U.S. patent application number 14/962316 was filed with the patent office on 2016-03-31 for power module and power conversion apparatus using same.
The applicant listed for this patent is Hitachi Automotive Systems, Ltd.. Invention is credited to Shinji HIRAMITSU, Yujiro KANEKO, Takahiro SHIMURA, Tokihito SUWA.
Application Number | 20160095264 14/962316 |
Document ID | / |
Family ID | 47295911 |
Filed Date | 2016-03-31 |
United States Patent
Application |
20160095264 |
Kind Code |
A1 |
KANEKO; Yujiro ; et
al. |
March 31, 2016 |
Power Module and Power Conversion Apparatus Using Same
Abstract
A power module includes a plurality of semiconductor devices
constituting upper/lower arms of an inverter circuit, a plurality
of conductive plates arranged to face electrode surfaces of the
semiconductor devices and a module case configured to accommodate
the semiconductor devices and conductive plates, wherein the module
case includes a heat-radiation member made of plate-like metal and
facing a surface of the conductive plate and a metallic frame body
having an opening that is closed by the heat-radiation member, and
wherein a heat-radiation fin unit having a plurality of
heat-radiation fins vertically arranged thereon is provided at a
center of the heat-radiation member, and a joint portion with the
frame body is provided at an peripheral edge of the heat-radiation
member, and the heat radiation member has a heat conductivity
higher than that of the frame body, and the frame body has a higher
rigidity than that of the heat-radiation member.
Inventors: |
KANEKO; Yujiro;
(Hitachinaka, JP) ; SUWA; Tokihito; (Hitachinaka,
JP) ; HIRAMITSU; Shinji; (Tokyo, JP) ;
SHIMURA; Takahiro; (Hitachinaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hitachi Automotive Systems, Ltd. |
Hitachinaka-shi |
|
JP |
|
|
Family ID: |
47295911 |
Appl. No.: |
14/962316 |
Filed: |
December 8, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14124172 |
Dec 5, 2013 |
9241429 |
|
|
PCT/JP2012/063065 |
May 22, 2012 |
|
|
|
14962316 |
|
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Current U.S.
Class: |
361/699 ;
361/715 |
Current CPC
Class: |
H01L 2224/40137
20130101; H01L 2924/181 20130101; Y02T 10/7072 20130101; H01L
2224/8384 20130101; Y02T 10/70 20130101; B60L 50/16 20190201; H05K
7/20927 20130101; H02P 29/60 20160201; H01L 2224/84801 20130101;
B60L 2200/26 20130101; H02P 27/06 20130101; H01L 2224/48091
20130101; H01L 2224/48247 20130101; H01L 23/3736 20130101; H01L
2224/73265 20130101; H01L 24/40 20130101; H01L 2924/13091 20130101;
H01L 24/36 20130101; H01L 2224/8484 20130101; Y02T 10/72 20130101;
H01L 2924/13055 20130101; H02M 7/003 20130101; B60L 2210/40
20130101; H01L 2224/33 20130101; H01L 23/473 20130101; H05K 7/209
20130101; H01L 23/36 20130101; H01L 2224/83801 20130101; H05K
7/20909 20130101; H01L 2224/48091 20130101; H01L 2924/00014
20130101; H01L 2924/181 20130101; H01L 2924/00012 20130101; H01L
2924/13091 20130101; H01L 2924/00 20130101; H01L 2924/13055
20130101; H01L 2924/00 20130101 |
International
Class: |
H05K 7/20 20060101
H05K007/20; H02P 27/06 20060101 H02P027/06; H02P 29/00 20060101
H02P029/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 8, 2011 |
JP |
2011-128304 |
Claims
1. A power module comprising: a module encapsulant body sealing a
power semiconductor device and a conductive plate facing an
electrode surface of the power semiconductor device; a heat
radiation member facing a surface of the conductive plate; and a
holding member which holds the heat radiation member and is
mechanically fixed to a housing of a power conversion apparatus,
wherein the heat radiation member has a thermal conductivity higher
than that of the holding member, and the holding member is of a
higher rigidity than that of the heat radiation member.
2. The power module according to claim 1, wherein the heat
radiation member is crimped to the module encapsulant body.
3. The power module according to claim 1, wherein the surface of
the conductive plate, which is on the opposite side from the power
semiconductor module, is exposed on a surface of the module
encapsulant body, and the heat radiation member is crimped to the
module encapsulant body through an insulating member.
4. The power module according to claim 1, wherein the holding
member is a metallic frame body having an opening portion that is
closed by the heat radiation member.
5. The power module according to claim 4, wherein the metallic
frame body and the heat radiation member constitute a module case
configured to accommodate the module encapsulant body.
6. The power module according to claim 4, wherein an external
peripheral edge of the heat radiation member is formed in a stepped
shape.
7. A power conversion apparatus comprising: a module encapsulant
body sealing a power semiconductor device and a conductive plate
facing an electrode surface of the power semiconductor device; a
heat radiation member facing a surface of the conductive plate; a
housing in which the module encapsulant body and the heat radiation
member are stored; and a holding member which holds the heat
radiation member and is mechanically fixed to the housing, wherein
the heat radiation member has a thermal conductivity higher than
that of the holding member, and the holding member is of a higher
rigidity than that of the heat radiation member.
8. The power conversion apparatus according to claim 7, further
comprising: a coolant channel forming body configured to form a
cooling channel in which coolant flows, wherein a surface of the
heat radiation member, which is on an opposite side from the
surface of the conductive plate, directly faces to the cooling
channel.
