Thermal management system for power converter

Abstract

A power converter assembly includes a housing, a cold plate in the housing, and a set of power converter components on the cold plate. The cold plate is configured to receive a coolant. A first medium in the housing surrounds the cold plate and the components. An expandable heat transfer structure is attached to one of the cold plate and the housing.

Description

[0001] Priority information

[0002] This application claims priority to Indian Patent Application No. 202211030257, filed on May 26, 2022. Technical Field

[0003] This disclosure relates to a thermal management system for a power converter. Background Technology

[0004] Gas turbine engines typically consist of a turbine and a rotor assembly. Gas turbine engines, such as turbofan engines, are used for aircraft propulsion. In the case of turbofan engines, the rotor assembly can be constructed as a fan assembly.

[0005] Gas turbine engines can have power converters, for example, connected to a generator. Power converters are used to convert electrical energy from one form to another. For example, a power converter can convert current between alternating current (AC) and direct current (DC). A power converter can also modify a combination of voltage, current, and / or frequency from the input power to obtain the desired output power.

[0006] In aircraft engines, power converters are expected to be lightweight, compact, integrated with the thermal management system (TMS), and operate at high altitudes where low ambient pressure increases the risk of dielectric breakdown. Improvements to power converters are desirable because high-power converters are expected to handle higher temperature operation (e.g., due to high voltage, high current heat loss, and / or engine thermal environment). Attached Figure Description

[0007] The complete and practical disclosure of this disclosure, including its best mode, is set forth in the description with reference to the accompanying drawings, for those skilled in the art, wherein:

[0008] Figure 1 This is a cross-sectional view of a gas turbine engine according to an exemplary aspect of this disclosure.

[0009] Figure 2 Based on exemplary aspects of this disclosure Figure 1 A schematic diagram of a gas turbine engine.

[0010] Figure 3 This is a perspective view of a power converter assembly according to an exemplary aspect of this disclosure.

[0011] Figure 4 Based on exemplary aspects of this disclosure Figure 3 A schematic diagram of the power converter assembly.

[0012] Figure 5This is a schematic diagram of a power converter assembly according to an exemplary aspect of this disclosure.

[0013] Figure 6 This is a schematic diagram of an expandable heat transfer structure according to an exemplary aspect of this disclosure.

[0014] Figure 7 This is a schematic diagram of an expandable heat transfer structure according to an exemplary aspect of this disclosure.

[0015] Figure 8 This is a schematic diagram of an expandable heat transfer structure according to an exemplary aspect of this disclosure.

[0016] Figure 9 This is a schematic diagram of an expandable heat transfer structure according to an exemplary aspect of this disclosure. Detailed Implementation

[0017] Reference will now be made in detail to the present embodiments of this disclosure, one or more examples of which are illustrated in the accompanying drawings. Detailed descriptions use both numerical and alphabetic names to refer to features in the drawings. Similar or related names in the drawings and specification are used to refer to similar or related portions of this disclosure.

[0018] The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" should not be construed as being more preferred or advantageous than other implementations. Furthermore, unless otherwise specifically indicated, all embodiments described herein should be considered exemplary.

[0019] For the purposes of the description below, the terms “upper,” “lower,” “right,” “left,” “vertical,” “horizontal,” “top,” “bottom,” “lateral,” “longitudinal,” and their derivatives, when oriented in the accompanying drawings, are used in connection with the invention. However, it should be understood that the invention can take various alternative variations unless expressly stated otherwise. It should also be understood that the specific devices shown in the drawings and described in the following specification are merely exemplary embodiments of the invention. Therefore, the specific dimensions and other physical characteristics associated with the embodiments disclosed herein are not considered limiting.

[0020] As used herein, the terms “first,” “second,” and “third” are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of a single component.

[0021] The terms "front" and "rear" refer to relative positions within a gas turbine engine or carrier, and to the normal operating posture of the gas turbine engine or carrier. For example, in the context of a gas turbine engine, "front" refers to the position closer to the engine inlet, and "rear" refers to the position closer to the engine nozzle or exhaust port.

[0022] The terms "upstream" and "downstream" refer to the relative directions of fluid flow within a fluid path. For example, "upstream" refers to the direction in which the fluid flows from, and "downstream" refers to the direction in which the fluid flows to.

[0023] The terms “connection,” “fixation,” “attachment,” etc., refer to direct connection, fixation, or attachment, as well as indirect connection, fixation, or attachment via one or more intermediate components or features, unless otherwise specified herein.

[0024] Unless the context clearly indicates otherwise, the singular forms “one,” “a,” and “this” include plural references.

[0025] The approximate language used in this specification and claims is intended to modify any quantitative expression that allows for variation without altering the underlying functionality. Therefore, values ​​modified by one or more terms such as “about,” “approximately,” and “substantially” are not limited to specified precise values. In at least some instances, approximate language may correspond to the precision of the instrument used to measure the value, or the precision of the method or machine used to construct or manufacture the component and / or system. For example, approximate language may refer to a margin of 1, 2, 4, 10, 15, or 20%. These approximate margins may be applied to a single value, or to a margin defining one or both endpoints of a numerical range and / or the range between those endpoints.

[0026] Throughout this specification and claims, scope limitations are combined and interchanged, and these scopes are identified and include all subscopes contained herein, unless otherwise indicated by context or language. For example, all scopes disclosed herein include endpoints, and endpoints may be combined independently of each other.

[0027] The term “turbine” or “turbomachinery” refers to a machine that includes one or more compressors, a heating section (e.g., a combustion section), and one or more turbines that together produce torque output.

[0028] The term "gas turbine engine" refers to an engine that has a turbine as its power source, either entirely or partially. Examples of gas turbine engines include turbofan engines, turboprop engines, turbojet engines, turboshaft engines, etc.

[0029] The term "combustion section" refers to any heat addition system for a turbine. For example, the term "combustion section" may refer to a section including one or more of a knock combustion assembly, a rotary detonation combustion assembly, a pulse detonation combustion assembly, or other suitable heat addition assemblies. In some exemplary embodiments, the combustion section may include an annular burner, a canister burner, a shell-and-tube burner, a trap vortex burner (TVC), or other suitable combustion systems or combinations thereof.

