Solid-state circuit breakers

Abstract

The present invention provides a circuit breaker, comprising: a current sensor having a normal sensor output and an overcurrent detection output; a solid-state switch module configured to have a closed state that allows current to flow through the circuit breaker and an open state that interrupts the current flowing through the circuit breaker; a gate driver configured to control the solid-state switch module including a desaturation function output, wherein the gate driver is configured to cause the solid-state switch module to interrupt the current flowing through the circuit breaker when the desaturation function output becomes an ON state; and an electronic trip circuit configured to output a trip signal to the gate driver when the normal sensor output reaches a first threshold level or the overcurrent detection output becomes an ON state.

Description

[0001] Cross-reference to related applications

[0002] This application relates to a co-assignment of U.S. Patent Application Serial No. 16 / 775985 (Attorney’s File No. 19-ETU-783-2), filed on January 29, 2020, entitled “SOLID STATE CIRCUIT INTERRUPTER”. Background Technology Technical Field

[0004] The concepts disclosed in this invention relate generally to circuit breakers, and more specifically to solid-state circuit breakers.

[0005] Background Information

[0006] Circuit breakers (such as, but not limited to, current circuit breakers) are typically used to protect circuits from overcurrent conditions, such as overload conditions, short circuits, or other fault conditions, such as arcing or grounding faults. Solid-state circuit breakers use solid-state components (such as semiconductor devices) to connect and disconnect current flowing from a power source to a load.

[0007] Solid-state circuit breakers offer faster tripping than traditional mechanical circuit breakers. However, these capabilities are not yet optimally utilized. Furthermore, solid-state circuit breakers present different safety and reliability issues compared to traditional mechanical circuit breakers. There is considerable room for improvement in solid-state circuit breakers. Summary of the Invention

[0008] According to one aspect of the concept disclosed in this invention, a circuit breaker configured to be electrically connected between a power source and a load includes: a current sensor configured to sense current flowing through the circuit breaker and having a normal sensor output proportional to the current flowing through the circuit breaker and an overcurrent detection (OCD) output that becomes on when the current flowing through the circuit breaker reaches a second threshold level; a solid-state switching module configured to have a closed state that allows current to flow through the circuit breaker and an open state that interrupts the current flowing through the circuit breaker; and a gate driver configured to control the solid-state switching module to interrupt the current flowing through the circuit breaker. The current, wherein the gate driver includes a desaturation (DESAT) function output that becomes on when the current flowing through the circuit breaker reaches a third threshold level, and wherein the gate driver is configured to cause the solid-state switching module to interrupt the current flowing through the circuit breaker when the DESAT function output becomes on; and an analog trip circuit configured to receive a normal sensor output and an OCD output and output a trip signal to the gate driver when the normal sensor output reaches a first threshold level or the OCD output becomes on, wherein the trip signal causes the gate driver to control the solid-state switching module to interrupt the current flowing through the circuit breaker.

[0009] According to one aspect of the concept disclosed in this invention, a circuit breaker configured to be electrically connected between a power source and a load includes: a separable contact configured to open to provide current isolation between the power source and the load; an operating mechanism configured to open and close the separable contact; a first position sensor sensing the position of the separable contact; a solid-state switch module configured to have a closed state allowing current to flow through the circuit breaker and an open state interrupting current flow through the circuit breaker; and an electronic trip unit configured to control the solid-state switch module to change between the open and closed states and to control the operating mechanism to open the separable contact, wherein, based on the output of the first position sensor, the electronic trip unit is configured to control the solid-state switch module to change from the open state to the closed state when the separable contact is in the closed position.

[0010] According to one aspect of the concept disclosed in this invention, a solid-state switching assembly for use in a circuit breaker includes: an input terminal; a first conductor; an output terminal; a second conductor; a solid-state switching module electrically connected to the input terminal via the first conductor and electrically connected to the output terminal via the second conductor, and including at least one solid-state switch; a heat sink attached to the solid-state switching module; a current sensor configured to sense current flowing through the solid-state switching module; and a plurality of metal oxide rheostats (MOVs).

[0011] According to one aspect of the concept disclosed in this invention, a circuit breaker includes: a frame comprising a plurality of compartments; and a plurality of solid-state switching assemblies, each solid-state switching assembly disposed in a corresponding compartment of the plurality of compartments, and comprising: an input terminal; a first conductor; an output terminal; a second conductor; a solid-state switching module electrically connected to the input terminal via the first conductor and electrically connected to the output terminal via the second conductor, and including at least one solid-state switch; a heat sink; a current sensor configured to sense current flowing through the solid-state switching module; and a plurality of metal oxide rheostats (MOVs).