9. The power conversion apparatus according to claim 8, wherein the
holding member partitions a part of the cooling channel.
10. The power conversion apparatus according to claim 8, wherein
the coolant channel forming body is integrally formed with the
housing.
11. The power conversion apparatus according to claim 7, wherein
the holding member constitutes a part of a coolant channel forming
body configured to form a cooling channel on an opposite side of
the heat radiation member from the power semiconductor device.
12. The power conversion apparatus according to claim 7, wherein
the heat radiation member is crimped to the module encapsulant
body.
13. The power conversion apparatus according to claim 7, wherein
the surface of the conductive plate, which is on an opposite side
from the power semiconductor module, is exposed on a surface of the
module encapsulant body, and the heat radiation member is crimped
to the module encapsulant body through an insulating member.
14. The power conversion apparatus according to claim 7, wherein
the heat radiation member comprises a first heat radiation member
and a second heat radiation member, and the module encapsulant body
is sandwiched between the first heat radiation member and the
second heat radiation member.
15. The power conversion apparatus according to claim 7, wherein
the heat radiation member has a plurality of heat radiation fins on
an opposite side from the module encapsulant body.
Description
CROSS REFERENCE
[0001] This application is a continuation of U.S. application Ser.
No. 14/124,172, filed Dec. 5, 2013, which is a National Stage
application of PCT International Application No. PCT/JP2012/063065,
filed May 22, 2012, which claims priority to Japanese Patent
Application No. 2011-128304, filed Jun. 8, 2011, the disclosures of
which are expressly incorporated by reference herein.
TECHNICAL FIELD
[0002] The present invention relates to a power module and a power
conversion apparatus using the same, which has power semiconductor
devices for performing switching operation for converting a direct
current electric power into an alternate current electric power or
converting an alternate current electric power into a direct
current electric power.
BACKGROUND ART
[0003] In recent years, it is desired to widely popularize hybrid
vehicles and electric automobiles in a short time in order to
reduce the environmental load. In hybrid vehicles and electric
automobiles, reduction of the sizes of mounted components and
reduction of the cost are regarded as important, and a power
conversion apparatus is not the exception and the size and the cost
of the power conversion apparatus are desired to be reduced. As a
result, since the density of heat generation becomes high, it is
necessary to improve the cooling performance.
[0004] Among electronic components constituting the power
conversion apparatus, the highest amount of heat generation is made
by a power module. A known example of method for cooling the power
module is a both-sides direct cooling method for inserting a power
module into a cooling channel and cooling the power module by way
of radiation fins provided at both sides (see PTL 1).
[0005] The power module described in PTL 1 is made by sandwiching a
semiconductor chip with conductive plates and performing vacuum
thermocompression bonding upon interposing insulating sheets
between the conductive plates and first and second heat sinks, and
adhering a bottom case, a top case, and a side case to the
integrally structured heat sinks with an adhesive.
CITATION LIST
Patent Literature
[0006] PTL 1: JP 2008-259267 A
SUMMARY OF INVENTION
Technical Problem
[0007] However, the power module described in PTL 1 has such
structure that the bottom case, the top case, and the side case are
adhered with the adhesive, and therefore there is a problem in the
rigidity, and there is concern about durability such as deformation
when the power module is mechanically fixed to the housing of the
power conversion apparatus, and deformation by creep, fatigue
fracture, and the like.
Solution to Problem
[0008] According to a first aspect of the present invention, there
is provided a power module including: a plurality of semiconductor
devices constituting upper/lower arms of an inverter circuit; a
plurality of conductive plates arranged to face electrode surfaces
of the semiconductor devices; and a module case configured to
accommodate the semiconductor devices and the conductive plates,
wherein the module case includes, a heat radiation member made of
plate-like metal and facing a surface of the conductive plate, and
a metallic frame body having an opening portion that is closed by
the heat radiation member, wherein a heat radiation fin unit having
a plurality of heat radiation fins vertically arranged thereon is
provided at a center of the heat radiation member, and a joint
portion with the frame body is provided at an external peripheral
edge of the heat radiation member, and the heat radiation member
has a heat conductivity higher than that of the frame body, and the
frame body is of a higher rigidity than that of the heat radiation
member.
[0009] According to a second aspect of the present invention, in
the power module according to the first aspect, it is preferable
that the heat radiation member is a first heat sink and a second
heat sink arranged to face each other.
[0010] According to a third aspect of the present invention, in the
power module according to the second aspect, it is preferable that
the first heat sink and the second heat sink have a fin peripheral
edge unit provided to enclose the heat radiation fin unit between
the joint portion and the heat radiation fin unit of them each, and
when pressure is applied to the first heat sink and the second heat
sink from an external side toward inside of the module case,
bending rigidity of the peripheral edge unit of the first heat sink
is configured to be less than bending rigidity of the peripheral
edge unit of the second heat sink, so that the peripheral edge unit
of the first heat sink is preferentially deformed.
[0011] According to a fourth aspect of the present invention, in
the power module according to the third aspect, it is preferable
that a thickness of the fin peripheral edge unit of the first heat
sink is thinner than a thickness of the fin peripheral edge unit of
the second heat sink.
