Circuit interrupter using inductor connection of step switches to achieve variable inductance during current interruption

Abstract

A circuit interrupter includes an inductor module connected in series with a hybrid interrupter switch between a power source and a load. The inductor module includes a coupled inductor including a primary winding connected in series between the power source and the interrupter module, and a secondary winding connected to the power source on its line side. The load side of the secondary winding is connected to a first stage switching device that forms a switch between the secondary winding and the interrupter module. In normal current conditions, the first stage switching device and the hybrid interrupter switch remain closed. During a fault, the first stage switching device is first opened, which significantly increases the magnetic flux in the inductor module and the impedance of the circuit, and thus reduces the current through the interrupter module. The hybrid switch is then turned on to complete the interruption.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 694275, filed September 13, 2024, entitled “CIRCUIT INTERRUPTER USING INDUCTOR CONNECTION WITH STAGED SWITCHING TO ACHIEVE VARIABLE INDUCTANCEDURING CURRENT INTERRUPTION,” the disclosure of which is incorporated herein by reference. Technical Field

[0003] The disclosed concepts generally relate to circuit interrupters, and more particularly to current interruption devices for circuit interrupters. Background Technology

[0004] Circuit interrupters, such as, but not limited to, circuit breakers, are typically used to protect circuit systems from damage caused by overcurrent conditions (such as overload conditions), short circuits, or other fault conditions (such as arcing faults or ground faults). Circuit interrupters may include mechanical interruption devices, solid-state (i.e., semiconductor) interruption devices, or hybrid interruption devices that include both mechanical and solid-state interruption devices.

[0005] Mechanical interrupt devices include mechanically operated separable electrical contacts that operate like a switch. These separable contacts are typically connected in series between a power source and a load, such that a line conductor connects the power source to one of the separable contacts, and a load conductor connects the other separable contact to the load. The separable contacts remain closed when the power supplied to the interrupter is within its normal operating range, and open when the power supplied exceeds its normal operating range. When the separable contacts are in the closed state and in contact with each other, current can flow from the power source to the load through the separable contacts and the line / load conductor. When the separable contacts are in the open state and separated from each other, current is prevented from flowing from the power source to the load. The separable contacts can be operated manually via a handle, remotely via an electrical signal, or automatically in response to a detected fault.

[0006] In solid-state interrupt devices, the semiconductor switch operates similarly to the separable contacts in mechanical interrupt devices. That is, the semiconductor switch is connected in series between the power source and the load, such that a line conductor connects the power source to the semiconductor switch, and a load conductor connects the semiconductor switch to the load. Figure 1 illustrates such a solid-state interruptor 10, which includes a semiconductor switch 11 connected in series between a power source 1 and a load 2. A line conductor 3 connects the power source 1 and the solid-state interruptor 10, and a load conductor 4 connects the solid-state interruptor 10 and the load 4. When on, the semiconductor switch 11 acts as a closed switch, allowing current to flow from the power source 1 through the line conductor 3, through the semiconductor switch, and through the load conductor 4 to the load 2. When off, the semiconductor switch 11 acts as an open switch, preventing current from flowing from the power source 1 to the load 2. Control logic is used to keep the semiconductor switch 11 on when the power supplied to the solid-state interruptor 10 is within the normal operating range, and to disconnect the semiconductor switch 11 when the power supplied to the solid-state interruptor 10 exceeds the normal operating range.

[0007] In circuit breakers with only mechanical interrupt devices, any stored energy in the circuit breaker will be released as an electric arc across the separable contacts when the separable contacts open under fault conditions or other non-zero energy states. In circuit breakers with only solid-state interrupt devices, the interrupt time is much faster than that of mechanical interrupt devices, but the conduction losses (i.e., the losses generated by the semiconductor switch conducting current under normal operation) are significantly higher than those of mechanical interrupt devices. Hybrid circuit breakers are designed to utilize the advantages of both mechanical and solid-state interrupters while minimizing their respective disadvantages.

[0008] In a hybrid circuit interrupter, a mechanical interruptor and a semiconductor switch are connected in parallel to form a hybrid interruptor located between a power source and a load. The hybrid circuit interrupter is designed such that when the power in the interrupter is within its normal operating range, current can only flow through the separable contacts of the mechanical interruptor, thus avoiding the relatively high conduction losses of the semiconductor switch. Figure 2 shows such a hybrid circuit interrupter 20, which includes a semiconductor switch 21 and a mechanically separable contact 23 connected in parallel to each other. The hybrid circuit interrupter 20 is connected in series between a power source 1 and a load 2. A line conductor 3 connects the power source 1 and the hybrid circuit interrupter 20, and a load conductor 4 connects the hybrid circuit interrupter 20 and the load 2. When the power is within its normal operating range, the mechanically separable contact 23 remains closed and the semiconductor switch 21 is open. When a fault condition is detected, the mechanically separable contact 23 is opened. After a small arc voltage is formed across the separable contact 23, the semiconductor switch 21 is turned on. The small arc voltage across the separable contact 23 drives current to commutate from the separable contact 23 to the semiconductor switch 21. Semiconductor switch 21 opens shortly after commutation to completely interrupt the current, and its interruption time is significantly shorter compared to a purely mechanical interruptor. As shown in Figures 1 and 2, solid-state circuit interruptors and hybrid circuit interruptors often include several MOV (metal oxide varistor) devices or other transient suppression devices to suppress transient voltages.

[0009] While existing hybrid circuit interrupters and solid-state interrupters can achieve relatively fast interrupt times, achieving even faster interrupt times in fault conditions and reducing fault current as quickly as possible is always desirable.

