HEAT SINK FOR A SOLID-STATE CIRCUIT BREAKER IN AN ELECTRICAL PANEL

Abstract

A solid-state circuit breaker (SSCB) includes an air-gap operating mechanism with components and electronics, including semiconductors and software algorithms, that control power and can interrupt extreme currents. The SSCB also includes an enclosure that houses the air-gap operating mechanism and electronics. The solid-state circuit breaker enclosure includes a heat sink that interacts with natural airflow, such as an existing vertical air duct, within an electrical panel. The heat sink is made of a thermally conductive and electrically insulating (TC / EI) plastic.

Description

HEAT SINK FOR A SOLID-STATE CIRCUIT BREAKER IN AN ELECTRICAL PANEL FIELD BACKGROUND Aspects of the present invention generally relate to a heat sink for a solid-state circuit breaker in an electrical enclosure, such that the heat sink interacts with and takes advantage of existing air currents within the electrical enclosure. DESCRIPTION OF RELATED TECHNIQUE Solid-state circuit breakers (SSCBs) are an emerging technology. They feature semiconductor switching components, such as metal-oxide-semiconductor field-effect transistors (MOSFETs), that interrupt the flow of electricity without arcing. They have significant advantages that make them desirable replacements for conventional circuit breakers. However, the semiconductor switching components in SSCBs generally produce more heat than the contacts in conventional circuit breakers. Because of this additional heat, SSCBs cannot directly replace conventional circuit breakers unless they are thoroughly investigated, for example through testing, and found suitable for use in the specific electrical panels where they are intended to be installed. The problem is how to minimize the temperature rise of solid-state circuit breaker (SSCB) components in an electrical panel. A more specific problem is how to minimize the temperature rise of SSCBs installed in existing production electrical panels originally designed for conventional circuit breakers. The electrical distribution industry is currently dominated by conventional circuit breakers that use mechanically separating contacts to interrupt current flow. When the contacts open, an electric arc is temporarily conducted through the air between the contacts, as the current is turned off, under all load-off conditions. Arcing is inherent because, whenever current flows, there will be inductive energy stored in the overall circuit that must be dissipated when the current flow stops. Arcing is resistive and produces a reverse voltage that stops the current flow. In general, circuit breakers are devices that safely stop the flow of electric current under a variety of conditions: normal rated current, overload currents (from 135% to 10 times the rated current), and short-circuit currents up to the device's rated interrupting capacity. Conventional circuit breakers accomplish this. However, arcing erodes the contacts, limiting the product's lifespan. At normal rated current, the switch's lifespan is typically limited to several thousand operations. QQRRnn / eznz / e / Yi, for example, up to 10,000 operations. Under overload conditions, the switching lifespan is reduced to fewer operations, for example, up to 50 operations. Under short-circuit conditions, a conventional circuit breaker may interrupt even fewer times and may then need to be replaced. Likewise, under overload and short-circuit conditions, the current rises to levels much higher than the rated current, which can stress downstream components. In contrast, SSCBs do not experience arcing, and the current can be cut off in nanoseconds or milliseconds before it rises to a high level. Therefore, an SSCB can potentially switch many thousands or even millions of times. It can potentially provide superior protection to branch circuits by eliminating damaging peak let-through currents. Clearly, the advantages of SSCBs would be a benefit to the public. However, the additional heat produced by SSCBs poses a challenge that must be addressed. Conventional circuit breakers have several heat sources: 1. The internal conductor path. For example, this includes the terminals, the movable contact arm, and flexible connectors. The production of cater is managed by appropriately sizing the conductor cross-sections. 2. The mechanically separable interface of the electrical contacts. The phenomenon of heat generation due to current obstructions at the contact interface of electrical contacts is well documented. The production of catar is managed by selecting the material and applying the appropriate spring force to press the contacts together. 3. The current-sensing device. Some circuit breakers, known as "thermal / magnetic" circuit breakers, contain bimetals and resistive elements in the current path, which intentionally generate heat to trigger automatic opening (aka "tripping"). Other circuit breakers detect current using electronic circuits with current transformers or resistive shunts. These are known as "electronic trip unit" (or ETU) breakers. ETU components produce some heat, but not necessarily as much as thermal / magnetic breakers. Conventional circuit breakers dissipate heat through two means: 1. Conduction in the cables or buses attached to the terminals. 2. Conduction, convection and radiation through the insulated casing to the surroundings. If multiple circuit breakers are installed in an electrical panel, the heat from the circuit breakers is then transferred to the interior of the electrical panel. Inside the electrical panel, the temperature rises. The heat from inside the panel eventually passes through the walls of the panel and QQRRnn / eznz / e / Yi dissipates into the environment by means of conduction, convection and radiation. SSCBs have all the heat sources of conventional circuit breakers (mentioned above) and more. SSCBs are required to have mechanically separated contacts in order to provide adequate electrical isolation by means of an air gap. These "air gap" contacts do not experience arcing like conventional breakers; however, they necessarily produce heat while in the ON state, like a conventional switch. SSCBs also have conduction paths and current-sensing devices. In addition, they also have the following heat sources: 1. Semiconductor switching components. These are