[0012] According to one aspect of the concept disclosed in this invention, a method of operating a circuit breaker having a solid-state switch module including a solid-state switch includes: monitoring characteristics of the solid-state switch; determining whether the characteristics of the solid-state switch meet or exceed a predetermined threshold; and providing an indication in response to determining whether the characteristics of the solid-state switch meet or exceed the predetermined threshold. Attached Figure Description

[0013] A complete understanding of the concepts disclosed in this invention can be obtained from the following description of preferred embodiments when read in conjunction with the accompanying drawings, wherein:

[0014] Figure 1 This is a schematic diagram of an exemplary embodiment of a circuit breaker according to the concept disclosed in this invention;

[0015] Figure 2 This is a circuit diagram of a power supply according to an exemplary embodiment of the concept disclosed in this invention;

[0016] Figure 3A and Figure 3B This is a circuit diagram of an exemplary embodiment of a simulated tripping circuit according to the concept disclosed in this invention;

[0017] Figure 4A and Figure 4B This is a circuit diagram of a gate driver circuit according to an exemplary embodiment of the concept disclosed in this invention;

[0018] Figure 5A and Figure 5B This is a partial assembly view of a circuit breaker according to an exemplary embodiment of the concept disclosed in this invention;

[0019] Figure 6A and Figure 6B This is a partial assembly view of a circuit breaker according to an exemplary embodiment of the concept disclosed in this invention;

[0020] Figure 7 This is a view of a partially disassembled circuit breaker according to an exemplary embodiment of the concept disclosed in this invention;

[0021] Figure 8 This is a partial internal side view of a circuit breaker according to an exemplary embodiment of the concept disclosed in this invention;

[0022] Figures 9A to 9C This is a view of a solid-state switch assembly according to an exemplary embodiment of the concept disclosed in this invention;

[0023] Figures 10A to 10D This is a view of a heat sink and a solid-state switch module according to an exemplary embodiment of the concept disclosed in this invention;

[0024] Figures 11A to 11B This is a view of a frame accommodating a solid-state switching assembly, according to an exemplary embodiment of the concept disclosed in this invention; and

[0025] Figure 12 This is a flowchart of a method for operating a circuit breaker according to an exemplary embodiment of the concept disclosed in the present invention. Detailed Implementation

[0026] Directional phrases used herein, such as, for example, left, right, front, back, top, bottom, and their derivatives, refer to the orientation of the elements shown in the accompanying drawings and do not limit the claims unless expressly stated herein.

[0027] As used in this article, the expression “connected” to two or more parts should be meant to mean that the parts are joined together directly or through one or more intermediate parts.

[0028] Figure 1 This is a schematic diagram of a circuit breaker 10 (e.g., but not limited to a circuit interrupter) according to an exemplary embodiment of the concepts disclosed in this invention. In some exemplary embodiments, the circuit breaker 10 is a 100A (I n =100A) Rated device (i.e., rated current I) n(It is 100A). The circuit breaker 10 is configured to be electrically connected between the power source 2 and the load 4. The circuit breaker 10 is configured to trip or switch open in the event of a fault condition (e.g., but not limited to an overcurrent condition) to interrupt the current flowing to the load 4, thereby protecting the load 4, the circuit associated with the load 4, and the components within the circuit breaker 10.

[0029] Circuit breaker 10 includes a solid-state switching assembly 200, which includes a solid-state switching module 202 and a current sensor 206. Circuit breaker 10 also includes a gate driver circuit 204 and an analog trip circuit 208 associated with the solid-state switching assembly 200. Circuit breaker 10 also includes an operating mechanism 300, separable contacts 302 and an electronic trip unit 304, and a power supply 100. Additionally, circuit breaker 10 includes position sensors 500, 502, and 504, as well as a closed button 506 and an open button 508. Those skilled in the art will understand that circuit breaker 10 does not need to include all of these components. For example, in an exemplary embodiment, circuit breaker 10 may include only a subset of these components without departing from the scope of the concepts disclosed herein.

[0030] Circuit breaker 10 is configured to provide solid-state circuit interruption via solid-state switching assembly 200 and current isolation via separable contacts 302. Solid-state switching module 202 includes one or more solid-state switches (e.g., but not limited to metal-oxide-semiconductor field-effect transistors (MOSFETs), insulated-gate bipolar transistors (IGBTs), or other suitable types of solid-state switches) electrically connected between power source 2 and load 4. Solid-state switching module 202 has a closed state and an open state; in the closed state, power is allowed to flow between power source 2 and load 4; in the open state, power is prevented from flowing between power source 2 and load 4.

[0031] Gate driver circuit 204 is configured to control the state of solid-state switch module 202. Gate driver circuit 204 has a desaturation-adjustable (DESAT) function, which changes from an off state to an on state when the current flowing through solid-state switch module 202 reaches a predetermined threshold level. In one exemplary embodiment, the predetermined threshold level is approximately 2250A (22.5 × 10⁻⁶). nThe DESAT function operates by monitoring the forward voltage drop of the solid-state switch in the solid-state switch module 202. When the forward voltage drop reaches a threshold level, the DESAT function becomes ON and the gate driver circuit 204 responsively causes the solid-state switch module 202 to ON, thereby interrupting the current flowing through the circuit breaker 10. In one exemplary embodiment, the DESAT function has a threshold voltage of 9V. Based on the on-resistance of the silicon carbide (SiC) MOSFET, the forward voltage drop will reach 9V when the current level is approximately 2250A. Therefore, the DESAT function will become ON when the current flowing through the solid-state switch module 202 reaches approximately 2250A. It should be understood that these thresholds are provided by way of example only. Different thresholds may be used without departing from the scope of the concepts disclosed in this invention.

