HK1242042B - Transformer-based power converters with 3d printed microchannel heat sink - Google Patents

Description

Transformer-based power converter with 3D-printed microchannel heat sink

Technical Field

The present disclosure generally relates to systems, methods, and articles for cooling components.

Background Art

Modern aircraft include generators that generate electricity during flight and supply it to the onboard power systems. These generators utilize the rotation of the aircraft's engines to generate AC power using various power generation techniques. The power generated in this manner can be, for example, 230V 400Hz AC power. When the aircraft is on the ground, the aircraft's engines can be shut down, stopping the onboard generators from generating power. Instead, the onboard power systems can receive AC power from a ground vehicle. The power provided from the ground vehicle can be, for example, 115V 400Hz AC power.

Although the power supply provides AC power, aircraft components often require DC power rather than AC power. AC-DC power conversion can be accomplished with the aid of multiple diode pairs, each of which is connected to a different phase of the AC input to provide a rectified DC output. However, such AC-DC conversion can result in a large amount of current harmonics that pollute the power generation and distribution systems. To reduce current harmonics, a multiphase autotransformer can be used to increase the number of AC phases supplied to the rectifier unit. For example, in an 18-pulse passive AC-DC converter, an autotransformer is used to transform a three-phase AC input spaced 120° apart into a system with nine phases spaced 40° apart. This has the effect of reducing the harmonics associated with AC-DC conversion.

A transformer typically contains windings of conductive material, such as wire. These windings are spaced close enough together so that, when connected to a load, current flowing through one winding will cause current to flow in the other winding. The winding through which current is driven is often called the primary winding, while the winding in which current is induced is often called the secondary winding. A transformer may also contain a core, such as a magnetic or iron core, around which the windings are wound.

A rectifier typically includes multiple diodes or thyristors configured to convert an AC signal to a DC signal. For example, a full-bridge rectifier can be used to convert an AC signal to a DC signal. Additional equipment can be used to provide power conditioning, such as interphase transformers, balancing inductors, interphase reactors, filters, etc.

In many applications, transformer size and/or weight are important factors in achieving practical and/or commercially successful devices. For example, power converters used in avionics must typically be lightweight and require a small footprint. However, such applications often require high performance, such as high-current, low-noise power conversion. Additionally or alternatively, many applications may require a low-cost power converter. Cost can be determined by a number of factors, including material type, material quantity, and/or manufacturing complexity, among other factors.

Many electromagnetic devices or components generate heat during use and require cooling to keep the temperature of the device or the surrounding environment sufficiently low. Certain devices (including transformers and inductors) contain current-carrying windings that generate a large amount of heat that needs to be dissipated. However, since these windings are usually tightly wound and may be coated with insulating materials, the heat generated internally must be transferred across several layers of insulation, transferred through the core material (which can exhibit poor thermal conductivity) or transferred along the winding conduction path and transferred to the wiring connected to the device or the connection of the high-voltage line to the bus. None of these heat flow paths is particularly efficient.

When electromagnetic devices operate at high power levels, heat dissipation becomes increasingly important. The high temperatures generated by these devices limit the power levels at which the devices can operate. Consequently, such temperature limitations can also adversely affect the volume and weight performance of equipment containing electromagnetic devices. This is particularly true in high-power density equipment operating at high ambient temperatures or in applications where effective cooling is required, such as in aerospace applications. Radiators are known for cooling electronic equipment, but are typically used only to remove heat from exposed surfaces of electromagnetic equipment.

Summary of the Invention

An electromagnetic component can be summarized as comprising: a core including a core winding portion having at least one winding surface; a winding wound around the core winding portion on the at least one winding surface; and an integral heat sink element including a heat receiving portion located between the winding surface of the core and at least a portion of the winding, the heat receiving portion of the heat sink element being formed of a thermally conductive material and having at least one fluid channel therein for receiving a fluid.

The radiator element may comprise a stack of sintered or melted material layers that are gathered to form the radiator element. The first portion of at least one fluid channel may extend in a first plane, and the second portion of at least one fluid channel may extend in a second plane, the second plane being different from the first plane. The heat receiving portion may comprise at least two fluid channels for receiving fluid, the respective first portions of the at least two fluid channels may extend in a first plane, and the respective second portions of the at least two fluid channels may extend in a second plane, the second plane being different from the first plane. The first plane may be an X-Y plane. The winding portion of the core may comprise four flat winding surfaces, and the heat receiving portion of the radiator element may be adjacent to one of the four flat winding surfaces. The radiator element may be formed from at least one of copper, a copper alloy, aluminum, or an aluminum alloy. The heat receiving portion of the radiator element may be adjacent to the winding surface and located below the winding. The heat receiving portion of the radiator element may comprise a first interface surface facing at least one of the at least one winding surface, and at least one winding surface may comprise a second interface surface complementary to the first interface surface of the heat receiving portion of the radiator element. The heat receiving portion may be formed of a thermally conductive material and have a plurality of fluid channels, each channel receiving a fluid therethrough. The electromagnetic component may include at least one of an inductor or a transformer. The fluid channel may include a first open end and a second open end, and the heat sink element may further include: an inlet port fluidically coupled to the first end of the fluid channel; and an outlet port fluidically coupled to the second end of the fluid channel.

