U.S. patent application number 14/291872 was filed with the patent office on 2015-10-01 for electronic assembly for an inverter.
This patent application is currently assigned to DEERE & COMPANY. The applicant listed for this patent is DEERE & COMPANY. Invention is credited to Aron Fisk, JOHN N. OENICK, BRIJ N. SINGH.
Application Number | 20150282291 14/291872 |
Document ID | / |
Family ID | 54149779 |
Filed Date | 2015-10-01 |
United States Patent
Application |
20150282291 |
Kind Code |
A1 |
SINGH; BRIJ N. ; et
al. |
October 1, 2015 |
ELECTRONIC ASSEMBLY FOR AN INVERTER
Abstract
An electronic assembly for an inverter comprises a substrate
having a dielectric layer and metallic circuit traces. A plurality
of terminals are arranged for connection to a direct current
source. A first semiconductor and a second semiconductor are
coupled together between the terminals of the direct current
source. A primary metallic island (e.g., strip) is located in a
primary zone between the first semiconductor and the second
semiconductor. The primary metallic island has a greater height or
thickness than the metallic circuit traces. The primary metallic
island provides a heat sink to radiate heat.
Inventors: |
SINGH; BRIJ N.; (WEST FARGO,
ND) ; OENICK; JOHN N.; (BETTENDORF, IA) ;
Fisk; Aron; (Fargo, ND) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DEERE & COMPANY |
MOLINE |
IL |
US |
|
|
Assignee: |
DEERE & COMPANY
MOLINE
IL
|
Family ID: |
54149779 |
Appl. No.: |
14/291872 |
Filed: |
May 30, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61971590 |
Mar 28, 2014 |
|
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|
Current U.S.
Class: |
361/689 ;
361/709 |
Current CPC
Class: |
H05K 1/021 20130101;
H05K 1/141 20130101; H05K 7/20436 20130101; H05K 1/0306 20130101;
H05K 7/20927 20130101; H05K 7/205 20130101; H05K 7/2089 20130101;
H05K 2201/066 20130101; H05K 1/0209 20130101 |
International
Class: |
H05K 1/02 20060101
H05K001/02; H05K 7/20 20060101 H05K007/20 |
Claims
1. An electronic assembly for an inverter, the electronic assembly
comprising: a substrate having a dielectric layer and metallic
circuit traces; a plurality of terminals for connection to a direct
current source; a first semiconductor and a second semiconductor
coupled together between the terminals of the direct current
source; and a primary metallic island located in a primary zone
between the first semiconductor and the second semiconductor, the
primary metallic island having a greater height or thickness than
the metallic circuit traces, the primary metallic island providing
a heat sink to radiate heat.
2. The electronic assembly according to claim 1 wherein the heat is
conducted away from the primary metallic island through thermally
conductive dielectric vias connected between the primary metallic
island and a ground plane or heat sink on an opposite side of the
substrate.
3. The electronic assembly according to claim 1 further comprising:
a first enclosure portion overlying the substrate and the primary
metallic island; wherein the heat is conducted away from the
primary metallic island through a first enclosure portion in
contact with, above or in close proximity to the primary metallic
island.
4. The electronic assembly according to claim 3 wherein a thermal
interface material, a thermally conductive adhesive or thermally
conductive lubricant is used between the primary metallic island
and the first enclosure portion.
5. The electronic assembly according to claim 3 wherein the first
semiconductor and the second semiconductor comprise surface mount
transistors that are mounted on the substrate and electrically
connected to corresponding ones of the metallic circuit traces and
wherein the first enclosure portion has an inner surface with a
mating shape and size that corresponds to the contour or adjoining
surface of the primary metallic island and the surface mount
transistors.
6. The electronic assembly according to claim 3 wherein the first
enclosure portion comprises a group of channels or micro-channels
within an adjoining cover or enclosure in contact with, above or in
close proximity to the primary metallic island for transfer of the
heat from the primary metallic island.
7. The electronic assembly according to claim 1 further comprising:
a plurality of first surface mount connectors mounted on the
substrate that are electrically connected to the terminals; and a
secondary metallic island located in a secondary zone between
adjacent surface mount connectors.
8. The electronic assembly according to claim 7 wherein the first
enclosure portion comprises a group of channels or micro-channels
within the first enclosure portion, and where an inner surface of
the first enclosure portion is in contact with, above or in close
proximity to the secondary metallic island for transfer of the heat
from the secondary metallic island.
9. The electronic assembly according to claim 1 further comprising:
a plurality of second surface mount connectors mounted on the
substrate that are electrically connected to a first phase output
terminal of the first semiconductor and the second semiconductor;
and a tertiary metallic island located in a tertiary zone between
adjacent surface mount connectors.
10. The electronic assembly according to claim 9 wherein the first
enclosure portion comprises a group of micro-channels within the
first enclosure portion, and where an inner surface of the first
enclosure portion is in contact with, above or in close proximity
to the tertiary metallic island for transfer of the heat from the
tertiary metallic island.
11. An electronic assembly for an inverter, the electronic assembly
comprising: a substrate having a dielectric layer and metallic
circuit traces; a first enclosure portion for mounting above the
substrate, the first enclosure portion having a plurality of
coolant channels located therein; a second enclosure portion for
mounting below the substrate; a plurality of terminals for
connection to a direct current source; a first semiconductor and a
second semiconductor coupled together between the terminals of the
direct current source; and a primary metallic island located in a
primary zone between the first semiconductor and the second
semiconductor, the primary metallic island having a greater height
or thickness than the metallic circuit traces, the primary metallic
island providing a heat sink to radiate heat for transfer via the
coolant channels within an adjoining first enclosure portion in
contact with, above or in close proximity to the primary metallic
island.
12. The electronic assembly according to claim 11 wherein the
coolant channels of the first enclosure portion further comprises:
a series of inlet coolant channels for conveying/circulating the
coolant within the first enclosure portion, the inlet channels
adapted to receive coolant from an inlet port.
13. The electronic assembly according to claim 11 wherein the
coolant channels of the first enclosure portion further comprises:
a series of outlet coolant channels for conveying/circulating the
coolant within the first enclosure portion, the outlet channels
adapted to receive coolant from an outlet port.
14. The electronic assembly according to claim 11 wherein the
coolant channels of first enclosure portion comprise: an inlet port
in the first enclosure portion for receiving a coolant; a series of
inlet coolant channels for conveying/circulating the coolant within
the first enclosure portion, the channels in communication with a
distributor portion associated with the port; a series of outlet
coolant channels for conveying/circulating the coolant within the
first enclosure portion, the channels in communication with an
transition portion between the curved arrangement and the outlet
coolant channels; and an outlet port in the first enclosure portion
for exhausting the coolant.
15. The method according to claim 14 further comprising: a radiator
for receiving the exhausted coolant; a pump associated with the
radiator to circulate the coolant within the radiator and first
enclosure portion.
16. The electronic assembly according to claim 11 further
comprising: a plurality of first surface mount connectors mounted
on the substrate that are electrically connected to the terminals
or to ones of the conductive traces; and a secondary metallic
island located in a secondary zone between adjacent surface mount
connectors.
17. The electronic assembly according to claim 16 further
comprising: a series of inlet coolant channels or a series of
outlet coolant channels in the first enclosure portion and
underlying the secondary metallic island.