[0032] The DESAT function of the gate driver circuit 204 causes the solid-state switch module 202 to open, thereby allowing the current flowing through the circuit breaker 10 to be interrupted very quickly. In some exemplary embodiments of the concepts disclosed in this invention, the DESAT-based interruption can be within 0.5 microseconds. In some exemplary embodiments of the concepts disclosed in this invention, the gate driver circuit 204 includes a capacitor configured to change the interruption based on the DESAT function. For example, the DESAT-based interruption time is based on the capacitance of the capacitor. Thus, the DESAT-based interruption time can be easily adjusted by changing the capacitor.

[0033] In some exemplary embodiments, the current sensor 206 is configured to provide a normal sensor output proportional to the current flowing through the circuit breaker 10 and an overcurrent detection (OCD) output that becomes on when the current flowing through the circuit breaker 10 reaches a threshold level. In one exemplary embodiment, the current sensor 206 is a Hall effect sensor.

[0034] The analog trip circuit 208 is configured to receive the normal sensor output and the OCD output from the current sensor 206. The analog circuit 208 is electrically connected to the gate driver circuit 204 and is configured to output a trip signal to the gate driver circuit 204. In response to the trip signal, the gate driver circuit 204 controls the solid-state switch module 202 to turn on, thereby interrupting the current flowing through the circuit breaker 10. The analog trip circuit 208 is configured to output a trip signal in response to the normal sensor output reaching a threshold level or the OCD output turning on. The analog trip circuit 208 is configured to output a trip signal in response to the OCD output turning on within a first predetermined time period and in response to the normal sensor output reaching a threshold level within a second predetermined time period. In one exemplary embodiment, the first predetermined time period is less than the second predetermined time period. In one exemplary embodiment, the first predetermined time period is 10 nanoseconds and the second predetermined time period is 100 nanoseconds. However, it should be understood that other predetermined time periods may be used without departing from the scope of the concepts disclosed in this invention. In one exemplary embodiment, the interruption of the current flowing through circuit breaker 10 based on the normal sensor output reaching a threshold level occurs within 4 microseconds, while the interruption based on the OCD output occurs within 2 microseconds. However, it should be understood that these are exemplary times, and other times may be used without departing from the scope of the concepts disclosed in this invention. In some exemplary embodiments, the threshold level associated with the normal current sensor output is approximately 200 A (2 × 10⁻⁶). n ) to 750A (7.5×I n Within the range of ), and the threshold level associated with the OCD output is approximately 750A (7.5 × I). n However, it should be understood that these are merely exemplary values ​​and may be adjusted without departing from the scope of the concepts disclosed in this invention.

[0035] By utilizing the DESAT function of the analog trip circuit 208 and the gate driver circuit 204, a three-level interrupt logic can be employed within the circuit breaker 10. The DESAT function provides the fastest interrupt based on the highest current threshold, a second fastest interrupt based on the OCD output based on a second highest current threshold, and a third fastest interrupt based on the normal sensor output based on a third highest current threshold. In one exemplary embodiment, the highest current threshold is approximately 2250A (22.5 × 10⁻⁶). n Furthermore, the fastest interruption occurs within 0.5 microseconds, and the second highest current threshold is approximately 750A (7.5 × I). n Furthermore, the second fastest interrupt is within 2.5 microseconds, and the third highest current threshold is selected from approximately 200A (2×I). n ) to 750A (7.5×I nWithin the range of ) and the third fastest interrupt is within 4 microseconds. Utilizing the DESAT function of the analog trip circuit 208 and the gate driver circuit 204, the interrupt can occur faster than through digital circuit protection such as that provided by the electronic trip unit 304.

[0036] In some exemplary embodiments of the concepts disclosed in this invention, the electronic trip unit 304 is further configured to output a trip signal to the gate driver circuit 204, causing the gate driver circuit 204 to control the solid-state switch module 202 to an open state. The electronic trip unit 304 may output a trip signal based on a current threshold lower than a third highest current threshold associated with a tripping event based on the normal sensor output of the analog trip circuit 208. The electronic trip unit 304 may be configured to output a trip signal based on an It trip curve, such that when the electronic trip unit 304 detects a fault condition based on the normal sensor output of the current sensor 206, the electronic trip unit 304 will output a trip signal to the gate driver circuit 204 at a time associated with the current level based on the It trip curve.