The electromagnetic component may further include: a fluid cooling system including: at least one fluid pump to move fluid; and at least one heat exchanger fluidly coupled to the at least one fluid pump; wherein the inlet port and the outlet port are fluidly coupled to the fluid pump and the heat exchanger.

The fluid in the fluid cooling system may include at least one of water, a water/glycol solution, a dielectric fluid, an oil, or a synthetic hydrocarbon fluid. The heat receiving portion of the heat sink element may have a length and a width, and the at least one fluid channel may include a plurality of fluid channels extending parallel to each other and parallel to the length of the heat receiving portion.

A power converter device can be summarized as comprising: an enclosure formed at least in part from a carbon fiber reinforced polymer; and a power converter electronics assembly disposed within the enclosure. The power converter electronics assembly includes: at least one magnetic component including a core having at least one winding surface and a winding wound around the core on the at least one winding surface; and an integral heat sink element including a heat receiving portion positioned between the winding surface of the core and at least a portion of the winding, the heat sink element being formed from a thermally conductive material and having at least one fluid channel therein for receiving a fluid through a first open end and discharging the fluid through a second open end opposite the first open end.

The heat sink element may comprise a stack of sintered or melted material layers that come together to form the heat sink element.

A method for manufacturing an electromagnetic component can be summarized as comprising: providing a core, the core comprising a core winding portion having at least one winding surface; providing a winding, the winding being wound on the core winding portion on the at least one winding surface; providing a three-dimensional design file, the design file specifying a three-dimensional design of an integral heat sink element, the integral heat sink element comprising a heat receiving portion having at least one fluid channel therein for receiving a fluid; providing the three-dimensional design file to an additive manufacturing system; forming the heat sink element based on the three-dimensional design file using the additive manufacturing system; and positioning the heat receiving portion of the heat sink element between the winding surface of the core and at least a portion of the winding.

Forming the heat sink element may include directing a high energy beam onto a build material in successive layers so as to cause such layers to combine into a three-dimensional design for the heat sink element specified by the design file. Forming the heat sink element may include forming the heat sink element using an additive manufacturing process selected from a group of additive manufacturing processes, including direct metal laser sintering (DMLS), selective laser melting (SLM), selective laser sintering (SLS), electron beam melting (EBM), laser metal forming (LMF), laser engineered net shaping (LENS), or direct metal deposition (DMD). Forming the heat sink element may include converting the three-dimensional information in the design file into a plurality of slices, each slice defining a cross-sectional layer of the heat sink element; and successively forming each layer of the heat sink element by melting metal powder using laser energy.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference numerals identify similar elements or actions. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes and angles of various elements are not drawn to scale, and some of these elements are arbitrarily enlarged and positioned to improve drawing legibility. Furthermore, the particular shapes of the drawn elements are not intended to convey any information about the actual shape of the particular element and have been selected solely for ease of identification in the drawings.

FIG1 is a schematic representation of a power converter according to one illustrated embodiment.

FIG2 is a schematic representation of an aircraft power system according to one illustrated embodiment.

3 is an isometric view of an electromagnetic component including a fluid-cooled heat sink element according to one illustrated embodiment.

4 is an exploded isometric view of the electromagnetic component of FIG. 3 according to one illustrated embodiment.

5 is a top view of the electromagnetic component of FIG. 3 , according to one illustrated embodiment.

6 is a front view of the electromagnetic component of FIG. 3 according to one illustrated embodiment.

7 is a right side view of the electromagnetic component of FIG. 3 according to one illustrated embodiment.

8 is an isometric cross-sectional view of the electromagnetic component of FIG. 3 taken along line 8 - 8 of FIG. 5 , according to one illustrated embodiment.

9 is an isometric cross-sectional view of the electromagnetic component of FIG. 3 taken along line 9 - 9 of FIG. 5 , according to one illustrated embodiment.

10A is a side view of a fluid cooled heat sink component according to one illustrated embodiment.

10B is a top view of a fluid-cooled heat sink component according to one illustrated embodiment.

10C is an isometric view of a fluid-cooled heat sink component according to one illustrated embodiment.

11 is an isometric cross-sectional view of a portion of an electromagnetic component including a fluid-cooled heat sink element according to one illustrated embodiment.

12 is an isometric view of an autotransformer rectifier unit (ATRU) and a fluid cooling system associated with the ATRU, according to one illustrated embodiment.

13A is an isometric view of an ATRU and fluid cooling system showing internal components of the ATRU, according to one illustrated embodiment.

13B is a top view of the ATRU and fluid cooling system according to one illustrated embodiment, showing the internal components of the ATRU.

14 is an isometric view of a rectifier heat sink base plate of an ATRU including multiple fluid channels, according to one illustrated embodiment.

15 is an isometric view of components of a fluid cooling system of an ATRU, according to one illustrated embodiment.

DETAILED DESCRIPTION

In the following description, certain specific details are set forth in order to provide a thorough understanding of the various disclosed embodiments. However, one skilled in the relevant art will recognize that the embodiments can be practiced without one or more of these specific details, or with other methods, components, materials, etc. In other instances, well-known structures associated with power electronic devices have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

Throughout the following description and claims, unless the context requires otherwise, the word "comprising" is synonymous with "including" and is inclusive or open-ended (ie, does not exclude additional unrecited elements or methodological acts).