[0030] When used with compressors, turbines, shafts, or spool components, the terms “low” and “high”, or their respective degrees of comparison (e.g., lower, higher, if applied), each refer to a relative speed within the engine, unless otherwise specified. For example, “low turbine” or “low-speed turbine” defines a component configured to operate at a rotational speed (such as the maximum permissible rotational speed) lower than that of a “high turbine” or “high-speed turbine” in the engine.

[0031] This disclosure generally relates to a power converter assembly including an expandable heat transfer structure.

[0032] The power converter can interface with a generator. The generator can be connected to the main shaft of the aircraft engine that drives the generator to produce electricity. Power is supplied from the generator to the power converter.

[0033] The components of the power converter may be potted (e.g., covered with an electrically insulating epoxy resin (e.g., dielectric epoxy resin) or other solid insulating material with good thermal conductivity) and / or surrounded by a dielectric to prevent high-voltage arcing and discharge, sparking and other damaging events.

[0034] Power converters can be located in high-temperature environments (e.g., high-heat ambient temperatures). Typically, the components of a power converter can dissipate heat directly to the coolant in a cold plate or to the dielectric surrounding the power converter. The power converter can also be isolated from ambient temperature by its housing.

[0035] The power converter assembly includes an expandable heat transfer structure disposed within the housing of the power converter, and particularly within a dielectric (e.g., a dielectric fluid) surrounding components of the power converter. The expandable heat transfer structure includes a conductive material such that heat is transferred from the dielectric to the expandable heat transfer structure and then from the expandable heat transfer structure to one of the housing or a cold plate to which the expandable heat transfer structure is attached.

[0036] Dielectric fluids (e.g., liquids or pressurized gases) are filled into the converter housing and isolated from the environment to prevent loss of the dielectric fluid (gas or liquid). Within the sealed container, the pressure of the dielectric fluid will fluctuate with temperature changes. Due to the incompressible nature of the material, pressure changes in liquids can be significant. Bellows compensate for the expansion of the dielectric fluid to prevent excessive pressure buildup within the converter housing. High pressure increases the risk of mechanical damage to the converter or the risk of leakage.

[0037] The density of the dielectric fluid or other dielectric in the expandable heat transfer structure can be less than the density of the dielectric material to reduce the overall weight of the power converter assembly.

[0038] Referring now to the accompanying drawings, where the same numbers denote the same elements throughout the drawings. Figure 1This is a schematic cross-sectional view of a gas turbine engine according to exemplary embodiments of the present disclosure. More specifically, for Figure 1 In one embodiment, the gas turbine jet engine is an aircraft turbofan engine 10, which is configured to be mounted on an aircraft, for example, in a lower wing configuration or a tail-mounted configuration.

[0039] like Figure 1 As shown, the turbofan engine 10 defines an axial direction A (extending parallel to the centerline axis 12 that provides a reference), a radial direction R, and a circumferential direction (i.e., the direction extending around the axial direction A; not shown).

[0040] Typically, the turbofan engine 10 includes a fan section 14 and a turbine 16 disposed downstream of the fan section 14. The turbine 16 is sometimes also referred to, or alternatively referred to, as the "core turbine engine".

[0041] The turbine 16 includes a housing 18, which is tubular and defines an inlet 20. The housing 18 surrounds, in a series configuration, a compressor section including a first boost or low-pressure (LP) compressor 22 and a second high-pressure (HP) compressor 24; a combustion section including a combustor 26; a turbine section including a first high-pressure (HP) turbine 28 and a second low-pressure (LP) turbine 30; and an exhaust nozzle section 32.

[0042] A high-pressure (HP) shaft 34 or spool drives the HP turbine 28 to the HP compressor 24. A low-pressure (LP) shaft 36 or spool drives the LP turbine 30 to the LP compressor 22. The compressor section, combustion section, turbine section, and injection exhaust nozzle section 32 are arranged in a sequential flow order and together define the core airflow path 37 through the turbine 16.

[0043] Fan section 14 includes a fan 38 (e.g., variable pitch, single stage). Fan 38 includes a plurality of fan blades 40 spaced apart and connected to disk 42. As shown, the fan blades 40 extend outward from disk 42 generally along a radial direction R.

[0044] The fan blade 40 is operatively coupled to one or more actuating members 44. For example, the actuating members 44 may be configured to change the pitch of the fan blade 40 together or independently relative to the pitch axis P. As described in further detail below, the fan blade 40 may have a positive pitch to generate positive thrust or a negative pitch to generate negative thrust.

[0045] Fan drive shaft 45 is operatively connected to and drives fan 38. Fan blades 40, disk 42, and actuation member 44 are rotatable together about centerline axis 12 via fan drive shaft 45. Fan section 14 is connected to turbine 16 during forward thrust operation. Specifically, fan drive shaft 45 is connected to LP shaft 36.

[0046] The disk 42 is covered by a rotatable forward nacelle 48, which has an aerodynamic profile to facilitate airflow through the multiple fan blades 40. Additionally, the fan section 14 includes an annular fan housing or outer nacelle 50, which at least partially, and in the depicted embodiment, circumferentially surrounds at least a portion of the fan 38 and turbine 16.

[0047] Furthermore, in the depicted embodiment, the nacelle 50 is supported relative to the turbine 16 by a plurality of outlet guide vanes 52. A downstream section 54 of the nacelle 50 extends over the outer portion of the turbine 16 to define a bypass airflow passage 56 therebetween.

[0048] During forward thrust operation of the turbofan engine 10, a volume of air 58 enters the turbofan engine 10 through the associated inlet 60 of the nacelle 50 and / or fan section 14. As the volume of air 58 passes through the fan blades 40, a first portion of the air 58, as indicated by arrow 62, is directed or delivered into the bypass airflow passage 56, while a second portion of the air 58, as indicated by arrow 64, is directed or delivered into the core airflow path 37.

[0049] As the second portion of air 64 is directed through the LP compressor 22 and the HP compressor 24 and into the combustor 26, the pressure of the second portion of air 64 increases. More specifically, the compressor section including the LP compressor 22 and the HP compressor 24 defines the total pressure ratio during operation of the turbofan engine 10 at rated speed. The total pressure ratio refers to the ratio of the outlet pressure of the compressor section (i.e., the pressure of the second portion of air 64 at the rear end of the compressor section) to the inlet pressure of the compressor section (i.e., the pressure of the second portion of air 64 at the inlet 20 of the compressor section).

