Circuit breaker having a passive clamp circuit including a capacitor, method of

Abstract

A circuit breaker having a passive clamp circuit including a capacitor, a method of operation, a DC network, and an aircraft are provided. The present invention relates to a circuit breaker (14), the circuit breaker (14) comprising: a main switching unit (16) configured to open in the event of a fault; and a passive clamping circuit (18) for absorbing energy and preventing overvoltage wherein the clamping circuit (18) is connected in parallel to the main switching unit (16). In order to improve functionality, it is proposed that the clamping circuit (18) comprises a plurality of passive transient suppression components (20.1, 20.2, 20.3) and a delay device (19) arranged and configured to shift the action of the passive transient suppression components (20.1, 20.2, 20.3) such that the passive transient suppression components respond sequentially rather than simultaneously.

Description

Technical Field

[0001] This invention relates to circuit breakers, particularly circuit breakers for aircraft, comprising: a main switching unit configured to interrupt operation in the event of a fault; and a clamping circuit for absorbing energy and preventing overvoltage. Furthermore, this invention relates to methods of operating such circuit breakers. Additionally, this invention relates to DC networks, such as DC networks in power distribution systems, particularly DC networks for aircraft, which include such circuit breakers, and to aircraft equipped with such DC networks. Background Technology

[0002] For technical background, please refer to the following literature:

[0003] [1]Wikipedia, "Circuit breaker", download from

[0004] https: / / en.wikipedia.org / wiki / Circuit_breaker on February 07,2024

[0005] [2]Wikipedia, "Clamper (electronics)", download from

[0006] https: / / en.wikipedia.org / wiki / Clamper_(electronics)on January 10,2024

[0007] [3]WO 2014 / 177874 A2

[0008] [4]WO 2022 / 272007 A2

[0009] [5] L.Camurca, J.Jacobsen and M.Liserre, "Passive Clamping Circuit for Reduced Switch Count in Solid State Circuit Breakers," 2021 IEEE 15thInternational Conference on Compatibility, Power Electronics and PowerEngineering (CPE-POWERENG), 2021

[0010] [6]EP 0 701 313 A1

[0011] [7]US 11 515 815 B2

[0012] [8]CN 204 906 177 U

[0013] [9]CN 116 093 912 A

[0014]

[10] CN 217 156 599 U

[0015]

[11] CN 104 348 146 B

[0016] References [5] and [6] disclose circuit breakers comprising: a main switching unit configured to open in the event of a fault; and a clamping circuit for absorbing energy and preventing overvoltage, wherein the clamping circuit is connected in parallel to the main switching unit and includes a primary passive protection circuit including a passive transient suppression component. [7] describes an overvoltage clamping circuit having a TVS diode that breaks down when the voltage exceeds a threshold. [8] describes a voltage clamping device having a TVS diode as a clamping element. [9] describes a peak voltage clamping circuit having a TVS tube, a TVS diode, and a capacitor to control the peak voltage.

[10] describes a surge protection circuit for high-power electronic devices having a TVS diode and a capacitor. Summary of the Invention

[0017] The purpose of this invention is to provide a circuit breaker with an advanced clamping solution.

[0018] To achieve this objective, the present invention provides a circuit breaker according to an embodiment. In another embodiment, a DC network and an aircraft having such a circuit breaker are provided.

[0019] Advantageous implementation methods are the subject of preferred embodiments of the present invention. Furthermore, methods of operation for implementation methods of circuit breakers are provided.

[0020] According to a first aspect of the present invention, a circuit breaker is provided, comprising: a main switching unit configured to interrupt in the event of a fault; and a passive clamping circuit for absorbing energy and preventing overvoltage, wherein the clamping circuit is connected in parallel to the main switching unit, wherein the clamping circuit includes a plurality of passive transient suppression components and a delay device arranged and configured to shift the action of the passive transient suppression components such that the passive transient suppression components respond sequentially rather than simultaneously.

[0021] In some implementations, the passive transient suppression component is selected from a group consisting of a rheostat and a TVS diode.

[0022] In some implementations, passive transient suppression components are connected in series.

[0023] In some embodiments, the clamping circuit includes n transient suppression components, where n is a natural number greater than 2, and the delay device includes n-1 delay components, each of which is associated with one of the transient suppression components such that the action of the transient suppression component is delayed.

[0024] In some implementations, the delay components are different from each other.

[0025] In some implementations, the delay component has different values.

[0026] In some implementations, the delay component is a capacitor.

[0027] In some implementations, the delay component is a capacitor with a different capacitance.

[0028] In some embodiments, the delay device includes at least one capacitor connected in parallel to one of the transient suppression components.

[0029] In some embodiments, the clamping circuit includes a first transient suppression component, a second transient suppression component, and a third transient suppression component connected in series, and wherein the delay device includes a first capacitor connected in parallel to the second transient suppression component and a second capacitor connected in parallel to the third transient suppression component, wherein the capacitance of the first capacitor and the capacitance of the second capacitor are different from each other.

