2 is connected to a DC resistor 24 and a short-circuit choke 11, which are connected in series. The short-circuit choke is in particular an inductance. The inductance 11 is, for example, an air-core inductor, particularly configured to limit a dl / dt in case of short- circuit. The inductance 11 is, for example, at least 150 pH. The inductance 11 is further connected to a supply voltage source 18. Exemplarily, the supply voltage source 18 comprises a capacitive DC link. The supply voltage source 18 is connected to a neutral conductor line 19 on a side opposite the inductance 11.

[0044] A third external terminal 22, e.g. being an input, relating to the first external terminal 14, and a fourth external terminal 23, e.g. being an output, relating to the second external terminal 15, are arranged at the neutral conductor line 19.

[0045] Between the first and third external terminals 14, 22 and between the second and fourth external terminals 15, 23, a voltage measurement device 17 is arranged, respectively. A mechanical switch 8 is arranged between the switching unit 2 and the second external terminal 15 . A further mechanical switch 9 is arranged between the third external terminal 22 and the fourth external terminal 23 . In particular, the switching unit 2 is located on an external conductor line 20 , at which the first and second external terminals 14 , 15 are located .

[0046] The switching unit 2 is further connected to a capacitor 7 . In particular, the capacitor 7 is arranged between and connected to the external conductor line 20 and the neutral conductor line 19 . Additionally, the capacitor 7 is connected in series to an equivalent series resistor 21 of the capacitor . The capacitor 7 has a capacitance per power of at least 25 pF / kW . The equivalent series resistor 21 o f the capacitor has a resistivity of at most 5 m .

[0047] Between the second external terminal 15 and the capacitor 7 , a stray resistor 25 and a stray inductance 26 are arranged . The stray resistor and the stray inductance are characteristic, for example , of a cable resistivity and a cable stray inductance , respectively . The stray inductance is approximately 1 pH / m .

[0048] Additionally, a load 12 is connected in parallel to the capacitor 7 , particularly between the external conductor line 20 and the neutral conductor line 19 . The load 12 i s , for example , a DC / DC or a DC / AC converter . In particular, the capacitor 7 and the load 12 are a common load .

[0049] The circuit breaker 1 comprises a control unit 13 , which particularly comprises a control device and a power supply . The current measurement device 16 and the voltage measurement device 17 are configured to provide measurement information to the control unit 13 . Particularly, the control unit 13 is configured to control the semiconductor switching module 5 , exemplarily each of the power semiconductor switches 3 , 4 . Additionally, the control unit 13 is particularly configured to control the switching state of each of the mechanical switch 8 , the further mechanical switch 9 and the mechanical bypass switch 10 .

[0050] Advantageously, the semiconductor switching module 5 is configured to break an electrical circuit to which the circuit breaker 1 is connected as well as to pre-charge the capacitor 7 with a sequence of electrical pulses . Exemplarily, the sequence of electrical pulses is generated by the power supply .

[0051] Advantageously, the control unit 13 is configured to provide a first gate driver as well as a second gate driver to the semiconductor switching module 5 . The semiconductor switching module 5 is configured to be controlled by the first gate driver and the second gate driver di f ferent from the first gate driver . Particularly, the first gate driver is characteristic of the pre-charging and the second gate driver is characteristic of breaking the electrical circuit .

[0052] In contrast to the circuit breaker 1 of Figure 1 , the circuit breaker 1 according to Figure 2 has no mechanical bypass switch 10 . In particular, the circuit breaker 1 of Figure 1 is of a form of an HCB and the circuit breaker 1 of Figure 2 is of a form of an SSCB .

[0053] A further stray resistor 27 and a further stray inductance 28 of Figure 2 are characteristic, for example , of a cable resistivity and a cable stray inductance , respectively . The further inductance is approximately 1 pH / m.

[0054] In method stage S I of the method of Figure 3 , a first gate driver is applied to the semiconductor switching module 5 for the pre-charging . In method stage S2 , a second gate driver is applied to the semiconductor switching module 5 for generating and breaking a corresponding circuit . In particular, the control unit 13 as described in connection with Figures 1 and 2 is configured to provide the f irst gate driver as well as the second gate driver to the semiconductor switching module 5 , dependent on measurement information, particularly dependent on the measurement information of the current measurement device 16 and the voltage measurement device 17 .