generally transistor components, such as FETs, MOSFETs, IGBTs, etc. Transistor components have an inherent resistance between the "drain" and the "source," known as Rds. In the ON state, current I flows continuously through the drain and the source. Therefore, power P is produced according to P = l2Rds. While semiconductor component manufacturers are constantly trying to reduce the value of Rds, at present, it is typically the largest source of heat in an SSCB. 2. Other electronic components. The SSCB may have other heat sources, such as a switching power supply, logic processor, passive components, etc. These typically produce less heat than the switching power component. For example, in North America, temperature rise in circuit breakers and electrical panels is regulated by strict safety temperature limits in industrial standards such as UL489 and UL67. Manufacturers must demonstrate through specified testing procedures that circuit breakers installed in electrical panels meet these temperature limits. Manufacturers must also ensure that electronic components do not exceed temperatures that cause damage. For example, in North America, there is a huge installed base of existing electrical panels and load centers that contain conventional circuit breakers. The most common branch circuits are protected by circuit breakers under 100 A; 15 and 20 A circuit breakers are especially common. It is common to add new circuit breakers to existing panels, for example, when a building is remodeled and the electrical wiring is expanded. It would be advantageous to allow new circuits to be protected by SSCBs. It would also be advantageous to be able to retrofit existing installations by replacing conventional circuit breakers with SSCBs, thereby improving circuit protection. Likewise, it would be advantageous for new installations to use existing production electrical panels with SSCBs, rather than requiring a new electrical panel design. Electrical distribution is a mature industry with significant investment in mass-produced products. Many thousands of electricians are trained in how to install these products. Many versions exist. QQRRnn / eznz / e / Yi circuit breakers and other accessories that are compatible with existing production panels. It would be advantageous if a new SSCB product could be used as a gradual upgrade to an existing product line, rather than requiring an entirely new product line that is incompatible with previous products. It is also anticipated that gradual improvements to existing production switchboards that would enhance heat transfer could be feasible, extending and increasing the usability of SSCBs. In this case, it would be advantageous to maintain maximum physical compatibility between SSCBs, conventional breakers, and switchboards. It would also be advantageous to maximize the use of parts already in production, such as those comprising switchboards and associated accessories. As an example, consider a 20 A rated miniature circuit breaker (MCB) installed in an electrical panel. Such a circuit breaker is typically loaded to no more than 80% of its rated current, i.e., 16 A. A typical heat generation value for a conventional MCB with a 16 A load might be around 1.5 watts. On the other hand, a typical heating value for a similarly rated and loaded SSCB might be around 5 watts. Clearly, the SSCB produces more heat. To avoid excessive temperature rise and to allow the maximum possible number of SSCBs in an electrical panel, it is desirable to minimize the temperature rise of the SSCB. Therefore, it would be useful to provide a device or means to reduce the temperature rise of an SSCB in a manner that would make the SSCB compatible with existing production switchgear, where such switchgear is already commercially available or already installed. Therefore, there is a need for a device or means to reduce the temperature rise of a solid-state circuit breaker (SSCB). SUMMARY Briefly described, aspects of the present invention relate to a heat sink for a solid-state circuit breaker. The field of the invention involves low-voltage circuit breakers, such as miniature circuit breakers (MCBs) or molded-case circuit breakers (MCCBs), which have a housing of insulated plastic material and are installed in electrical enclosures. The present invention provides improved heat dissipation for SSCBs. It further provides improved heat dissipation for SSCBs installed in existing production electrical enclosures. In accordance with an illustrative embodiment of the present invention, a solid-state circuit breaker (SSCB) comprises an air-gap operating mechanism including components and electronics including semiconductors and software algorithms that control power and can interrupt extreme currents. The SSCB further comprises a housing that houses the air-gap operating mechanism components and electronics. The SSCB housing QQRRnn / eznz / e / Yi solid-state circuit includes a heat sink that interacts with natural airflow within an electrical enclosure. The heat sink contains a thermally conductive and electrically insulating (TC / EI) plastic. In accordance with an illustrative embodiment of the present invention, an electrical enclosure comprises an existing vertical air channel formed in a space in front of a main bus of the electrical enclosure. The electrical enclosure further comprises a plurality of solid-state circuit breakers (SSCBs), such that conventional breakers and SSCBs can be combined in the electrical enclosure. The electrical enclosure further comprises a plurality of heat sinks, such that each solid-state circuit breaker (SSCB) has its own integral heat sink. Each heat sink interacts with the existing vertical air channel within the electrical enclosure, and the plurality of heat sinks are completely enclosed within the electrical enclosure.Each solid-state circuit breaker comprises an air-gap operating mechanism that includes components and electronics, including semiconductors and software algorithms that control power and can interrupt extreme currents. The SSCB further comprises a housing that houses the air-gap operating mechanism components and electronics. The solid-state circuit breaker housing includes one of the plurality of heat sinks. The heat sink comprises a thermally conductive and electrically insulating (TC / EI) plastic. In accordance with an illustrative