[0050] A second portion of compressed air 64 from the compressor section is mixed with fuel and burned in the combustion section to provide combustion gas 66. The combustion gas 66 is directed from the combustor 26 through the HP turbine 28, where a portion of the thermal and / or kinetic energy from the combustion gas 66 is extracted via a sequential stage of HP turbine stator blades 68 coupled to the housing 18 and a plurality of HP turbine rotor blades 70 coupled to the HP shaft 34 or spool, thereby causing the HP shaft 34 or spool to rotate, thus supporting the operation of the HP compressor 24.

[0051] The combustion gas 66 is then guided through the LP turbine 30, where a second portion of thermal and kinetic energy is extracted from the combustion gas 66 via a sequential stage of LP turbine stator blades 72 connected to the housing 18 and a plurality of LP turbine rotor blades 74 connected to the LP shaft 36 or spool, thereby causing the LP shaft 36 or spool to rotate, thus supporting the operation of the LP compressor 22 and / or the rotation of the fan 38.

[0052] Combustion gas 66 is then directed through the exhaust nozzle section 32 of turbine 16 to provide propulsive thrust. Simultaneously, the pressure of the first portion of air 62 increases significantly as it is directed through the bypass airflow passage 56 before exiting the fan nozzle exhaust section 76 of turbofan engine 10, also providing propulsive thrust. HP turbine 28, LP turbine 30, and exhaust nozzle section 32 at least partially define a hot gas path 78 for directing combustion gas 66 through turbine 16.

[0053] During operation of the turbofan engine 10, fan 38 defines the fan pressure ratio. As used herein, the term "fan pressure ratio" refers to the ratio of the air pressure immediately downstream of the fan to the air pressure immediately upstream of the fan.

[0054] It should be understood that Figure 1 The exemplary engine 10 depicted is merely an example, and in other exemplary embodiments, engine 10 may have any other suitable configuration. For example, aspects of this disclosure can be used with any other suitable aero gas turbine engine, such as a turboshaft engine, turboprop engine, turbojet engine, etc. Furthermore, aspects of this disclosure can also be used with any aerospace-derived gas turbine engine, such as a marine gas turbine engine.

[0055] Still referencing Figure 2 A schematic diagram of a turbofan engine 10 is provided, which also includes a motor 80 coupled to a fan drive shaft 45. The motor 80 is configured to function as a generator to convert the rotation of the fan drive shaft 45 into electrical energy. The motor 80 is also configured to function as an electric motor to convert electrical energy into the rotation of the fan drive shaft 45.

[0056] The motors can be positioned alternatively and multiple motors can be envisioned. For example, the motors can be located on the LP axis and / or HP axis.

[0057] The motor 80 typically includes a stator and a rotor, the rotor being rotatable relative to the stator. Additionally, the motor 80 can be constructed in any suitable manner to convert mechanical power to electrical power and electrical power to mechanical power. For example, the motor can be constructed as an asynchronous or induction motor operable to generate or utilize alternating current (AC) electricity. Alternatively, the motor can be constructed as a synchronous motor operable to generate or utilize AC or direct current (DC) electricity. In this way, it will be appreciated that the stator, rotor, or both can typically include one or more of a plurality of coils or windings arranged in any suitable number of phases, one or more permanent magnets, one or more electromagnets, etc. Other exemplary motors may also be used.

[0058] Furthermore, it will be appreciated that, in the illustrated exemplary embodiment, the motor 80 is generally constructed coaxially with the centerline axis 12 of the turbofan engine 10, and in the illustrated embodiment, the motor 80 is also constructed coaxially with the fan drive shaft 45 and the LP shaft 36. With this configuration, the motor 80 can be referred to as an "embedded" motor. However, in other embodiments, the motor 80 may not be coaxial with the centerline axis 12 of the turbofan engine 10, but may be eccentric and connected via, for example, a suitable gear train.

[0059] The energy storage device 82 is configured to store electrical energy generated by the motor 80. When operating as a motor, the energy storage device 82 provides the stored electrical energy to the motor 80.

[0060] A power converter assembly 81 (e.g., a power conditioning and distribution device) can connect the motor 80 to the energy storage device 82. Typically, the power converter assembly 81 may include power electronics or similar structures for, for example, converting power between AC and DC power. The power converter assembly 81 is referenced below. Figure 3 Detailed description.

[0061] However, it will be appreciated that in other exemplary embodiments, the motor 80 may additionally or alternatively be electrically connected to any other suitable power source and / or power storage component and electrical load.

[0062] refer to Figure 2 The controller 90 can control the power converter assembly 81. Generally speaking, Figure 2 The controller 90 depicted is configured to receive data sensed from one or more sensors, or commands received from one or more systems, and, for example, make control decisions based on the received data or commands.

[0063] In one or more exemplary embodiments, Figure 2The controller 90 depicted may be a standalone controller, or alternatively, it may be integrated into one or more of a controller for the turbofan engine 10, a controller for an aircraft including the turbofan engine 10, etc.

[0064] Referring specifically to the operation of controller 90, in at least some embodiments, the controller may include one or more computing devices 144. Computing device 144 may include one or more processors 144A and one or more memory devices 144B. The one or more processors 144A may include any suitable processing device, such as a microprocessor, microcontroller, integrated circuit, logic device, and / or other suitable processing device. The one or more memory devices 144B may include one or more computer-readable media, including but not limited to non-transitory computer-readable media, RAM, ROM, hard disk drives, flash drives, and / or other memory devices.

[0065] One or more memory devices 144B may store information accessible by one or more processors 144A, including computer-readable instructions 144C executable by one or more processors 144A. Instructions 144C may be any set of instructions that, when executed by one or more processors 144A, cause one or more processors 144A to perform operations. In some embodiments, instructions 144C may be executed by one or more processors 144A to cause one or more processors 144A to perform operations such as any operations and functions configured for the controller 90 and / or computing device 144, operations for operating the turbofan engine 10 (as described herein), and / or any other operations or functions of one or more computing devices 144.

[0066] Instruction 144C can be software written in any suitable programming language or can be implemented in hardware. Additionally and / or optionally, instruction 144C can be executed in logical and / or virtual threads on processor 144A.