[0012] According to a fifth aspect of the present invention, in the
power module according to any of the second to fourth aspects, it
is preferable that the plurality of conductive plates include a
first conductive plate connected via a metal bonding material with
an electrode surface of the semiconductor device, a second
conductive plate connected via the metal bonding material with the
other electrode surface of the semiconductor device, a module
primary encapsulant body made by sealing the semiconductor device,
the first conductive plate, and the second conductive plate with an
encapsulant and the module case are crimped with an insulating
member, and a portion of the first and second conductive plates is
exposed from the encapsulant so as to be in contact with the
insulating member.
[0013] According to a sixth aspect of the present invention, in the
power module according to any of the second to fifth aspects, it is
preferable that the frame body and the first heat sink, and the
frame body and the second heat sink are joined by fused junction or
solid-state welding.
[0014] According to a seventh aspect of the present invention,
there is provided a power conversion apparatus configured to
convert electric power from a direct current to an alternate
current or from an alternate current to a direct current, using
switching operation of a semiconductor device, the power conversion
apparatus including: the power module according to any of the
second to sixth aspects; and a channel forming body configured to
from a cooling channel in which coolant flows, wherein the power
module has first and second heat sinks arranged in the cooling
channel and performs heat exchange with a coolant flowing in the
cooling channel, so that heat from the semiconductor device is
radiated to the coolant.
[0015] According to an eighth aspect of the present invention, in
the power conversion apparatus according to the seventh aspect, it
is preferable that the channel forming body is formed with an
opening portion in communication with the cooling channel, the
power module includes a cylindrical unit in a cylindrical shape
having a bottom; and a flange portion formed in an opening of the
cylindrical unit and fixed to the channel forming body to close the
opening portion of the channel forming body, wherein the
cylindrical unit is formed by joining the first heat sink and the
second heat sink to the frame body, and a heat radiation fin
provided on each of the first heat sink and the second heat sink is
vertically arranged to protrude in the cooling channel.
Advantageous Effects of Invention
[0016] According to the present invention, a power module achieving
not only a high degree of rigidity but also a high degree of heat
radiation performance and a power conversion apparatus using the
same can be provided.
BRIEF DESCRIPTION OF DRAWINGS
[0017] FIG. 1 is a figure illustrating a control block of a hybrid
vehicle.
[0018] FIG. 2 is a figure for explaining a configuration of an
electric circuit of an inverter circuit.
[0019] FIG. 3 is a perspective view illustrating an external
appearance of a power conversion apparatus.
[0020] FIG. 4 is an exploded perspective view illustrating the
power conversion apparatus.
[0021] FIG. 5 is a perspective view illustrating a case of FIG. 4
when it is seen from below.
[0022] FIG. 6 is a perspective view illustrating a power
module.
[0023] FIG. 7 is a cross sectional schematic view illustrating the
power module.
[0024] FIG. 8 is a cross sectional schematic view illustrating a
module primary encapsulant body and a supporting mold body.
[0025] FIG. 9 is a circuit diagram illustrating a circuit
configuration of the power module.
[0026] FIG. 10 is a perspective view illustrating a conductive
plate assembly from which a module case, an insulating sheet, and
first and second sealing resins are removed.
[0027] FIG. 11 is a perspective view illustrating how the module
primary encapsulant body is inserted into the module case.
[0028] FIG. 12 is a cross sectional schematic view illustrating a
module case.
[0029] FIG. 13 is an exploded perspective view illustrating the
module case.
[0030] FIG. 14 is a cross sectional schematic view illustrating a
frame body.
[0031] FIG. 15 is a cross sectional schematic view illustrating how
the module primary encapsulant, body is inserted into the module
case.
[0032] FIG. 16 is a cross sectional schematic view illustrating the
state in which the module is pressurized and the first and second
heat sinks are brought into pressurized contact with the module
primary encapsulant body.
DESCRIPTION OF EMBODIMENTS
[0033] Hereinafter, an embodiment for carrying out the present
invention will be explained with reference to drawings. FIG. 1 is a
figure illustrating a control block of a hybrid vehicle. An engine
EGN and a motor generator MG1 generate driving torque for a
vehicle. The motor generator MG1 has not only a function of
generating the rotation torque but also converting the mechanical
energy applied from the outside to the motor generator MG1 into an
electric power.
[0034] The motor generator MG1 is, for example, a synchronous
machine or an induction machine, and as described above, operates
not only as a motor but also as a generator in accordance with
operation method. When the motor generator MG1 is mounted on an
automobile, the motor generator MG1 is preferably small and outputs
high level of output power, and a permanent magnet synchronous
electric motor using a magnet Such as neodymium is suitable for the
motor generator MG1. In addition, the permanent magnet synchronous
electric motor generates less heat in the rotor as opposed to an
inductive electric motor, and therefore, from this point of view,
the permanent magnet synchronous electric motor is also
advantageous as an automobile motor.
[0035] The output torque of the engine EGN is transmitted to the
motor generator MG1 via a torque distribution mechanism TSM. The
rotation torque from the torque distribution mechanism TSM or the
rotation torque generated by the motor generator MG1 is transmitted
to wheels via a transmission TM and a differential gear DIF. On the
other hand, during driving with regenerative braking, the rotation
torque from the wheels is transmitted to the motor generator MG1,
and on the basis of the provided rotation torque, an alternate
current electric power is generated. As explained later, the
generated alternate current electric power is converted by a power
conversion apparatus 200 into a direct current electric power,
which charges a high voltage battery 136, and the charged electric
power is used again for driving energy.
[0036] Subsequently, the power conversion apparatus 200 will be
explained, which converts the electric power from a direct current
to an alternate current or from an alternate current to a direct
current by switching operation of the semiconductor device. The
inverter circuit 140 is electrically connected with the battery 136
via a direct current connector 138, and the electric power is
exchanged between the battery 136 and the inverter circuit 140.