[0030] In some embodiments, the clamping circuit includes a primary passive protection circuit that includes a plurality of transient suppression components, and wherein the delay device has at least one primary capacitor configured to charge during clamping when the main switch is open, wherein the clamping circuit further includes a discharge circuit that includes at least one secondary capacitor and is configured to discharge at least one primary capacitor when the main switch unit is closed.

[0031] In some embodiments, the clamping circuit includes a plurality of primary capacitors configured to charge when the main switching unit is turned off, and wherein the discharge circuit includes an arrangement of secondary capacitors and is configured to discharge the primary capacitors when the main switching unit is turned on.

[0032] In some embodiments, the discharge circuit includes a plurality of decoupling resistors configured to decouple at least one secondary capacitor from the primary passive protection circuit during clamping.

[0033] In some embodiments, the clamping circuit includes a series of transient suppression sections, each transient suppression section including a passive protection circuit unit and a discharge circuit unit connected in parallel with each other, wherein each passive protection circuit unit includes a passive transient suppression component, and wherein at least one or more passive protection circuit units additionally include a primary capacitor, and wherein each discharge circuit unit includes a secondary capacitor, wherein the capacitance of the secondary capacitor is selected such that each transient suppression section has the same charge.

[0034] In some implementations, each transient suppression section includes a TVS diode as a transient suppression component and a balancing resistor connected in parallel with a secondary capacitor, wherein the resistance of the balancing resistor of the transient suppression unit is selected such that the resistance of the balancing resistor is proportional to the cutoff voltage of the TVS diode to which the balancing resistor is connected.

[0035] In some implementations, each transient suppression segment includes at least one of the decoupling resistors for decoupling the passive protection circuit unit from the secondary capacitor during clamping.

[0036] According to another aspect, an operating method for operating a circuit breaker including a discharge circuit according to those embodiments is proposed, the operating method comprising the following steps:

[0037] a) In case of a fault, disconnect the main switching unit and apply the entire bus voltage to the clamping circuit; charge the primary and secondary capacitors until a steady state is reached;

[0038] b) When the fault event ends, close the main switch unit and short-circuit the clamping circuit, discharge the secondary capacitor and discharge the primary capacitor via the discharge circuit.

[0039] In some implementations, step a) includes:

[0040] a1) In the initial time after the main switch unit is disconnected, the discharge circuit is decoupled from the primary passive protection circuit by means of a decoupling resistor.

[0041] In some implementations, step a) includes:

[0042] a2) Charge the sum of capacitors in each transient suppression segment with the same charge.

[0043] In some implementations, step b) includes:

[0044] b1) The voltage is limited by the transient suppression component to prevent further charging, and all capacitors are discharged to a lower voltage via the decoupling resistor.

[0045] According to another aspect, the present invention provides a DC network, particularly a DC network for a power distribution system, preferably a DC network for an aircraft, the DC network comprising: at least one electrical energy source and at least one energy sink; and at least one circuit breaker according to any of the foregoing embodiments, connected between at least one source and at least one sink.

[0046] According to another aspect, the present invention provides an aircraft that includes such a DC network (e.g., as part of a power distribution system) or at least one circuit breaker according to any of the embodiments mentioned above.

[0047] Preferred applications of embodiments of the present invention are power electronic devices, DC switches, and voltage clamping circuits. Embodiments of the present invention are applicable to all applications dealing with DC power systems and their protection. Embodiments of the present invention are particularly useful in any situation where overcurrent must be interrupted.

[0048] Embodiments of the present invention provide a solid-state circuit breaker (SSCB) comprising: a main switching unit configured to interrupt the circuit when the current flowing through the solid-state circuit breaker exceeds a maximum current threshold; and a clamping circuit for absorbing energy and preventing overvoltage.

[0049] Embodiments of the present invention provide advanced clamping for minimizing voltage overshoot.

[0050] Embodiments of the present invention provide an advanced clamping solution, particularly suitable for aircraft, that enables the manipulation of voltage overshoot. This allows unavoidable voltage spikes to be intelligently redirected to mitigate their impact on the power grid and reduce the maximum voltage that occurs.

[0051] Some implementations utilize standard TVS diodes as clamping elements, but other similar transient suppression components, such as varistors, can also be implemented.

[0052] In some embodiments, a clamping circuit is used to clamp transient voltages. This clamping circuit includes a delay device for shifting the operation of several transient suppression components. The delay device can be made of any suitable delaying element. In some embodiments, a capacitor is used as the delaying element.

[0053] In some implementations, a rheostat or TVS diode is used as a transient suppression element.

[0054] Embodiments of the present invention enable a significant reduction in voltage overshoot (inductive during main switch off) and TVS-based voltage overshoot (during clamping) in fault conditions. Due to the passive design, the clamping circuit can be designed in an optimal manner with minimal weight and profile.

[0055] In some embodiments, the recessed characteristics of TVS diodes are utilized by “turning on” the diodes with a short time delay (achieved through capacitors connected in parallel). In some embodiments, this method is used in conjunction with passive circuits that utilize the hysteresis characteristics of some TVS diodes. In known devices, diodes are simply connected in series regardless of different timings, and additional “buffer circuits” are connected in parallel for overvoltage filtering (prior art; see, for example, [5] through

[11] ). The circuit according to the preferred embodiment of the invention employs a completely different (smarter and more efficient) approach here.