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It should also be noted that the term "or" is generally employed in its broadest sense, i.e., to mean "and/or," unless the context clearly dictates otherwise.

The titles and abstracts provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.

Embodiments of the present disclosure relate to systems and methods that allow for a reduction in weight and size of electronic device components, such as transformer rectifier units (TRUs) or autotransformer rectifier units (ATRUs).

In some embodiments, a lightweight fluid cooling system is utilized to provide high heat dissipation for a transformer assembly of a TRU or ATRU by providing a thermal interface at the interface between the windings (which are typically the hottest points in such an assembly) and the magnetic core of the transformer assembly. The lightweight cooling system may include fluid-cooled winding heat sink elements or "fingers," which may be thermally conductive rods with microchannels positioned between the core and windings of the transformer or between turns of the transformer windings. A fluid (e.g., liquid, gas) is passed through the microchannels of the heat sink fingers to provide direct cooling to the heat-generating windings of the transformer.

The heat sink element can be formed from any suitable relatively high thermal conductivity material, such as copper, aluminum, or alloys (e.g., aluminum alloys 1050A, 6061, and 6063, and copper alloys). For example, copper can have a thermal conductivity greater than 300 watts per meter Kelvin (W/(m·K)), while aluminum or aluminum alloys can have a thermal conductivity greater than 150 W/(m·K).

In some embodiments, the heat sink element can be produced by additive manufacturing techniques, which are processes that join materials to form an object based on three-dimensional (3D) model data, typically layer by layer, as opposed to subtractive manufacturing techniques. Non-limiting examples of additive manufacturing techniques include direct metal laser sintering (DMLS), selective laser melting (SLM), selective laser sintering (SLS), electron beam melting (EBM), laser metal forming (LMF), laser engineered net shaping (LENS), or direct metal deposition (DMD).

DMLS is an additive manufacturing process that uses a laser to sinter powdered materials (e.g., metals). The laser is automatically aimed at points in the space defined by a 3D model and combines the materials together to create a solid structure. SLM uses a similar concept, but in SLM, the material is fully melted rather than sintered, allowing for different properties in the resulting product.

The DMLS process involves the use of a 3D CAD model, from which a file (e.g., an .STL file) is created and sent to the software executed on the DMLS machine. Technicians can work with the 3D model to correctly orient the geometry of the part build and, if necessary, add support structures. Once this "build file" is complete, the model is sliced into layer thicknesses that the machine will build and download to the DMLS machine. DMLS machines can use relatively high-power lasers, such as a 200-watt Yb fiber laser. Inside the build chamber area, there may be a material dispensing platform and a build platform, as well as a recoater blade for moving powder over the build platform. The technology uses a focused laser beam to locally sinter metal powder, melting it into a fixed part. The part is built layer by layer, typically using extremely thin layers (e.g., 20 micron thick). This process allows highly complex geometries to be created directly from 3D CAD data, fully automatically, in a few hours, and without any tools. DMLS is a mesh process that produces parts with high accuracy and detail resolution, good surface quality, and superior mechanical properties.

One existing solution uses one or two solid metal bars to conduct heat over a long path to a cold plate attached to the outside of the transformer. Heat generated internally is also conducted to the cold plate through the outer surface of the winding, although the heat must first be conducted from a hot spot closer to the core of the transformer winding to the outer surface of the coil.

In the embodiments discussed herein, the heat conduction path from the heat generating elements (eg, windings) to the cooling fluid is significantly shortened. This reduces the temperature difference between the windings and the cooling fluid.

Embodiments of the present disclosure also provide higher heat transfer rates from the transformer windings to the cooling fluid due to the high compressive forces between the heat-generating surfaces of the windings and the heat sink fingers. Heat conduction across the interface is proportional to the applied pressure. This is advantageous over existing solutions, which use a compliant silicone rubber material to press the outer surface of the transformer winding against the cold plate. This material has low thermal conductivity, and the pressure applied across the interface is typically low. Consequently, embodiments of the present disclosure provide significantly higher heat transfer efficiency.

Conventional air cooling or cold plate cooling solutions require a thermally conductive power supply enclosure ("chassis") to dissipate the generated heat. As discussed in further detail below, the use of the lightweight fluid cooling system described above allows the use of a carbon fiber epoxy material to form the chassis housing the TRU or ATRU. Advantageously, the carbon fiber epoxy chassis has lower weight and higher strength than chassis formed from thermally conductive materials (e.g., aluminum).

FIG1 is a schematic representation of the building blocks of an example power converter 100 that can provide embodiments of the present disclosure. The power converter 100 is configured to convert a three-phase AC input to a DC output. For illustration, the power converter 100 includes a three-phase to n-phase autotransformer 102, an n-pulse rectifier 104, and a fluid cooling system 105 that can be used to cool one or more components of the autotransformer and/or the rectifier. Other forms and/or topologies of power converters can be employed.