embodiment of the present invention, a method of reducing temperature rise in a solid-state circuit breaker (SSCB) is described. The method comprises providing an air-gap operating mechanism including components, providing electronics including semiconductors and software algorithms that control power and can interrupt extreme currents, and providing a housing housing the air-gap operating mechanism components and electronics. The solid-state circuit breaker housing includes a heat sink that interfaces with a vertical air channel within an electrical enclosure. The vertical air channel is formed in a space in front of a main bus of the electrical enclosure. The heat sink comprises a thermally conductive and electrically insulating (TC / EI) plastic. The features and advantages described above, as well as others, will become more apparent to those skilled in the art upon reference to the following detailed description and the accompanying drawings. While it would be desirable to provide one or more of these or other advantageous features, the teachings disclosed herein extend to those embodiments that fall within the scope of the appended claims, regardless of whether they achieve one or more of the aforementioned advantages. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of this disclosure, and the advantages thereof, QQRRnn / eznz / e / Yi Reference is made below to the following descriptions taken in conjunction with the accompanying drawings, where like numbers designate like objects. FIGS. 1-5 illustrate a solid-state circuit switch with a heat sink, in accordance with an exemplary embodiment of the present invention. FIG. 6 illustrates a printed circuit board (PCB) assembly with field effect transistors (FETs) and overmolded plastic parts including an integral heat sink, in accordance with an exemplary embodiment of the present invention. FIGS. 7-8 illustrate a solid-state circuit breaker installed in an existing electrical panel, in accordance with an exemplary embodiment of the present invention. FIGS. 9-10 illustrate a location of an air channel and heat sinks extending into the air channel, in accordance with an exemplary embodiment of the present invention. FIGS. 11-12 illustrate air currents arising from a stack effect, in accordance with an exemplary embodiment of the present invention. FIG. 13 illustrates a heat flow view of the same partially cutaway view as FIG. 12, in accordance with an exemplary embodiment of the present invention. FIG. 14 illustrates graphs of temperature distribution across the heat sink at various degrees of thermal conductivity, in accordance with an exemplary embodiment of the present invention. FIG. 15 illustrates a method of reducing a temperature rise in a solid-state circuit breaker (SSCB), in accordance with an exemplary embodiment of the present invention. DETAILED DESCRIPTION Various technologies pertaining to systems and methods that facilitate a heat sink for a solid-state circuit breaker will now be described with reference to the drawings, where like reference numerals represent like elements throughout. The drawings discussed below and the various embodiments used to describe the principles of the present disclosure in this patent document are for illustrative purposes only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any suitably arranged apparatus. It should be understood that the functionality described as being performed by certain elements of the system can be performed by multiple elements.Similarly, for example, one element may be configured to perform a functionality described as being performed by multiple elements. The numerous innovative teachings of the present application will be described with reference to non-limiting example embodiments. QQRRnn / eznz / e / Yi To facilitate understanding of the embodiments, principles, and features of the present invention, they are explained below with reference to implementation in illustrative embodiments. In particular, they are described in the context of a heat sink for a solid-state circuit breaker. However, the embodiments of the present invention are not limited to use in the devices or methods described. The components and materials described hereinafter as constituents of the various embodiments are intended to be illustrative and not restrictive. Many suitable components and materials that would perform the same or a similar function as the materials described herein are intended to be encompassed within the scope of the embodiments of the present invention. These and other embodiments of the heat sink for a solid-state circuit breaker according to the present disclosure are described below with reference to FIGS. 1-15 herein. Like reference numerals used in the drawings identify similar or identical elements throughout the various views. The drawings are not necessarily drawn to scale. Consistent with one embodiment of the present invention, FIGS. 1-5 depict a solid-state circuit breaker (SSCB) 105 including a heat sink 107 for reducing a temperature rise in the solid-state circuit breaker 105, in accordance with an exemplary embodiment of the present invention. FIG. 1 illustrates the solid-state circuit breaker 105 with the heat sink 107 interacting with a natural air flow, such as an existing vertical air channel (not seen), within an electrical panel (not seen). The natural air flow is the enclosure in which a single solid-state circuit breaker 105 is housed in a small enclosure, with the heat sink 107 driving air currents within the enclosure, but perhaps not having a discernible “air channel” as with multiple solid-state circuit breakers in a larger electrical panel. Heat sink 107 comprises a thermally conductive and electrically insulating (TC / EI) plastic. "Thermally conductive and electrically insulating (TC / EI)" materials typically include additives such as boron nitride. Boron nitride provides high thermal conductivity, yet allows the resin base to retain its electrically insulating properties. Extensive material testing confirms its superior thermally conductive and electrically insulating properties. The heat sink 107 is comprised of a thermally conductive but electrically insulating (TC / EI) plastic. The heat sink 107 comprises part of an external molded case of the circuit breaker 105, and therefore must be electrically insulating for safety and