[0056] Some implementations provide devices and apparatus for rapidly discharging a clamping circuit, including a capacitor, after an event in which a transient voltage has been clamped has ended. Therefore, the clamping circuit can easily handle new transient events. Thus, no current-limiting protection circuit is required.

[0057] A preferred embodiment of the present invention provides a safe-operating SSCB, wherein a clamping circuit with lighter weight and potentially higher integration is provided. In particular, a bidirectional SSCB with a lighter clamping circuit is provided. Therefore, the SSCB is improved for use in aircraft. Attached Figure Description

[0058] The embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

[0059] Figure 1 It is a schematic plan view of an implementation of an aircraft having a DC network for a power distribution system, including semiconductor circuit breakers;

[0060] Figure 2 Such as, protected by a semiconductor switching circuit breaker (SSCB) according to a comparative example. Figure 1 A block diagram of the DC network of the aircraft's power distribution system;

[0061] Figure 3 This is a graph showing the voltage and current of an SSCB with a passive clamping circuit according to a comparative example under fault conditions;

[0062] Figure 4 It shows what happens after overcurrent. Figure 2 Typical (idealized) voltage waveforms in a circuit breaker;

[0063] Figure 5 DC networks protected by semiconductor switching circuit breakers (SSCBs) having clamping circuits according to a first embodiment of the present invention, particularly Figure 1 A block diagram of the DC network for the aircraft;

[0064] Figure 6 It shows the relationship with Figure 4 The same in, but in Figure 5 The simulation performed in the circuit; and

[0065] Figure 7 This is a block diagram of a clamping circuit according to a second embodiment of the present invention. Detailed Implementation

[0066] Embodiments of the present invention relate to power electronic devices, and particularly to DC networks 50 and their protection. Specifically, embodiments of the present invention relate to a circuit breaker 14, wherein transient voltages are clamped by a passive clamping circuit 18, the passive clamping circuit 18 including transient suppression components 20.1, 20.2, 20.3 and a delay device 19 for influencing the switching of these components. By way of example, reference is made to devices including, for example... Figure 1 The possible uses of the DC network 50 in the aircraft 100 illustrate some possible embodiments of the invention. Figure 3 An example of a DC network 50 is shown, which includes a circuit breaker 14, particularly an SSCB (Solid State Circuit Breaker) or a DC circuit breaker, and the circuit breaker 14 includes a clamping circuit 18 according to a comparative example. Figure 5 and Figure 7 An enhanced clamping circuit 18 according to an embodiment of the present invention is shown, which can be used instead of the clamping circuit 18 of the comparative example.

[0067] Figure 1 An aircraft 100 is shown having a DC network in the form of a power distribution system protected by a circuit breaker 14, such as a semiconductor switching circuit breaker (SSCB) or other type of DC circuit breaker.

[0068] according to Figure 1 The example aircraft 100 shown includes: at least one DC power source 10 that provides DC power via a DC bus 118 having a DC bus voltage VDC; at least one power electronic device 116, as an example of a sink 12 of a DC network 50; and at least one power-consuming device 112 that is supplied with power from the power source 10 via the power electronic device 116.

[0069] The power-consuming component 112 can be any type of aircraft component powered by AC or DC electricity, such as an electric actuator, motor pump, or electric motor 124. In some embodiments, the DC network 50 is part of the electric propulsion system 120 of the aircraft 100, wherein, for example, motor 124 is a propulsion motor for driving flight propulsion elements of the aircraft 100, such as propeller 126.

[0070] In some embodiments, the power electronic device 116 is an inverter 128 for supplying AC power converted from DC power source 10 to power consuming device 112. The DC power source 10 may be or include a battery 130 or a fuel cell, or a DC power network including a plurality of batteries 130 and / or fuel cells (not shown).

[0071] Figure 2 Examples of DC networks 48 are shown. Figure 1 A block diagram of an exemplary circuit of the aircraft's power distribution system 50 according to a comparative example. The DC network 48 may include a single or multiple sources 10 and sinks 12. For simplicity, only one source 10 and one device 18 are shown here as an example of a bidirectional load such as a source and / or sink 12. Furthermore, a line inductance L is indicated. At least one source 10 provides a system operating voltage V. system (e.g., DC bus voltage) and current i SSCB The power source is a source 10. At least one junction 12 is supplied with power from the source 10 via a solid-state circuit breaker (SSCB) 14 connected between the at least one junction 12 and the source 10. The SSCB 14 includes a main switching unit 16 (DC circuit breaker) and a clamping circuit 36.

[0072] DC networks 48 are becoming increasingly important in modern power supply systems 50. Due to the lack of voltage zero crossings, special considerations must be made to protect the network in fault conditions. The main component is the so-called DC circuit breaker, which disconnects the circuit in fault conditions. Unfortunately, the energy stored in the inductor must be dissipated in this process. The rapid tripping of the DC circuit breaker results in a high di / di value, and therefore a high voltage spike, which can damage components in the network without protective measures. One solution is to limit overvoltage, i.e., limit overvoltage and dissipate line energy (energy stored in the DC line (inductor)).