The autotransformer 102 is configured to receive a three-phase input signal 106 and includes a three-phase primary winding 108 and an n-phase secondary winding 110. The autotransformer 102 is configured to provide an n-phase AC signal 112. The rectifier 104 includes a plurality of branches 114 coupled to respective outputs of the n-phase AC signal 112. As shown, each branch includes two diodes 116. Other rectifying devices, such as thyristors, may be used. The rectifier 104 generates a DC output 118.

Higher-pulse rectification generally provides lower ripple on the DC output and lower AC input current distortion, and therefore generally results in higher power quality for the power converter. Typically, a 6-pulse converter topology may be considered suitable for some avionics equipment rated less than 35VA. For a significant number of aerospace applications, a 12-pulse converter topology is generally acceptable. For example, a 24-pulse topology may be used for higher-power equipment or when high power quality is desired or specified.

Avionics applications may typically employ a TRU or ATRU (e.g., power converter 100 of FIG. 1 ) to convert three-phase AC power (e.g., 115V AC operating at a fixed frequency (e.g., 400Hz), 115V AC 360Hz to 800Hz variable frequency power, 230V AC 360Hz to 800Hz variable frequency power, etc.) to DC power (e.g., 28V DC power, 270V DC power, 540V DC power, etc.). The load presented to power converter 100 may typically be, for example, between 4 amps and 400 amps. Typical functions of power converters used in avionics may include accommodating short-term overloads to clear downstream faults, providing galvanic isolation between the aircraft's AC and DC power sources, performing power conditioning to ensure acceptable power quality on both the AC and DC sides of the power converter for proper functioning of the aircraft's electrical systems and electrical loads, performing self-monitoring and fault reporting, etc. TRUs are used when galvanic isolation is required and/or when the ratio of input voltage to output voltage is large. The TRU is used to generate a 28V DC aircraft bus from a 115V AC or 230V AC aircraft power supply. The ATRU does not provide galvanic isolation. The ATRU is used when this isolation is not required and is most effective when the ratio of input voltage to output voltage is low. The ATRU is typically used to convert 115V AC 3-phase power to 270V DC or 230V AC 3-phase power to 540V DC to provide these voltages as a power distribution bus on the aircraft or to power individual large loads (such as motors). Power converters (such as the power converter 100 of Figure 1) can be used in other applications and configured to provide other functions. The TRU and ATRU can adopt topologies that use additional equipment (such as interphase transformers, balancing inductors, interphase reactors, filters, etc.) to provide desired functions, such as acceptable power quality.

FIG2 is a functional block diagram of an exemplary aircraft power system 150. As shown, an aircraft engine or turbine 152 drives a generator 154. Generator 154 provides an AC power signal to a power converter 156 (e.g., power converter 100 shown in FIG1). Power converter 156 can be cooled by a fluid cooling system 157 according to one or more of the embodiments discussed below. The power generated on the aircraft can be, for example, 115 volt AC power at 400 Hz or variable frequency. Other voltage levels and frequencies can be used. Power converter 156 is connected to a DC bus 158 and provides a DC power signal to the DC bus. One or more loads 160 (e.g., flight equipment, including critical flight equipment) can be connected to the DC bus 158 and can draw power from the DC bus. Typically, flight equipment can operate using 28 volt DC power. Other output voltage levels can be used.

3 through 9 illustrate an electromagnetic device or component 170 in the form of an autotransformer. The electromagnetic component 170 may also take the form of other types of electromagnetic components, such as a transformer or an inductor. As shown in FIG4 , the electromagnetic component 170 includes a core element 172 comprising first and second "E-shaped" core subelements 172A and 172B. The first core subelement 172A has a body portion 174A, a first outer leg 176A extending from a first end of the body portion, a second center leg 178A extending from the middle of the body portion, and a third outer leg 180A extending from a second end of the body portion opposite the first end. The first core subelement 172A includes a top surface 182A and a bottom surface 184A ( FIG6 ) opposite the top surface, with "top" and "bottom" referring to the orientation shown in FIG3 . The second core subelement 172B has a body portion 174B, a first outer leg 176B extending from a first end of the body portion, a second center leg 178B extending from the middle of the body portion, and a third outer leg 180B extending from a second end of the body portion opposite the first end. The second core subelement includes a top surface 182B and a bottom surface 184B opposite the top surface.

Legs 176A, 178A, and 180A of first core sub-element 172A abut corresponding legs 176B, 178B, and 180B, respectively, of second core sub-element 172B such that the first and second core sub-elements collectively function as a single core element 172 having first outer legs 176, second center leg 178, and third outer leg 180. In some embodiments, one or more of legs 176A, 178A, and 180A of first core sub-element 172A may be separated from corresponding ones of legs 176B, 178B, and 180B of second core sub-element 172B by a gap, depending on the specific application of the electromagnetic component.

Core element 172 can be formed from a high-permeability material, such as high-permeability steel, iron, or ferrite. Core element 172 can be constructed from a solid sheet of material or can be formed by stacking thin, mutually insulated laminated layers. Furthermore, core sub-elements 172A and 172B can be formed in other shapes, such as a "U" shape, an "E-I" shape, or the like.