18. The electronic assembly according to claim 11 further
comprising: a plurality of second surface mount connectors mounted
on the substrate that are electrically connected to a first phase
output terminal of the first semiconductor and the second
semiconductor; and a tertiary metallic island located in a tertiary
zone between adjacent surface mount connectors.
19. The electronic assembly according to claim 18 further
comprising: a series of inlet coolant channels or a series of
outlet coolant channels in the first enclosure portion and
underlying the tertiary metallic island.
20. The electronic assembly according to claim 11 wherein an inner
surface of the first enclosure portion conforms in size and shape
to mate with the substrate as populated with one or more
surface-mount components.
21. The electronic assembly according to claim 20 wherein the
surface mount components comprise one or more of the following
components: transistors, capacitors and connectors.
22. The electronic assembly according to claim 11 wherein the first
semiconductor and the second semiconductor comprise surface mount
transistors that are mounted on the substrate and electrically
connected to corresponding ones of the metallic circuit traces.
23. The electronic assembly according to claim 11 wherein the
second enclosure portion has one or more cooling fins for heat
dissipation.
24. The electronic assembly according to claim 11 wherein the first
enclosure portion and the second enclosure portion mate to form a
housing for the substrate.
Description
RELATED APPLICATION
[0001] This document (including the drawings) claims priority and
the benefit of the filing date based on U.S. provisional
application No. 61/971,590, filed Mar. 28, 2014 under 35 U.S.C.
.sctn.119 (e), where the provisional application is hereby
incorporated by reference herein.
FIELD OF THE INVENTION
[0002] This disclosure relates to an electronic assembly for an
inverter.
BACKGROUND
[0003] In certain prior art, an electronic assembly may have
inadequate heat dissipation that reduces the longevity or maximum
power output of power semiconductor switches. Accordingly, there is
need for an electronic assembly for an inverter with improved heat
dissipation.
SUMMARY
[0004] In one embodiment, an electronic assembly for an inverter
comprises a substrate having a dielectric layer and metallic
circuit traces. A plurality of terminals is arranged for connection
to a direct current source. A first semiconductor and a second
semiconductor are coupled together between the terminals of the
direct current source. A primary metallic island (e.g., strip) is
located in a primary zone between the first semiconductor and the
second semiconductor. The primary metallic island has a greater
height or thickness than the metallic circuit traces. The primary
metallic island provides a heat sink to radiate heat.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a perspective view of one embodiment of the
electronic assembly for an inverter.
[0006] FIG. 2 is a perspective, exploded view of the electronic
assembly of FIG. 1 that further illustrates an upper housing
assembly and a lower housing assembly.
[0007] FIG. 3 is a perspective view of the electronic assembly of
FIG. 2 that is assembled.
[0008] FIG. 4 is a first cross section of FIG. 3 along reference
line 4-4 of FIG. 3, where reference line 4-4 is also shown in FIG.
1 and FIG. 2.
[0009] FIG. 5 is a second cross section of FIG. 3 along reference
line 5-5 of FIG. 3, where reference line 5-5 is also shown in FIG.
1 and FIG. 2.
[0010] FIG. 6 is a third cross section of FIG. 3 along reference
line 6-6 of FIG. 3, where reference line 6-6 is also shown in FIG.
1 and FIG. 2.
[0011] FIG. 7 is a cross section of one embodiment of an electronic
assembly that illustrates an enlarged portion of rectangular region
7 of FIG. 4.
[0012] FIG. 8 is a cross section of another embodiment that is
analogous to the small enlarged portion of rectangular region 7 of
FIG. 4, where a thermal interface material is present.
[0013] FIG. 9 is a cross section of yet another embodiment that is
analogous to the small enlarged portion of rectangular region 7 of
FIG. 5, where a conductive via and a ground plane is present.
[0014] FIG. 10 is an illustrative example of a fluid cooling system
that incorporates the electronic assembly of FIG. 1.
[0015] Like reference numbers in different drawings indicate like
elements.
DETAILED DESCRIPTION
[0016] In one embodiment, FIG. 1 shows a circuit board assembly 11
of an electronic assembly 200 for an inverter. The circuit board
assembly 11, of the electronic assembly 200, comprises a substrate
34 having a dielectric layer 54 and one or more metallic circuit
traces on one or both sides of the substrate 34. Direct current
terminals are arranged for connection to a direct current source. A
first semiconductor 20 and a second semiconductor 22 are coupled
together between the terminals of the direct current source. A
primary metallic island 24 (e.g., strip) is located in a primary
zone between the first semiconductor 20 and the second
semiconductor 22. The primary metallic island 24 has a greater
height or thickness than the metallic circuit traces. The primary
metallic island 24 provides a heat sink to radiate heat.
[0017] In one embodiment, the direct current terminals (42, 44)
comprise surface mount connectors, such as a female surface mount
connector that is generally cylindrical and that comprises a metal
or an alloy material. Each connector (36, 38, 40, 42, 44) may
comprise a surface mount connector. Each connector (36, 38, 40, 42,
44) may have a mounting pad 48 at one end for mounting to a
corresponding conductive pad 50 on the substrate 34, where the
conductive pad 50 is associated with or electrically connected to
one or more conductive traces (e.g., 406).
[0018] As illustrated, the electronic assembly 200 shows three
phases or three switching sections, where each phase has a first
semiconductor 20 coupled to a second semiconductor 22. At the
inputs of each switching section, the first direct current terminal
42 and the second direct current terminal 44 provide direct current
to each phase or switching section. The output of each switching
section is defined by set of alternating current connectors.
[0019] For each phase, the first semiconductor 20 may comprise a
semiconductor switch (e.g., low-side semiconductor switch) that
with at least one of its switching terminals coupled to one side
(e.g., low side or negative terminal) of the direct current bus or
direct current source that feeds the direct current terminals. For
example, the switching terminals may refer to the emitter and
collector if the first semiconductor 20 comprises a transistor, or
the switching terminals may refer to the source and drain if the
first semiconductor 20 comprises a field effect transistor. A
control terminal (e.g., base or gate) of the first switching
transistor is coupled to a control circuit or a driver that is not
shown.
[0020] For each phase, the second semiconductor 22 may comprise a
semiconductor switch (e.g., high-side semiconductor switch) that
with at least one of its switching terminals coupled to one side
(e.g., high side or positive terminal) of the direct current bus or
direct current source that feeds the direct current terminals. For
example, the switching terminals may refer to the emitter and
collector if the first semiconductor 20 comprises a transistor, or
the switching terminals may refer to the source and drain if the
first semiconductor 20 comprises a field effect transistor. A
control terminal (e.g., base or gate) of the first switching
transistor is coupled to a control circuit or a driver that is not
shown.
[0021] The output of each switching section is defined by set of
alternating current (AC) connectors (36, 38, 40). As illustrated in
FIG. 1, the alternating current connectors comprise a first AC
connector 36, a second AC connector 38 and a third AC connector 40
for the first phase switching section, the second phase switching
section and third phase switching section, respectively. In one
embodiment, the AC connectors (36, 38, 40) comprise surface mount
connectors, such as a female surface mount connector that is
generally cylindrical and that comprises a metal or an alloy
material. Each surface mount connector (36, 38, 40) may have a
mounting pad 48 at one end for mounting to a corresponding
conductive pad 50 on the substrate 34, where the conductive pad 50
is associated with or electrically connected to one or more
conductive traces (e.g., 406).