When the motor generator MG1 is operated as a motor, the inverter
circuit 140 generates alternate current electric power on the basis
of the direct current electric power provided via the direct
current connector 138 from the battery 136, and is provided via the
alternate current terminal 188 to the motor generator MG1. The
configuration including the motor generator MG1 and the inverter
circuit 140 operates as electric power generation unit.
[0037] It should be noted that, in the present embodiment, the
electric power generation unit is activated as an electric motor
unit with the electric power of the battery 136, so that the
vehicle can be driven with only the power of the motor generator
MG1. Further, in the present embodiment, the electric power
generation unit is activated as a power generation unit with the
motive power of the engine EGN or the motive power provided by the
wheels, so that the battery 136 can be charged.
[0038] The power conversion apparatus 200 includes a capacitor
module 500 for smoothing the direct current electric power provided
to the inverter circuit 140.
[0039] The power conversion apparatus 200 includes a communication
connector for receiving commands from a host control apparatus or
transmitting data representing the state to the host control
apparatus. The power conversion apparatus 200 causes a control
circuit 172 to calculate the amount of control of the motor
generator MG1 on the basis of a command given by the connector,
further perform calculation to determine whether to operate as a
motor or as an electric power generator, and generates a control
pulse based on a calculation result, and provides the control pulse
to the driver circuit 174. The driver circuit 174 generates a
driving pulse for controlling the inverter circuit 140 on the basis
of the provided control pulse.
[0040] Subsequently, the configuration of the electric circuit of
the inverter circuit 140 will be explained with reference to FIG.
2. It should be noted that, in the present embodiment, an insulated
gate bipolar transistor is used as a semiconductor device, and this
will be hereinafter abbreviated as IGBT.
[0041] A series circuit 150 of upper/lower arms is constituted by
an IGBT 328 and a diode 156 of an upper arm and an IGBT 330 and a
diode 166 of a lower arm. The inverter circuit 140 includes the
series circuits 150 in association with three phases, i.e.,
U-phase, V-phase, and W-phase of the alternate current electric
power which is to be output.
[0042] In this embodiment, these three phases correspond to the
phases winding wires of the three phases of armature winding wire
of the motor generator MG1. The series circuit 150 of the
upper/lower arms of each of the three phases outputs an alternate
current electric current from an intermediate electrode 169 which
is a middle portion of the series circuit. The intermediate
electrode 169 is connected to an alternate current bus bar 802
which is an alternate current electric power line to a motor
generator MG1 via an alternate current terminal 159 and an
alternate current terminal 188.
[0043] The collector electrode 153 of the IGBT 328 of the upper arm
is electrically connected via the positive terminal 157 to a
capacitor terminal 506 at a positive side of the capacitor module
500. The emitter electrode of the IGBT 330 of the lower arm is
electrically connected via a negative terminal 158 to a capacitor
terminal 504 at a negative side of the capacitor module 500.
[0044] As described above, the control circuit 172 receives a
control command from a host control apparatus via the connector 21,
and on the basis of this, the control circuit 172 generates a
control pulse which is a control signal for controlling the IGBT
328 and the IGBT 330 constituting the upper arm or the lower arm of
the series circuit 150 of each phase constituting the inverter
circuit 140, and the control pulse is provided to the driver
circuit 174.
[0045] On the basis of the control pulse, the driver circuit 174
provides the driving pulse for controlling the IGBT 328 and the
IGBT 330 constituting the upper arm or the lower arm of the series
circuit 150 of each phase to the IGBT 328 and the IGBT 330 of each
phase. The IGBT 328 and the IGBT 330 perform conduction or cutting
off operation on the basis of the driving pulse provided from the
driver circuit 174, convert the direct current electric power
provided by the battery 136 to three-phase alternate current
electric power, and this converted electric power is provided to
the motor generator MG1.
[0046] The IGBT 328 of the upper arm includes a collector electrode
153, an emitter electrode 155 for a signal, and a gate electrode
154. The IGBT 330 of the lower arm includes a collector electrode
163, an emitter electrode 165 for a signal, and a gate electrode
164. The diode 156 of the upper arm is electrically connected
between the collector electrode 153 and the emitter electrode 155.
The diode 166 is electrically connected between the collector
electrode 163 and the emitter electrode 165.
[0047] It should be noted that switching power semiconductor device
may be Metal Oxide Semiconductor-type Field Effect Transistor
(hereinafter abbreviated as MOSFET), and in this case, the diode
156 and the diode 166 are unnecessary. When the direct current
voltage is relatively high, the switching power semiconductor
device is preferably be an IGBT, and when the direct current
voltage is relatively low, the switching power semiconductor device
is preferably be a MOSFET.
[0048] The capacitor module 500 includes a capacitor terminal 506
at the positive side, a capacitor terminal 504 at the negative
side, a power supply terminal 509 at the positive side, and the
power supply terminal 508 at the negative side. The direct current
electric power of the high voltage from the battery 136 is provided
via the direct current connector 138 to the power supply terminal
509 at the positive side and the power supply terminal 508 at the
negative side, and the direct current electric power is provided to
the inverter circuit 140 from the capacitor terminal 506 at the
positive side and the capacitor terminal 504 at the negative side
of the capacitor module 500.