to meet the requirements of LJL489. Therefore, the heat sink 107 cannot be made of traditional heat sink materials, such as aluminum or copper. Fortunately, relatively new plastic materials with conductive properties are available. QQRRnn / eznz / e / Yi improved thermal conductivity, but electrically insulating. The following graph illustrates the relative thermal conductivity of various materials: Table I QQRRnn / eznz / e / Yi Material Thermal conductivity k [W / (m°K)] Common plastics 0.1 to 0.5 Thermally conductive and electrically insulating plastics (TC / EI) 5 to 20 Extruded aluminum 205 Copper 400 From Table I above, it can be seen that TC / EI plastics have thermal conductivities ("k") an order of magnitude higher than common plastics, but much lower than aluminum or copper. Such high k values ​​are unnecessary, but the much lower values ​​provide a significant benefit in reducing the temperature rise of the transistor components in circuit breaker 105. The TC / EI plastic of the heat sink 107 can be produced by partially overmolding a printed circuit board (PCB), such that the plastic covers the heat-producing transistor components. By overmolding, air gaps are eliminated, such that heat is conducted from the transistor components to the heat sink 107 with minimal temperature rise. Alternatively, the heat sink 107 could be produced as a separate piece that covers the transistor components. If produced as a separate piece, then heat transfer could be enhanced with a thermally conductive interface material, such as grease, film, or gasket. The TC / EI plastic of the heat sink 107 can also be held in place without overmolding. In one embodiment, the solid state circuit breaker (SSCB) 105 comprises a base 110, a main cover 112, and an outer cover 115. The solid state circuit breaker (SSCB) 105 further comprises a traditional air gap operating mechanism (not seen) including components. The solid state circuit breaker (SSCB) 105 further comprises electronics 120 (e.g., FET 122, see FIG. 4 ) including semiconductors and software algorithms that control power and can interrupt extreme currents. The solid state circuit breaker (SSCB) 105 further comprises a housing 125 (made up of the base 110, the main cover 112 and the outer cover 115) that houses the components of the air gap operating mechanism and the electronics 120. The housing 125 of the solid state circuit breaker (SSCB) 105 includes the heat sink 107. Optionally, the solid-state circuit breaker (SSCB) 105 further comprises perforations 130 in the main cover 112. The perforations 130 allow airflow, but prevent the insertion of objects that touch delicate or electrically live parts. The solid-state circuit breaker (SSCB) 105 further comprises a plurality of air vents 135 to provide airflow for cooling electronic components, such as the electronics 120. The solid state circuit breaker (SSCB) 105 further comprises two plastic overmolded parts 140(1-2), such that the heat sink 107 is integral with the first overmolded part 140(1), while a second overmolded part 140(2) is disposed at a distance from the first overmolded part 140(1), as seen in FIG. 2 (the outer cover 115 is removed). The solid-state circuit breaker (SSCB) 105 further comprises a printed circuit board 145, a terminal lug 147, and a plug-in connection 150 (see FIG. 3 ). In FIG. 5 , the vent locations of the air vents 135 are shown. The vent feature such as a rear vent is still present at a location 155, even with the heat sink 107 added. One or more “vent openings,” such as the air vents 135, in the solid-state circuit breaker 105 include a “rear vent” that allows airflow to exit the solid-state circuit breaker 105 into the existing vertical air channel. Optionally, the heat sink 107 may be present without the air vents 135. An exemplary SSCB shown in FIG. 3 shows the power transistor components in two groups of four field effect transistors (FETs). One group of four FETs is conveniently located near an air channel. This group of FETs is overmolded with TC / EI plastic and has an integral finned heat sink extending into the air channel. In addition, the second group of four FETs is also overmolded with a second piece of TC / EI plastic. A known connector or bridge means is provided to transfer heat from the second piece of TC / EI plastic to the first piece, and then to the external fins of the heat sink. An exemplary SSCB in FIGS. 2 and 3 has cylindrical posts extending from two overmolded plastic pieces. This increases heat transfer by increasing surface area. These posts allow for two-dimensional airflow within the circuit breaker 105. The posts could possibly not be cylindrical; however, cylinders are preferred for lower flow resistance, and they are easy to produce in a mold. The posts are an optional feature. They could be omitted if more powerful internal airflow is required, or if they are not moldable with the chosen plastic resin. In addition to the heat sink 107, ventilation openings are provided in the circuit breaker 105. One of the openings, the "rear vent," allows airflow to exit the breaker 105 into an existing vertical air channel. One or more other vents are located on the outside of the breaker housing at locations other than the existing vertical air channel. These "other vents" allow air to enter the circuit breaker 105. The airflow in the existing vertical air channel produces a "Bernoulli effect" that draws air across the breaker 105, thereby increasing the cooling of the interior of the breaker. See FIG. 14. Air enters through the "other vents" and exits through the "rear vent." The air Heated QQRRnn / eznz / e / Yi entering the existing vertical air channel from the “rear vents” also increases the stack effect. The stack effect and air currents are entirely internal to the electrical panel. No vents are added to the electrical panel. Air currents help spread heat within the electrical panel. Heat is transferred through the steel walls of the electrical panel through convection and conduction to the external environment. Air velocities are increased by the added heat of the SSCBs, which increases heat transfer to the environment. Otherwise, there is no change in the design of the electrical panel itself. The client does not need to change the way the electrical panel is installed. The air sink 107 may be located on a rear portion 160 (see