[0067] One or more memory devices 144B may further store data 144D that can be accessed by the processor 144A. For example, data 144D may include data indicating the temperature or pressure of the power converter assembly, and any other data and / or information described herein.

[0068] The computing device 144 may also include a network interface 144E for communicating, for example, with other components of a turbofan engine, an aircraft incorporating a gas turbine engine, etc. The controller 90 is operatively coupled to one or more aircraft systems (e.g., a flight management system or other aircraft control system) via, for example, the network interface, enabling the controller 90 to receive data or commands.

[0069] Network interface 144E may include any suitable components for use with one or more network interfaces, including, for example, transmitters, receivers, ports, controllers, antennas and / or other suitable components.

[0070] The technologies discussed herein refer to computer-based systems and the actions taken by and from computer-based systems, as well as the information sent to and from computer-based systems. Those skilled in the art will recognize that the inherent flexibility of computer-based systems allows for a wide variety of possible configurations, combinations, and divisions of tasks and functions among components and within assemblies. For example, the processes discussed herein can be implemented using a single computing device or multiple computing devices working in combination. Databases, memory, instructions, and applications can be implemented on a single system or distributed across multiple systems. Distributed components can operate sequentially or in parallel.

[0071] Although the embodiments described herein are for turbofan engine 10, the system described herein can be implemented in any environment where power is converted from one form to another using power converter assembly 81.

[0072] Non-limiting examples of power converters may include increasing or decreasing voltage signals, increasing or decreasing current, converting AC power to DC power, converting DC power to AC power, combinations thereof, etc. Non-limiting examples of environments in which power converter components are used may include mobile or stationary structures, and mobile vehicles including land, sea, and air vehicles.

[0073] refer to Figure 3 The power converter assembly 81 is described in further detail below. The power converter assembly includes a housing 202 (e.g., as shown in the dashed box). The heat-generating components of the power converter assembly are included within a cavity 204 defined by the housing 202.

[0074] The housing 202 may be constructed from a thermally conductive material such as aluminum. The housing 202 may include additional housing elements constructed for thermal management considerations, such as pin fins, parallel fins, etc.

[0075] The outer surface of housing 202 may be exposed to one or more external cooling media (e.g., external cooling media 205) for thermal management. External cooling media 205 provides heat transfer away from power converter assembly 81. External cooling media 205 may include ambient air or forced convection air supplied to the outer surface of housing 202.

[0076] For example, the power converter assembly includes a temperature sensor 210 for measuring ambient temperature and a control valve 212 for circulating an external cooling medium 205. The controller 90 can receive measurements from the temperature sensor 210 and control the control valve 212 based on the measurements from the temperature sensor 210 to circulate the external cooling medium 205 around the housing 202.

[0077] Alternatively or additionally, the power converter assembly 81 may include an actuator that uses a temperature-sensing element (e.g., a shape memory alloy) to thermally connect to or isolate the housing. At low ambient temperatures, the shape memory alloy may come into contact with the ambient temperature of the external cooling medium 205. At higher ambient temperatures, the shape memory alloy may deform and break contact with the ambient temperature of the external cooling medium 205 or otherwise sever the contact. Thus, the shape memory alloy prevents heat conduction from the ambient temperature of the external cooling medium 205 to the converter housing or enclosure 202. In some examples, the enclosure 202 may be covered with a heat-shielding or radiation-shielding metal.

[0078] The power converter assembly 81 may also include coolant channels that are in thermal contact with the housing 202 (e.g., integral with or attached to the housing 202), such as in a cooling system for a cold plate applied to the housing 202, as discussed below. If the external thermal environment is hotter than the interior of the power converter assembly 81, the coolant channels are configured to remove heat from the housing. An expandable heat transfer structure 280, connected to the housing 202 and described in further detail below, can dissipate heat to the housing 202 and then to the coolant channels in thermal contact with the housing 202.

[0079] The power converter assembly 81 may include several thermal conditioning devices, including a cold plate 216. The cold plate 216 may define a portion of the housing 202, such as a bottom wall. Alternatively, the cold plate 216 may be separable from the housing 202. The cold plate 216 may be formed of metal or other conductive materials.

[0080] The housing 202 may have an inlet port 226 and an outlet port 228 outside the cavity 204, the inlet port 226 and the outlet port 228 extending through the housing 202 to provide external connections for receiving and returning coolant 230 to the cold plate 216, respectively.

[0081] The power converter assembly 81 may additionally include a coolant reservoir 240, shown as a schematic container including coolant 230. The coolant reservoir 240 is coupled to an inlet port 226 and configured to deliver coolant 230 to the cold plate 216 via the inlet port 226. The coolant reservoir 240 is configured to receive coolant 230 from the cold plate 216 via an outlet port 228.

[0082] The coolant reservoir 240 may include a coolant pump 242 integrated with the coolant reservoir 240, which is capable of delivering 2-4 gallons per minute (GPM) of coolant 230 (depending on the coolant) to the power converter assembly 81.

[0083] The coolant reservoir 240 may be configured with integrated or external mechanisms to cool and / or maintain the temperature of the coolant 230 below a threshold. The threshold may be a function of the specific environment and / or specific characteristics of the power converter assembly 81.

[0084] For example, for coolant 230, the threshold temperature for the gas turbine engine environment is 90 degrees Celsius. However, alternative ambient temperatures or a specified operating temperature range may be included.

[0085] Coolant 230 may include liquids or gases. For example, coolant 230 may include various liquids present in aircraft engines, including lubricating oil, fuel, supercritical CO2, or other specialized heat transfer fluids.

[0086] Figure 3 A perspective view of the cold plate 216 of the power converter assembly 81 is shown, illustrating components 250 of the power converter assembly 81 on the cold plate 216. Components 250, for example, generate heat when performing power conversion functions.

[0087] For further reference Figure 4 The diagram schematically illustrates a power converter assembly 81. Component 250 may include a first component group 252 and a second component group 254. The first component group 252 may be high-power devices, such as high-power switching modules (e.g., silicon carbide power metal-oxide-semiconductor field-effect transistors (MOSFETs), silicon-carbide insulated-gate bipolar transistors (IGBTs), silicon MOSFETs, silicon IGBTs, gate drivers, controllers), which perform most of the work and generate most of the heat. The second component group 254 may be auxiliary devices or "factory balancing" devices (e.g., capacitors, inductors, resistors, busbars, control boards, gate driver boards, interface boards, etc.).