[0049] On the other hand, the direct current electric power
converted from the alternate current electric power by the inverter
circuit 140 is provided to the capacitor module 500 from the
capacitor terminal 506 at the positive side and the capacitor
terminal 504 at the negative side, and the direct current electric
power is provided from power supply terminal 509 at the positive
side and the power supply terminal 508 at the negative side via the
direct current connector 138 to the battery 136, and is accumulated
in the battery 136.
[0050] The control circuit 172 includes a microcomputer for
performing calculation processing of switching timing of the IGBT
328 and the IGBT 330. Input information into the microcomputer
includes a target torque value required for the motor generator
MG1, an electric current value provided from the series circuit 150
to the motor generator MG1, and a magnetic pole position of the
rotor of the motor generator MG1.
[0051] The target torque value is based on the command signal which
is output from the host control apparatus, not shown. The electric
current value is detected on the basis of a detection signal
provided by the electric current sensor 180. The magnetic pole
position is detected on the basis of the detection signal which is
output from a rotation magnetic pole sensor (not shown) such as a
resolver provided in the motor generator MG1. In the present
embodiment, for example, the electric current sensor 180 detects
the 3-phase electric current values. Alternatively, the electric
current sensor 180 detects may detect two-phase electric current
values, or may obtain the 3-phase electric currents by
calculation.
[0052] The microcomputer in the control circuit 172 calculates
electric current command values of d axis, q axis of the motor
generator MG1 on the basis of the target torque value, and
calculates the voltage command value of d axis, q axis on the basis
of difference between the electric current command values of d
axis, q axis thus calculated and the electric current value of d
axis, q axis thus detected, and converts the voltage command values
of d axis, q axis thus calculated into voltage command values of
U-phase, V-phase, W-phase on the basis of the detected magnetic
pole position. Then, the microcomputer generates a pulse-like
modulated wave on the basis of comparison between a fundamental
wave (sine wave) and a carrier wave (triangular wave) based on
U-phase, V-phase, W-phase voltage command values, and outputs the
modulated wave thus generated to a driver circuit 174 as a PWM
(pulse width modulation) signal.
[0053] When the driver circuit 174 drives the lower arm, the drive
signal obtained by amplifying the PWM signal is output to the gate
electrode 164 of the IGBT 330 of the lower arm corresponding
thereto. When the driver circuit 174 drives the upper arm, the PWM
signal is amplified upon shifting the level of the reference
potential of the PWM signal to the level of the reference potential
of the upper arm. This is adopted as the drive signal, and is
output to the gate electrode 154 of the IGBT 328 of the upper arm
corresponding thereto.
[0054] In addition, the microcomputer in the control circuit 172
performs abnormality detection (over current, over voltage, over
temperature, and the like), and protects the series circuit 150.
Accordingly, the control circuit 172 receives sensing information.
For example, a corresponding driving unit (IC) receives information
about the electric currents flowing through the emitter electrodes
of each IGBT 328 and each IGBT 330 from the signal emitter
electrode 155 and the signal emitter electrode 165 of each arm.
Accordingly, each driving unit (IC) performs over current
detection, and when the over current is detected, the switching
operation of the corresponding IGBT 328, IGBT 330, is stopped, so
that the IGBT 328 and the IGBT 330 are protected from over
current.
[0055] The microcomputer receives information about the temperature
of the series circuit 150 from a temperature sensor (not shown)
provided in the series circuit 150. The microcomputer receives
information about the voltage of the series circuit 150 at the
direct current positive side. The microcomputer performs the over
temperature detection and the over voltage detection on the basis
of the information, and when the over temperature or the over
voltage is detected, all the switching operation of the IGBT 328
and the IGBT 330 is stopped.
[0056] FIG. 3 is a perspective view illustrating an external
appearance of the power conversion apparatus 200. FIG. 4 is a
figure for explaining an internal configuration of the case 10 of
the power conversion apparatus 200, and is an exploded perspective
view of the power conversion apparatus 200. The power conversion
apparatus 200 includes a case 10 accommodating the power modules
300a to 300c and the capacitor module 500, a bus bar assembly 800
arranged above the capacitor module 500, a driver circuit board 22
arranged above the bus bar assembly 800, a metal base plate fixed
above the case 10, a control circuit board 20 accommodated in the
metal base plate 11, and a lid 8 fixed to the upper portion of the
metal base plate 11.
[0057] The case 10 is provided with a channel forming body 12 for
forming a channel in which coolant such as water flows, and a lower
cover 420 for closing the opening at the lower side of the channel
forming body 12 is attached on the lower surface of the case 10. As
described above, this is configured so as to allow the works to be
performed in order from the upper side to arrange the channel
forming body 12 in the lower portion of the power conversion
apparatus 200, and subsequently fix necessary components such as
the capacitor module 500, the bus bar assembly 800, the substrate,
and the like, and this improves the productivity and the
reliability.
[0058] FIG. 5 is a figure for explaining the case 10 and the
channel forming body 12, and is a figure showing the case 10 as
illustrated in FIG. 4 when it is seen from below. The channel
forming body 12 forms a U-shaped cooling channel 19 which is along
the inner periphery of the three sides of the case 10. The cooling
channel 19 includes a first channel unit 19a formed along a side in
the longitudinal direction of the case 10, a second channel unit
19b formed along a side in the lateral direction of the case 10,
and a third channel unit 19c formed along a side in the
longitudinal direction of the channel forming body 12. The second
channel unit 19b forms a returning channel of the cooling channel
19 forming the U shape.