[0010] Therefore, there is still room for improvement in circuit interrupters and their current interruption devices. Summary of the Invention

[0011] These and other requirements are met by an embodiment of a circuit interrupter that includes an inductor module connected in series between a power supply and a load. The inductor module includes a coupled inductor comprising an inductor core, a primary winding connected in series between the power supply and the interrupter module, and a secondary winding connected to the power supply on its line side. The load side of the secondary winding is connected to a first-stage switching device, which forms a switch between the secondary winding and the interrupter module. The interrupter module includes a hybrid interrupter switch. Under normal current conditions, both the first-stage switching device and the hybrid interrupter switch remain closed. When the first-stage switching device is closed, the inductor module is nearly short-circuited, resulting in very little flux in the inductor core. During a fault, the first-stage switching device is first opened, which significantly increases the flux in the inductor module and the impedance of the entire circuit, and thus reduces the current through the interrupter module. Then, the hybrid switch is opened to complete the interrupt. Since turning on the first-stage switching device in the inductor module significantly reduces the current to be interrupted by the interruptor module in the event of a fault, as well as the expected peak current, the interruptor module can use components with a significantly reduced rated interrupt current.

[0012] According to one aspect of the present disclosure, a circuit interrupter configured to connect between a power source and a load includes: a line conductor configured to be connected to the power source, a load conductor configured to be connected to the load, an inductor module, an interrupter module, and a controller. The inductor module includes: an inductor core, a first winding (a first conductor wound around a first portion of the inductor core), a second winding (a second conductor wound around a second portion of the inductor core), and a first-stage switch. The interrupter module is connected in series with the inductor module between the line conductor and the load conductor, such that the line side of the interrupter module is connected to the load side of the inductor module at a common node, and the load side of the interrupter module is connected to the load conductor. The interrupter module is configured to interrupt current flowing from the power source to the load. A first end of the first winding is connected to the line conductor, and a second end of the first winding is connected to the common node. A first end of the second winding is connected to the line conductor, and a second end of the second winding is connected to a first end of the first-stage switch. The first-stage switch is connected between the second end of the second winding and the common node. The controller is configured to drive the first-stage switch to close under normal current conditions and to drive the first-stage switch to open when a fault current condition is detected.

[0013] According to another aspect of the present disclosure, a method for conducting and interrupting current includes: providing a circuit interrupter having an inductor module and an interruptor module connected in series between a line conductor and a load conductor; connecting the line conductor to a power source and the load conductor to a load; maintaining a first-stage switch and the interruptor module in a closed state under normal current conditions; driving the first-stage switch to an open state upon detecting a fault condition; and driving the interruptor module to an open state after the first-stage switch has been driven to its open state upon detecting a fault condition. The inductor module includes: an inductor core, a first winding (a first conductor wound around a first portion of the inductor core), a second winding (a second conductor wound around a second portion of the inductor core), and a first-stage switch. The line side of the interruptor module is connected to the load side of the inductor module at a common node. A first end of the first winding is connected to the line conductor, and a second end of the first winding is connected to the common node. A first end of the second winding is connected to the line conductor, and a second end of the second winding is connected to a first end of the first-stage switch. The first-stage switch is connected between the second end of the second winding and the common node. Attached Figure Description

[0014] The invention can be fully understood by reading the following description in conjunction with the accompanying drawings, wherein:

[0015] Figure 1 is a schematic diagram of a prior art solid-state circuit interrupter;

[0016] Figure 2 is a schematic diagram of a hybrid circuit interrupter in the prior art;

[0017] Figure 3 This is a schematic diagram of an improved DC circuit interrupter according to an example embodiment of the disclosed concept, the DC circuit interrupter including an inductor module having an inductor module for normal current conduction connected in series with the interrupter module.

[0018] Figure 4 This is a schematic diagram of an improved AC circuit interrupter according to an example embodiment of the disclosed concept, the AC circuit interrupter including an inductor module having an inductor module for normal current conduction connected in series with the interrupter module.

[0019] Figure 5 This is a schematic diagram of an improved DC circuit interrupter according to an example embodiment of the disclosed concept, the DC circuit interrupter including an inductor module having an inductor module for normal current conduction connected in series with the interrupter module.

[0020] Figure 6This is a schematic diagram of an improved AC circuit interrupter according to an example embodiment of the disclosed concept, the AC circuit interrupter including an inductor module having an inductor module for normal current conduction connected in series with the interrupter module.

[0021] Figure 7 This is a flowchart of a method for conducting and interrupting current between a power source and a load, based on an example embodiment of the disclosed concept;

[0022] Figure 8-13 It shows when using Figure 4 The graphs shown illustrate how the current and voltage levels change in an AC circuit breaker when using the new inductor module; and

[0023] Figure 14-19 It shows when using Figure 6 The graph shown illustrates how the current and voltage levels change in an AC circuit breaker when using the new inductor module. Detailed Implementation

[0024] Directional phrases used herein, such as left, right, front, back, top, bottom, and their derivatives, relate to the orientation of the elements shown in the accompanying drawings and, unless expressly stated herein, do not limit the claims.

[0025] As used herein, unless the context clearly indicates otherwise, the singular forms of “a,” “an,” and “the” include plural references.

[0026] As is used in this article, when ordinal numbers such as “first” and “second” are used to modify nouns, this use is only intended to distinguish one item from another and is not intended to require order unless otherwise stated.