[0088] Electrical connections 256, 258 between component 250 inside housing 202 and device or component outside housing (e.g., for control signals, see...). Figure 4 It can extend through the housing 202 at a sealed opening (not shown).

[0089] Component 250 may be covered with an electrically insulating epoxy resin 260 potting material with good thermal conductivity (i.e., potting, see [link]). Figure 4 (e.g., dielectric epoxy resin or other conductive epoxy resin), thermally conductive plastics or other solid insulating materials, to provide insulation and reduce creep.

[0090] Creep, or creep distance (or leakage distance), is related to the surface shape of an insulator (e.g., conductive epoxy 260). Creep distance represents the shortest distance along the surface of an insulator between its conductive ends. For example, one end may be at an elevated voltage level, while the other end may be at a lower voltage or ground. IEEE defines leakage distance as the sum of the shortest distances measured along the insulating surfaces between conductive components. Leakage can cause damage to the insulator and eventually lead to its failure.

[0091] Conductive epoxy resin 260 can directly connect at least some components 250 to the cold plate 216. Conductive epoxy resin 260 improves the connection between components 250 (i.e., heat source) and cold plate 216 to improve heat transfer from components 250.

[0092] In some embodiments, the potting surrounding component 250 may include a fluid transport path for cooling.

[0093] Within housing 202, cold plate 216 and component 250 are surrounded by first medium 270. Heat can be transferred from component 250 to first medium 270. For example, first medium 270 can provide heat transfer for component 250 (e.g., cover, inductor, resistor, contactor, busbar, etc.).

[0094] Heat can be transferred from the first medium 270 to the cold plate 216 and / or the housing 202. As described in further detail below, heat can also be transferred via the expandable heat transfer structure 280 (see...). Figure 4 The medium is transferred from the first medium 270 to the cold plate 216 and / or to the housing 202.

[0095] The first dielectric 270 provides dielectric resistance and electrical insulation to components 250 to help prevent breakdown between components 250. The first dielectric 270 can be a liquid or pressurized gas that provides the desired dielectric resistance within the housing 202. For example, the first dielectric 270 can include a dielectric liquid, such as one from 3M. TM Fluorinert TM A range of liquids, transformer mineral oils, synthetic ester-based oils, and synthetic hydrocarbons, such as Alpha 6 Fluid. TM (DSI Ventures TM ) or Ampcol-100 TM (EngineeredFluids TM The medium can also be a pressurized gas using dry air, nitrogen, SF6, or environmentally friendly alternatives such as g3 gas mixtures.

[0096] Breakdown distance (sometimes called dry arc distance, flashover distance, or tight string distance) depends on the medium surrounding the insulator. Breakdown distance is the shortest path a voltage can travel from a higher voltage "flash" or arc to a lower voltage (or ground). IEEE defines dry arc distance as the shortest distance between terminal electrodes through the surrounding medium.

[0097] The power converter assembly 81 includes an expandable heat transfer structure 280 within a housing 202 (e.g., in a cavity 204). The expandable heat transfer structure 280 may be connected to the housing 202 or a cold plate 216 and disposed within a first medium 270. The expandable heat transfer structure 280 provides additional surface area in contact with the first medium 270 to improve heat transfer from the first medium 270 to the housing 202 or the cold plate 216. For example, the expandable heat transfer structure 280 may include fins, a cylinder, or another expandable surface area.

[0098] The expandable heat transfer structure 280 may be formed of a thermally conductive material to absorb heat from the first medium 270 and transfer the heat to the cold plate 216 or the housing 202 to remove heat from the first medium 270. For example, the conductive material may include metals, thermally conductive plastics, alumina, ceramics, combinations thereof, etc.

[0099] According to an exemplary aspect of this disclosure, the expandable heat transfer structure 280 can be formed or "printed" using an additive manufacturing process (e.g., a 3D printing process). Using such a process allows the expandable heat transfer structure 280 to be formed monolithically, as a single integral component, or as any suitable number of sub-components. Specifically, the manufacturing process allows the expandable heat transfer structure 280 to be formed monolithically and include various features that would be impossible using prior manufacturing methods.

[0100] As used herein, the term "additive manufacturing" or "additive manufacturing technology or process" generally refers to a manufacturing process in which successive layers of material are provided to one another to "stack" a three-dimensional part. In some embodiments, the successive layers are typically fused together to form an integral part that may have various integral sub-parts.

[0101] While the additive manufacturing techniques described herein provide the means to manufacture complex objects by typically building them point-by-point, layer-by-layer in a vertical direction, other manufacturing methods are possible and within the scope of this disclosure. For example, although the discussion herein relates to the addition of material to form continuous layers, those skilled in the art will understand that the methods and structures disclosed herein can be implemented using any additive manufacturing technique or manufacturing technology. For instance, embodiments of this disclosure may use layer-additive processes, layer-subtractive processes, or hybrid processes.

[0102] Suitable additive manufacturing techniques according to this disclosure include, for example, fused deposition modeling (FDM), selective laser sintering (SLS), 3D printing (e.g., by inkjet and laser), stereolithography (SLA), direct selective laser sintering (DSLS), electron beam sintering (EBS), electron beam melting (EBM), laser engineered net-shape (LENS), laser net-shape manufacturing (LNSM), direct metal deposition (DMD), digital light processing (DLP), direct metal laser sintering (DMLS), and other known processes.

[0103] The additive manufacturing process described herein can be used to form expandable heat-conducting structures 280 using any suitable material. More specifically, according to example embodiments, it can be partially, integrally, or incorporating, but not limited to, thermally conductive plastics, pure metals, cobalt alloys, iron-cobalt-vanadium alloys, nickel alloys, chromium alloys, titanium, titanium alloys, magnesium, magnesium alloys, aluminum, aluminum alloys, austenitic alloys (e.g., by name). (Those available from specialty metal companies) and metal-ceramic composites (e.g., aluminum SiC matrix), alumina, ceramics, and combinations thereof.