[0059] An inlet pipe 13 through which the coolant flows in and an
outlet pipe 14 through which the coolant flows out are provided on
a side surface of the case 10 that at the opposite side to the side
where the second channel unit 19b is formed. The coolant flows in
the direction of a flow direction 417 indicated by an arrow, and
flows through the first channel unit 19a via the inlet pipe 13 as
shown by a flow direction 418. Further, the coolant flows through
the second channel unit 19b as shown by a flow direction 421,
thereafter flows through the third channel unit 19c as shown by a
flow direction 422, and further, flows out through the outlet pipe
14 as shown by a flow direction 423. All of the first channel unit
19a, the second channel unit 19b, and the third channel unit 19c
are formed such that the size in the depth direction is larger than
the size in the width direction.
[0060] The opening unit 404 of the channel forming body 12 at the
lower surface side is closed by a lower cover 420 attached to the
lower surface of the case 10. A seal member 409 is provided between
the lower cover 420 and the case 10 so as to maintain airtightness.
The lower cover 420 is provided with protruding units 406a to 406c
which protrude toward the direction opposite to the side where the
cooling channel 19 is arranged. The protruding units 406a to 406c
is provided in association with the power modules 300a to 300c
arranged in the cooling channel 19 explained later.
[0061] As illustrated in FIG. 4, opening units 400a to 400c in
communication with the cooling channel 19 are also formed at the
case upper surface side of the channel forming body 12, and the
opening unit 404 formed at the case lower surface side and the
opening units 400a to 400c at the case upper surface side are
formed to face each other, and therefore, this configuration can be
easily manufactured by aluminum casing. The channel forming body 12
and the case 10 are integrally made by casting aluminum material,
so that the thermal conductivity of the entire power conversion
apparatus 200 is improved, and the efficiency of cooling is
improved. Further, by integrally making the channel forming body 12
and the case 10, the mechanical strength can also be improved.
[0062] Back to FIG. 4, on the upper surface of one of the sides
(side where the first channel unit 19a of FIG. 5 is formed) of the
channel forming body along the longitudinal direction of the case
10, an opening unit 400a and an opening unit 400b are formed along
the side surface of the case 10, and as shown by a broken line, an
opening unit 400c is formed on the upper surface at the other side
thereof (side where the second channel unit 19b of FIG. 5 is
formed). Each of the opening units 400a to 400c is closed by the
inserted power modules 300a to 300c. An accommodating space 405 for
accommodating the capacitor module 500 is formed between the
channel forming body 12 at both sides. By accommodating the
capacitor module 500 in such accommodating space 405, the capacitor
module 500 is cooled by coolant flowing through the cooling channel
19. The capacitor module 500 is arranged to be enclosed by the
cooling channel 19 (the first to third channel units 19a to 19c) as
shown in FIG. 5, and therefore, the capacitor module 500 is
efficiently cooled.
[0063] As described above, the cooling channel 19 is formed along
the outer side surface of the capacitor module 500, and therefore,
the cooling channel 19, the capacitor module 500, and the power
modules 300a to 300c are arranged in an organized manner, and the
entire size is further reduced. In addition, the first channel unit
19a and the third channel unit 19c are arranged along the longer
sides of the capacitor module 500, and the distance between the
power modules 300a to 300c inserted and fixed in the cooling
channel 19 and the capacitor module 500 is maintained at a
substantially same distance. Therefore, the circuit constant of the
power module circuit and the smoothing capacitor can easily
maintain balance in each phase of the three phases, which makes a
circuit configuration that can easily reduce the spike voltage.
[0064] The bus bar assembly 800 is arranged above the capacitor
module 500. The bus bar assembly 800 includes an alternate current
bus bar 802 and a holding member, and holds the electric current
sensor 180. The driver circuit board 22 is arranged above the bus
bar assembly 800. The metal base plate 11 is arranged between the
driver circuit board 22 and the control circuit board 20.
[0065] The metal base plate 11 is fixed to the case 10. The metal
base plate 11 functions as an electromagnetic shield for the
circuit group mounted on the driver circuit board and the control
circuit board 20, releases heat generated by the driver circuit
board 22 and the control circuit board 20, and cools the driver
circuit board 22 and the control circuit board 20.
[0066] A cap 18 is a member for closing a work window for
connecting a terminal extended from the DC-DC converter. The lid 8
fixed to the metal base plate 11 has a function of protecting the
control circuit board 20 from external electromagnetic noise.
[0067] The case 10 according to the present embodiment is such that
a portion where the channel forming body 12 is accommodated is in a
substantially rectangular solid shape, but a protruding
accommodating unit 10a is formed from one side surface side of the
case 10. The protruding accommodating unit 10a includes a terminal
extended from the DC-DC converter, a direct current bus bar (not
shown), and a resistor 450. In this case, the resistor 450 is a
resistor device for discharging the charges accumulated in the
capacitor device of the capacitor module 500. As described above,
the electric circuit components between the battery 136 and the
capacitor module 500 are integrated in the protruding accommodating
unit 10a, and therefore, this can suppress complexity of the
wiring, and contribute to the reduction of the size of the entire
apparatus.
[0068] The configuration of the power modules 300a to 300c used for
the inverter circuit 140 will be explained with reference to FIGS.