[0027] As used herein, the term "controller" means a programmable analog and / or digital device capable of storing, retrieving, and processing data; a processor; a control circuit; a computer; a workstation; a personal computer; a microprocessor; a microcontroller; a microcomputer; a central processing unit; a mainframe computer; a minicomputer; a server; a networked processor; or any suitable processing device or equipment.

[0028] As used herein, the expression “coupled” means that these parts are directly or indirectly (i.e., through one or more intermediate parts or components) connected or operating together, as long as there is an association. As used herein, “direct coupling” means that two elements are in direct contact with each other. As used herein, “fixedly coupled” or “fixed” means that two components are coupled so that they move as a whole while maintaining a constant orientation relative to each other.

[0029] As used in this article, the term "several" refers to one or more integers (i.e., multiple).

[0030] Now for reference Figure 3 and Figure 4 These illustrations show schematic diagrams of a DC circuit interrupter 100 and an AC circuit interrupter 200, respectively, according to exemplary embodiments of the disclosed concept, including novel inductor modules 110 and 210 with solid-state switches, and implementing graded current interruption. The DC circuit interrupter 100 and AC circuit interrupter 200 are functionally similar and will be described simultaneously, wherein any DC characteristics specific to the DC circuit interrupter 100 will be discussed separately as needed, and any AC characteristics specific to the AC circuit interrupter 200 will be discussed separately as needed. The DC circuit interrupter 100 is configured to be connected in series between a DC power supply 81 and a DC load 82, and the AC circuit interrupter 200 is configured to be connected in series between an AC power supply 91 and an AC load 92. Both circuit interrupters 100 and 200 include two main stages: a first stage is a current reduction stage implemented by the novel inductor modules 110 and 210, and a second stage is a current interruption stage implemented by interrupter modules 120 and 220. As further detailed below, each disclosed inductor module 110, 210 connects the inductor to the line side of the circuit interrupter 100, 200 in a novel manner, thereby reducing the interrupt rated current and peak expected current in the components of the interrupter modules 120, 220.

[0031] Each circuit breaker 100, 200 includes a controller 101, 201. Controllers 101, 201 are configured to connect and disconnect all solid-state devices and initiate the opening of all mechanically separable contacts in circuit breaker 100, 200. In this document, whenever solid-state devices in circuit breaker 100, 200 are described as being connected or disconnected, and mechanically separable contacts in circuit breaker 100, 200 are described as being opened, it should be understood that all such connection / disconnection and opening are initiated by controllers 101, 201.

[0032] In each circuit interrupter 100, 200, inductor modules 110, 210 are connected in series with interrupter modules 120, 220 between power supplies 81, 91 and loads 82, 92. Each interrupter module 120, 220 shown is a hybrid interrupter, functioning similarly to a known hybrid interrupter previously described herein in conjunction with Figure 2; however, although the prior art hybrid circuit interrupter 20 carries all the current flowing to load 2, each interrupter module 120, 220 in each disclosed circuit interrupter 100, 200 carries only a portion of the total current flowing to loads 82, 92, because each inductor module 110, 210 is designed to also carry a portion of the total current flowing to loads 82, 92. That is, as will be further detailed below, the introduction of inductor modules 110, 210 in circuit interrupters 100, 200 reduces the current that interrupter modules 120, 220 would otherwise have to carry without inductor modules 110, 210.

[0033] Power supplies 81 and 91, inductor modules 110 and 210, interrupt modules 120 and 220, and loads 82 and 92 are all connected in series. Inductor modules 110 and 210 and interrupt modules 120 and 220 each have a line side and a load side. The line sides of inductor modules 110 and 210 are connected to power supplies 81 and 91 via line conductors 83 and 93. The load sides of inductor modules 110 and 210 and the line sides of interrupt modules 120 and 220 are interconnected via common nodes 102 and 202. The load sides of interrupt modules 120 and 220 are connected to loads 82 and 92 via load conductors 84 and 94.

[0034] Inductor modules 110, 210 include a first conductor winding 111, 211 (hereinafter referred to as the "first winding") and a second conductor winding 112, 212 (hereinafter referred to as the "second winding") wound on inductor cores 113, 213. The first winding 111, 211, the second winding 112, 212, and the inductor cores 113, 213 form coupled inductors 114, 214. The inductor cores 113, 213 may be made of, for example, but not limited to, copper. The first winding 111, 211 is wound around a first portion of the inductor cores 113, 213, and its first end is connected to line conductors 83, 93, and its second end is connected to common nodes 102, 202. The second windings 112 and 212 are wound around the second part of the inductor cores 113 and 213, and are connected at the first end to the line conductors 83 and 93, and at the second end to the secondary side nodes 150 and 250.

[0035] In the DC circuit interrupter 100, a first-stage switch 115 and a DC current regulator 116 are connected in series between the secondary-side node 150 and the common node 102. The first-stage switch 115 is connected between the secondary-side node 150 and the DC current regulator 116, and the DC current regulator 116 is connected between the first-stage switch 115 and the common node 102. Specifically, the first-stage switch 115 is a solid-state switch and is sometimes referred to as solid-state switch 115 hereinafter. The DC current regulator 116 ensures that the current is equally distributed between the first winding 111 and the second winding 112. However, without departing from the scope of the disclosed concept, arrangements other than the regulator 116 may be used to ensure the equal distribution of current between the first winding 111 and the second winding 112. A first MOV 131 is connected in series between the line conductor 83 and the secondary-side node 150 and in parallel with the second winding 112. The second MOV 132 is connected in series between the secondary-side node 150 and the common node 102, and in parallel with the series-connected solid-state switch 115 and DC-DC current regulating converter 116. Circuit interrupters 100, 200, and circuit interrupters 300, 400 (discussed later herein, and...) Figure 5-6 All MOV devices included in (shown in the image) are used to suppress transient voltages.