FIG. 1) of the solid state circuit breaker 105, and the air sink 107 is configured to extend into the existing vertical air channel of the electrical panel. The air sink 107 is part of an external molded case, such that a plastic piece, such as the two overmolded plastic pieces 140(1-2), of the heat sink 107 is overmolded onto the printed circuit board 145, such that the plastic piece covers the semiconductors of the solid state circuit switch 105. The plastic piece must be separated into two or more pieces if the semiconductors are located at different locations on the printed circuit board 145, such that a thermal bridge (see description with respect to FIG. 2) conducts heat between the two or more pieces and ultimately to a plurality of fins 165 external to the solid state circuit switch 105. The air sink 107 includes the plurality of fins 165 on an exterior of the solid state circuit switch 105, and the plurality of fins 165 extend into the existing vertical air channel.The plurality of fins 165 are arranged in a space in the electrical panel behind the solid state circuit breaker 105 that is otherwise empty. The heat transfer means between the two overmolded pieces can be achieved in multiple alternative ways. First, a copper or aluminum bridge could connect the two overmolded plastic pieces 140(1-2). Second, the main cover 112, for example as shown in FIG. 2, could also be molded from a TC / EI plastic, touching the two overmolded plastic pieces 140(1-2), and serving as a thermal bridge. Third, instead of overmolding, the main cover 112 and the air sink 107 could be a single integrated piece, pressing against both groups of FETs. Fourth, the second molded piece 140(2) could be omitted, by providing a suitable thermal bridge on the PCB itself from copper layers on the PCB. Fifth, the TC / EI plastic of the heat sink may incorporate one or more copper or aluminum overmolded pieces to further enhance heat transfer. The air sink 107 can be completely enclosed within the electrical box, and no airflow is provided behind the electrical box. The electrical box can be installed directly on a wall or can be installed inside the wall with a flush front. A switch Conventional QQRRnn / eznz / e / Yi and solid state circuit breaker can be combined in the electrical panel. As shown in FIG. 6 , a printed circuit board (PCB) assembly 600 with field effect transistors (FETs) and a plastic part with overmolded plastic parts 610(1-2) including an integral heat sink 607 is illustrated, in accordance with an exemplary embodiment of the present invention. The solid state circuit switch 605 further comprises a plurality of cylindrical posts 615 extending from the plastic part with the two overmolded plastic parts 610(1-2) to increase heat transfer by increasing a surface area, since the plurality of cylindrical posts 615 allow for 2-dimensional airflow within the solid state circuit switch 605. FIGS. 7-8 illustrate a solid-state circuit breaker installed in an existing electrical panel 700, in accordance with an exemplary embodiment of the present invention. The electrical panel 700 shown in FIG. 7 has wires shown similar to a UL test. In FIG. 7, the electrical panel 700 has been simplified (deformed) for illustration purposes. For example, unused knockouts have been omitted. The electrical panel 700 comprises an existing vertical air channel (shown in FIG. 9) formed in a space in front of a main bus of the electrical panel 700. With respect to FIG. 8, the electrical panel 700 further comprises a plurality of solid state circuit breakers (SSCBs) 805(1-n), such that conventional breakers and SSCBs may be combined within the electrical panel 700. The electrical panel 700 further comprises a plurality of heat sinks (as seen in FIG. 9), such that each solid state circuit breaker 805 has its own integral heat sink. Each heat sink interacts with the vertical air channel within the electrical panel 700, and the plurality of heat sinks are totally enclosed within the electrical panel 700. FIGS. 9-10 illustrate one location of two existing vertical air channels 902(1-2) and a plurality of heat sinks 907(1-n) extending into the existing vertical air channels 902(1-2), in accordance with an exemplary embodiment of the present invention. With respect to FIG. 9, a partially cutaway view of the electrical panel 700 is shown with the SSCBs 805(1-n) installed therein. The two existing vertical air channels 902(1-2) are located behind the SSCBs 805(1-n). The plurality of heat sinks 907(1-n) extend into these two existing vertical air channels 902(1-2). FIG. 10 shows another partially cutaway view of the electrical panel 700 with the SSCBs 805(1-n) installed therein. An embodiment of the present invention provides a heat sink 107 that interacts with and takes advantage of existing air currents within the electrical box 700. The space in front of a main bus of the electrical box 700 provides an air volume into which air can enter, flow freely in a vertical direction, and exit at the top. This air volume comprises an air channel 902 of rectangular cross-section with open ends. Three sides of the rectangle are provided by a plastic base mounting on the electrical box 700 at the QQRRnn / eznz / e / Yi where the main bus is mounted. The front side of the air channel 902 is enclosed by the row of circuit breakers mounted on the electrical panel 700. (These circuit breakers could be SSCBs or conventional circuit breakers.) The characteristics of the electrical panel 700 are common to a whole family of commercial switchboards. Ohmic losses in the main bus generate heat that is transferred by convection to the air in the air channel 902. The heated air becomes buoyant and rises. The rising air comprises an air current that flows upward through the electrical panel 700. The buoyant airflow effect is similar to a fireplace chimney, and this is called the "stack effect." The heat sink 107 is located at the rear of the SSCB 105 and extends into this air channel 902.Because convective heat transfer increases with airflow velocity, this positioning of the heat sink 107 provides advantageous heat transfer. The heat sink 107 adds heat to the airflow, thereby increasing the flow velocity and enhancing the stack effect. FIGS. 11-12 illustrate air currents arising from a stack effect, in accordance with an exemplary embodiment of the present