[0037] Circuit breaker 10 also includes an operating mechanism 300 and a separable contact 302. The separable contact 302 is configured to open to provide current isolation between the power source 2 and the load 4. The operating mechanism 300 is configured to open and close the separable contact 302. For example, the operating mechanism 300 may include a movable arm that, upon movement, causes the separable contact 302 to open or close. An electronic trip unit 304 is configured to control the operating mechanism 300 to open the separable contact 302. For example, the electronic trip unit 304 may be configured to control the operating mechanism 300 to open the separable contact 302 only after the solid-state switch module 202 has been turned on. For example, in a mechanical circuit breaker, the separable contact is designed to interrupt the current flowing through the circuit breaker and has associated components such as an arc-extinguishing chamber to manage arc discharge caused by circuit interruption. Circuit breaker 10 is a solid-state circuit breaker in which the current is interrupted by the solid-state switch module 202. The separable contacts 302 do not need to be designed to interrupt current and do not need to have associated arc-extinguishing chambers or other components, as they are only intended to open after the solid-state switch module 202 has interrupted current. Thus, the electronic trip unit 304 can be configured to control the operating mechanism 300 to open the separable contacts 302 only after the solid-state switch module 202 has been turned on. Similarly, the electronic trip unit 304 can be configured to cause the gate driver circuit 204 to turn the solid-state switch module 202 to the closed state only after the separable contacts 302 have closed. This prevents bouncing arcs caused by the bouncing of the separable contacts 302. In some exemplary embodiments, the separable contacts 302 are closed by manual intervention from the user via, for example, a reset switch. In some exemplary embodiments, the operating mechanism 300 is configured to close the separable contacts 302 in response to a closing signal from the electronic trip unit 304.

[0038] In some exemplary embodiments of the concepts disclosed in this invention, the circuit breaker 10 includes a position sensor 500. The position sensor 500 is configured to sense whether the separable contact 302 is in an open or closed position. The output of the position sensor 500 can be provided to an electronic trip unit 304. Based on the output of the position sensor 500, the electronic trip unit 304 can determine the position of the separable contact 302. Similarly, the electronic trip unit 304 can receive the output of the gate driver circuit 204 indicating the state of the solid-state switch module 202. Using these outputs, the electronic trip unit 304 can ensure that the separable contact 302 opens only after the solid-state switch module 202 has already become open and ensure that the solid-state switch module 202 becomes closed only after the separable contact 302 has become closed.

[0039] In some exemplary embodiments, the circuit breaker 10 includes a closing button 506 and an opening button 508. It should be understood that the button is used as an example. It should be understood that any user-actuable element may be employed without departing from the scope of the concepts disclosed in this invention. In one exemplary embodiment, the electronic trip unit 304 is configured to control the operating mechanism 300 to close the separable contact 302, and then output a closing signal to the gate driver circuit 204 such that the gate driver circuit 204 closes the solid-state switch module 202 in response to actuation of the closing button 506. In one exemplary embodiment, the electronic trip unit 304 is configured to output a trip signal to the gate driver circuit 204 such that the gate driver circuit 204 opens the solid-state switch module 202, and then control the operating mechanism 300 to open the separable contact 302 in response to actuation of the opening button 508. In some exemplary embodiments, a position sensor 502 may be used to sense actuation of the closing button 506, and a position sensor 504 may be used to sense actuation of the opening button 508. The electronic trip unit 304 may be configured to receive the outputs of position sensors 502, 504 and sense the actuation of the close button 506 and the open button 508 based on the outputs of position sensors 502, 504.

[0040] Position sensors 500, 502, and 504 can be any suitable type of sensor for sensing the position of a component. For example, position sensors 500, 502, and 504 can be microswitches actuated by the movement of their corresponding components. For instance, position sensor 500 can be a microswitch provided by a movable arm of operating mechanism 300, such that the movement of the movable arm opening or closing separable contact 302 actuates position sensor 500, and based on the output of position sensor 500, electronic trip unit 304 can sense the current position of separable contact 302. Similarly, position sensors 502 and 504 can be microswitches configured such that actuation of turn button 506 and turn button 508 actuates position sensors 502 and 504, respectively.

[0041] Power supply 100 is configured to receive power from power source 2 and convert the power from power source 2 into power usable by components of circuit breaker 10. For example, power supply 100 can convert alternating current from power source 2 into direct current usable by components of circuit breaker 10. Power from power supply 100 can provide power to operate components such as, but not limited to, electronic trip unit 304, gate driver circuit 204, operating mechanism 300 (e.g., a solenoid included in the operating mechanism), current sensor 206, and analog trip circuit 208. Power supply 100 can generate direct current at multiple voltages (e.g., but not limited to 24V, 15V, 5V, and 3.3V). In one exemplary embodiment, power supply 100 may be omitted, and power to operate components of circuit breaker 10 may be provided by an external power source. In some exemplary embodiments, electronic trip unit 304 is configured to turn solid-state switch module 202 on and to open separable contact 302 in the event that power from power supply 100 or an external power source is unavailable. In some exemplary embodiments, power supply 100 is configured to use the line-to-line voltage from power source 2 to generate direct current for use by components of circuit breaker 10. For example, power supply 100 is not connected between the line conductors and the neutral conductor, but rather between multiple line conductors. Although Figure 1 A single pole of circuit breaker 10 is shown, but it should be understood that circuit breaker 10 may have multiple poles, with multiple linear phases of power flowing through circuit breaker 10 and power supply 100 connected to multiple linear phases.