6 to 16. It should be noted that, all of the power modules 300a to
300c have the same structure, and therefore, the structure of the
power module 300a will be explained representing each of them. The
cross sectional views of FIGS. 7, 8, 12 and 14 to 16 are cross
sectional schematic views (schematic diagrams) taken along line A-A
of FIG. 6. It should be noted that they are also cross sectional
schematic views (schematic diagrams) taken along line B-B, and
reference symbols in parentheses are given to the constituent
elements shown in the cross section taken along line B-B. In the
cross sections taken along line A-A and line B-B, a positioning pin
601 and a positioning hole 382c explained later would not appear,
but are shown for the sake of convenience.
[0069] In FIGS. 6 to 10, 15 and 16, the signal terminal 325U
corresponds to the gate electrode 154 as illustrated in FIG. 2, and
the signal terminal 325L corresponds to the gate electrode 164 as
illustrated in FIG. 2. In FIG. 6, the signal terminal 327
corresponds to the signal emitter electrodes 155, 165. The direct
current positive terminal 315B is the same as the positive terminal
157 as illustrated in FIG. 2, and the direct current negative
terminal 319B is the same as the negative terminal 158 as
illustrated in FIG. 2. The alternate current terminal 320B is the
same as the alternate current terminal 159 as illustrated in FIG.
2.
[0070] FIG. 6 is a perspective view illustrating the power module
300a. FIG. 7 is a cross sectional schematic view illustrating the
power module 300a. FIG. 8 is a cross sectional schematic view
illustrating a module primary encapsulant body 302 accommodated in
the power module 300a and a supporting mold body 600 connected to
the module primary encapsulant body 302. FIG. 9 is a circuit
diagram illustrating the circuit configuration of the power module
300a. FIG. 10 is a perspective view illustrating the conductive
plate assembly, wherein the module case 37 of the power module
300a, the insulating sheet 333, and the first and second sealing
resins 348, 351 are removed to help understanding. In FIG. 10, a
signal wire 326 is not shown.
[0071] As illustrated in FIGS. 6 and 7, the power module 300a
includes a metallic module case 37, and in the module case 37, a
module primary encapsulant body 302 (see FIG. 8) is accommodated.
The module primary encapsulant body 302 is configured to include
power semiconductor devices (IGBT 328, IGBT 330, diode 156, diode
166) constituting the series circuit 150 as shown in FIGS. 2 and
9.
[0072] The circuit configuration of the power module will be
explained will be explained with reference to FIG. 9. As
illustrated in FIG. 9, the collector electrode of the IGBT 328 at
the upper arm side and the cathode electrode of the diode 156 at
the upper arm side are connected via the conductive plate 315.
Likewise, the collector electrode of the IGBT 330 at the lower arm
side and the cathode electrode of the diode 166 at the lower arm
side are connected via a conductive plate 320. The emitter
electrode of the IGBT 328 at the upper arm side and the anode
electrode of the diode 156 at the upper arm side are connected via
a conductive plate 318. Likewise, the emitter electrode of the IGBT
330 at the lower arm side and the anode electrode of the diode 166
at the lower arm side are connected via a conductive plate 319. The
conductive plates 318 and 320 are connected via an intermediate
electrode 329. With such circuit configuration, the series circuit
150 of the upper/lower arms is formed.
[0073] As illustrated in FIGS. 8 and 10, the power semiconductor
devices (IGBT 328, IGBT 330, diode 156, diode 166) have plate-like
flat structure, the electrodes of the power semiconductor device
are formed on the front and back surfaces.
[0074] The electrodes of the power semiconductor device are
sandwiched by the conductive plate 315 and the conductive plate
318, or the conductive plate 320 and the conductive plate 319
provided to face the electrode surfaces thereof. More specifically,
the conductive plate 315 and the conductive plate 318 are in
laminated arrangement in which they are arranged substantially
parallel to each other to face each other with the IGBT 328 and the
diode 156 interposed therebetween. Likewise, the conductive plate
320 and the conductive plate 319 are in laminated arrangement in
which they are arranged substantially parallel to each other to
face each other with the IGBT 330 and the diode 166 interposed
therebetween. As illustrated in FIG. 10, the conductive plate 320
and the conductive plate 318 are connected via the intermediate
electrode 329. With this connection, the upper arm circuit and the
lower arm circuit are electrically connected, and an upper/lower
arms series circuit is formed.
[0075] The conductive plate 315 at the direct current side and the
conductive plate 320 at the alternate current side are arranged
substantially in the same plane. The collector electrode of the
IGBT 328 at the upper arm side and the cathode electrode of the
diode 156 at the upper arm side are fixed to the conductive plate
315. The collector electrode of the IGBT 330 at the lower arm side
and the cathode electrode of the diode 166 at the lower arm side
are fixed to the conductive plate 320. Likewise, the conductive
plate 318 at the alternate current side and the conductive plate
319 at the direct current side are arranged substantially in the
same plane. The emitter electrode of the IGBT 328 at the upper arm
side and the anode electrode of the diode 156 at the upper arm side
are fixed to the conductive plate 318. The emitter electrode of the
IGBT 330 at the lower arm side and the anode electrode of the diode
166 at the lower arm side are fixed to the conductive plate
319.
[0076] Each conductive plates 315, 318, 319, 320 according to the
present embodiment is preferably a wire for a high electric current
circuit, and is preferably made of a material of which thermal
conductivity is high such as pure copper, copper alloy, or the like
and of which electric resistance is low, and the thickness thereof
is preferably equal to or more than 0.5 mm.