invention. FIG. 11 shows a side partially cutaway view of electrical panel 700 with SSCBs 805(1-n) installed therein. For example, an air channel 1102 is shown on the left side. Air channel 1102 is located behind SSCBs 805(1-n). A plurality of heat sinks 907(1-n) extend into these channels. FIG. 12 shows another side of the partially cutaway view of the electrical panel 700 with the SSCBs 805(1 -n) installed therein. Arrows 1212 indicate a direction of air flow. FIG. 13 illustrates another view of a heat flux 1307(2) of FIG. 12, in accordance with an exemplary embodiment of the present invention. This is a sectional view of one 805(1) of the SSCBs 805(1-n). Small simulation arrows indicate the air flow velocity. Arrows 1403(1-2) indicate that air enters the SSCB 805(1) through these vents. An arrow 1403(3) indicates that air exits the SSCB 805(1) into the air channel 1102. This is an illustration of the Bernoulli effect, where the air velocity in the air channel 1102 draws air across the SSCBs 805(1-n). FIG. 14 illustrates AD simulation graphs of the temperature distribution across the heat sink 107 at various degrees of thermal conductivity, in accordance with an exemplary embodiment of the present invention. The conductivity values ​​of the TC / EI plastics give temperature distributions that more closely resemble aluminum than common plastics. FIG. 15 illustrates a method 1500 of reducing a temperature rise in the solid-state circuit breaker (SSCB) 107, in accordance with an exemplary embodiment of the present invention. Reference is made to the elements and features described in FIGS. 1-14. It should be appreciated that some steps are not required to be performed in any particular order and that some steps are optional. QQRRnn / eznz / e / Yi The method 1500 comprises a step 1505 of providing an air-gap operating mechanism including components. The method 1500 further comprises a step 1510 of providing electronics including semiconductors and software algorithms that control power and can interrupt extreme currents. The method 1500 further comprises a step 1515 of providing a housing that houses the air-gap operating mechanism components and electronics. The solid-state circuit breaker housing includes the heat sink 107 that interfaces with an existing vertical air channel within an electrical enclosure. The existing vertical air channel is formed in a space in front of a main bus of the electrical enclosure. The heat sink 107 comprises a thermally conductive and electrically insulating (TC / EI) plastic. Conventional switches generally do not have heat sinks 107 on the rear of the switch 105 and do not require them. The advantages of SSCBs over conventional circuit breakers have been described above. Previous uses of overmolding and thermally conductive plastics did not involve cooling solid-state semiconductor components and did not involve the finned heat sink 107 on the exterior of the switch 105. Typically, there is no room for such outer fins because they increase the size of the switch's outer envelope. However, in embodiments of the present invention, an otherwise empty space in the electrical panel behind the switch 105 is utilized. Therefore, the heat sink fins do not have a disadvantage of requiring extra space. Hybrid breakers appear to exist, but without many examples in production. In theory, hybrid breakers should not produce more heat than conventional breakers and therefore might not require additional heat sinks. However, they are (hypothetically) more complex than conventional breakers or SSCBs because they must provide arcing contacts, a means of extinguishing an arc (albeit with reduced arc energy compared to conventional breakers), solid-state switching components, and a means of switching current from the main current path to the solid-state components. Hybrid breakers are inherently slower and provide less current limiting than SSCBs. They have less load-endurance capability than SSCBs due to the arcing contacts. On the other hand, some hybrid switches can be compatible with existing enclosures. Some conventional switch designs have been converted to hybrids. Some concepts have the serious disadvantage that a customer must provide airflow behind the 700 electrical panel. This is not a requirement for most existing conventional breaker panels. Such a panel cannot be installed directly on a wall; nor can it be installed inside a wall with the face flush with the wall, as existing conventional panels are. Therefore, this concept does not allow for retrofitting existing installations. The panel is not compatible with conventional circuit breakers or existing accessories. On the other hand, QQRRnn / eznz / e / Yi part, the heat sink 107 is completely enclosed within the electrical box 700. Each SSCB has its own integral heat sink. This is distinct from other designs, in which each breaker is equipped only with a base plate as a heat transfer interface and must be attached to an external heat sink. The electrical box 700 does not have an external heat sink. The electrical box 700 can be installed in a conventional manner, in the same manner as with previous conventional breakers. Conventional breakers and SSCBs can be combined in the same box 700. This allows the customer to use lower-cost conventional circuit breakers on some of the circuits, if desired. Unlike other designs, the present invention does not rely on external airflow behind the electrical box 700. Rather, it utilizes an air channel internal to the electrical box 700. While a solid-state circuit breaker design is described herein, a range of one or more other circuit breakers are also contemplated by the present invention. For example, other circuit breakers may be implemented based on one or more of the features presented above, without departing from the spirit of the present invention. The techniques described herein may be particularly useful for a thermally conductive and electrically insulating (TC / EI) plastic where the thermal conductivity (k) of a heat sink TC / EI plastic is in a range of 5 to 20 W / (m°K). While particular embodiments are described in terms of this range, the techniques described herein are not limited to that range, but may be used with other ranges as well. While embodiments of the present invention have been disclosed in exemplary forms, it will be apparent to those skilled in the art that many modifications, additions and deletions can be made therein without departing from the spirit and scope of the invention and its equivalents as set forth in the following claims. The embodiments and the various advantageous features and details thereof are more fully explained with reference to the non-limiting embodiments illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known starting materials, processing techniques, components, and equipment are omitted so as not to unnecessarily obscure the detailed embodiments. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments, are given by way of illustration only and not by way of limitation. Various substitutions, modifications, additions, and / or rearrangements within the spirit and / or scope of the underlying inventive concept will become apparent to those skilled in the art from the present disclosure. As used herein, the terms "comprise," "comprising," "include," "including," "has," "having," or any other variation thereof are intended to cover a non-exclusive inclusion. For example, a method, article, or apparatus comprising a list of elements is not necessarily limited to only those elements, but may include other elements. QQRRnn / cznz / e / Yi items that are not expressly listed or are inherent to said procedure, article or apparatus. Additionally, no example or illustration given herein should be construed in any way as restrictions on, limits upon, or express definitions of any term or terms with which they are used. Rather, these examples or illustrations should be considered as described with respect to a particular embodiment and as illustrative only. Those skilled in the art will appreciate that any term or terms with which these examples or illustrations are used will encompass other embodiments that may or may not be given herein or elsewhere in the specification, and all such embodiments are intended to be included within the scope of those term or terms. In the foregoing specification, the invention has been described with reference to specific embodiments. However, one skilled in the art appreciates that various modifications and changes can be made without departing from the scope of the invention. Accordingly, the specification and figures should be considered in an illustrative, rather than restrictive, sense, and all such modifications are intended to be included within the scope of the invention. Although the invention has been described with respect to specific embodiments thereof, these embodiments are merely illustrative, and not restrictive, of the invention. The description herein of illustrated embodiments of the invention is not intended to be exhaustive or to limit the invention to the precise forms disclosed herein (and in particular, the inclusion of any particular embodiment, feature, or function is not intended to limit the scope of the invention to that embodiment, feature, or function). Rather, the description is intended to describe illustrative embodiments, features, and functions, so as to provide one skilled in the art with a context for understanding the invention without limiting the invention to any particularly described embodiment, feature, or function.While specific embodiments of, and examples for, the invention are described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the invention, as those skilled in the art will recognize and appreciate. As indicated, such modifications can be made to the invention in light of the foregoing description of illustrated embodiments of the invention and are to be included within the spirit and scope of the invention.Thus, while the invention has been described herein with reference to particular embodiments thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosures, and it will be appreciated that, in some instances, some features of the embodiments of the invention will be employed without corresponding use of other features, without departing from the scope and spirit of the invention as set forth. Thus, many modifications can be made to adapt a particular situation or material to the essential scope and spirit of the invention. QQRRnn / eznz / e / Yi The respective occurrences of the phrases "in a (number) embodiment," "in a (item) embodiment," or "in a specific embodiment," or similar terminology, in various places throughout this specification do not necessarily refer to the same embodiment. Furthermore, particular features, structures, or characteristics of any particular embodiment may be combined in any suitable manner with one or more other embodiments. It should be understood that other variations and modifications of the embodiments described and illustrated herein are possible in light of the teachings herein and should be considered within the spirit and scope of the invention. In the description herein, numerous specific details, such as examples of components and / or methods, are provided to provide a complete understanding of embodiments of the invention. However, one skilled in the art will recognize that an embodiment may be practiced without one or more of the specific details, or with other apparatus, systems, assemblies, methods, components, materials, parts, and / or the like. In other instances, well-known structures, components, systems, materials, or operations are not specifically shown or described in detail to avoid obscuring aspects of embodiments of the invention.While the invention may be illustrated by the use of a particular embodiment, this does not and does not limit the invention to any particular embodiment, and one skilled in the art will recognize that additional embodiments are readily apparent and form part of the present invention. It will also be appreciated that one or more of the elements depicted in the drawings / figures may also be implemented in a more separate or integrated manner, or even eliminated or rendered inoperable in certain cases, as may be useful according to a particular application. The benefits, other advantages, and solutions to problems have been described above with respect to specific embodiments. However, the benefits, advantages, solutions to problems, and any components that may make any benefit, advantage, or solution occur or become more pronounced should not be construed as a critical, required, or essential feature or component.