[0073] In the event of a fault, such as a short circuit in one of devices 18, SSCB 14 acts as a safety device to limit the fault current and disconnect source 10 and sink 12. SSCB 14 includes clamping circuit 36 ​​as a protection against overvoltage.

[0074] Figure 3Typical voltages during switching events of an SSCB according to a comparative example are shown, where the SSCB has conventional passive clamping circuitry. Such passive clamping systems are commonly used in the prior art, including, for example, TVS diodes, rheostats, etc. Figure 3 The reference numerals shown in the attached figures indicate: i SSCB Current on SSCB

[0075] v SSCB Voltage on SSCB

[0076] V system System operating voltage

[0077] V clamp Voltage clamped by surge discharger

[0078] CI Current Interruption (Power Semiconductor = Main Switch Module Shutdown)

[0079] fe fault event

[0080] iL Nominal load current

[0081] i Power_semiconductor Current through the main switching unit

[0082] i surge_arrestor Current through the passive clamping component

[0083] t time

[0084] All these methods share the common characteristic of having very soft components, which means that relatively large overshoot and high voltage must be expected during clamping. If the system operating voltage V... system Approaching the maximum permissible operating voltage of a semiconductor can become problematic, as this voltage could be exceeded and the component damaged in fault conditions. Therefore, existing clamping circuits require large semiconductor devices with high maximum permissible operating voltages. Furthermore, most clamping components exhibit strong temperature dependence. To avoid high losses due to leakage current during normal operation, the clamping voltage is significantly higher than the maximum operating voltage.

[0085] Refer again Figure 2 This illustrates a prior art technique for overvoltage limiting using a standard TVS diode D1. In the event of a fault, a bidirectional main switch 16 (e.g., a MOSFET) disconnects the circuit, and the resulting overvoltage is blocked by D1.

[0086] Unfortunately, D1 is not an ideal component and therefore clamps the voltage relatively softly. In some cases, this can lead to large overshoot and pose a potential risk of component damage. Using a TVS with lower breakdown voltage is also not an option, as the voltage must not be lower than the operating voltage, and a certain amount of reverse voltage is required to reduce the breakdown current.

[0087] Figure 4 The figure shows a typical (idealized) voltage waveform following an overcurrent event. This curve does not account for inductor overshoot during commutation. The curve only shows the behavior of the TVS diode D1, namely overshoot (650V–+900V in this example) and foldback behavior (voltage drops below the nominal clamping voltage of diode D1). This overshoot leads to a major limitation in protection system design.

[0088] If more than one TVS diode is used, for example, to achieve a higher voltage or to optimally set the desired clamping value, the overvoltage behavior of each diode is added together to form the total overvoltage, i.e., approximately n*V_overshoot, where n is the number of components in series.

[0089] Figure 5 and Figure 7 A block diagram of a circuit having a circuit breaker according to an embodiment of the present invention is shown.

[0090] The circuit breaker 14 includes: a main switching unit 16 configured to open in the event of a fault; and a passive clamping circuit 18 for absorbing energy and preventing overvoltage. The clamping circuit 18 is connected in parallel to the main switching unit 16 and includes a plurality of passive transient suppression components 20.1, 20.2, 20.3 and a delay device 19 arranged and configured to shift the action of the passive transient suppression components 20.1, 20.2, 20.3 such that these passive transient suppression components respond sequentially rather than simultaneously.

[0091] The passive transient suppression components 20.1, 20.2, and 20.3 can be of any suitable type, such as variable resistors. In the illustrated embodiment, the transient suppression components 20.1, 20.2, and 20.3 are TVS diodes D1, D2, and D3. In some embodiments, the same transient suppression components 20.1, 20.2, and 20.3 are used. For example, the same TVS diodes can be used such that D1 = D2 = D3.

[0092] One concept implemented in an embodiment of the invention is to shift the operation of each diode D1, D2, D3, so that these diodes respond sequentially rather than simultaneously. This allows for a significant reduction in the total peak voltage, resulting in a more efficient clamping circuit design.

[0093] The delay device 19 can be of any suitable type. In some embodiments, the delay device 19 has n-1 delay elements 21.1, 21.2, each of which is associated with one of the transient suppression elements 20.1, 20.2, 20.3, such that the operation of the transient suppression element is shifted sequentially. In the illustrated embodiment, the delay elements 21.1, 21.2 are capacitors C1, C2, each of which is connected in parallel to one of the TVS diodes D2, D3.

[0094] Figure 5 and Figure 7 This illustrates a possible implementation of advanced clamping. The "diode shifting" function is achieved by capacitors C1 and C2 connected in parallel with different capacitance values.