A first winding 186A, comprising multiple turns of insulated wire, is wound on a first insulating layer 188A around a first leg 176 of the core element 172 ( FIG. 4 ). A second winding 186B, comprising multiple turns of insulated wire, is wound on a second insulating layer 188B around a second leg 178 of the core element 172. A third winding 186C, comprising multiple turns of insulated wire, is wound on a third insulating layer 188C around a third leg 180 of the core element 172. Windings 186A, 186B, and 186C (collectively, “windings 186”) may be electrically connected to a power source and/or a load (not shown) in a manner based on the particular application of the electromagnetic component.

The electromagnetic component 170 is shown mounted on a base plate 190 using a plurality of fasteners 192 (e.g., screws, etc.), which may generally perform support and heat dissipation functions. The electromagnetic component 170 may be connected to the base plate 190 in any of a variety of ways. For example, in the illustrated embodiment, clamps 194A and 194B may be provided to secure the first and second core sub-elements 172A and 172B, respectively, to the support base plate 190 using corresponding brackets 196A and 196B and one or more fasteners 192. Spacers 198A and 198B are positioned on the body portions 174A and 174B of the respective core sub-elements 172A and 172B, respectively, to receive the clamps 194A and 194B, respectively. The spacers 198 may be formed, for example, of a compliant silicone rubber material and may be used to minimize stress or pressure imparted by the clamps 194A and 194B, respectively, on the core sub-elements 172A and 172B, particularly due to movement or vibration during use. The spacer 198 can have an adhesive surface to allow it to adhere to the core sub-element or clamp. In some embodiments, the spacer 198 can be thermally conductive. In addition, the first core sub-element 172A and the second core sub-element 172B can be fastened together using a strap or loop 200, the ends of which are connected by a clip 202.

The electromagnetic component 170 includes heat sink elements 204A, 204B, and 204C (collectively, "heat sink elements 204") associated with the respective legs 176, 178, and 180 of the core element 172 of the electromagnetic component. The structure of the heat sink element 204 is best shown in Figures 10A to 10C. The heat sink elements 204A, 204B, and 204C can be associated with the legs 176, 178, and 180 and the respective windings 186A, 186B, and 186C, respectively. The heat sink element 204 can be integrally formed from a thermally conductive material, such as aluminum or copper, or other metals or metal alloys.

As shown in the partial perspective views of the heat sink elements 204 in Figures 10A to 10C, each heat sink element includes a first end portion 206 and a second end portion 208 spaced apart from the first end portion by a substantially flat thermal interface or heat receiving portion 210. The heat receiving portion 210 includes a top surface 212 and a bottom surface 214 spaced apart from the top surface. In the illustrated embodiment, the heat receiving portion 210 has a length L of approximately 4.25 inches (10.8 cm), a width W of approximately 1.125 inches (2.86 cm), and a height H of approximately 0.25 inches (0.64 cm) between the top surface 212 and the bottom surface 214. The first and second end portions 206 and 208 include upward-facing fluid ports 216 (Figure 3) that can be coupled to a fluid fitting 218. Four microchannels 220 extend across the length L of the heat receiving portion 210 between the lower portion 222 of each fluid port 216 in a parallel flow configuration. In some embodiments (such as the embodiment shown), the radiator element 204 is manufactured using a 3D additive manufacturing process, which allows the microchannel 220 to be placed in more than one X-Y plane. In the embodiment shown, the microchannel 220 has a circular cross-section and each has a diameter of about 0.13 inches (0.33 centimeters). Therefore, the top and bottom of each of the microchannels in the heat receiving part 210 are respectively about 0.06 inches from the top surface 212 and bottom surface 214 of the heat receiving part 210. In other embodiments, these microchannels can have cross-sections of other shapes, such as rectangles, squares, ellipses, etc. The radiator element 204 can also include one or more bores 224 facing downwards, which receive fasteners (such as screws) to fix the radiator element to a support (such as base plate 190) (Figure 4). In operation, fluid can flow into one of the fluid ports 216 of the radiator element 204, flow through each of the microchannels 220 and flow out from another of these fluid ports. As discussed below, one or more tubes of a fluid cooling system may be coupled to the fluid ports 216 of the heat sink element 204 to fluidly couple the microchannels 220 of multiple heat sink elements together in one or more series or parallel configurations (see FIG. 15 ).

3, 8, and 9, the heat receiving portion 210 of the heat sink element 204 is sized and shaped to extend between the bottom surface 184 of the first leg 176 of the core element 172 and the innermost turns or turns of the first winding 186A to conduct heat generated in the first winding outward from the electromagnetic component 170. As shown in FIG9 and FIG10C, the edge 226 of the bottom surface 214 of the heat receiving portion 210 of the heat sink element 204 can be rounded to maintain a high-quality thermal interface between the heat sink element and the first winding 186A and to protect the innermost turns of the first winding from other sharp edges. The length L, width W, and/or shape of the heat receiving portion 210 of the heat sink element 204 can vary, but can be substantially similar to the length, width, and/or shape of the first leg 176 of the core element 172 around which the first winding 186A is wound. For example, in a case where the legs of the core element are cylindrical, the heat receiving portion can be formed in the shape of a partial (e.g., half, quarter) cylindrical shell having an inner surface radius similar to the outer radius of the cylindrical legs of the core element so that the inner surface of the heat receiving portion is adjacent to at least a portion of the outer surface of the legs of the core element.