[0036] In AC circuit interrupter 200, a first-stage switch 215 is connected in series between secondary-side node 250 and common node 202. Similar to first-stage switch 115, first-stage switch 215 is also a solid-state switch and is sometimes referred to as solid-state switch 215 below. In AC circuit interrupter 200, the turns ratio of the first winding 211 and the second winding 212 is selected to ensure a natural current distribution between the first winding 211 and the second winding 212. A first MOV 231 is connected in series between line conductor 93 and secondary-side node 250 and in parallel with the second winding 212. A second MOV 232 is connected in series between secondary-side node 250 and common node 202 and in parallel with solid-state switch 215.

[0037] Referring again to both DC circuit interrupter 100 and AC circuit interrupter 200, interrupter modules 120 and 220 also include solid-state switches 121 and 221. Since inductor modules 110 and 210 and interrupter modules 120 and 220 all include solid-state (SS) switches, in order to clearly distinguish between the solid-state switches of inductor modules 110 and 210 and the solid-state switches of interrupter modules 120 and 220, solid-state switches 115 and 215 will be referred to as "first-level SS switches" in the following text, and solid-state switches 121 and 221 will be referred to as "second-level SS switches" in the following text.

[0038] Interrupt modules 120 and 220 are hybrid interruptors, including second-stage SS switches 121 and 221 and mechanically separable contacts 123 and 223 connected in parallel with the second-stage SS switches 121 and 221. Interrupt modules 120 and 220 are connected to a common node 102 on their line side and to loads 82 and 92 on their load side. It should be understood that the interruptor modules 120 and 220 function similarly to the known hybrid interruptors previously described herein in conjunction with Figure 2, such that the second-stage SS switches 121 and 221 are normally open (i.e., switched on), and the mechanical contacts 123 and 223 are normally closed. Interrupt MOVs 133 and 233 are connected in parallel with the second-stage SS switches 121 and 221 and the mechanically separable contacts 123 and 223. Without departing from the scope of the disclosed concept, interruptor modules 120, 220 may contain only mechanical interruptors or only solid-state interruptors instead of the hybrid interruptors shown in the figures. However, it is foreseeable that most circuit interruptor users would prefer to use hybrid interruptors in interruptor modules 120, 220 due to the relatively low conduction losses of mechanically separable contacts 123, 223 when conducting current under normal operating conditions and the relatively fast interruption speed of the second-stage SS switches 121, 221 when interrupting fault current.

[0039] Controllers 101 and 201 are configured to ensure that the first-stage SS switches 115 and 215 are turned on under normal operating conditions. The first-stage SS switches 115 and 215 act as closed switches when they are turned on, and when the first-stage SS switches 115 and 215 are closed, the coupling inductors 114 and 214 are effectively short-circuited, resulting in almost no magnetic flux in the inductor cores 113 and 213, and very low inductance in the inductor modules 110 and 210. Current flows through the inductor modules 110 and 210 and the interruptor modules 120 and 220 to power the loads 82 and 92. In the AC circuit interrupter 200, since the first winding 211 and the second winding 212 are connected as follows... Figure 4 The winding is arranged in a manner indicated by the dot convention, so that the current is naturally distributed between the first winding 211 and the second winding 212 to minimize the magnetic flux in the inductor core 213.

[0040] In the event of a fault, controllers 101 and 201 are configured to disconnect the first-stage SS switches 115 and 215, making them open. The opening of the first-stage SS switches 115 and 215 causes the second windings 112 and 212 to open, thereby establishing magnetic flux in the inductor cores 113 and 213 and significantly increasing the inductance in the circuit. Controllers 101 and 201 are also configured to open the mechanical contacts 123 and 223 in the interruptor modules 120 and 220 shortly after disconnecting the first-stage SS switches 115 and 215, and then close the second-stage SS switches 121 and 221 to commutate current from the mechanical contacts 123 and 223 to the second-stage SS switches 121 and 221. After commutation, the second-stage SS switches 121 and 221 are disconnected to completely interrupt the current.

[0041] It is worth noting that since the first-stage SS switches 115 and 215 carry a portion of the total current, the introduction of coupling inductors 114 and 214 in circuit interrupters 100 and 200 reduces the current carried by the interrupt components in interrupter modules 120 and 220. This results in the interrupted current during interruption operations by interrupter modules 120 and 220 being significantly lower than the current without inductor modules 110 and 210. Furthermore, opening the first-stage SS switches 115 and 215 in inductor modules 110 and 210 before opening the mechanical contacts 123 and 223 and energizing the second-stage SS switches 121 and 221 in interrupter modules 120 and 220 increases the circuit impedance, which also significantly reduces the current interrupted by interrupter modules 120 and 220. In other words, during the interrupt operation, a portion of the interrupt current in inductor modules 110 and 210 is interrupted, and interrupting the current in inductor modules 110 and 210 before interruptor modules 120 and 220 begin interrupting increases the impedance of the circuit, thereby further reducing the current to be interrupted in interruptor modules 120 and 220 due to the increased circuit impedance.