[0095] Figure 5 It is shown that it has a DC network 50, for example for such as Figure 1 A block diagram of an exemplary circuit for the power distribution system of the aircraft 100. The DC network 50 may include one or more sources 10 and sinks 12. For simplicity, only one source 10 and one sink 12 are shown here. At least one source 10 provides electrical energy having a source voltage VDC (e.g., DC bus voltage) and a current Iin. At least one sink 12 is supplied with electrical energy from the source 10 via a circuit breaker 14 (e.g., a DC circuit breaker, a solid-state circuit breaker SSCB) connected between the at least one sink 12 and the source 10. The sink 12 may be a bidirectional load (or a bidirectional source). Furthermore, Figure 5 The value in the text indicates the line inductance L.

[0096] In the event of a fault, such as a short circuit, circuit breaker 14 acts as a safety device to interrupt the fault current and disconnect source 10 and sink 12. Circuit breaker 14 has a main switching unit 16 with at least one main electrical switch. In some embodiments, circuit breaker 14 is a bidirectional SSCB with a bidirectional main switching unit 16, which may include two main electrical switches. The term "electrical switch" is used as a designation for any semiconductor switch such as IGBT, MOSFET, etc.

[0097] During normal operation, the main switch unit 16 is closed (connected), so that the collector 12 is connected to the source 10 and is supplied with DC power having a DC bus voltage VDC and a line current Iin.

[0098] The main switch unit 32 is configured to open in case of a fault. The rapid opening of the DC circuit breaker—circuit breaker 14—results in a high dI / dt value and thus a high voltage peak, which, without protective measures, could damage components in the network.

[0099] Therefore, the circuit breaker 14 is equipped with a clamping circuit 18, which includes transient suppression components 20.1, 20.2, 20.3, such as rheostats, MOVs, or TVS diodes D1, D2, D3, and a delay device 19, which has primary capacitors C1, C2.

[0100] according to Figure 5 The clamping circuit 18 of the first embodiment constitutes a primary passive protection circuit 26. In the example shown, the primary passive protection circuit 26 includes a first passive transient suppression component, a second transient suppression component, and a third passive transient suppression component 20.1, 20.2, 20.3, which are, for example, in the form of a first TVS diode to a third TVS diode D1, D2, D3 (e.g., TVS diodes of the same type, D1 = D2 = D3). The passive transient suppression components 20.1, 20.2, 20.3 are connected in series. Furthermore, the example shown of the primary passive protection circuit 26 includes a plurality of primary capacitors C1, C2. For example, the first primary capacitor C1 is connected in parallel to the second transient suppression component 20.2, and the second primary capacitor C2 is connected in parallel to the third transient suppression component 20.3. The primary capacitors C1 and C2 are examples of delay components of a delay device.

[0101] Figure 6 It shows the relationship with Figure 4 A similar simulation, but with a delay device 19—represented here by additionally placed capacitors C1 and C2—is performed. It can be seen that the voltage peaks of the individual diodes occur with a time delay. Therefore, the total clamping voltage can be significantly reduced (approximately 720V instead of 900V). The estimated results have also been successfully demonstrated in a laboratory setting.

[0102] Embodiments of the present invention, such as, for example Figure 5 and Figure 7 As shown, it achieves relative to, for example Figure 2 The prior art circuit shown represents at least one, several, or all of the following improvements:

[0103] • Significant reduction in overvoltage

[0104] • Better adjustment of voltage behavior

[0105] Stricter restrictions can be adjusted (→ more flexible credit limit reductions)

[0106] • Better utilization of components

[0107] Very high energy clamping capability with low weight and volume

[0108] • Significantly steeper clamping characteristics

[0109] • Rapid passive discharge → It can function effectively even under conditions of several consecutive faults.

[0110] Figure 7 The clamping circuit 18 includes Figure 5 Protection circuit 26, which provides the same protection as the reference circuit 26. Figure 5 The same function described. Below is... Figure 7 The additional functions of the implementation method will be explained.

[0111] Figure 5 The clamping circuit 18 is an example of a protection measure used to protect the DC network 50 from peak voltages. In some embodiments, the primary protection circuit 16 of the clamping circuit 18 includes TVS diodes D1, D2, and D3 and primary capacitors C1 and C2. In a fault condition, capacitors C1 and C2 are charged when the main switching unit 16 is disconnected.

[0112] Capacitors C1 and C2 must discharge after the switch across diodes D1, D2, and D3 is closed to prepare the primary protection circuit 16 for another transient event. This can be achieved using a discharge resistor on each primary capacitor C1 and C2. Figure 5 (Not shown in the diagram) This is to be accomplished. The resistor value that can be used will be a trade-off between the standoff loss (main switch unit 16 is open) and the discharge time once the main switch unit 16 is closed. In a system with a standoff voltage of 800V and a standoff current of 1kA, a typical resistor value generates losses in the single-digit watt range and requires several seconds to discharge the primary protection circuit 16. These limitations are detrimental to system performance and reliability.

[0113] If a new transient event occurs before the primary capacitors C1 and C2 are fully discharged, a significant voltage spike will be generated across the main switching unit 16. Therefore, the main switching unit 16 must limit the current beyond what is necessary to respond to fault conditions immediately after system startup.