[0022] For each phase, primary metallic island 24 (e.g., strip) is
located in a primary zone between the first semiconductor 20 and
the second semiconductor 22. In one configuration, each primary
metallic island 24 generally has a greater height or thickness than
the metallic circuit traces. For example, the primary metallic
island 24 provides a heat sink to radiate or conduct heat to an
interior of the first enclosure portion 100 or the first housing
assembly 132. The first enclosure portion 100 may communicate the
radiated or conducted heat toward a conduit or transition for
circulating or conveying coolant through the first enclosure
portion 100. In one embodiment, the primary metallic island 24
comprises a copper pour.
[0023] A secondary metallic island 26 (e.g., strip) is located in a
secondary zone between adjacent surface mount connectors or between
any DC terminal (42, 44) and any adjacent AC connector (36, 38,
40). For example, the secondary metallic island 26 provides a heat
sink to radiate/conduct heat to an interior of the first enclosure
portion 100 or the first housing assembly 132. The first enclosure
portion 100 may communicate the radiated or conducted heat towards
a conduit or transition for circulating or conveying coolant
through the first enclosure portion 100. In one embodiment, the
secondary metallic island 26 comprises a copper pour.
[0024] A tertiary metallic island 28 is located on the substrate 34
between a second semiconductor switch 22 and a corresponding AC
connector, or more generally between a second semiconductor switch
22 and surface mount connector. In one configuration, each tertiary
metallic island 28 generally has a greater height or thickness than
the metallic circuit traces. For example, the tertiary metallic
island 28 provides a heat sink to radiate or conduct heat to an
interior of the first enclosure portion 100 or the first housing
assembly 132. The first enclosure portion 100 may communicate the
radiated or conducted heat toward a conduit or transition for
circulating or conveying coolant through the first enclosure
portion 100. In one embodiment, the tertiary metallic island 28
comprises a copper pour.
[0025] A quaternary metallic island 30 is located on the substrate
34 proximate to a first semiconductor 20 switch (e.g., for each
phase). In one configuration, each quaternary metallic island 30
generally has a greater height or thickness than the metallic
circuit traces. For example, the quaternary metallic island 30
provides a heat sink to radiate or conduct heat to an interior of
the first enclosure portion 100 or the first housing assembly 132.
The first enclosure portion 100 may communicate the radiated or
conducted heat toward a conduit or transition for circulating or
conveying coolant through the first enclosure portion 100. In one
embodiment, the quaternary metallic island 30 comprises a copper
pour.
[0026] In one embodiment, the first semiconductor switch 20 and the
second semiconductor switch 22 comprise metal-oxide semiconductor
field-effect transistors (MOSFET's), or insulated gate bi-polar
transistors (IGBT's) composed of silicon, silicon carbide, gallium
nitride, or other semiconductor material that is packaged in the
form of planar chipsets. These chipsets could be realized in planar
shape, packaged and ready for pick-and-placement manufacturing
processes on substrate. The thermal management is enhanced by a
housing (with integral coolant channels within the first enclosure
portion 100 (in FIG. 4) and the second enclosure portion 102)
offers the opportunity to raise current density (A/cm2) of the
substantially planar first semiconductor switch 20 and the second
semiconductor switch 22 (e.g., MOSFET/IGBT chipsets). Therefore, at
a given current rating of electronics assembly 200 it is possible
to use a die of smaller size than otherwise possible for the
semiconductor material used in the first semiconductor switch 20
and the second semiconductor switch 22, depending of type of
switching devices used in inverter design.
[0027] The reduction of the die size of the semiconductor or
package size of the first semiconductor switch 20 and the second
semiconductor switch 22 is supported by double-sided thermal
management of the substantially planar chipsets coupled with
lateral withdrawal of heat flux through power interconnects.
Accordingly, the first semiconductor switch 20 and the second
semiconductor switch 22 are placed in a thermally managed
environment that allows each semiconductor die to operate at lower
junction temperature (Tj). Here, the thermally managed environment
may be referred to as multi-sided thermal management of power
switching devices (20, 22). A lower value of Tj at a given power
offers opportunity to decrease the die size and package size the
first semiconductor switch 20 and the second semiconductor switch
22 without compromising or decreasing inverter capability.
Decreasing the size of the die of Si, SiC and GaN material in the
semiconductor switches (20, 22) could proportionally increase the
area of the conductive traces, islands, heat sink areas, or bus bar
around each chipset making it more effective for lateral flow of
heat flux from die to the coolant channel in within the first
enclosure portion 100 (FIG. 4) and the second enclosure portion
102.
[0028] In one configuration, a group of capacitors 56 may be
mounted on or to the substrate 34. For example, as shown in FIG. 1,
a first array of capacitors 56 is mounted on a first side of the
substrate 34, whereas a second array of capacitors 56 is mounted on
a second side of substrate 34 opposite the first side. Although two
rows of four capacitors 56 are shown on each side of the substrate
34, any suitable number of capacitors 56 may be used. As shown,
each capacitor 56 has a first terminal 58 and a second terminal 60.
In one configuration, each capacitor 56 may comprise an
electrolytic capacitor 56.
[0029] In one embodiment, the capacitors comprise surface-mount,
low-profile film capacitors. The package of the capacitors 56 with
high-surface area conductive terminals (58, 60) and thermal
interface material around the capacitors 56 facilitates conductive
thermal management for lower temperature rise per ampere current
filtered and higher ampere per unit capacitance (e.g., micro-Farad
(uF)) required or used. The thermal interface material comprises a
cured (e.g., substantially cross-linked) polymer, elastomer or
plastic or solid dielectric material that is positioned, inserted,
injected as a resin in an uncured state, in liquid phase, or in a
semi-solid phase between the interior of the first enclosure and
the second enclosure and the capacitors 56 for enhanced heat
dissipation. The capacitors 56 can be configured as parts that can
withstand lead-free reflow temperature profile needed for surface
mount manufacturing line, for example.
[0030] As illustrated in FIG. 1, an ancillary substrate 46 is
mounted in a different plane that is generally parallel to or
offset from the plane of the substrate 34. A connector has a
dielectric portion and terminals, where the connector is mounted on
or through the ancillary substrate 46. The ancillary circuit board
may have one or more openings 52. For example, the ancillary
circuit board may have ancillary openings 52 for each phase or
switching section, such that a second enclosure portion 102 or a
second housing assembly 134 may contact or be in close proximity to
the switching section to conduct heat away from the switching
section.
[0031] In an alternate embodiment, the heat is conducted away from
one or more metallic islands (e.g., 24, 28, 30) through one or more
thermally conductive vias 900 (e.g., thermally conductive
through-holes, thermally conductive blind vias, or thermally and
electrically conductive vias, or other structures) connected
between the one or more metallic islands (e.g., 24, 28, 30) and a
heat-sink island 901 or heat sink on an opposite side of the
substrate 34, as best illustrated in FIG. 9. In one embodiment, the
heat sink or heat-sink island 901 is isolated on a phase-by-phase
basis, such that each phase heat-sink island (e.g., first phase
heat sink island) is mechanically separate and electrically
isolated (e.g., electromagnetically isolated over an operational
frequency range) from respective other phase heat sink islands
(e.g., on an underside or the opposite side of the substrate 34) of
the other phase outputs (e.g., second phase heat-sink island and
third phase heat-sink island) of the electronic assembly 200.
Further, cumulative with or separate from the heat transfer through
the thermally conductive vias 900, the heat is transferred to the
fluid or coolant in the coolant channel (e.g., within the first
enclosure portion 100 or second enclosure portion).