[0042] The turns ratio of the coupling inductors 114 and 214 is 1:N, where N is typically expected to be 1, but may be greater than 1 where permissible, such as by optimization factors such as the rated voltage of the first-stage SS switches 115 and 215, the target current decay rate of the main circuit, and / or the maximum acceptable losses that may result from using the first-stage SS switches 115 and 215. The rated current of the first-stage SS switches 115 and 215 is 1 / (N+1) of the main circuit, and the rated voltage is N times that of the main circuit. When N=1, the rated current of the first-stage SS switches 115 and 215 is half that of the main circuit, and the rated voltage is the same as that of the main circuit. Although the first-stage SS switches 115 and 215 will produce stable conduction losses under normal operating conditions, these losses will be less than or equal to half the losses produced in known solid-state circuit interrupters (such as solid-state circuit interrupter 10 shown in Figure 1) excluding the coupling inductors 114 and 214. In addition, the first-stage SS switches 115 and 215 will open within tens of microseconds after the fault occurs, causing the inductance of the main circuit to rise immediately and the current to decrease, so that the interrupt modules 120 and 220 only need to interrupt the reduced current.

[0043] Now for reference Figure 5 and Figure 6 These illustrations show schematic diagrams of a DC circuit interrupter 300 and an AC circuit interrupter 400, respectively, based on exemplary embodiments of the disclosed concept, including novel inductor modules 310 and 410 with hybrid switches, and implementing graded current interruption. The DC circuit interrupter 300 and the AC circuit interrupter 400 are functionally similar and will be described simultaneously, wherein any DC characteristics specific to the DC circuit interrupter 300 will be discussed separately as needed, and any AC characteristics specific to the AC circuit interrupter 400 will be discussed separately as needed. Through comparison... Figure 5 and Figure 3 It can be seen that the DC circuit interrupter 300 is structurally similar to the DC circuit interrupter 100 in most respects; and similarly, through comparison... Figure 6 and Figure 4 It can be seen that AC circuit interrupter 400 is structurally similar to AC circuit interrupter 200 in most respects. Therefore, all components in circuit interrupters 300 and 400 that are functionally equivalent to the corresponding components in circuit interrupters 100 and 200 use similar reference numerals, making... Figure 5 The last two digits of the reference numerals used for a given component in the figure will be... Figure 3 The last two digits of the reference numerals used for the corresponding components in the figures are the same, and make... Figure 6 The last two digits of the reference numerals used for a given component in the figure will be... Figure 4 The last two digits of the reference numerals used for the corresponding components in the figures are the same.

[0044] The only structural difference between DC circuit interrupters 300 and 100 and between AC circuit interrupters 400 and 200 is that inductor modules 310 and 410 include first-stage switches 317 and 417 (hereinafter referred to as first-stage hybrid interrupter switches 317 and 417) as hybrid interrupters, instead of first-stage switches 115 and 215 as solid-state switches. Hybrid interrupter switches 317 and 417 include mechanical contacts 318 and 418 and semiconductor switches 319 and 419 connected in parallel. Since both inductor modules 310 and 410 and interrupter modules 320 and 420 include mechanical contacts, to clearly distinguish the mechanical contacts of inductor modules 310 and 410 from those of interrupter modules 320 and 420, mechanical contacts 318 and 418 are referred to as "first-stage mechanical contacts" and mechanical contacts 323 and 423 are referred to as "second-stage mechanical contacts" below.

[0045] In the DC circuit interrupter 300, a hybrid interruptor switch 317 and a DC current regulator converter 316 are connected in series between the secondary-side node 350 and the common node 302. Specifically, the hybrid interruptor switch 317 is connected between the secondary-side node 350 and the DC current regulator converter 316, and the DC current regulator converter 316 is connected between the hybrid interruptor switch 317 and the common node 302. In the AC circuit interrupter 400, a hybrid interruptor switch 417 is connected in series between the secondary-side node 450 and the common node 402.

[0046] Controllers 301 and 401 are configured to ensure that, under normal operating conditions, the first-stage mechanical contacts 318 and 418 are closed and the semiconductor switches 319 and 419 are open (i.e., on). When the first-stage mechanical contacts 318 and 418 are closed, the coupling inductors 314 and 414 are nearly short-circuited, resulting in relatively low magnetic flux in the coupling inductors 314 and 414, and very low inductance in the inductor modules 310 and 410. Current flows through the inductor modules 310 and 410 and the interrupt modules 320 and 420 to power the loads 82 and 92. It should be understood that the interrupt modules 320 and 420 function similarly to the interrupt modules 120 and 220, ensuring that the second-stage SS switches 321 and 421 are open under normal operating conditions (i.e., on), and that the second-stage mechanical contacts 323 and 423 are closed under normal operating conditions. Similar to interrupt modules 120 and 220, without departing from the scope of the disclosed concept, interrupt modules 320 and 420 may also contain only mechanical interrupts or only solid-state interrupts instead of the hybrid interrupts shown in the figures. However, it is foreseeable that most users of circuit interrupters 300 and 400 would prefer to use hybrid interrupts in interrupt modules 320 and 420.

[0047] In the event of a fault, controllers 301 and 401 are configured to first open the first-stage mechanical contacts 318 and 418 of the hybrid interruptor switches 317 and 417, and then turn on the semiconductor switches 319 and 419 to commutate current to the semiconductor switches 319 and 419; and shortly thereafter, to turn off the semiconductor switches 319 and 419, causing the hybrid interruptor switches 317 and 417 to become open. The opening of the hybrid interruptor switches 317 and 417 causes the second windings 312 and 412 to open, thereby establishing magnetic flux in the inductor cores 313 and 413 and significantly increasing the inductance in the circuit. Controllers 301 and 401 are also configured to open the second-stage mechanical contacts 323 and 423 in the interruptor modules 320 and 420 shortly after opening the hybrid interruptor switches 317 and 417, and then turn on the second-stage SS switches 321 and 421 to commutate current to the second-stage SS switches 321 and 421. After commutation, disconnect the second-stage SS switches 321 and 421 to completely interrupt the current.