[0114] To address this drawback, the circuit breaker 14 according to some embodiments of the present invention has a clamping circuit 18, wherein an additional capacitor arrangement is added. Examples of this are shown in... Figure 7 As shown in the image.

[0115] According to this further embodiment of the invention, the clamping circuit 18 of the circuit breaker 14 has a primary passive protection circuit 26, which has at least one transient suppression component 20.1, 20.2, 20.3, and at least one primary capacitor C1, C2, and a discharge circuit 28 additionally including at least one secondary capacitor C3, C4, C5. The discharge circuit 28 is configured to discharge at least one primary capacitor C1, C2 when the main switching unit 16 is closed.

[0116] exist Figure 7 In the example, the clamping circuit 18 according to an embodiment of the present invention has the same characteristics as... Figure 2 The comparative example shown includes a primary protection circuit 26 similar to the clamping circuit 18, and a discharge circuit 28 additionally arranged as secondary capacitors C3, C4, and C5. For example, a primary protection circuit 26 is added, such as... Figure 7 The right side shows a series of three secondary capacitors C3, C4, and C5.

[0117] When the main switch unit 16 is closed and the voltage at the clamping circuit 18 approaches zero, the additional capacitors C3, C4, and C5 discharge the primary capacitors C1 and C2. The clamping performance is not significantly affected by the additional components. This process occurs quite quickly. A precise speed can be set. Other alternative implementations are described below.

[0118] In embodiments of the invention, the required discharge process can be completed in the range of 50 to 100 microseconds, instead of taking several seconds. The leakage current when the main switch unit 16 is closed is also reduced. The proposed clamping circuit 18 is also completely passive.

[0119] In some embodiments, the discharge circuit 28 further includes a plurality of decoupling resistors R4, R5, R6, R7, which are configured to decouple at least one secondary capacitor C3, C4, C5 from the primary passive protection circuit 26 during clamping.

[0120] In some embodiments, the discharge circuit 28 further includes a plurality of balancing resistors R1, R2, and R3. The balancing resistors R1, R2, and R3 are configured to balance the charging between transient suppression sections 22.1, 22.2, and 22.3 when the switch is turned off. During clamping, the balancing resistors R1, R2, and R3 are decoupled via decoupling resistors R4, R5, R6, and R7.

[0121] Figure 7The clamping circuit 18 includes a series of transient suppression sections 22.1, 22.2, 22.3. Each transient suppression section 22.1, 22.2, 22.3 includes a portion or segment of a passive protection circuit 26—hereinafter referred to as passive protection circuit units 24.1, 24.2, 24.2—and a portion or segment of a discharge circuit 28—hereinafter referred to as discharge circuit units 30.1, 30.2, 30.3. In each transient suppression section 22.1, 22.2, 22.3, the corresponding passive protection units 24.1, 24.2, 24.3 and the corresponding discharge circuit units 30.1, 30.2, 30.3 are connected in parallel with each other. Each passive protection circuit unit in passive protection circuit units 24.1, 24.2, 24.3 includes a passive transient suppression component 20.1, 20.2, 20.3. At least one or more of the passive protection circuit units 24.1, 24.2, and 24.3 additionally include a primary capacitor C1 and C2. Each discharge circuit unit 30.1, 30.2, and 30.3 includes a secondary capacitor C3, C4, and C5.

[0122] The capacitances of secondary capacitors C3, C4, and C5 are selected such that each transient suppression segment 22.1, 22.2, and 22.3 has the same charge.

[0123] exist Figure 7 In the implementation, a series of three transient suppression segments 22.1, 22.2, and 22.3 are provided. Since each transient suppression segment 22.1, 22.2, and 22.3 in the example shown has diodes D1, D2, and D3 as transient suppression segments, it can also be referred to as a diode segment.

[0124] R1, R2, and R3 are passive balancing resistors. The values ​​of these resistors are proportional to the cutoff voltages of the TVS diodes D1, D2, and D3 to which they are connected. Depending on the leakage current requirements, these balancing resistors R1, R2, and R3 can have fairly large values. Generally, these values ​​can be selected in the high range of kiloohms to megaohms.

[0125] R4, R5, R6, and R7 are decoupling resistors. During clamping, these resistors decouple diodes D1, D2, D3 and primary capacitors C1, C2 from the rest of the system. For 1kV and 500A, the values ​​of these resistors are typically in the range of 10 Ohms.

[0126] As described above, the capacitances of the additional secondary capacitors C3, C4, and C5 are selected such that each diode segment—transient suppression segments 22.1, 22.2, and 22.3—has the same charge.

[0127] The possible choices of capacitors are illustrated in more detail in the example. Assume that the capacitance of the second primary capacitor C2 is twice that of the first primary capacitor: C2 = 2 × C1. The diode voltage is taken from... Figure 3 An example with the values ​​shown above. Several possible solutions exist: One solution is that C4 must be the same size as C2, and C5 must be the same size as C1. Then C3 must be half the sum of C1 and C4. The voltage across D1 is twice that of the others, which, if the charges are the same, halves the capacitance of C3.