[0032] The circuit board assembly 11 of electronic assembly 200 may
comprise a plurality of first surface mount connectors mounted on
the substrate 34 that are electrically connected to the terminals
and a secondary metallic island 26 located in a secondary zone
between adjacent surface mount connectors.
[0033] FIG. 2 illustrates a housing assembly that encloses the
circuit board assembly 11 of FIG. 1. In one embodiment, the housing
comprises a first housing assembly 132 and a second housing
assembly 134, where the first housing assembly 132 mates with the
second housing assembly 134. The first housing assembly 132
comprises a first enclosure portion 100 and a third enclosure
portion 104. The second housing assembly 134 comprises a second
enclosure portion 102 and a fourth enclosure portion 106.
[0034] As shown, the first enclosure portion 100 and the second
enclosure portion 102 have mounting holes (108, 110) for receiving
one or more fasteners 117 to fasten or joint the first enclosure
portion 100 to the second enclosure portion 102, where the circuit
board assembly 11 of FIG. 1 is sandwiched between the first and
second enclosure portions 102 or enclosed by the first and second
enclosure portions 102. The third enclosure portion 104 is secured
to or attached to the first enclosure portion 100. For example, the
third enclosure portion 104 may comprise a heat sink or upper cover
of the housing assembly. Similarly, the fourth enclosure portion
106 may comprise a heat sink or a lower cover of the housing
assembly. The fourth enclosure portion 106 is secured to or
attached to the second enclosure portion 102. In one embodiment,
the first enclosure portion 100 and the second enclosure portion
102 are composed of a polymer, a plastic, a polymer matrix with a
filler, such as reinforced fiber or carbon fiber. For instance, the
first enclosure portion 100 and the second enclosure portion 102
may be manufactured by a three-dimensional printer capable of
printing a three-dimensional structure with various openings 52,
conduits or passageways for conducting fluid to cool the circuit
board assembly 11 or its heat generating components. In an
illustrative configuration, the third enclosure portion 104 and the
fourth enclosure portion 106 may be constructed of a metal
material, a metallic material, an alloy material or heat sink
material, such as aluminum, cast aluminum. The third enclosure
portion 104 and the fourth enclosure portion 106 may be constructed
with a three-dimensional printer capable of printing a
three-dimensional structure from a polymer, plastic or resin that
contains electrically conductive particles, such as metallic
particles to promote heat dissipation, or any suitable thermally
conductive polymeric materials.
[0035] A first interior surface of the first enclosure portion 100
may conform substantially in size and shape to mate or interlock
with the one side of the circuit board assembly 11, whereas a
second interior surface of second enclosure portion 102 may conform
substantially in size and shape to mate or interlock with an
opposite side. For example, the first enclosure portion 100 has
generally cylindrical recesses that engage with corresponding AC
connectors and DC terminals on the substrate 34. Further, the first
enclosure portion 100 has a first switching section 75 recess that
is generally rectangular, polyhedron-like, or that otherwise
conforms to the shape and size of the first switching section 75
above the substrate 34; a second switching section 77 recess 126
that is generally rectangular, polyhedron-like, or that otherwise
conforms to the shape and size of the second switching section 77
above the substrate 34; a third switching section 79 recess that is
generally rectangular, polyhedron-like, or that otherwise conforms
to the shape and size of the third switching section 79 above the
substrate 34. With respect the capacitor 56 arrays, the first
enclosure has an aggregate capacitor recess or individual capacitor
recesses that conform to the size and shape of corresponding
capacitors 56 on the circuit board assembly 11.
[0036] The second enclosure portion 102 has raised protrusions 124
that for each switching section, where the raised protrusions 124
can contact the underside of each switching section. In an
alternate embodiment, the second enclosure portion 102 has raised
protrusions that for each switching section, where the raised
protrusions can contact the underside of each switching section
with a thermally conductive interface material, as illustrated in
FIG. 8. The thermally conductive interface material comprises an
intervening thermally conductive adhesive, an intervening thermally
conductive grease, or an intervening thermally conductive polymer.
As shown, the second enclosure portion 102 has an aggregate
capacitor 56 recess that conforms to the size and shape of
corresponding capacitors 56 on the circuit board assembly 11.
[0037] As shown, the first enclosure portion 100 has a first inlet
116 and a first outlet 118 for receiving and exhausting a coolant,
respectively. Similarly, the second enclosure portion 102 has a
second inlet 120 and a second outlet 122 for receiving and
exhausting a coolant, respectively. FIG. 10 provides an
illustrative example of one embodiment of how the coolant is
circulated or conveyed through the electronic assembly 200 to
provide enhanced cooling of the switching sections, capacitors 56
or other components within the electronic assembly 200.
[0038] FIG. 3 shows the electronic assembly 200 of FIG. 2 in its
assembled state. Each of the AC connectors (36, 38, 40) and DC
connectors (42, 44) may be connected to conductors 130 or cables
via mating connectors 128 (e.g., male plugs) that mate with the
corresponding connectors (e.g., surface mount connectors or female
connectors) of the electronic assembly 200. For example, the DC
connectors (42, 44) may be connected or coupled to a direct current
(DC) source, such as a battery, a generator, a fuel cell electrical
output, or rectified alternator. Meanwhile, the AC connectors may
be coupled or connected to corresponding phases of an electric
motor (e.g., any conventional, unconventional or mutually coupled
switched reluctance motor or permanent magnet alternating current
motor) to be controlled, or an alternator or other electric
machine.
[0039] FIG. 4 illustrates a cross section of the electronic
assembly 200 along reference line 4-4. Like reference numbers in
FIG. 1 through FIG. 4, inclusive, indicate like elements or
features. The cross section of FIG. 4 shows the coolant channels
(420, 422, 424, 421, 428) that extend between the first inlet 116
and the first outlet 118 of the first housing assembly 132 or the
first enclosure portion 100. The cross section of FIG. 4 also shows
the coolant channels (411, 412, 414, 416, 418) that extend between
the second inlet 120 and the second outlet 122 of the second
housing assembly 134 or the second enclosure portion 102. In one
embodiment, between the first inlet 116 and the first outlet 118, a
first coolant channel (420, 422, 424, 421, 428) is fully contained
within the first enclosure portion, which eliminates the need for
cooperating ports in the electronic assembly 200 for the transfer
of coolant between the first enclosure portion 100 and the second
enclosure portion 102. Similarly, between the second inlet 120 and
the second outlet 122, a second coolant channel is fully contained
within the second enclosure portion 102, which eliminates the need
for any cooperating ports in the electronic assembly 200 for the
transfer of coolant between the first enclosure portion 100 and the
second enclosure portion 102. Accordingly, any gaskets, seals, or
adhesive between those cooperating ports, in the first enclosure
portion 100 and the second enclosure portion 102, are eliminated
and do not leak.
[0040] For illustrative purposes, FIG. 4 will be described such
that the visible portion of the first coolant channel is designated
as an outbound portion (420, 422, 424, 421, 428) of the first
coolant channel, although the first coolant channel has an inbound
portion that looks similar to the outbound portion. The outbound
portion and the inbound portion of the first coolant channel are
generally interchangeable because they are merely defined with
respect to the direction of fluid or coolant flow, and with respect
to the orientation of the pump discharge or pump input with respect
the first inlet and first outlet. For example, the inbound portion
and the outbound portion are redefined when the connections between
the first inlet, the first output to the pump are reversed.