[0048] Similar to circuit interrupters 100 and 200, since the first-stage hybrid interruptor switches 317 and 417 carry a portion of the total current, the introduction of coupling inductors 314 and 414 in circuit interrupters 300 and 400 reduces the current carried by the interrupt components in interruptor modules 320 and 420. This results in interruptors 320 and 420 interrupting a significantly lower current during interruption operations compared to when inductor modules 310 and 410 are not present. Furthermore, opening the first-stage hybrid interruptor switches 317 and 417 before opening the second-stage mechanical contacts 323 and 423 and energizing the second-stage SS switches 321 and 421 in interruptor modules 320 and 420 increases the circuit impedance, which also significantly reduces the current interrupted by interruptor modules 320 and 420.

[0049] The turns ratio of the coupling inductors 314 and 414 is 1:N, where N is typically expected to be 1, but may be greater than 1 where permissible, such as by optimization factors such as the rated voltage of the first-stage hybrid interruptor switches 317 and 417, the target current decay rate of the main circuit, and / or the maximum acceptable losses that may result from using the first-stage hybrid interruptor switches 317 and 417. The rated current of the first-stage hybrid interruptor switches 317 and 417 is 1 / (N+1) of the main circuit, and the rated voltage is N times that of the main circuit. When N=1, the rated current of the first-stage hybrid interruptor switches 317 and 417 is 1 / 2 of the main circuit, and the rated voltage is the same as that of the main circuit. The first-stage hybrid interruptor switches 317 and 417 will open within a few hundred microseconds after a fault occurs, causing the inductance of the main circuit to rise immediately and the current to decrease, so that the interruptor modules 320 and 420 only need to interrupt the reduced current. It is worth noting that, compared with the circuit interrupters 100 and 200 using first-stage SS switches 115 and 215, the use of hybrid interrupter switches 317 and 417 in the first stage in the event of a fault results in a slower opening and requires an increase in the inductor size.

[0050] Figure 7 This is a flowchart of a method 500 for conducting and interrupting current according to an example embodiment of the disclosed concept. Figure 7 The method is possible, for example, with Figure 3-6 Any of the circuit interrupters 100, 200, 300, and 400 shown are used together and in combination Figure 3-6 The circuit interrupters 100, 200, 300, and 400 shown have been described. However, it should be understood that the method can also be used in other devices without departing from the scope of the disclosed concept. The method begins at step 501, wherein circuit interrupters 100, 200, 300, and 400 are provided having inductor modules 110, 210, 310, and 410 connected in series with interrupter modules 120, 220, 320, and 420, and are connected between power supplies 81 and 91 and loads 82 and 92. At step 502, under normal current conditions, first-stage switches 115, 215, 317, and 417 remain closed, and interrupter modules 120, 220, 320, and 420 remain closed. It should be understood that keeping the first-stage solid-state switches 115 and 215 of circuit interrupters 100 and 200 in the closed state means keeping the solid-state switches 115 and 215 on, and keeping the first-stage hybrid interrupter switches 317 and 417 of circuit interrupters 300 and 400 in the closed state means keeping the first-stage mechanical contacts 318 and 418 closed, while keeping the first-stage solid-state switches 319 and 419 open.

[0051] At step 503, upon detecting a fault, the first-stage switches 115, 215, 317, and 417 are driven to the open state. It should be understood that driving the first-stage solid-state switches 115 and 215 to the open state means disconnecting the solid-state switches 115 and 215. It should be understood that driving the first-stage hybrid interruptor switches 317 and 417 to the open state means first opening the first-stage mechanical contacts 318 and 418 and connecting the first-stage solid-state switches 319 and 419 to commutate current to the first-stage solid-state switches 319 and 419, and then disconnecting the first-stage solid-state switches 319 and 419 to interrupt the current in the inductor modules 310 and 410.

[0052] At step 504, after the first-stage switches 115, 215, 317, and 417 are driven to the open state due to a detected fault, interruptor modules 120, 220, 320, and 420 are also driven to the open state. It should be understood that driving interruptor modules 120, 220, 320, and 420 to the open state means first opening the second-stage mechanical contacts 123, 223, 323, and 423 and connecting the second-stage solid-state switches 121, 221, 321, and 421 to commutate current to these switches, and then disconnecting them to interrupt the current in interruptor modules 120, 220, 320, and 420.

[0053] Figure 8 The diagram illustrates the main circuit current flowing between the AC power source and the load in a conventional circuit breaker that only has a mechanical interrupter (e.g., a mechanically separable contact) available for interrupting the current. Figure 9 It shows in Figure 4 In the improved AC circuit interrupter 200 disclosed herein, the main circuit current flows between the AC power supply and the load. Figure 8 and Figure 9 In the figure, a sudden increase in current that begins exactly 2.1 milliseconds prior corresponds to a fault event, while the subsequent drop in current after the fault current reaches its peak indicates that an interrupt is being executed. It is noteworthy that the behavior of the main circuit current in the AC circuit interrupter 200 is similar to that of the main circuit current in the prior art solid-state circuit interrupter 10 shown in Figure 1 (a separate graph of the main circuit current in the prior art solid-state circuit interrupter 10 is not shown in the figure). In comparison... Figure 9 and Figure 8 In such cases, the advantages of using a solid-state interruptor (i.e., the first-stage solid-state switch 215 in the circuit interrupter 200) instead of a mechanical interruptor to interrupt fault current are obvious. Specifically, as... Figure 8 As shown, in a traditional circuit breaker, the main circuit current reaches a peak of approximately 85kA, while... Figure 9In the disclosed improved AC circuit interrupter 200, the peak current of the main circuit is limited to only about 8kA.