11 illustrates another embodiment of a heat sink element 230 in which a heat receiving portion 238 of the heat sink element can be sized and shaped to extend between adjacent turns 240 and 242 of a winding 244, without being adjacent to the bottom surface 232 of the leg 234 of the core element 236. In these embodiments, both the top and bottom surfaces of the heat receiving portion 238 of the heat sink element 230 can be in physical contact with the winding 244.

3-9 , the second and third heat sink elements 204B and 204C are substantially the same as the first heat sink element 204A, and thus a description of the functionality of the second and third heat sink elements will not be repeated herein for the sake of brevity.

The specific shape and size of the radiator elements, as well as the shape, size, and number of the microchannels 220 in each radiator element, can be selected based on several factors, such as the size and power level of the electromagnetic component with which the radiator element will be used, and the amount of cooling required. In addition, the shape of the radiator elements can be easily scaled to electromagnetic components of different sizes. Advantageously, because in some embodiments the shape of the radiator elements roughly corresponds to the footprint of the electromagnetic component, these radiator elements do not increase the footprint of the component and only slightly increase the volume of the space occupied by the component. Therefore, the radiator elements provide effective cooling for a variety of components under a variety of conditions.

As described above, clamps 194A and 194B may be provided to secure the first core sub-element 172A and the second core sub-element 172B, respectively, to the support base plate 190 via corresponding brackets 196A and 196B and one or more fasteners 192. Advantageously, clamping the first and second core sub-elements 172A and 172B in this manner presses the core sub-elements, heat sink element 204, and windings 186 more tightly together, which improves thermal conduction between the windings and the heat sink element.

FIG12 shows a fluid cooling system 250 coupled to an enclosure or housing 252 of an ATRU 254 containing the electromagnetic components 170 of FIG3 through FIG9. FIG13A and FIG13B show the internal components of the ATRU 254 within the housing 252. In the illustrated embodiment, the housing 252 is substantially rectangular in shape and is formed by a front panel 256, a rear panel 258 (FIG. 13A), a top panel 260, a bottom panel 262 (FIG. 13A), a left side panel 264, and a right side panel 266. The housing 252 also includes handles 268 and 270 located on the front panel 256 and the rear panel 258, respectively, to allow a user to more easily carry and transport the ATRU 254.

As shown in Figures 13A and 13B, the ATRU 254 includes the electromagnetic component 170 of Figures 3 to 9, an electromagnetic component 272, which may be, for example, an interphase transformer, and a rectifier unit 273. The components of the electromagnetic component 170 are discussed above. The electromagnetic component 272 is similar in many respects to the electromagnetic component 170, and therefore a detailed discussion of the electromagnetic component 272 is not required.

Electromagnetic component 272 includes heat sink elements 274A and 274B (see FIG15 ) positioned beneath respective legs of its core element 278 and adjacent respective windings 276A and 276B of the electromagnetic component. Heat sink elements 274A and 274B are similar to heat sink element 204 of electromagnetic component 170 of FIGS. 3 to 9 and include similar fluid-carrying microchannels (not shown) that allow fluid to flow therethrough to dissipate heat generated in windings 276A and 276B. Fluid fittings 218 are coupled to heat sink elements 274A and 274B to allow tubing of fluid cooling system 250 to be fluidically coupled to the microchannels within the heat sink elements.

The rectifier unit 273 includes a plurality of diodes 280 secured to a heat sink base plate 282. As shown in FIG14 (which depicts an isometric, partial perspective view of the heat sink base plate 282), the base plate includes a plurality of microchannels 283 extending between a first fluid port 284 and a second fluid port 286. In some embodiments, the heat sink base plate 282 can be produced by an additive manufacturing process, similar to the heat sink elements 204 and 274 associated with the electromagnetic components 170 and 272, respectively. Referring back to FIG13A, the fluid ports 284 and 286 of the heat sink base plate 282 can be coupled to a fluid fitting 218, which can be coupled to a tube or pipe of the fluid cooling system 250.

The fluid cooling system 250 may include a fluid pump 288 to circulate fluid through the network of tubes and radiator elements. The fluid cooling system 250 may also include a heat exchanger 290 (eg, a radiator) fluidly coupled to the pump to cool the fluid flowing therethrough.

FIG15 illustrates an exemplary configuration of connections for the fluid cooling system 250. In this illustration, fluid can enter the chassis 252 at the rear panel 258 through an inlet fluid fitting 218A. Inlet fluid fitting 218A is coupled to a tube 292A, which in turn is coupled to a fluid fitting 218B at the proximal end (as shown) of the heat sink element 204A associated with the electromagnetic component 170. Tube 292B couples the distal ends of the heat sink elements 204A and 204B together through fittings 218C and 218D, and tube 292C couples the proximal ends of the heat sink elements 204B and 204C together through fittings 218E and 218F, so that fluid can flow sequentially through the heat sink elements 204A, 204B, and 204C. Tube 292D at the distal end of heat sink element 204C is coupled to fluid fitting 218G at the distal end of heat sink element 204C and to first fluid fitting 218H of rectifier heat sink base plate 282. Another tube 292E is coupled between second fluid fitting 218I of rectifier heat sink base plate 282 and fluid fitting 218J of heat sink element 274A of electromagnetic component 272. Tube 292F, coupled to fluid fittings 218K and 218L at the proximal ends of heat sink elements 274A and 274B, respectively, allows fluid to flow sequentially through the heat sink elements. Tube 292G at the distal end of heat sink element 274B is coupled between fluid fitting 218M and outlet fluid fitting 218N coupled to rear panel 258 of chassis 252. Tubes, or channels as described herein, can have a cross-sectional shape that is circular, rectangular, or any other shape.