Claims

CLAIMS 1. A solid-state circuit breaker (SSCB) comprising: an air-gap operating mechanism including components; electronics including semiconductors and software algorithms that control power and can interrupt currents; and a housing housing the components of the air-gap operating mechanism and the electronics, wherein the solid-state circuit breaker housing includes: a heat sink that interacts with natural airflow within an electrical enclosure, wherein the heat sink contains a thermally conductive and electrically insulating (TC / EI) plastic.

2. The solid-state circuit breaker of claim 1, characterized in that the heat sink is located at a rear portion of the solid-state circuit breaker and the heat sink extends into an existing vertical air channel.

3. The solid state circuit breaker of claim 2, wherein the heat sink is part of an external molded case, such that a plastic piece of the heat sink is overmolded onto a printed circuit board, such that the plastic piece covers semiconductors of the solid state circuit breaker, wherein the plastic piece must be separated into two or more pieces if the semiconductors are located at different locations on the printed circuit board, such that a thermal bridge conducts heat between the two or more pieces and ultimately to a plurality of fins external to the solid state circuit breaker.

4. The solid-state circuit breaker of claim 3, further comprising: a plurality of cylindrical posts extending from the plastic part to increase heat transfer by increasing a surface area, since the plurality of cylindrical posts allow a 2-dimensional air flow within the solid-state circuit breaker.

5. The solid-state circuit breaker of claim 1, wherein the heat sink includes a plurality of fins on an exterior of the solid-state circuit breaker and the plurality of fins extend into an existing vertical air channel, wherein the plurality of fins are disposed in a space in the electrical panel behind the solid-state circuit breaker that is otherwise empty.

6. The solid state circuit breaker of claim 1, further comprising: QQRRnn / eznz / e / Yi one or more vents in the solid state circuit breaker, wherein one of the vents is a "rear vent" allowing airflow to exit the solid state circuit breaker into an existing vertical air channel.

7. The solid-state circuit breaker of claim 1, characterized in that the heat sink is fully enclosed within the electrical box.

8. The solid-state circuit breaker of claim 1, characterized in that no air flow is provided behind the electrical box.

9. The solid-state circuit breaker of claim 1, characterized in that the electrical panel can be installed directly on a wall or can be installed inside the wall with a front flush with the wall.

10. The solid-state circuit breaker of claim 1, characterized in that a conventional switch and the solid-state circuit breaker can be combined in the electrical panel.

11. An electrical enclosure comprising: an existing vertical air channel formed in a space in front of a main bus of the electrical enclosure; a plurality of solid state circuit breakers (SSCBs), wherein conventional breakers and SSCBs can be combined in the electrical enclosure; a plurality of heat sinks, such that each solid state circuit breaker has its own integral heat sink, wherein each heat sink interacts with the existing vertical air channel within the electrical enclosure and the plurality of heat sinks are totally enclosed within the electrical enclosure, wherein each solid state circuit breaker comprises: an air gap operating mechanism including components; electronics including semiconductors and software algorithms that control power and can interrupt extreme currents;and a housing housing the components of the air gap operating mechanism and electronics, wherein the solid state circuit breaker housing includes: one of the plurality of heat sinks, wherein the heat sink comprises a thermally conductive and electrically insulating (TC / EI) plastic; 12. The electrical panel of claim 11, wherein the heat sink is located at a rear portion of the solid-state circuit breaker and the heat sink extends into the existing vertical air channel.

13. The electrical panel of claim 12, characterized in that the heat sink is part of an external molded case, such that a plastic piece of the heat sink is overmolded onto a printed circuit board, such that the plastic piece covers the semiconductors of the solid state circuit breaker, wherein the plastic piece must be separated into two or more pieces if the semiconductors are located at different locations on the printed circuit board, such that a thermal bridge conducts heat between the two or more pieces and finally to a plurality of fins external to the solid state circuit breaker.

14. The electrical panel of claim 13, characterized in that it further comprises: a plurality of cylindrical posts extending from the plastic piece to increase heat transfer by increasing a surface area, since the plurality of cylindrical posts allow a 2-dimensional air flow within the solid state circuit breaker.

15. The electrical panel of claim 11, wherein the heat sink includes a plurality of fins on an exterior of the solid state circuit breaker and the plurality of fins extend into the existing vertical air channel, wherein the plurality of fins are disposed in a space 15 in the electrical panel behind the solid state circuit breaker that is otherwise empty.

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