[0054] Figure 10-13 The improved AC circuit interrupter 200 is shown in conjunction with... Figure 9 The time of the main circuit current shown corresponds to various other electrical signals. Figure 10 The current in the first winding 211 and the second winding 212 is shown. Figure 11 The voltage across the inductor core 213 is shown. Figure 12 The voltage across the first-stage solid-state switch 215 is shown. Figure 13 The diagram illustrates the current in the magnetized inductor core 213 during a first-stage interruption operation, after the first-stage solid-state switch 215 is turned off (thus opening the second winding 212), with current flowing only in the first winding 211. It is noteworthy that once the second winding 212 is turned on, the peak current in the inductor module 210 is limited to approximately 4 kA. Figure 10 Furthermore, the peak current to be interrupted by the interrupt module 220 in the main circuit will be limited to less than 1kA (in Figure 9-10 In the middle, the main circuit current at approximately 2.5ms).

[0055] Figure 14 This again illustrates the main circuit current flowing between the AC power source and the load in a conventional circuit breaker with only mechanical interruptors (e.g., mechanically separable contacts) available for interrupting the current. It is worth noting that... Figure 14 The waveform shown is Figure 8 The waveforms shown are the same. Figure 14 It contains again Figure 8 The waveforms are used to simplify comparisons. Figure 15 The waveforms in the circuit are similar to those of traditional circuit breakers. Figure 15 It shows Figure 6 In the improved AC circuit interrupter 400 disclosed herein, the main circuit current flows between the AC power supply and the load. Figure 14 and 15 In the figure, a sudden increase in current that begins exactly 2.1 milliseconds prior corresponds to a fault event, while the subsequent drop in current after the fault current reaches its peak indicates that an interrupt is being executed. It is noteworthy that the behavior of the main circuit current in the AC circuit interrupter 400 is similar to that of the main circuit current in the prior art hybrid circuit interrupter 20 shown in Figure 2 (a separate graph of the main circuit current in the prior art hybrid circuit interrupter 20 is not shown in the figure). In comparison... Figure 15 and Figure 14 In such cases, the advantages of using a hybrid interruptor (i.e., the first-stage hybrid interruptor switch 417 in the circuit interrupter 400) instead of a mechanical interruptor to interrupt fault current are obvious. Specifically, as... Figure 14 As shown, in a traditional circuit breaker, the main circuit current reaches a peak of approximately 85kA, while... Figure 15 In the disclosed improved AC circuit interrupter 400, the peak current of the main circuit is limited to only about 24kA.

[0056] Figure 16-19 The improved AC circuit interrupter 400 is shown in conjunction with... Figure 15 The time of the main circuit current shown corresponds to various other electrical signals. Figure 16 The current in the first winding 411 and the second winding 412 is shown. Figure 17 The voltage across the inductor core 413 is shown. Figure 18 The voltage across the first-stage hybrid interruptor switch 417 is shown. Figure 19 The diagram illustrates the current in the magnetized inductor core 413 during the first-level interrupt operation, after the first-level hybrid interruptor switch 417 is driven to the open state (thus opening the second winding 412), with current flowing only in the first winding 411. It is noteworthy that once the second winding 412 is open, the peak current in the inductor module 410 will be limited to approximately 12 kA. Figure 16 ), and the peak current interrupted by the interrupt module 420 in the main circuit will be limited to less than 1kA (in Figure 15-16 In the middle, the main circuit current at approximately 2.5ms).

[0057] In summary, the use of inductor modules 110, 210, 310, and 410 in the disclosed circuit interrupters 100, 200, 300, and 400 allows the interrupter components to carry only a portion of the total current in the circuit interrupter. Furthermore, by implementing graded interruption by driving inductor modules 110, 210, 310, and 410 to their open states before driving interrupter modules 120, 220, 320, and 420 to their open states, the impedance of the circuit increases after the inductor modules are driven to their open states, significantly reducing the current interrupted by the interrupter modules. That is, the inductor modules only need to interrupt a portion of the total current, while the interrupter modules only need to interrupt a very low current. In existing circuit interrupters, increasing the ratings leads to more switches and power components, resulting in increased size, cost, and complexity of gate drivers, power supplies, etc. For circuit interrupters with higher ratings that would allow for the inclusion of inductors, the disclosed invention reduces the ratings of the power components. A significant and obvious advantage of this invention compared to existing products is that it reduces the ratings of expensive power components and lowers system losses, while achieving speeds close to those of solid-state circuit breakers.

[0058] While specific embodiments of the invention have been described in detail, those skilled in the art will understand that various modifications and substitutions can be made to these details based on the overall teachings of this disclosure. Therefore, the specific arrangements disclosed are merely illustrative and do not limit the scope of the disclosed concept, which will be covered by the appended claims and any and all their equivalents.