[0042] Figure 2This is a circuit diagram of a power supply 100 according to an exemplary embodiment of the concepts disclosed in this invention. In this exemplary embodiment, the power supply 100 includes a three-phase line input 110, a rectifier diode bridge 120, a filter circuit 130, a DC / DC converter 140, and an output 150. The three-phase line input 110 receives power from multiple linear phases and provides an inter-line AC voltage input to the rectifier diode bridge 120. The rectifier diode bridge 120 converts the AC voltage to a DC voltage and outputs the DC voltage to the filter circuit 130. The filter circuit 130 limits the current input, thereby protecting the power supply circuit 100 from current inrushes, and filters the DC voltage via shunts (C10, C11, C12, C13, R1, R2, R3, and R4). The DC / DC converter 140 receives the filtered DC voltage from the filter circuit 130 and converts the filtered high DC voltage to a low DC voltage, such as 24V, 15V, 5V, or 3.3V. The DC / DC converter 140 then outputs a low DC voltage to power the components of the circuit breaker 10. The line voltage is stepped down to, for example, 24V, 15V, 5V, or 3.3V DC to meet the voltage requirements of the electronic components of the circuit breaker 10. When line-to-line voltage is unavailable, an external 24V power supply can be used. If neither an external power supply nor line-to-line voltage is available, the solid-state switch module 202 can be switched on. Although Figure 2 An example of a circuit used within power supply 400 is shown, but it should be understood that... Figure 2 These are merely exemplary embodiments. The circuit components may be rearranged, added, removed, or implemented in different ways without departing from the scope of the concepts disclosed in this invention.

[0043] Figure 3A and Figure 3B This is a circuit diagram of an exemplary embodiment of a simulated trip circuit 208 according to the concepts disclosed herein. The simulated trip circuit 208 includes a normal sensor input 210 and an OCD input 212. The normal sensor input 210 is configured to receive the normal sensor output of a current sensor 206, which is proportional to the current flowing through the circuit breaker 10. The OCD input 212 is configured to receive the OCD output of the current sensor 206. The simulated trip circuit 208 also includes a trip signal output 214 electrically connected to a gate driver circuit 204. In response to the normal sensor output reaching a threshold level or the OCD output becoming on, the simulated trip circuit 208 is configured to output a trip signal at output 214. The simulated trip circuit 208 is configured to compare the normal sensor output with a threshold level, without requiring a comparison of the OCD output with a threshold level. By bypassing this check on the OCD output, the simulated trip circuit 208 can output a trip signal based on the OCD output more quickly than a trip signal based on the normal sensor output. Figure 3A and Figure 3B An example of the logic circuit used in the analog trip circuit 208 is shown. However, it should be understood that... Figure 3A and Figure 3B The examples shown are merely exemplary implementations of the simulated trip circuit 208. It should be understood that the circuit components may be rearranged, added, removed, or implemented in different ways without departing from the scope of the concepts disclosed in this invention.

[0044] Figure 4A and Figure 4B This is a circuit diagram of a gate driver circuit 204 according to an exemplary embodiment of the concepts disclosed in this invention. The gate driver circuit 204 includes an enable input 216 and a DESAT input 222. The gate driver circuit 204 also includes a driver output 224 and a fault output 218. The gate driver circuit 204 further includes a driver 220 and a capacitor 226. The enable input 216 is electrically connected to an analog trip circuit 208 and an electronic trip unit 304. The driver output 224 and the DESAT input 222 are electrically connected to a solid-state switch module 202. The fault output 218 is electrically connected to the electronic trip unit 218. The solid-state switch module 202 is configured to change between an open and closed state based on the driver output 224. The driver 220 is configured to control the state of the driver output 224 based on a trip signal received at the enable input 216 or the DESAT input 222. The driver 220 is configured to implement DESAT functionality based on the DESAT input 222. The timing associated with the change in driver output 224 based on DESAT input 222 is partially based on the capacitance of capacitor 226. Driver 220 is also configured to control the state of fault output 218 such that the electronic trip unit 304 can be notified when gate driver circuit 204 has controlled solid-state switch module 202 to be in an open or closed state. It should be understood that Figure 4A and Figure 4B The example shown is merely an exemplary implementation of the gate driver circuit 204. It should be understood that the circuit components may be rearranged, added, removed, or implemented in different ways without departing from the scope of the concepts disclosed in this invention.

[0045] Figure 5A and Figure 5B This is a partial assembly view of a circuit breaker 10 according to an exemplary embodiment of the concept disclosed in the present invention. Figure 5A and Figure 5B Examples are shown of a closed button 506 and an open button 508, position sensors 502 and 504, a portion of an operating mechanism 300, and a portion of a separable contact 302. Figure 5A and Figure 5BThe example shown illustrates a three-pole operating mechanism 300 with a movable rotary arm having a common movable separable contact 302. Position sensors 502 and 504 are associated with a closed button 506 and an open button 508, respectively, such that actuation of the closed button 506 and the open button 508 causes actuation of position sensors 502 and 504. For example, a protrusion is connected to the closed button 506 and the open button 508 and moves together with the actuation of the closed button 506 and the open button 508. For example, when the closed button 508 is actuated, the protrusion associated with the closed button 508 can move against the position sensor 504. Figure 5A and Figure 5B A portion of the separable contact 302 is shown. Specifically, Figure 5A and Figure 5B The movable contact of separable contact 302 is shown. It should be understood that the fixed contact is associated with the movable contact. Moving the movable contact away from the fixed contact opens the separable contact 302.