[0128] In the following text, for those including Figure 7 The implementation method of the operation method of the circuit breaker 14 of the clamping circuit 18 will be described. The possible steps of the discharge process are:

[0129] 1. When the main switch unit 16 is disconnected, the entire bus voltage is applied to the clamping circuit 18. After reaching steady state via the balancing resistors (R1, R2, R3), all capacitors C1 to C5 are charged to near the cutoff voltage of the connected TVS diodes D1, D2, D3. During longer time intervals (>1ms), the decoupling resistors R4 to R7 can be approximated as short circuits due to their relatively small values.

[0130] 2. After closing the main switch unit 16 and short-circuiting the clamping circuit 18, a portion of the charge in all capacitors C1 to C5 flows out through diodes D1 to D3, but primarily through decoupling resistors R4 to R7. During the first peak, current flows through the transient suppression component, and then the entire current flows through decoupling resistors R4 to R7. Since the capacitor charge is the same in each diode segment 22.1, 22.2, 22.3, all capacitors C1 to C5 reach approximately 0V after the discharge process.

[0131] 3. During the next transient event, the "diode shift" function of clamping circuit 18 operates as expected. During the short clamping time, decoupling resistors R4, R5, R6, and R7 decouple the discharge network—discharge circuit 28.

[0132] By combining the discharge circuit 28 with the diode shift clamping circuit 18, the discharge time can be reduced from a few seconds to a range of two-digit microseconds. Therefore, transient events during or shortly after the activation of the DC network 50 can be intercepted without causing peaking of the switching voltage.

[0133] Due to the passive nature of the clamping circuit 18, no significant additional complexity is introduced into the system. This reduces integration speed, product development time, and facilitates certification.

[0134] List of reference numerals

[0135] 10 Energy / Voltage Source

[0136] 12 Exchanges

[0137] 14 Circuit Breakers

[0138] 16 Main Switch Unit

[0139] 18 Clamping Circuit

[0140] 19 Delay device

[0141] 20.1 First Transient Suppression Component

[0142] 20.2 Second Transient Suppression Component

[0143] 20.3 Third Transient Suppression Component

[0144] 21.1 First Delay Component

[0145] 21.2 Second Delay Component

[0146] 22.1 First Transient Suppression Section

[0147] 22.2 Second Transient Suppression Section

[0148] 22.3 Third Transient Suppression Section

[0149] 24.1 First Passive Protection Circuit Unit

[0150] 24.2 Second Passive Protection Circuit Unit

[0151] 24.3 Third Passive Protection Circuit Unit

[0152] 26 Primary Passive Protection Circuit

[0153] 28 Discharge Circuit

[0154] 30.1 First Discharge Circuit Unit

[0155] 30.2 Second Discharge Circuit Unit

[0156] 30.3 Third Discharge Circuit Unit

[0157] 50 DC network

[0158] 100 aircraft

[0159] 112 Electrical Consumable Components

[0160] 116 Power electronic devices

[0161] 118 DC bus

[0162] 120 Electric Propulsion System

[0163] 124 motors

[0164] 126 propellers

[0165] 128 inverter

[0166] 130 battery

[0167] D1 First TVS diode

[0168] D2 Second TVS diode

[0169] D3 Third TVS diode

[0170] C1 First primary capacitor

[0171] C2 Second primary capacitor

[0172] C3 Primary capacitor

[0173] C4 Secondary capacitor

[0174] C5 Third-stage capacitor

[0175] L-line inductor

[0176] R1 First balancing resistor

[0177] R2 Second balancing resistor

[0178] R3 Third balancing resistor

[0179] R4 is the first decoupling resistor (used to decouple the primary protection circuit and the discharge circuit during clamping).

[0180] R5 is the second decoupling resistor (used to decouple the primary protection circuit and the discharge circuit during clamping).

[0181] R6 is the third decoupling resistor (used to decouple the primary protection circuit and the discharge circuit during clamping).

[0182] R7 Fourth decoupling resistor (used to decouple the primary protection circuit and the discharge circuit during clamping).

Claims

1. A circuit breaker (14), comprising: A main switch unit (16) configured to open in case of a fault; The system also includes a passive clamping circuit (18) for absorbing energy and preventing overvoltage, wherein the clamping circuit (18) is connected in parallel to the main switching unit (16), characterized in that the clamping circuit (18) includes a plurality of passive transient suppression components (20.1, 20.2, 20.3) and a delay device (19), wherein the delay device (19) is arranged and configured to shift the action of the passive transient suppression components (20.1, 20.2, 20.3) such that the passive transient suppression components (20.1, 20.2, 20.3) respond sequentially rather than simultaneously.

2. The circuit breaker (14) according to claim 1, wherein, The passive transient suppression components (20.1, 20.2, 20.3) are selected from a group consisting of a variable resistor and a TVS diode (D1, D2, D3).

3. The circuit breaker (14) according to any one of the preceding claims, wherein, The passive transient suppression components (20.1, 20.2, 20.3) are connected in series.