Using this exemplary configuration, fluid may be circulated through the various radiator elements of the ATRU 254 .

The panels 256, 258, 260, 262, 264, and 266 of the housing 252 are formed from a carbon fiber epoxy material, which substantially reduces the weight of the ATRU 254 while improving its durability compared to housings made from thermally conductive materials (e.g., aluminum). As described above, the heat sink element dissipates sufficient heat to render the ATRU 254 unnecessary for a thermally conductive housing. The carbon fiber epoxy housing 252, combined with the fluid cooling system 250 of the present disclosure, advantageously provides a 30% to 50% weight reduction for the mechanical and structural portions of the ATRU 254 compared to conventional ATRUs. By directly cooling the hottest points of the magnetic device, the device can be redesigned for a smaller size, further improving the reduction in size and weight.

Furthermore, while embodiments of the present disclosure may be directed to relatively large magnetic devices in ATRUs or TRUs having output powers of 5 kW and higher (eg, 50 kW), these embodiments may also be applied to other magnetic devices of varying sizes.

Embodiments of the present disclosure minimize the size of the fluid-cooled heat sink element and place this heat sink element directly where it is most effective. As described above, the heat receiving portions or fingers of the heat sink element are built into the magnetic component and positioned between the windings and the core, or optionally, partially through the windings.

Additive manufacturing processes using 3D metal printing can be used to produce heat sink components, which provide benefits that cannot be achieved using other methods (e.g., conventional machining) or would require additional work. These benefits include the ability to have cooling channels in more than one X-Y plane and the inherent surface roughness of 3D printed channels in producing turbulent rather than laminar flow. Specifically, the surface roughness produced by the 3D printing process produces a higher heat transfer rate to the fluid compared to traditional machining processes. In addition, at certain linear fluid velocities and viscosities, the rough surface produces lower friction, thereby producing lower pressure loss in the fluid cooling system.

In addition, 3D printed heat sink elements can have dimensional channels that are more streamlined for the flow of fluid, which creates less resistance and reduces pressure loss. 3D printed fluid channels also allow fluid to pass through traditionally difficult-to-reach areas to provide direct cooling to hot spots in such areas. In addition, small areas (such as 3D radii) that are important for fluid pressure loss can be freely implemented without being restricted by special tools and/or tool access. In general, the cross-section of the fluid channels of a 3D printed heat sink element can be freely selected, so these channels can have the minimum thickness feasible.

Additionally, 3D-printed heat sink components have a much higher density than heat sink components produced by conventional methods (e.g., casting and/or brazing). Therefore, porosity in 3D-printed heat sink components is less of a concern. Consequently, the walls of 3D-printed heat sink components can be designed to be thinner than those manufactured using conventional methods, which can reduce the overall size of the 3D-printed heat sink component.

Alternatively, a larger heat sink element can be provided that has cooling channels in only one X-Y plane, where the heat sink element is made in two halves that are joined together during manufacturing using conventional machining. These heat sink elements can be connected in series with microchannel heat sinks needed to cool other components in the assembly. These other heat sinks can be produced using additive manufacturing techniques or conventional machining techniques.

The foregoing detailed description has described various embodiments of devices and/or processes through the use of block diagrams, schematics, and examples. As long as such block diagrams, schematics, and examples contain one or more functions and/or operations, those skilled in the art will understand that each function and/or operation within such block diagrams, flow charts, or examples can be implemented individually and/or collectively through many different hardware, software, firmware, or virtually any combination thereof.

Those skilled in the art will recognize that many of the methods or algorithms set forth herein may employ additional acts, may omit acts, and/or may perform acts in an order different from that specified.

In addition, those skilled in the art will appreciate that the mechanisms taught herein can be distributed as a variety of forms of program products, and that the exemplary embodiments apply equally regardless of the specific type of non-transitory signal-bearing media used to actually perform the distribution. Examples of non-transitory signal-bearing media include, but are not limited to, recordable media such as floppy disks, hard drives, CD ROMs, digital tapes, and computer memory.

The various embodiments described above can be combined to provide further embodiments. All U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications, and non-patent publications mentioned in this specification and/or listed in the application data sheet (including but not limited to U.S. patent application serial number 14/627,556) are incorporated herein by reference in their entirety. If necessary, several aspects of the embodiments can be modified to adopt the systems, circuits, and concepts of the various patents, applications, and publications to provide further embodiments.

These and other changes can be made to the embodiments in light of the above detailed description. Generally, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, but should be construed to encompass all possible embodiments and the full scope of equivalents to which such claims are entitled. Therefore, the claims are not limited by this disclosure.