[0041] In one embodiment, an outbound portion (420, 422, 424, 421,
428) of the first coolant channel comprises a first inlet
transverse chamber 420, a set of first inner outbound conduits 422,
a set of first outbound transitions 424, a set of first outer
outbound conduits 421, and a first outer transverse chamber 428, a
set first inbound outer conduits, a set of first inbound
transitions, a set of first inner inbound conduits. The outbound
portion (420, 422, 424, 421, 428) of first coolant channel is
coupled between the first inlet 116 and the first outlet 118 and
may follow a circuitous path or serpentine path through the first
enclosure portion 100 between the first inlet 116 and the first
outlet 118. The outbound portion (420, 422, 424, 421, 428) of the
first coolant channel can be described in conjunction with the
direction of fluid flow from the first inlet 116 to the first
outlet 118, where the outbound path travels from the first inlet
116 and where the inbound path travels toward the first outlet
118.
[0042] In the first coolant channel, the first inlet 116
communicates with the first inlet transverse chamber 420. A set of
first inner outbound conduits 422 comprise one or more first inner
outbound conduits emanating from (e.g., longitudinally in FIG. 4 in
the plane of the sheet) the first inlet transverse chamber 420. The
respective set of inner outbound conduits 422 is coupled to a
corresponding set of first outbound transitions 424. In one
embodiment, each first outbound transition 424 region may comprise
a substantially spiral, substantially elliptical, or substantially
circular, or otherwise curved channel that links or connects a
respective one of the first inner outbound conduits 422 to
corresponding one of the first outer outbound conduits 424. In one
configuration, one end of the set of first outer outbound conduits
421 is coupled to a corresponding set of the first outbound
transitions 424, whereas the opposite end of the set of first outer
outbound conduits 421 is coupled to the first outer transverse
chamber 428.
[0043] In the second coolant channel (411, 412, 414, 416, 418), the
second inlet 120 communicates with the second inlet transverse
chamber 411. A set of second inner outbound conduits 412 comprise
one or more second inner outbound conduits emanating from (e.g.,
longitudinally in FIG. 4 in the plane of the sheet) the second
inlet transverse chamber 411. The respective set of inner outbound
conduits 412 is coupled to a corresponding set of second outbound
transitions 414. In one embodiment, each second outbound transition
414 may comprise a substantially spiral, substantially elliptical,
or substantially circular, or otherwise curved channel that links
or connects a respective one of the second inner outbound conduits
412 to corresponding one of the second outer outbound conduits 416.
In one configuration, one end of the set of second outer outbound
conduits 416 is coupled to a corresponding set of the second
outbound transition 414, whereas the opposite end of the set of
second outer outbound conduits 416 is coupled to the second outer
transverse chamber 418, or a series of generally parallel curved
conduits or loops.
[0044] In one embodiment, one or more of the transitions (424, 414)
may comprise a substantially spiral, substantially elliptical,
substantially circular or otherwise curved channel that
circumnavigates or surrounds an exterior of a connector (e.g.,
surface-mount connector) associated with the substrate 34.
Accordingly, each such transition (e.g., 424) has an inner diameter
or generally cylindrical surface 410 that is configured to mate
with, nest with, or interlock with a generally cylindrical outer
surface 408 of the connector 40. As shown in FIG. 4, a transition
424 (e.g., first transition or upper transition) surrounds the
exterior of the connector 40 in close proximity for heat transfer
of thermal energy from the connector 40 to the coolant in the first
coolant channel, whereas the transition 414 (e.g., second
transition or lower transition) does not surround the connector
(e.g., 40) in the configuration shown. The transition 414 may be
composed of or associated with a metal or metallic structure in
close proximity to a heat sink or fourth enclosure portion 106.
[0045] In one illustrative configuration, first enclosure portion
100 has an inner surface with a mating shape and size that
corresponds to the contour or adjoining first surface mount
connectors (36, 38, 40) or that corresponds to direct terminals
(42, 44). The first enclosure portion 100 has a transition region
(e.g., 414) of channels in a spiral path around an outer diameter
of the first surface mount connector to provide thermal path for
heat dissipation from the surface mount connector (36, 38, 40) or
direct terminals (42, 44). For example, the inner surface is
substantially cylindrical and engages a corresponding outer
cylindrical surface of a corresponding one of the first surface
mount connectors (36, 38, 40) or direct terminals (42, 44).
[0046] The first housing assembly 132 comprises a first enclosure
portion 100 that overlies the substrate 34 and the primary metallic
island 24; wherein the heat is conducted away from the primary
metallic island 24 through a first enclosure portion 100 in contact
with, above or in close proximity to the primary metallic island
24. For example, the heat is conducted from the primary metallic
island 24 through the enclosure portion to the ambient air around
the first enclosure portion 100. Cumulative with or separate from
the heat transfer to the ambient air around the first enclosure
portion 100, the heat is transferred to the fluid or coolant in the
coolant channel. Heat or thermal energy is conducted away from the
tertiary metallic island 28 through a first enclosure portion 100
in contact with, above or in close proximity to the tertiary
metallic island 28. Heat or thermal energy is conducted away from a
quaternary metallic island 30 through a first enclosure portion 100
in contact with, above or in close proximity to the quaternary
metallic island 30. As illustrated, one or more conductive traces
are on one or more sides of the substrate 34. The connector 32 may
be surface-mounted to conductive pads on one side of the substrate,
and may be mounted through a connector opening 15 (in FIG. 2) in
the first enclosure portion 100.
[0047] In FIG. 4, the third enclosure portion 104 has one or more
fins 402 or radiating elements for radiating thermal energy. In an
alternative embodiment, the third enclosure portion 104 may be
configured as a heat sink and forged, cast, stamped or otherwise
formed from metal, an alloy or metallic material. Similarly, the
fourth enclosure portion 106 has one or more fins 404 or radiating
elements for radiating thermal energy. In an alternative
embodiment, the fourth enclosure portion 106 may be configured as a
heat sink and forged, cast, stamped or otherwise formed from metal,
an alloy or metallic material.
[0048] FIG. 5 shows a cross section of the electronic assembly 200
along reference line 5-5. Like reference numbers in FIG. 4 and FIG.
5 indicate like elements. The cross section of FIG. 5 does not show
the cross section of any transitions or the cross section any AC
connector (36, 38, 40) or DC terminal (42, 44). Further, the cross
section of FIG. 5 falls between the first coolant channel and the
second coolant channel within the first enclosure portion 100 and
the second enclosure portion 102, respectively.
[0049] FIG. 6 shows a cross section of the electronic assembly 200
along reference line 6-6. Like reference numbers in FIG. 4 and FIG.
6 indicate like reference numbers. The cross section of FIG. 4 may
disclose an outbound transition and corresponding outbound portions
of the first and second conduits, whereas the cross section of FIG.
5 may show an inbound transition and the corresponding inbound
portions of the first and second conduits.
[0050] A set of first outer inbound conduits 521 comprise one or
more first outer inbound conduits 521 emanating from (e.g.,
longitudinally in FIG. 4 in the plane of the sheet) the first outer
transverse chamber 528, or a series of generally parallel curved
conduits or loops. The respective set of outer inbound conduits 521
is coupled to a corresponding set of first inbound transitions 524.