[0046] Figure 6A and Figure 6B This is a partial assembly view of a circuit breaker 10 according to an exemplary embodiment of the concept disclosed in the present invention. Figure 6A A portion of the operating mechanism 300 and the separable contact 302 in the closed position is shown. Figure 6B A portion of the operating mechanism and separable contact 302 in the open position is shown. Figure 6A and Figure 6B A position sensor 500 configured to sense whether the separable contact 302 is in a closed or open position is also shown. The position sensor 500 may be associated with a portion of a movable arm of the operating mechanism 300 such that the movable arm abuts against the position sensor when the separable contact 302 is in the closed position and is removed from the position sensor 500 when the separable contact 302 is in the open position.

[0047] Figure 7 This is a partial disassembled front view of a circuit breaker 10 according to an exemplary embodiment of the concept disclosed in the present invention. Figure 7 A closed button 506 and an open button 508, as well as a status indicator 510 indicating the position of a separable contact 302, are shown as exemplary embodiments of the concepts disclosed in this invention.

[0048] Figure 8 This is a partial internal side view of a circuit breaker 10 according to an exemplary embodiment of the concept disclosed in this invention. The current path 600 through the circuit breaker is indicated by arrows. Figure 8As shown, the current flowing from power source 2 through circuit breaker 10 first flows through separable contact 302. The current then continues to flow through solid-state switch assembly 200 and current sensor 206 located adjacent to the output of solid-state switch assembly 200, and then the current is supplied to load 4.

[0049] Figures 9A to 9C This is a view of an exemplary embodiment of a solid-state switch assembly 200 according to the concepts disclosed herein. The solid-state switch assembly 200 includes a solid-state switch module 202 and a current sensor 206. The solid-state switch assembly 200 also includes an input terminal 250 and an input conductor 252. The input terminal 250 is configured to receive power from a power source 2 via a separable contact 302 and to supply power to the solid-state switch module 202 via the input conductor 252. The solid-state switch assembly 200 also includes an output terminal 256 and an output conductor 254. When the solid-state switch module 202 is in a closed state, power flows through the solid-state switch module 202 to the load conductor 254 and subsequently to the output terminal 256. The output terminal 256 is configured to be electrically connected to a load 4. The solid-state switch assembly 200 also includes a module cover 258.

[0050] exist Figure 9C In the original text, module cover 258 is omitted. The solid-state switch assembly 200 also includes an MOV 262 covered by module cover 258, such as... Figure 9C As shown in the image.

[0051] The solid-state switch assembly 200 also includes a heatsink 260. The heatsink 260 is attached to the solid-state switch module 200 and referenced. Figures 10A to 10D Further description.

[0052] Figure 10A and Figure 10B This is a view of a heat sink 260 according to an exemplary embodiment of the concept disclosed in the present invention, and Figure 10C and Figure 10D This is a view of a solid-state switch module 202 attached to a heat sink 260, according to an exemplary embodiment of the concept disclosed in this invention. The heat sink 260 includes a first planar member 264 and a second planar member 268 extending from one side of the first planar member 264. The heat sink 260 also includes a plurality of forks 270 extending from the opposite side of the first planar member 264.

[0053] like Figure 10C and Figure 10D As shown, the solid-state switch component 202 is configured to be attached to the second planar component 268. In one exemplary embodiment, the solid-state switch component 202 can be attached to the second planar component 268 using fasteners 272. The heat sink 260 may be made of a metallic material and is used to dissipate heat generated by the solid-state switch module 202.

[0054] Figure 11A and Figure 11B This is a view of a frame 280 for housing a solid-state switching assembly 200, according to an exemplary embodiment of the concepts disclosed in this invention. The frame 280 includes compartments 282, each compartment housing one solid-state switching assembly 200. Figure 11A and Figure 11B In the exemplary embodiment shown, frame 280 includes three compartments 282 and houses three solid-state switch assemblies 200. Each solid-state switch assembly 200 may correspond to one pole of circuit breaker 10. Therefore, frame 280 is suitable for a 3-pole circuit breaker. However, it should be understood that frame 280 may be modified to have a different number of compartments 282 without departing from the scope of the concept disclosed in this invention.

[0055] The solid-state switch assembly 200 features a modular design. Depending on the application, components of the solid-state switch assembly 200 can be replaced with other components of similar shape. For example, for applications with different voltage and current requirements, solid-state switch module 202 can be replaced with another solid-state switch module 202. The remaining components of the solid-state switch assembly 200 can remain unchanged, thereby enabling wider application of the solid-state switch assembly 200 without requiring a complete redesign of the entire assembly. Similarly, in applications with different current requirements, current sensor 206 can be replaced with another current sensor 206. Likewise, other components of the solid-state switch assembly 200 can be replaced.