[0104] Those skilled in the art will recognize that a variety of materials and methods for bonding those materials can be used, and that such materials and methods are contemplated within the scope of this disclosure. As used herein, the reference to “fusion” can refer to any suitable process used to produce an adhesive layer of any of the materials described above. For example, if the material is a powdered metal, a bond can be formed by a melting process. Those skilled in the art will recognize that other methods of fusing materials into parts by additive manufacturing are possible, and the subject matter of this disclosure can be implemented using these methods.

[0105] Furthermore, the additive manufacturing methods disclosed herein allow for the formation of a single part from multiple materials. Therefore, the parts described herein can be formed from any suitable mixture of the aforementioned materials. For example, parts can include multilayers, segments, or sections formed using different materials, processes, and / or on different additive manufacturing machines. In this way, parts with different materials and material properties can be constructed to meet the needs of any particular application.

[0106] An exemplary additive manufacturing or printing process will now be described. The additive manufacturing process utilizes three-dimensional information (e.g., a three-dimensional computer model) of the expandable heat transfer structure 280 to manufacture a part. Therefore, a three-dimensional design model of the part can be defined prior to manufacturing. In this regard, a model or prototype of the expandable heat transfer structure 280 can be scanned to determine the three-dimensional information of the part. As another example, a suitable computer-aided design program can be used to construct a model of the part to define a three-dimensional design model of the expandable heat transfer structure 280.

[0107] The design model can include 3D numerical coordinates of the entire construction of a component, including its outer and inner surfaces. For example, the design model can define the body, component base, surfaces, any surface features (such as irregularities or datum features), and internal channels, openings, support structures, etc. In one example embodiment, the three-dimensional design model is converted into multiple slices or segments, for example, along a central (e.g., vertical) axis or any other suitable axis of the expandable heat transfer structure 280. Each slice can define a two-dimensional (2D) cross-section of the component with respect to a predetermined height. Multiple consecutive 2D cross-sectional slices together form a 3D component. The component is then “built” slice by slice or layer by layer until completion.

[0108] In this way, the parts described herein can be manufactured using additive manufacturing processes, or more specifically, by continuously forming each layer, for example, by fusing and sintering metal powder using laser energy or heat. For example, certain types of additive manufacturing processes may use energy beams (e.g., electron beams) or electromagnetic radiation (e.g., laser beams) to sinter or melt powder materials. Any suitable laser and laser parameters can be used, including considerations regarding power, laser beam size, and scanning speed. The building material can be formed from any suitable powder or material, which can be selected to enhance strength, durability, and lifespan, particularly at high temperatures.

[0109] While the thickness can be selected based on any number of parameters and, according to alternative embodiments, can be any suitable size, each continuous layer can be, for example, between approximately 0.25 mils and 200 mils. Therefore, using the additive forming method described above, the component described herein can have a cross-section as thin as one thickness (e.g., 10 mils) of the associated powder layer used during the additive forming process.

[0110] Furthermore, using additive manufacturing processes, the surface finish and characteristics of a part can be varied as needed depending on the application. For example, these can be adjusted (e.g., to make it smoother or rougher) by selecting appropriate laser parameters during the additive manufacturing process. A rougher finish can be achieved by increasing the laser scanning speed or the thickness of the powder layer, and a smoother finish can be achieved by decreasing the laser scanning speed or the thickness of the powder layer. The scanning pattern and / or laser power can also be changed to alter the surface finish in selected areas of the part.

[0111] It is worth noting that, in the exemplary embodiments, certain features of the expandable heat transfer structure 280 described herein may have been previously impossible due to manufacturing limitations. However, this disclosure advantageously utilizes current advances in additive manufacturing technology to develop exemplary embodiments of these components substantially according to this disclosure. Additive manufacturing offers a variety of manufacturing advantages, including ease of manufacture, reduced costs, and increased precision.

[0112] In this regard, additive manufacturing methods allow even multi-part components to be formed into a single continuous metal part, thus incorporating fewer sub-parts and / or joints compared to existing designs. The integral formation of these multi-part components through additive manufacturing can advantageously improve the overall assembly process. For example, integral formation reduces the number of individual parts that must be assembled, thereby reducing associated time and overall assembly costs. Furthermore, it can advantageously mitigate existing problems related to, for example, leakage, the quality of joints between separated parts, and overall performance.

[0113] Furthermore, the additive manufacturing methods described above enable the creation of more complex and tortuous shapes and contours for the components described herein. For example, such components may include thin cross-sectional layers and novel surface features. All these features can be relatively complex and tortuous to avoid detection and / or prevent third-party counterfeiting. Additionally, additive manufacturing processes can produce individual components made of different materials, allowing different parts of the component to exhibit different performance characteristics. The continuous, additive nature of the manufacturing process makes it possible to construct these features.

[0114] The expandable heat transfer structure 280 may include a first end 282, a second end 284, and a bellows structure 286 (e.g., an accordion structure), the bellows structure 286 being configured to expand or contract to increase or decrease the distance between the first end 282 and the second end 284. In other embodiments, the expandable heat transfer structure 280 may have another structure, such as an air bladder or flexible fins.

[0115] For reference only Figure 6-9 , Figure 6 An expandable heat transfer structure 680 is shown, which includes a distal end 682 that can expand in direction 684 via a bellows structure. Figure 7 An expandable heat transfer structure 780 is shown, which is cylindrical and includes a distal end 782 that can expand in direction 784 via a gusset structure.

[0116] Figure 8 An expandable heat transfer structure 880 that can expand via a gas spring structure is shown. The expandable heat transfer structure 880 includes a piston 882 and a cylinder 884. The piston 882 is configured to move in a direction 888 through an opening 886 in the cylinder 884 in response to pressure changes inside and / or outside the expandable heat transfer structure 880.

[0117] Figure 9 An expandable heat transfer structure 980 is shown, which includes curved aluminum sidewalls 982, 984 and a flexible distal end 986 that can expand in direction 988. The expandable heat transfer structure 980 can be used as fins to enhance convective heat transfer.

[0118] Continue to refer to Figure 4 Some expandable heat transfer structures 280 have their first ends 282 connected to the cold plate 216, and these expandable heat transfer structures 280 extend from the cold plate 216 into the first medium 270. Other expandable heat transfer structures 280 have their second ends 284 connected to the housing 202, and these expandable heat transfer structures 280 extend from the housing 202 into the first medium 270.