In one embodiment, each first inbound transition 524 may comprise a
substantially spiral, substantially elliptical, or substantially
circular, or otherwise curved channel that links or connects a
respective one of the first outer inbound conduits 521 to
corresponding one of the first inner inbound conduits 522. In one
configuration, one end of the set of first inner inbound conduits
522 is coupled to a corresponding set of the first inbound
transitions 524, whereas the opposite end of the set of first inner
inbound conduits 522 is coupled to the first inlet transverse
chamber 520. The first inlet transverse chamber may be coupled to
the first inlet 116 or the first outlet 118.
[0051] A set of second outer inbound conduits 516 comprise one or
more second outer inbound conduits 516 emanating from (e.g.,
longitudinally in FIG. 4 in the plane of the sheet) the second
outer transverse chamber 518 or a series of generally parallel
curved conduits or loops. The respective set of second outer
inbound conduits 516 is coupled to a corresponding set of second
inbound transitions 514. In one embodiment, each second inbound
transition 514 may comprise a substantially spiral, substantially
elliptical, or substantially circular, or otherwise curved channel
that links or connects a respective one of the second outer inbound
conduits 516 to corresponding one of the second inner inbound
conduits 512. In one configuration, one end of the set of second
inner inbound conduits 512 is coupled to a corresponding set of the
second inbound transitions 514, whereas the opposite end of the set
of second inner inbound conduits 512 is coupled to the second
outlet transverse chamber 511. The second outlet transverse chamber
511 may be coupled to the second inlet 120 or the second outlet
122.
[0052] In FIG. 4 through FIG. 6, the first enclosure portion 100
comprises a group of channels or micro-channels within the first
enclosure portion 100 for conveying fluid or coolant, and where an
inner surface of the first enclosure portion 100 is in contact
with, above or in close proximity to one or more metallic islands
(e.g., the primary metallic island 24, secondary metallic island
26, tertiary metallic island 28, or quaternary metallic island 30)
for transfer of the heat from the metallic islands to the coolant
or fluid within the channel or micro-channels. In one
configuration, each AC connector (36, 38, 40) comprises surface
mount connector is mounted on the substrate 34. Each AC connector
is electrically connected to each corresponding phase output
terminal of a switching section, such as the first semiconductor 20
and the second semiconductor 22. A tertiary metallic island 28 is
located in a tertiary zone between adjacent connectors (26, 38, 40,
42, 44) or between adjacent surface mount connectors.
[0053] In one example, the second enclosure portion 102 comprises a
group of channels or micro-channels within the second enclosure
portion 102, and where an inner surface of the second enclosure
portion 102 is in contact with, above or in close proximity an
opposite side of the substrate 34 on which one or more metallic
islands are found for transfer of the heat from one or more
metallic islands. In one configuration, the first semiconductor 20
and the second semiconductor 22 comprise surface mount transistors
that are mounted on the substrate 34 and electrically connected to
corresponding ones of the metallic circuit traces (e.g., 406 in
FIG. 4) and wherein the second enclosure portion 102 has an inner
surface with a mating shape and size that corresponds to the
contour or adjoining surface of the opposite side of the substrate
34 and any associated components (e.g., electrical or electronic
components) on the substrate 34.
[0054] FIG. 7 illustrates an enlarged rectangular portion of the
cross section of the electronic assembly 200 shown in FIG. 4. FIG.
7 clearly shows the transition that engages a connector (e.g.,
surface mount connector) that is connected to corresponding
connector portion (e.g., plug) and conductor. Here, the
corresponding connector portion is illustrated as right-angle
connector although any connector (e.g., straight connector or
ordinary connector) may fall within the scope of the
disclosure.
[0055] In FIG. 7, the first enclosure portion 100 comprises a first
conduit. In turn, the first conduit comprises a group of generally
parallel and longitudinally extending channels or first
micro-channels within the first enclosure portion 100, where an
adjoining portion of the first enclosure portion 100 provides a
thermal path between one or more metallic islands and the first
conduit. As indicated previously, the metallic islands include one
or more of the following islands: a primary metallic island 24, a
secondary metallic island 26, a tertiary metallic island 28 and a
quaternary metallic island. In one embodiment, the channels are
synonymous with the inbound and outbound paths previously described
herein.
[0056] As illustrated in FIG. 7, the second enclosure portion 102
comprises a second conduit. In turn, the second conduit comprises a
group of generally parallel and longitudinally extending channels
or second micro-channels within the second enclosure portion 102,
where an adjoining portion of the second enclosure portion 102
provides a thermal path between one or more metallic islands and
the second conduit. As indicated previously, the metallic islands
include one or more of the following islands: a primary metallic
island 24, a secondary metallic island 26, a tertiary metallic
island 28 and a quaternary metallic island 30.
[0057] The third enclosure portion 104 is secured to the first
connector portion. The third connector portion comprises a cover or
heat sink (e.g., cover with external cooling fins or generally
parallel ridges), to provide a supplemental path for transfer of
the heat from one or more metallic islands of the electronic
assembly 200. The fourth enclosure portion 106 is secured to the
second connector portion. The fourth connector portion comprises a
cover or heat sink (e.g., cover with external cooling fins or
generally parallel ridges), to provide a supplemental path for
transfer of the heat from one or more metallic islands of the
electronic assembly 200.
[0058] The electronic assembly 200 of FIG. 8 is similar to the
electronic assembly 200 of FIG. 7, except that the electronic
assembly 200 of FIG. 8 further includes a thermal interface
material (801, 802, 803), a thermally conductive adhesive or
thermally conductive lubricant. For example, the thermal interface
material (801, 802, 803) is used between the primary metallic
island 24 and the first enclosure portion 100, between the tertiary
metallic island 28 the first enclosure portion 100, and between the
quaternary metallic island 30 and the first enclosure portion 100.
Like reference numbers in FIG. 7 and FIG. 8 indicate like elements
or features.
[0059] In one embodiment, the thermal interface material is a gap
filer that can be used between the circuit board assembly 100 and
an interior of the electronic assembly 200. For example, a thermal
interface material may be injected, forced or put into a first gap
between the circuit board assembly 100 and the generally conforming
interior surface of the first enclosure portion 100 and between a
second gap between the circuit board assembly 100 and the second
enclosure portion 102. The thermal interface material can fill
irregular depressions, recesses or voids in a layer. The thermal
interface material is well suited for leaving behind zero or
negligible bond lines after the thermal interface material is
cured. Thermal interface material is used to avoid short circuits
and metal-to-metal contact, where a live metal terminal (or an
electrically conductive structure at a potential different than
ground) may contact a metal component at electrical ground
potential. The thermal interface material is well suited for
carrying heat away from active components to coolant channels
formed in the first enclosure portion 100, the second enclosure
portion 102, or in the housing. For example, the thermal interface
material can be in direct connect with the metallic islands (e.g.,
30, 24, 28) or heat sinking strips on the substrate. Further, the
thermal interface material may overlie the capacitors 56 and may
fill a void between the capacitors 56 and the interior of the first
enclosure portion 100 and the second enclosure portion 102 to draw
or conduct heat away from the capacitors 52.
[0060] In one configuration, the thermal management material is
applied (e.g., sprayed on) and when it cures it is a dielectric
structure with relatively high thermal conductivity, such as about
240 Watt/meter-Kelvin in the x-y direction and about 5
Watt/meter-Kelvin in the Z direction. Where the x-y plane is the
plane of the surface of the substrate 34 such that heat transfer
theoretically takes place with an anisotropic gradient within the
electronic assembly 200.