Claims (19)

1. An electromagnetic component, comprising: The core includes a core winding portion having at least one winding surface; Windings, wound on the core winding portion on the surface of at least one winding; and An integral heat sink element, formed by direct 3D printing, comprises a stack of sintered or molten material layers that aggregate to form the integral heat sink element. The integral heat sink element includes a fluid port and a heat receiving portion having a flat surface located between the winding surface of the core and at least a portion of the winding. The heat receiving portion of the heat sink element is formed of a thermally conductive material and has at least one fluid channel for receiving fluid. Each of the at least one fluid channel includes a central element extending parallel to the flat surface within the heat receiving portion, and further includes an end element extending from the central element at a non-zero angle to connect the central element to the fluid port. 2. The electromagnetic component of claim 1, wherein the heat receiving portion includes at least two fluid channels for receiving fluid, a corresponding first portion of the at least two fluid channels extending in a first plane, and a corresponding second portion of the at least two fluid channels extending in a second plane, the second plane being different from the first plane. 3. The electromagnetic component according to claim 2, wherein the first plane is an X-Y plane. 4. The electromagnetic component according to claim 1, wherein the winding portion of the core comprises four flat winding surfaces, and the heat receiving portion of the heat sink element is adjacent to one of the four flat winding surfaces. 5. The electromagnetic component according to claim 1, wherein the heat sink element is formed of at least one of copper, copper alloy, aluminum, or aluminum alloy. 6. The electromagnetic component according to claim 1, wherein the heat receiving portion of the heat sink element is adjacent to the winding surface and located below the winding. 7. The electromagnetic component of claim 1, wherein the heat receiving portion of the heat sink element includes a first interface surface facing at least one of the at least one winding surface, and the at least one winding surface includes a second interface surface complementary to the first interface surface of the heat receiving portion of the heat sink element. 8. The electromagnetic component according to claim 1, wherein the heat receiving portion is formed of a thermally conductive material and has a plurality of fluid channels, each fluid channel receiving fluid passing through it. 9. The electromagnetic component according to claim 1, wherein the electromagnetic component comprises at least one of an inductor or a transformer. 10. The electromagnetic component of claim 1, wherein the fluid channel includes a first open end and a second open end, and the heat sink element further includes: A fluid connection to the inlet port at the first end of the fluid channel; and The fluid is connected to the outlet port at the second end of the fluid channel. 11. The electromagnetic component according to claim 10, further comprising: A fluid cooling system, comprising: At least one fluid pump that moves the fluid; and At least one heat exchanger fluidly connected to at least one fluid pump; The inlet port and the outlet port are fluidly connected to the fluid pump and the heat exchanger. 12. The electromagnetic component of claim 11, wherein the fluid in the fluid cooling system comprises at least one of water, a water/glycol solution, a dielectric fluid, oil, or a synthetic hydrocarbon fluid. 13. The electromagnetic component of claim 1, wherein the heat receiving portion of the heat sink element has a length and a width, and the at least one fluid channel comprises a plurality of fluid channels extending parallel to each other and parallel to the length of the heat receiving portion. 14. A power converter device, comprising: A shroud at least partially formed of carbon fiber reinforced polymer; and A power converter electronics assembly housed within the enclosure, the power converter electronics assembly comprising: At least one magnetic component includes a core having at least one winding surface and a winding wound on the core on the at least one winding surface; and An integral heat sink element is formed by direct 3D printing and includes a heat receiving portion located only between or partially through the winding surface of the core and at least a portion of the winding. The heat receiving portion of the heat sink element is formed of a thermally conductive material and has at least one fluid channel that receives fluid through a first open end and discharges the fluid through a second open end opposite to the first open end. 15. The power converter device of claim 14, wherein the heat sink element comprises a stack of sintered or molten material layers forming the heat sink element. 16. A method for manufacturing an electromagnetic component, the method comprising: A core is provided, the core comprising a core winding portion having at least one winding surface; A winding is provided, the winding being wound on the core winding portion on the at least one winding surface; Provide a 3D design file specifying a 3D design of an integral heat sink element, the integral heat sink element including a heat receiving portion having at least one fluid channel for receiving fluid; The three-dimensional design file is provided to the additive manufacturing system; The heat sink element is formed based on the three-dimensional design file using the additive manufacturing system; and The heat receiving portion of the heat sink element is placed between the winding surface of the core and at least a portion of the winding. 17. The method of claim 16, wherein forming the heat sink element comprises directing a high-energy beam onto the building material in a continuous layer so that such layers are combined into a three-dimensional design of the heat sink element specified in the design document. 18. The method of claim 16, wherein forming the heat sink element comprises forming the heat sink element using an additive manufacturing process selected from a set of additive manufacturing processes, the set of additive manufacturing processes including: direct metal laser sintering, selective laser melting, selective laser sintering, electron beam melting, laser metal forming, laser engineered net forming, or direct metal deposition. 19. The method of claim 16, wherein forming the heat sink element comprises: The 3D information in the design file is converted into multiple slices, each slice defining a cross-sectional layer of the heat sink element; and Each layer of the heat sink element is continuously formed by melting metal powder using laser energy.