[0119] Heat can be transferred from the first medium 270 to the expandable heat transfer structure 280 via convection, to the cold plate 216 via convection, and to the housing 202 via convection. Heat can also be transferred from the expandable heat transfer structure 280 to the cold plate 216 via conduction, and to the housing 202 via conduction.

[0120] The expandable heat transfer structure 280 may be filled with a second medium 290 (e.g., gas) and sealed. Therefore, the expandable heat transfer structure 280 is configured to regulate the pressure of the first medium 270.

[0121] As the pressure of the environment surrounding the turbofan engine 10 decreases (e.g., at a higher altitude of the turbofan engine 10), the likelihood of breakdown or creep in the power converter assembly 81 may increase.

[0122] A second medium 290 can be selected, and the pressurized expandable heat transfer structure 280 can be sealed and pressurized such that as the pressure around the power converter assembly 81 decreases, the pressure drop around the component 236 in the housing 202 is reduced. Specifically, as the pressure of the first medium 270 decreases (e.g., due to temperature changes), the pressurized expandable heat transfer structure 280 can expand to maintain or reduce the pressure drop of the first medium 270 around the component 250, thereby reducing the possibility of breakdown or creep between components 250.

[0123] The expandable heat transfer structure 280 can also contract to release pressure buildup in the first medium 270. For example, the expandable heat transfer structure 280 allows the first medium 270 to expand (e.g., due to temperature changes).

[0124] Since the weight of the first medium 270 contributes to the weight of the power converter assembly 81, the weight of the power converter assembly 81 can be reduced by decreasing the volume of the first medium 270 within the housing 202. Specifically, the volume of the first medium 270 can be reduced by one or more expandable heat transfer structures 280. Therefore, since the second medium 290 can be selected to have a lower weight than the first medium 270, the weight of the power converter assembly 81 can be reduced. For example, the first medium 270 can be oil, and the second medium 290 can be an inert gas.

[0125] The components in housing 202 can occupy a large proportion (e.g., 60%) of the total volume of cavity 204 of housing 202. The spacing between the components may depend on voltage, breakdown, creep, etc. In the remaining volume of cavity 204 of housing 202, there will be a volume attributable to the first medium 270 (dielectric fluid) and the expandable heat transfer structure 280. For example, the expandable heat transfer structure 280 may occupy 25-60% of the remaining volume or 10-25% of the total volume.

[0126] The power converter assembly 81 can have a high power density. For example, the power converter assembly 81 can have a power density of at least 14 kW / kg. The power density is increased at least by adding an expandable heat transfer structure 280 to reduce the weight of the power converter assembly 81.

[0127] Typically, the power converter assembly 81 includes component 250 and one or more cold plates 216 for cooling component 250. (Reference) Figure 5 The power converter assembly 81, comprising two cold plates (first cold plate 216A and second cold plate 216B), is described in further detail. However, it should be understood that other numbers of cold plates may be considered.

[0128] Cold plates 216A and 216B can be made of metal or an electrically insulating material such as thermally conductive plastic. Cold plates 216A and 216B can have extended heat transfer surfaces, such as fins, to maximize heat transfer from the first medium 270 to the cold plates 216A and 216B.

[0129] As described above, component 250 may include a first component group 252 and a second component group 254. The first component group 252 may be high-power devices, such as high-power switching modules (e.g., silicon carbide power MOSFETs, silicon carbide IGBTs, silicon MOSFETs, silicon IGBTs, gate drivers, controllers, etc.), which perform most of the work and generate most of the heat. The second component group 254 may be auxiliary devices or "factory balancing" equipment (e.g., capacitors, inductors, resistors, busbars, etc.).

[0130] The first component group 252 can be disposed on the first cold plate 216A, and the second component group 254 can be disposed on the second cold plate 216B.

[0131] A large proportion of heat dissipation (e.g., 75%) may occur with the first component group 252, and a small proportion of heat dissipation (e.g., 25%) may occur with the second component group 254.

[0132] The first cooling plate 216A is positioned upstream of the second cooling plate 216B relative to the coolant reservoir 240, such that the coolant 230 is first used to transfer heat from the first component group via the first cooling plate 216A, and subsequently used to transfer heat from the second component group via the second cooling plate 216B. Thus, the first component group 252 is cooled by the dedicated cooling plate 216A, wherein the coolant 230 is first received from the coolant reservoir 240.

[0133] The power converter assembly includes potable components disposed in a dielectric that protects against high-voltage arcing and discharge, sparking, and other damaging events.

[0134] Power converters can be located in high-temperature environments (e.g., high-temperature environments, such as 100-300 degrees Celsius). Generally, the components of a power converter are protected from ambient temperature by a housing, and heat can be dissipated to a coolant in a cold plate or to the dielectric surrounding the power converter.

[0135] The power converter assembly includes an expandable heat transfer structure. Heat is transferred from the dielectric to the expandable heat transfer structure, and then from the expandable heat transfer structure to one of the housing or a cold plate to which the expandable heat transfer structure is attached, to remove heat from the dielectric.

[0136] Operating at high altitudes exposes you to lower pressures, which can lead to high-voltage arcing and discharge, sparking, breakdown, creep, insulation breakdown, and other damage events. For example, at 50,000 feet above the average seal height, pressures can be on the order of 0.15 atmospheres. Under such conditions, for the same geometry and spacing, and the same material medium, breakdown and discharge can occur at only 1 / 10th of the pressure under atmospheric conditions.

[0137] To prevent such events, the power converter 81 is sealed and a first medium 270 is used to provide sufficient dielectric protection. For the sealed power converter 81, the volume of the first medium 270 changes with temperature, and thus the pressure within the sealed power converter 81 also changes.

[0138] Expandable heat transfer structures are pressurized with gas or other media. Therefore, when the pressure and volume of the medium are lower at lower temperatures, the volume of the expandable heat transfer structure expands, and when the pressure and volume of the medium are higher at higher temperatures, the volume of the expandable heat transfer structure contracts.

[0139] As an example, for a typical dielectric liquid, in a rigid and leak-proof container, a 1-degree temperature increase can result in a 0.15% volume change and a pressure increase of approximately 10 bar. The expandable heat transfer structure 280 (e.g., filled gas) is compressible to accommodate the pressure increase and prevent a large increase in dielectric fluid pressure.