[0061] As illustrated in FIG. 1, where flip chip or flip die
methods are used for the first semiconductor switch 20 and the
second semiconductor switch 22, a first thermal interface material
layer could overlie (or be bonded to) one side of the substrate 34
and second thermal interface material layer could overlie (or be
bonded to) the first thermal interface material layer, where the
multiple thermal interface layers tend to provide shock absorption
and vibration stress reduction.
[0062] In one configuration, if the thermally conductive material
comprises a resin that cures as dielectric material, the thermally
conductive material offers better abrasion resistance and greater
adhesion to surrounding components and interior of the housing than
conductive grease, for example.
[0063] In an alternate embodiment, the substrate 34, as an
un-populated (bare board) circuit board (e.g., ceramic substrate),
has a coefficient of thermal expansion (CTE) interface layer to
match a first CTE of the metallic islands (e.g., heavy copper pours
pattern) to a second CTE of the substrate 34 for thermal
management. For example, the CTE interface layer comprises a
dielectric layer (e.g., substantially planer layer) of polymer,
plastic or fiber filled polymer that resides between the metallic
islands (e.g., 30, 24 and 28) and the substrate 34. In one
illustrative example, the CTE interface layer comprises a polyimide
or bismaleimide triazine (BT) material bonded to a substrate 34,
such as a ceramic substrate (e.g., FR4). Further, the CTE interface
layer, which comprises a polyimide or bismaleimide triazine (BT)
material bonded to a substrate 34, may be used to provide a CTE
compliance between a substrate 34 and an ancillary substrate 46 or
between substrate 34 and a gate driver circuit board underlying the
connector 32.
[0064] In one embodiment, the electronic assembly 200 of FIG. 9 is
similar to the electronic assembly 200 of FIG. 7, except that the
electronic assembly 200 of FIG. 9 further includes a thermally
conductive via 900 (e.g., a plastic via, polymer via, a dielectric
thermally conductive via, a thermoplastic via or thermoplastic
insert) in thermal communication with a heat sink metallic island
901 or ground plane on an opposite side of the substrate 34 from
the metallic islands (24, 28, 30). One or more thermally conductive
vias 900 (e.g., thermoplastic vias or thermoplastic inserts) can be
composed of a dielectric material that is thermally conducting, but
electrically insulated: (1) to ensure that metallic islands (28,
24, 30) do not form or facilitate an electrical connection (e.g.,
an electrical short circuit, if the metallic island is configured
to be electrically floating or at operational voltage potential
other than ground potential) or (2) to isolate different phase
outputs of an inverter or electronic assembly 200 where a common
ground plane is used between one or more metallic islands (24, 38,
30) and a corresponding heat sink metallic island 901 or ground
plane.
[0065] In an alternate embodiment, the electronic assembly 200 of
FIG. 9 is similar to the electronic assembly 200 of FIG. 7, except
that the electronic assembly 200 of FIG. 9 further includes a
thermally conductive via 900, a blind conductive via, or plated
through-hole in thermal communication with a heat sink metallic
island 901 or ground plane on an opposite side of the substrate 34
from the metallic islands (24, 28, 30), where the thermally
conductive via 900 comprises an electrically conductive and
thermally conductive metallic via . For example, in certain
embodiments of this disclosure, thermally conductive vias 900 can
connect (e.g., electrically and mechanically) one or more of the
metallic islands (28, 24, 30) on a first side of the substrate 34
with one or more heat-sink metallic islands 901 or one or more
ground planes on a second side of the substrate 34, where the
second side is opposite the first side. FIG. 9 shows generally that
thermally conductive vias 900 (e.g., dielectric thermally
conductive vias, thermally conductive metallic vias, or both) 900
are connected (e.g., thermally, mechanically, or electrically, or
any combination of the foregoing connection types) between the
primary metallic island 24 and the metallic ground plane 901,
between the tertiary metallic island 28 and the heat-sink metallic
island 901 (also referred to as a metallic ground plane or a
phase-specific ground plane), and between the quaternary metallic
island 30 and the metallic ground plane 901. Like reference numbers
in FIG. 7 and FIG. 8 indicate like elements or features.
[0066] FIG. 10 is a perspective view of an illustrative example of
a fluid cooling system 900 that incorporates the electronic
assembly 200 of FIG. 1. The fluid cooling system 900 comprises a
radiator 950 that is coupled to a pump 952 with tubing 958. In
turn, the pump 952 is coupled to an electronic assembly 200 via
tubing (956, 962, 943). The radiator 950 has connection ports (948,
951). At least one connection port (e.g., 951) is connected to a
pump inlet 954 or pump outlet 956 via tubing 958, where the
opposite connection 964 from the pump 952 is connected to the
electronic assembly 200 via tubing. For example, a first radiator
connection port 951 is coupled to a pump inlet 954, whereas a
second radiator connection port 948 is coupled to a pump outlet 964
through tubing (944, 946), one or more fittings 947, internal
channels within the electronic assembly 200, and tubing (943, 962,
956).
[0067] The electronic assembly 200 has a first enclosure portion
100 and a second enclosure portion 102 that are secured together to
form a housing. The housing also features a third enclosure portion
104 and the fourth enclosure portion 106. The first enclosure
portion 100 has a first inlet 116 and first outlet 118. The second
enclosure portion 102 has a second inlet 120 and the second outlet
122.
[0068] As illustrated, the pump outlet 964 is coupled to the first
inlet 116 and the second inlet 120 of the electronic assembly 200
via tubes (956, 962, 943) and tee fittings, Y-fittings or other
appropriate connectors 947. Similarly, the second radiator port is
coupled to the first outlet 118 and the second outlet 122 via tubes
and tee fittings, Y-fittings, or other appropriate connectors
947.
[0069] During or prior to operation, the radiator 950 is filled
with a fluid or coolant. The radiator 950 can provide a reservoir
of coolant; the channels and associated chambers within the
electronic assembly 200 can provide a reservoir of coolant, or both
the radiator 950 the electronic assembly 200 can provide a
reservoir of coolant. The pump 952 conveys fluid or coolant into
the first inlet 116 for circulation of the fluid or coolant within
the first enclosure portion 100. The fluid or coolant exits the
first enclosure portion 100 at the first outlet 118 that is coupled
to the radiator 950 with tubing. Similarly, the pump 952 conveys
fluid or coolant into a second inlet 120 for circulation of the
fluid or coolant within the second enclosure portion 102. The fluid
or coolant exits the second enclosure portion 102 at the second
outlet 122 that is coupled to the radiator 952 with tubing.
[0070] The circuit board assembly 11 may be manufactured in
accordance with various techniques, where some examples follow
here. The circuit board assembly 11 (e.g., power switching printed
circuit board) is populated with or by mounting surface mount film
capacitor elements, connector sockets and planar power switching
devices on one side or both sides the substrate 34 and ancillary
substrate 46. For example, the components may be mounted using a
pick-and-place mechanization. The electronic assembly provides
control and gate driver functionality circuits including low
voltage connector for battery and electric machine harness.
[0071] The housing (100, 102, 104, 106) may comprise a case or
cover that is molded (e.g., injection molded), constructed by
three-dimensional printing or otherwise formed. For example, in one
embodiment the electronics assembly 200 can be made in a highly
automated process using three-dimensional printing for the first
enclosure portion 100 and the second enclosure portion 102 to
support the formation on integral coolant channels in the housing.