[0056] Figure 12 This is a flowchart of a method for operating a circuit breaker according to an exemplary embodiment of the concepts disclosed herein. This method can be implemented, for example, in the circuit breaker 10 described herein. Solid-state circuit breakers, such as circuit breaker 10, present new challenges regarding health status and remaining lifespan compared to mechanical circuit breakers. For example, monitoring the health status of a solid-state switch differs from monitoring the health status of a mechanical switch. However, in both cases, it is important to monitor when the switch reaches the end of its lifespan and becomes at risk of failure.

[0057] Figure 12 The method begins at 700, where characteristics of the solid-state switch assembly 200 are monitored. In some exemplary embodiments, the solid-state switch of the solid-state switch module 202 is monitored. In some exemplary embodiments, MOV 262 is monitored. It should be understood that both can be monitored. The monitored characteristics may be junction temperature, solid-state switch forward voltage drop (for IGBT solid-state switches), body diode forward voltage drop (for MOSFET solid-state switches), gate threshold voltage (for MOSFET solid-state switches), or gate leakage current (for MOSFET solid-state switches). The monitored characteristic may also be the voltage across MOV 262.

[0058] At 702, it is determined whether the monitored characteristic exceeds a threshold level. The threshold level can be selected based on the monitored characteristic and the monitored device. For the voltage on MOV 262, the threshold can be a time-varying range. For example, the voltage on MOV 262 can be monitored for a period of time after the solid-state switch is turned on. The threshold range varies during this time period, and it is determined whether the voltage on MOV 262 exceeds this threshold range at a specific time. If the characteristic does not exceed the threshold level, the method returns to 700. However, if the characteristic exceeds the threshold level, the method proceeds to 704.

[0059] At 704, an indication is provided. This indication may be provided via a display on the circuit breaker 10 or any other suitable type of indication, such as, for example, an LED indicator, wired or wireless communication to an external device. The indication notifies the user or technician that a component needs repair or replacement. It should be understood that additional steps may be taken, such as repairing or replacing the component or controlling the circuit breaker 10 to trip in response to determining that the monitored characteristic exceeds a threshold level.

[0060] Junction temperature is an indicator of the performance of a solid-state switch. For example, some solid-state switches should maintain a threshold junction temperature below 150 degrees Celsius. If the junction temperature reaches this threshold, the solid-state switch may be damaged and fail. Therefore, the junction temperature of a solid-state switch is a useful characteristic to monitor.

[0061] The forward voltage drop, or body diode forward voltage drop, is also an indicator of the goodness of a solid-state switch. When the forward voltage drop or body diode forward voltage drop reaches its threshold value for operation at rated current, the solid-state switch can become damaged and fail. The forward voltage drop or body diode forward voltage drop can be caused by many factors, such as high current, poor thermal conductivity, or poor thermal management. Therefore, the forward voltage drop and body diode forward voltage drop are useful characteristics to monitor.

[0062] Gate threshold voltage or gate leakage current are also useful characteristics to monitor in solid-state switches. Gate threshold voltage or gate leakage current exceeding threshold levels can damage or cause solid-state switches to fail. Gate leakage current is more sensitive to solid-state switch degradation and can be monitored during the switching and conduction of solid-state switches, making it more practical than monitoring gate threshold voltage. However, both gate threshold voltage and gate leakage current are useful characteristics to monitor for determining the goodness of solid-state switches.

[0063] When MOV 262 begins to degrade, the voltage across MOV 262 will increase or decrease. MOV 262 clamps its voltage for a period of time after the solid-state switch is turned on; therefore, this is the relevant time period for monitoring the voltage across MOV 262. An exemplary threshold range could be ±10% of the normal clamping voltage of MOV 262. For example, a voltage drift of more than 10% from its normal clamping voltage is an indication that MOV 262 is degrading and should be repaired or replaced. Therefore, the voltage across MOV 262 is another useful characteristic to monitor.

[0064] While some examples of characteristics to be monitored have been described, it should be understood that other characteristics may be monitored without departing from the scope of the concepts disclosed herein. It should also be understood that additional actions may be performed as supplementary or alternative to providing indications in response to a characteristic exceeding its threshold.

[0065] While specific embodiments of the concepts disclosed in this invention have been described in detail, those skilled in the art will understand that various modifications and substitutions to those details can be developed based on the overall teachings of this disclosure. Therefore, the specific arrangements disclosed are merely illustrative and do not limit the scope of the concepts disclosed in this invention, which is defined by the full scope of the appended claims and any and all their equivalents.