[0140] The gas in the expandable heat transfer structure 280 can have a density of about 1 / 1000 that of a dielectric liquid. Therefore, the volume occupied by gas instead of liquid can lead to a significant weight reduction.

[0141] The density of the medium in an expandable heat transfer structure can be less than that of the dielectric to reduce the overall weight of the power converter assembly and increase its power density.

[0142] This written description uses examples to disclose this disclosure, including best practices, and also enables those skilled in the art to practice the disclosure, including making and using any device or system and performing any combination of methods. The patentable scope of the invention is defined by the claims, but may include other examples that would occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they comprise structural elements that are not different from the literal language of the claims, or if they comprise equivalent structural elements that are not substantially different from the literal language of the claims.

[0143] Further details are provided by the following topics:

[0144] A power converter assembly includes: a housing; a cold plate in the housing, wherein the cold plate is configured to receive a coolant; a set of power converter components on the cold plate; a first medium surrounding the cold plate and components in the housing; and an expandable heat transfer structure attached to one of the cold plate and the housing.

[0145] According to one or more of these clauses, the power converter assembly wherein an expandable heat transfer structure is attached to a cold plate.

[0146] According to one or more of these clauses, the power converter assembly wherein the first medium is a liquid or pressurized gas that provides dielectric resistance.

[0147] According to one or more of these clauses, the power converter assembly wherein the first medium is oil.

[0148] According to one or more of these clauses, the power converter assembly wherein the expandable heat transfer structure includes a conductive material configured to transfer heat to one of the cold plate and the housing.

[0149] According to one or more of these clauses, the power converter assembly wherein the expandable heat transfer structure has an expandable surface area.

[0150] According to one or more of these clauses, the power converter assembly wherein the expandable heat transfer structure is additively manufactured.

[0151] According to one or more of these clauses, the power converter assembly wherein the expandable heat transfer structure is filled with gas.

[0152] According to one or more of these clauses, the power converter assembly wherein the first medium is a liquid that provides dielectric resistance.

[0153] According to one or more of these clauses, a power converter assembly wherein at least one of the components is covered by a solid insulating material.

[0154] According to one or more of these clauses, the power converter assembly is a first cold plate, and the power converter assembly further includes a second cold plate.

[0155] According to one or more of these clauses, the power converter assembly wherein the first cold plate and the second cold plate are configured such that the first cold plate is located upstream of the second cold plate.

[0156] According to one or more of these clauses, the power converter assembly includes a first component group and a second component group, wherein the first component group is located on a first cold plate and the second component group is located on a second cold plate.

[0157] According to one or more of these clauses, the power converter assembly wherein the first component group is configured to generate more heat than the second component group.

[0158] According to one or more of these clauses, a power converter assembly, wherein the first component group includes a high-power switching module.

[0159] According to one or more of these clauses, the power converter assembly wherein the high-power switching module includes at least one of a MOSFET, an IGBT, and a gate driver.

[0160] According to one or more of these clauses, a power converter assembly, wherein the second component group includes auxiliary components.

[0161] According to one or more of these clauses, the power converter assembly, wherein the auxiliary component includes at least one of a capacitor, an inductor, a resistor, a busbar, a control board, a gate driver board, and an interface board.

[0162] According to one or more of these clauses, a power converter assembly wherein the first medium is sealed in a housing.

[0163] According to one or more of these clauses, the power converter assembly wherein the expandable heat transfer structure includes at least one of a bellows structure, a gusset plate structure, and a gas spring structure.

Claims

1. A power converter assembly, characterized in that, include: case; A cold plate, located within the housing, wherein the cold plate is configured to receive coolant; A set of power converter components, the set of power converter components being placed on the cold plate; A first medium surrounds the cold plate and the component within the housing; and An expandable heat transfer structure is attached to one of the cold plate and the housing.

2. The power converter assembly according to claim 1, characterized in that, The expandable heat transfer structure is attached to the cold plate.

3. The power converter assembly according to claim 1, characterized in that, The first medium is a liquid or pressurized gas that provides dielectric resistance.

4. The power converter assembly according to claim 1, characterized in that, The first medium is oil.

5. The power converter assembly according to claim 1, characterized in that, The expandable heat transfer structure includes a conductive material configured to transfer heat to the cold plate and the housing.

6. The power converter assembly according to claim 1, characterized in that, The expandable heat transfer structure described herein has an expandable surface area.

7. The power converter assembly according to claim 1, characterized in that, The expandable heat transfer structure described herein is manufactured using additive manufacturing.

8. The power converter assembly according to claim 1, characterized in that, The expandable heat transfer structure is filled with gas.

9. The power converter assembly according to claim 8, characterized in that, The first medium is a liquid that provides dielectric resistance.

10. The power converter assembly according to claim 1, characterized in that, At least some of the components are covered by a solid insulating material.

11. The power converter assembly according to claim 1, characterized in that, The cold plate is a first cold plate, and the power converter assembly further includes a second cold plate.

12. The power converter assembly according to claim 11, characterized in that, The first cold plate and the second cold plate are configured such that the first cold plate is located upstream of the second cold plate.

13. The power converter assembly according to claim 12, characterized in that, The components include a first component group and a second component group, wherein the first component group is located on the first cold plate and the second component group is located on the second cold plate.

14. The power converter assembly according to claim 13, characterized in that, The first component group is configured to generate more heat than the second component group.

15. The power converter assembly according to claim 13, characterized in that, The first component group includes a high-power switching module.

16. The power converter assembly according to claim 15, characterized in that, The high-power switching module includes at least one of a MOSFET, an IGBT, and a gate driver.

17. The power converter assembly according to claim 13, characterized in that, The second component group includes auxiliary components.

18. The power converter assembly according to claim 17, characterized in that, The auxiliary components include at least one of a capacitor, an inductor, a resistor, a busbar, a control board, a gate driver board, and an interface board.

19. The power converter assembly according to claim 1, characterized in that, The first medium is sealed in the housing.

20. The power converter assembly according to claim 1, characterized in that, The expandable heat transfer structure includes at least one of a bellows structure, a gusset plate structure, and a gas spring structure.

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