The housing comprises a first enclosure 100 and a second enclosure
portion 102. Each enclosure portion (100, 102) has an interior
surface shape/profile and features that conform to the shape and
profile of parts and interconnects placed on the circuit board
assembly 11 and a control gate and driver circuit board underlying
connector 32. Accordingly, the electronic assembly 200 is well
suited for high density packaging and using less volume for the
capacity (e.g., current or power) output of the electronic assembly
200. In one configuration, the substrate 34 may be connected to the
ancillary substrate 46 (or gate driver circuit board) by using a
ball grid array (BGA) interconnect. For instance, an assembled
substrate 34 with components mounted thereon could go through
reflow process with control and gate drive circuit board.
[0072] The connecters (36, 38, 40, 42, 44) comprise surface mount
connectors that support plug (pin) and socket type of electrical
connections between the load (e.g., electric motor, generator or
machine) and the energy source (e.g., DC energy source) for the
electronic assembly 200. The connectors are populated between
capacitor elements and planar chipsets of the first semiconductor
switch 20 and the second semiconductor switch 22. The above
placement of the connectors (36, 38, 40, 42, 44) in the electronic
assembly 200 supports electrical design functionality (e.g.,
minimization of system inductance and avoidance of unnecessary
current loops), thermal design functionality (e.g., space between
chipsets (20,22) and capacitors (56) used to separate parts that
operate at substantial temperature difference and also socket
increase overall surface area for improved heat sinking), and
mechanical functionality (e.g., minimization of overall area needed
for circuit board 11).
[0073] In one embodiment, the ancillary substrate 46 or a circuit
board underlying connector 32 comprises a gate driver circuit and
control board. The ancillary substrate 46 may be associated with a
gate driver circuit for controlling one or more phases of the first
semiconductor switches 20 and the second semiconductor switches.
The gate driver circuit may be miniaturized using method of
Application Specific Integrated Circuit (ASIC). ASIC used to
miniaturize gate driver circuit not only simplifies the layout of
the conductive by circuit confinement but also increases immunity
from electromagnetic interference and stray effects caused by
change in current over time and change in voltage over time. The
gate driver circuit features a current sensing circuit and low
voltage control with discrete circuits. In one configuration, the
current sensing circuit is placed close to or adjacent to inverter
alternating current output or one or more metallic islands, where
the current sensing circuit is accompanied by any necessary
shielding and flux/field concentrators. The low voltage control and
discrete circuits can be embedded within a Field Programmable Gate
Array (FPGA) and discrete electronics parts and integrated
circuits. The gate driver circuit and control board is populated
with surface mount low voltage connector harness connection with
battery and sensors placed on electric motor/generator driven by
inverter.
[0074] In one embodiment, the housing can be formed by a
three-dimensional (3-D) printed process or injection molded
process. The housing has surface shape/profile and features
conforming to the circuit board assembly 11 used in inverter
assembly. The housing facilitates enhanced thermal management of
the semiconductor switches (20, 22), film capacitor 56 (e.g., film
capacitors), connectors (e.g., 36, 38, 40, 42, 44) interconnects on
the circuit board 11, and all heat generating circuits placed on
the circuit board 11.
[0075] To form the housing with 3-D printing process, first a laser
scanner is used to scan the circuit board 11. The laser scanner
produces one or more three-dimensional images of the profile of the
circuit board. Separate laser images of each side of the circuit
board 11 are collected as input data. Second, a pre-form thermal
interface material (TIM) screen that can be deposited on the
component-populated circuit board 11. TIM allows a close contact
between heat generating components or regions, heat conducting
components or regions, or heat radiating components or regions
within assembly 200 and an interior of the housing. In an alternate
configuration, a layer of TIM with an optimized thickness (e.g.,
optimized for electrical insulation and thermal conduction) can be
deployed on the interior face of first enclosure portion 100 and
the second enclosure portion 102.
[0076] Third, the housing can be composed of a polymer, plastic or
metallic material. In one configuration, the housing is 3-D printed
from a light weight metal such as aluminum or a polymer metallic
composite based on one or more scanned profiles or scanned images
collected by the laser scanner. The 3-D printed housing conforms to
parts and features of circuit board 11. For example, the 3-D
printed housing of inverter can touch or contact all components and
parts on the circuit board 11. As illustrated in FIG. 4 and FIG. 7,
the 3-D printed housing will have built-in coolant channels or
micro-channels for coolant that creates turbulent flow of coolant.
The coolant channels making double-sided cooling of the
semiconductor switches (20, 22) effective along with the lateral
withdrawal of heat from power devices by thermal management of
interconnects. This automated 3-D printing process for the inverter
housing will effectively reduce unused volume or empty space within
electronic assembly 200 that supports reduced package size of the
electronic assembly 200. The 3-D printing will allow thickness
optimization of the inverter housing/enclosure, therefore, 3-D
printing process if exploited properly can significantly reduce the
material needed, and thus a significant costs saving can be
realized as the 3-D printing process matures. The 3-D printed
housing facilitates improved access of the semiconductor switches
(20, 22) to thermal conductive liquid that results in a higher
power rating for the inverter.
[0077] In an alternate embodiment, injection molding could be used
to form the housing or enclosure portions (100, 102). The housing
promotes resistance to vibrations and shocks because the enclosure
portions (100, 102) are tightly packed with TIM and the circuit
board 11, encapsulated with TIM. Unused and exposed areas of
circuit board 11 will have conductive land patterns or metallic
islands to effectively increases overall contact area between
circuit board 11 and the pre-formed thermal interface material
(TIM). TIM provides electrical insulation and thermal conduction
between the circuit board assembly 11 parts and the housing, such
as the first enclosure portion 100 and the second enclosure portion
102.
[0078] A TIM layer can be placed, wrapped, injected, sprayed or
deposited over one or more of the following parts or components
within the inverter assembly: the enclosures (100 102), the
substrate 34, the ancillary substrate 46, printed circuit board 11,
capacitors 56, metallic islands (30, 24, 28), strips, pads, islands
or fin shaped metallic features or patterns on the surface of the
circuit board 11, connectors or power sockets (36, 38, 40, 42, 44),
any heat generating circuits on control and gate driver circuit
board, any parts that need containment for vulnerability to
vibration and shocks, and/or any parts that would otherwise be
susceptible to thermal shocks or temperature swings. The thermal
interface material (TIM) between inverter circuit board 11 and
enclosure portions (100, 102) helps to realize high-capacity (e.g.,
current output), high packaging density (e.g., current output per
spatial volume occupied by the assembly 200).
[0079] TIM facilitates enhanced heat dissipation from the
electronic assembly 200, such as a possible, double-sided cooling
approach for the semiconductor switches (20, 22). For example, TIM
might enable a significant increase in the number of power and
thermal cycles for the semiconductor switches (20, 22). This heat
dissipation approach potentially results in an improvement in
semiconductor device reliability as compared to power semiconductor
devices used in conventional electronic assemblies. Thermal
interface material (TIM) that is bonded to the interior and
components of the assembly 200 tends to minimize thermal resistance
from junction to coolant channels in the heat exchanger (inverter
cold plate). An increased margin between allowed maximum junction
temperature (e.g., Tj_max, such as approximately 175 degrees
Celsius and beyond) for power devices and maximum coolant
temperature (e.g., as high as 105 degrees Celsius) provide an
opportunity for decreased die size of the semiconductor
devices.
[0080] Having described the preferred embodiment, it will become
apparent that various modifications can be made without departing
from the scope of the invention as defined in the accompanying
claims.
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