[0055] The pre-charge can be performed bidirectional . Exemplarily, in case of a voltage at a side of the load does not increase within a predetermined time , the pre-charge immediately due to a fault at the side of the load .

[0056] This patent application claims the priority of the German patent application 10 2024 105 750 . 5 , the disclosure of which is hereby incorporated by reference .

[0057] Reference signs list

[0058] 1 circuit breaker

[0059] 2 switching unit

[0060] 3 first power semiconductor switch

[0061] 4 second power semiconductor switch

[0062] 5 semiconductor switching module

[0063] 6 clamping device

[0064] 7 capacitor

[0065] 8 mechanical switch

[0066] 9 further mechanical switch

[0067] 10 mechanical bypass switch

[0068] 11 short-circuit choke

[0069] 12 load

[0070] 13 control unit

[0071] 14 first external terminal

[0072] 15 second external terminal

[0073] 16 current measurement device

[0074] 17 voltage measurement device

[0075] 18 supply voltage source

[0076] 19 neutral conductor line

[0077] 20 external conductor line

[0078] 21 equivalent series resistor

[0079] 22 third external terminal

[0080] 23 fourth external terminal

[0081] 24 DC resistor

[0082] 25 stray resistor

[0083] 26 stray inductance

[0084] 27 further stray resistor

[0085] 28 further stray inductance

Claims

Claims1. Circuit breaker (1) for an electrical circuit including- a switching unit (2) comprising- a semiconductor switching module (5) , and- a clamping device (6) connected in parallel to the semiconductor switching module (5) , and- a capacitor (7) connected to the switching unit (2) , wherein- the semiconductor switching module (5) is configured to break the electrical circuit,- the semiconductor switching module (5) is configured to pre-charge the capacitor (7) with a sequence of electrical pulses ,- the semiconductor switching module (5) is configured to be controlled with a first gate driver and a second gate driver different from the first gate driver, and- the first gate driver is characteristic of the pre-charging and the second gate driver is characteristic of breaking the electrical circuit.

2. Circuit breaker (1) according to claim 1, wherein- a mechanical switch (8) is connected to the switching unit(2 ) , and- the mechanical switch (8) is arranged between the switching unit (2) and the capacitor (7) .

3. Circuit breaker (1) according to one of claims 1 and 2, wherein- a mechanical bypass switch (10) is connected in parallel to the semiconductor switching module (5) and the clamping device ( 6 ) .

4. Circuit breaker (1) according to one of claims 1 to 3, wherein- a short-circuit choke (11) is connected in series to the switching unit (2) .

5. Circuit breaker (1) according to one of claims 1 to 4, wherein- the semiconductor switching module (5) comprises at least two power semiconductor switches (3, 4) connected in series to one another.

6. Circuit breaker (1) according to one of claims 1 to 5, wherein- amplitudes of an electrical current of the sequence of electrical pulses are smaller than an amplitude of a predefined instantaneous trip current.

7. Circuit breaker (1) according to one of claims 1 to 6, wherein- an amplitude of an electrical current of the electrical pulses decreases for consecutive electrical pulses while a load voltage increases.

8. Method for operating a circuit breaker (1) according to one of claims 1 to 7, comprising:- applying the first gate driver to the semiconductor switching module (5) for the pre-charging, and- applying the second gate driver to the semiconductor switching module (5) for generating and breaking a corresponding circuit.

9. Method for determining a sequence of electrical pulses for a circuit breaker (1) according to one of claims 1 to 7, comprising :- providing a capacitor (7) information of a capacitor (7) , - providing a first inductivity information of connections,- providing a second inductivity information of a short- circuit choke,- determining a duty cycle dependent on the capacitor (7) information, the first inductivity information and the second inductivity information.

10. Computer program comprising instructions which, when the computer program is executed by a computer, cause the computer program to execute the method according to claim 8 and / or 9.

11. Computer-readable storage medium, on which the computer program according to claim 10 is stored.

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