Claims

1. A circuit breaker configured to be electrically connected between a power source and a load, the circuit breaker comprising: A current sensor configured to sense the current flowing through the circuit breaker, and having a normal sensor output proportional to the current flowing through the circuit breaker and an overcurrent detection (OCD) output that becomes on when the current flowing through the circuit breaker reaches a second threshold level. A solid-state switch module, the solid-state switch module being configured to have a closed state that allows current to flow through the circuit breaker and an open state that interrupts the current flowing through the circuit breaker; A gate driver configured to control the solid-state switching module to interrupt the current flowing through the circuit breaker, wherein the gate driver includes a desaturation (DESAT) function output that becomes on when the current flowing through the circuit breaker reaches a third threshold level, and wherein the gate driver is configured to cause the solid-state switching module to interrupt the current flowing through the circuit breaker when the DESAT function output becomes on. and A simulated trip circuit is configured to receive the normal sensor output and the OCD output, and to output a trip signal to the gate driver when the normal sensor output reaches a first threshold level or the OCD output becomes in the ON state. The trip signal causes the gate driver to control the solid-state switching module to interrupt the current flowing through the circuit breaker. in: The simulated trip circuit is configured to output the trip signal based on the normal sensor output, causing the solid-state switch module to interrupt the current flowing through the circuit breaker for a first predetermined time period. The simulated trip circuit is configured to output the trip signal based on the OCD output, causing the solid-state switch module to interrupt the current flowing through the circuit breaker for a second predetermined time period. The gate driver is configured such that the solid-state switching module interrupts the current flowing through the circuit breaker based on the DESAT function during a third predetermined time period, and The third predetermined time period is shorter than the second predetermined time period, and the second predetermined time period is shorter than the first predetermined time period.

2. The circuit breaker according to claim 1, wherein the first predetermined time period is about 4 microseconds, the second predetermined time period is about 2.5 microseconds, and the third predetermined time period is about 0.5 microseconds.

3. The circuit breaker of claim 1, wherein the simulated trip circuit is configured to output the trip signal based on receiving the normal sensor output within approximately 100 nanoseconds of the normal sensor output, and wherein the simulated trip circuit is configured to output the trip signal based on receiving the OCD output within approximately 10 nanoseconds of the OCD output.

4. The circuit breaker of claim 1, wherein the gate driver includes a capacitor, and wherein the third predetermined time is partially based on the capacitance of the capacitor.

5. The circuit breaker of claim 1, wherein the first threshold level is in the range of about 2 times to about 7.5 times the rated current of the circuit breaker, wherein the second threshold level is about 7.5 times the rated current, and wherein the third threshold level is about 22.5 times the rated current.

6. The circuit breaker of claim 1, wherein the DESAT function output is based on the voltage drop of the solid-state switch in the solid-state switch module, the voltage drop being based on the level of the current flowing through the solid-state switch module.

7. The circuit breaker according to claim 1, wherein the current sensor is a Hall effect sensor.

8. The circuit breaker according to claim 1, wherein the solid-state switch module includes at least one solid-state switch.

9. The circuit breaker according to claim 1, further comprising: Separable contacts; and An operating mechanism configured to open the separable contact. Opening the separable contact provides current isolation between the power source and the load.

10. A circuit breaker configured to be electrically connected between a power source and a load, the circuit breaker comprising: Separable contacts, which are configured to open to provide current isolation between the power source and the load; An operating mechanism configured to open and close the separable contact; A first position sensor, configured to sense the position of the separable contact; A solid-state switch module, the solid-state switch module being configured to have a closed state that allows current to flow through the circuit breaker and an open state that interrupts the current flowing through the circuit breaker; An electronic trip unit is configured to control the solid-state switch module to change between the open state and the closed state and to control the operating mechanism to open the separable contact, wherein, based on the output of the first position sensor, the electronic trip unit is configured to control the solid-state switch module to change from the open state to the closed state when the separable contact is in the closed position; The first switch that can be operated by the user; and A second switch that can be operated by the user. The electronic trip unit is configured to control the solid-state switch to change from the closed state to the open state, and subsequently control the operating mechanism to open the separable contact in response to the user's operation of the first switch. The electronic trip unit is configured to control the operating mechanism to close the separable contact, and subsequently control the solid-state switch module to change to the closed state in response to the user's operation of the second switch.

11. The circuit breaker of claim 10, wherein the electronic trip unit is configured to control the solid-state switch module to change from the closed state to the open state before controlling the operating mechanism to open the separable contact.

12. The circuit breaker according to claim 10, further comprising: A second position sensor is configured to sense the position of the first switch; and A third position sensor is configured to sense the position of the second switch. Based on the output of the second position sensor, the electronic trip unit is configured to control the solid-state switch to change from the closed state to the open state, and subsequently, in response to the user's operation of the first switch, control the operating mechanism to open the separable contact. Based on the output of the third position sensor, the electronic trip unit is configured to control the operating mechanism to close the separable contact, and subsequently control the solid-state switch module to change to the closed state in response to the user's operation of the second switch.

13. The circuit breaker of claim 10, wherein the operating mechanism includes a movable arm coupled to the separable contact such that moving the movable arm opens or closes the separable contact, and wherein the first position sensor is configured to sense the position of the separable contact based on the movement of the movable arm.

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