4. The circuit breaker (14) according to any one of the preceding claims, wherein, The clamping circuit includes n transient suppression components (20.1, 20.2, 20.3), where n is a natural number greater than 2, and the delay device includes n-1 delay components (21.1, 21.2), each delay component being associated with one of the transient suppression components such that the action of the transient suppression component is delayed.

5. The circuit breaker according to claim 4, wherein, The delay components (21.1, 21.2) Different from each other, and / or Having different values, and / or These are capacitors with different capacitances (C1, C2).

6. The circuit breaker (14) according to any one of the preceding claims, wherein, The delay device (19) includes at least one capacitor (C1, C2), which is connected in parallel to one of the transient suppression components (20.1, 20.2, 20.3).

7. The circuit breaker (14) according to claims 4 to 6, wherein, The clamping circuit includes a first transient suppression component, a second transient suppression component, and a third transient suppression component (20.1, 20.2, 20.3) connected in series, and wherein the delay device (19) includes a first capacitor (C1) connected in parallel to the second transient suppression component (20.2) and a second capacitor (C2) connected in parallel to the third transient suppression component, wherein the capacitance of the first capacitor (C1) and the capacitance of the second capacitor (C2) are different from each other.

8. The circuit breaker (14) according to any one of the preceding claims, wherein, The clamping circuit (18) includes a primary passive protection circuit (26), which includes the plurality of transient suppression components (20.1, 20.2, 20.3), and wherein the delay device has at least one primary capacitor (C1, C2) configured to charge during clamping when the main switch (16) is open. The clamping circuit (18) further includes a discharge circuit (28), which includes at least one secondary capacitor (C3, C4, C5) and is configured to discharge the at least one primary capacitor (C1, C2) when the main switch unit (16) is closed.

9. The circuit breaker (14) according to claim 8, wherein, The clamping circuit (18) includes a plurality of primary capacitors (C1, C2) configured to charge when the main switching unit (16) is open, and wherein the discharge circuit (28) includes an arrangement of secondary capacitors (C3, C4, C5) and is configured to discharge the primary capacitors (C1, C2) when the main switching unit (16) is closed; and / or The discharge circuit (28) includes a plurality of decoupling resistors (R4, R5, R6, R7) configured to decouple the at least one secondary capacitor (C3, C4, C5) from the primary passive protection circuit (26) during clamping.

10. The circuit breaker according to any one of claims 8 or 9, wherein, The clamping circuit (18) includes a series of transient suppression sections (22.1, 22.2, 22.3), each transient suppression section including a passive protection circuit unit (24.1, 24.2, 24.3) and a discharge circuit unit (30.1, 30.2, 30.3) connected in parallel with each other. Each passive protection circuit unit (24.1, 24.2, 24.3) includes a passive transient suppression component (20.1, 20.2, 20.3), and at least one or more of the passive protection circuit units (24.1, 24.2, 24.3) additionally include a primary capacitor (C1, C2). Each discharge circuit unit (30.1, 30.2, 30.3) includes a secondary capacitor (C3, C4, C5). The capacitance of the secondary capacitors (C3, C4, C5) is selected such that each transient suppression segment (22.1, 22.2, 22.3) has the same charge.

11. The circuit breaker (14) according to claim 10, wherein, Each transient suppression segment (22.1, 22.2, 22.3) includes a TVS diode (D1, D2, D3) as a transient suppression component (20.1, 20.2, 20.3) and a balancing resistor (R1, R2, R3) connected in parallel with the secondary capacitor (C3, C4, C5), wherein the resistance of the balancing resistor (R1, R2, R3) of the transient suppression unit (22.1, 22.2, 22.3) is selected such that the resistance of the balancing resistor (R1, R2, R3) is proportional to the cutoff voltage of the TVS diode (D1, D2, D3) to which the balancing resistor (R1, R2, R3) is connected.

12. The circuit breaker (14) according to any one of claims 9 to 11, wherein, Each transient suppression section (22.1, 22.2, 22.3) includes at least one of the decoupling resistors (R4, R5, R6, R7) for decoupling the passive protection circuit unit (24.1, 24.2, 24.3) from the secondary capacitor (C3, C4, C5) during clamping.

13. An operating method for operating a circuit breaker (14) according to any one of claims 8 to 12, the operating method comprising the following steps: a) In the event of a fault, disconnect the main switch unit (16) and apply the entire bus voltage to the clamping circuit (18); charge the primary capacitor (C1, C2) and the secondary capacitor (C3, C4, C5) until a steady state is reached; b) When the fault event ends, close the main switch unit (16) and short-circuit the clamping circuit (18), discharge the secondary capacitors (C3, C4, C5) and discharge the primary capacitors (C1, C2) via the discharge circuit.

14. A DC network (50) for an aircraft (100), the DC network (50) comprising: At least one electrical energy source (10) and at least one electrical energy sink (12); And at least one circuit breaker (14) according to any one of claims 1 to 12, which is connected between the at least one source (10) and the at least one sink (12).

15. An aircraft (100) comprising a DC network (50) according to claim 14 or at least one circuit breaker (14) according to any one of claims 1 to 12.

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