Claims

1. A circuit interrupter configured to connect between a power source and a load, the circuit interrupter comprising: Line conductors, which are configured to be connected to the power source; A load conductor, which is configured to be connected to the load; Inductor module, the inductor module comprising: Inductor core; The first winding is a first conductor wound around a first portion of the inductor core; The second winding is a second conductor wound around a second portion of the inductor core; and First-stage switch; An interrupt module, connected in series with the inductor module between the line conductor and the load conductor, such that the line side of the interrupt module is connected to the load side of the inductor module at a common node, and the load side of the interrupt module is connected to the load conductor, the interrupt module being configured to interrupt the current flowing from the power supply to the load; and Controller Wherein, a first end of the first winding is connected to the line conductor, and a second end of the first winding is connected to the common node. Wherein, the first end of the second winding is connected to the line conductor, and the second end of the second winding is connected to the first end of the first-stage switch. Wherein, the first-stage switch is connected between the second end of the second winding and the common node, and The controller is configured to drive the first-stage switch to close under normal current conditions and to drive the first-stage switch to open when a fault current condition is detected.

2. The circuit interrupter according to claim 1, in, The controller is configured to drive the interrupt module to a closed state under normal current conditions, and The controller is configured to drive the interrupt module to the open state after the first-level switch is driven open when a fault current condition is detected.

3. The circuit interrupter according to claim 1, in, The interrupt module includes a second-level hybrid interrupt, which includes: A second-stage mechanical contact, connected between the common node and the load conductor; and The second-stage solid-state switch is connected in parallel with the second-stage mechanical contacts. The controller is configured to drive the second-stage mechanical contacts to a closed state under normal current conditions, and The controller is configured to drive the second-stage solid-state switch to disconnect under normal current conditions.

4. The circuit interrupter according to claim 3, in, The controller is configured to, upon detecting a fault current: After the first-stage switch is opened, the second-stage mechanical contacts are opened. Turn on the second-stage solid-state switch to commutate current from the second-stage mechanical contacts to the second-stage solid-state switch, and After the current is commutated to the second-stage solid-state switch, the second-stage solid-state switch is disconnected.

5. The circuit interrupter according to claim 1, in, The first-stage switch is a solid-state switch. The controller is configured to turn on the first-stage switch under normal current conditions and to turn off the first-stage switch when a fault current condition is detected.

6. The circuit interrupter according to claim 1, in, The first-level switch is a first-level hybrid interrupter, which includes: A first-stage mechanical contact, which connects the second end of the second winding and the common node; and The first-stage solid-state switch is connected in parallel with the first-stage mechanical contact. The controller is configured to drive the first-stage mechanical contact to a closed state under normal current conditions, and The controller is configured to drive the first-stage solid-state switch to disconnect under normal current conditions.

7. The circuit interrupter according to claim 6, in, The controller is configured to, upon detecting a fault current: Drive the first-stage mechanical contact to open. Turn on the first-stage solid-state switch to commutate current from the first-stage mechanical contacts to the first-stage solid-state switch, and After the current is commutated to the first-stage solid-state switch, the first-stage solid-state switch is disconnected.

8. The circuit interrupter according to claim 1, in, The circuit interrupter is configured to be used with an AC power supply, and The first winding and the second winding have a turns ratio that ensures that the current is equally distributed between the first winding and the second winding.

9. The circuit interrupter according to claim 1, in, The circuit interrupter is configured to be used in conjunction with a DC power supply. The inductor module further includes a DC current regulating converter. Wherein, the second terminal of the first-stage switch is connected to the first terminal of the DC current regulating converter, and The second terminal of the DC current regulating converter is connected to the common node.

10. A method for conducting and interrupting current, the method comprising: A circuit interrupter is provided, the circuit interrupter having an inductor module and an interrupter module connected in series between a line conductor and a load conductor, the inductor module comprising: Inductor core; The first winding is a first conductor wound around a first portion of the inductor core; The second winding is a second conductor wound around a second portion of the inductor core; and First-stage switch; Connect the line conductor to the power source and the load conductor to the load; Under normal current conditions, the first-stage switch and the interrupter module remain in the closed state; Upon detecting a fault, the first-stage switch is activated to the open state; and After the first-level switch is driven to the open state upon detecting a fault, the interrupt module is then driven to the open state. The line side of the interrupter module and the load side of the inductor module are connected at a common node. Wherein, a first end of the first winding is connected to the line conductor, and a second end of the first winding is connected to the common node. Wherein, the first end of the second winding is connected to the line conductor, and the second end of the second winding is connected to the first end of the first-stage switch, and The first-stage switch is connected between the second end of the second winding and the common node.

11. The method according to claim 10, in, The first-stage switch is a solid-state switch. Specifically, keeping the first-stage solid-state switch in the closed state includes keeping the solid-state switch on, and Driving the first-stage switch to its open state includes disconnecting the solid-state switch.

12. The method according to claim 10, in, The first-stage switch is a first-stage hybrid interrupter, which includes a first-stage mechanically separable contact and a first-stage solid-state switch connected in parallel with the first-stage mechanically separable contact. Specifically, maintaining the first-stage switch in a closed state under normal current conditions includes maintaining the first-stage mechanically separable contacts closed and maintaining the first-stage solid-state switch open. Specifically, driving the first-stage switch to the open state when a fault condition is detected includes: Open the first-stage mechanically separable contact and turn on the first-stage solid-state switch, and Then disconnect the first-stage solid-state switch.

13. The method according to claim 10, in, The interrupt module includes a second-stage hybrid interrupter, which comprises a second-stage mechanically separable contact and a second-stage solid-state switch connected in parallel with the second-stage mechanically separable contact. Specifically, maintaining the interruptor module in a closed state under normal current conditions includes keeping the second-stage mechanically separable contacts closed and keeping the second-stage solid-state switch open. Specifically, after driving the first-level switch to the open state upon detecting a fault, driving the interrupt module to the open state includes: Open the second-stage mechanically separable contact and connect the second-stage solid-state switch, and Then disconnect the second-stage solid-state switch.

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