[0077] As illustrated in FIG. 8, each of conductive plates 315,
318, 319, 320 is formed with a device fixing unit so as to protrude
to the power semiconductor device side. Each power semiconductor
device is fixed to the device fixing unit via the metal bonding
material 160. The metal bonding material 160 is, for example, low
temperature sintering joining materials including silver sheet and
small metallic particles, or Pb-free solder of which thermal
conductivity is high and of which environment performance is high,
or, for example, Sn--Cu solder, Sn--Ag--Cu solder, Sn--Ag--Cu--Bi
solder, or the like.
[0078] Each of conductive plates 315, 318, 319, 320 also serves as
the function of heat sink, and therefore, the external size of the
device fixing unit is preferably, substantially the same as the
external size of the power semiconductor device, or preferably
formed to be larger than the external size of the power
semiconductor device. Therefore, the thermal conductive path can be
ensured, and the heat radiation performance is expected to
improve.
[0079] In the present embodiment, the external size of the device
fixing unit of the conductive plate 315 and the conductive plate
320 is formed to be larger than the external size of the power
semiconductor device, and the external size of the device fixing
unit of the conductive plate 318 and the conductive plate 319 is
substantially the same as the external size of the power
semiconductor device, but is formed to be slightly smaller than the
external size of the power semiconductor device. Therefore, the
conductive plates 318, 319 are arranged at the upper side, and the
conductive plates 315, 320 are arranged at the lower side, and when
the conductive plates 315, 318, 319, 320 are collectively connected
to the power semiconductor device by solder in this state, the
solder can be prevented from flowing and dropping to the lower
side. As a result, the solder can be prevented from short-circuited
with the solder and the conductive plate at the lower side because
of the solder flows and falls to the lower side.
[0080] The signal wire 324U and the signal wire 324L for connection
with the driver circuit board 22 are connected with the gate
electrode of the power semiconductor device by wire bonding, ribbon
bonding, or the like. The wire and the ribbon are preferably
aluminum. Using solder and the like instead of the wire and the
ribbon, the signal wire 324U and the signal wire 324L may be
connected to the gate electrode. The signal wire 324U and the
signal wire 324L preferably use pure copper or copper alloy. It
should be noted that the signal wire 324U and the signal wire 324L
are integrally formed with the conductive plates 315, 320, and the
like.
[0081] The conductive plate assembly connected to the signal wires
324U, 324L is arranged in a mold for transfer mold, and the mold is
filled with a first sealing resin 348 such as epoxy resin, and the
first sealing resin 348 is formed, whereby the conductive plate
assembly including the power semiconductor device is sealed by the
first sealing resin 348, so that the module primary encapsulant
body 302 is formed. When the transfer mold is performed, the outer
side surfaces of the conductive plates 315, 318, 319, 320 arranged
on both sides of the power semiconductor device are exposed by the
first sealing resin 348, and become heat radiation surface to the
module case 37. The size of the heat radiation surface is
preferably larger than the external size of the device fixing unit.
Accordingly, the thermal conduction path is ensured, and the heat
radiation performance is expected to improve. It should be noted
that the entire outer side surfaces of the conductive plates 315,
318, 319, 320 facing the inner surface of the module case 37 may be
exposed from the first sealing resin 348 to be used as heat
radiation surface, or a portion corresponding to each power
semiconductor device may be exposed to be used as heat radiation
surface.
[0082] As illustrated in FIG. 8, the conductive plate 315 and the
like is sealed by the first sealing resin 348 while the heat
radiation surface thereof is exposed, and, as illustrated in FIG.
7, the insulating sheet 333 having high heat conductivity is bonded
to the heat radiation surface by thermocompression bonding. In the
present embodiment, the insulating sheet 333 in which ceramic
particles are dispersed in epoxy resin is employed. The module
primary encapsulant body 302 sealed by the first sealing resin 348
is inserted into the module case 37, and the wide surface of the
module case 37 is pressurized, so that it is bonded on the inner
surface of the module case 37 by thermocompression bonding with the
insulating sheet 333 interposed therebetween. The space remaining
in the module case 37 is filled with the second sealing resin 351,
so that the module case 37 is sealed. The configuration and method
for crimping the module primary encapsulant body 302 to the module
case 37 by pressurizing the module case 37 will be explained
later.
[0083] As described above, the conductive plate 315 and the like
are bonded to the inner wall of the module case 37 by
thermocompression bonding with the insulating sheet 333 interposed
therebetween, whereby the space between the conductive plate 315
and the like and the inner wall of the module case 37 can be
reduced, and the heat generated by the power semiconductor device
can be efficiently transmitted to the module case 37, and the heat
can be radiated from the pin fins vertically arranged on the module
case 37. Further, the insulating sheet 333 is given a certain
thickness and flexibility, and the insulating sheet 333 can absorb
generation of the thermal stress, and it is preferable for use with
the power conversion apparatus 200 for a vehicle where the
temperature greatly changes.
[0084] Subsequently, the supporting mold body 600 will be
explained, which is made by holding, with resin, the driver circuit
174, the capacitor module 500 or the motor generator MG1, and the
relay wires connected to the wires including the terminal of the
module primary encapsulant body 302. As illustrated in FIG. 6,
outside of the module case 37, a metallic direct current positive
wire 315A and a direct current negative wire 319A for electrically
connecting with the capacitor module 500 are provided, and at the
end portions thereof, a direct current positive terminal 315B (157)
and a direct current negative terminal 319B (158) are respectively
formed. Further, outside of the module case 37, a metallic
alternate current wire 320A for providing alternate current
electric power to the motor generator MG1 is provided, and at an
end thereof, an alternate current terminal 320B (159) is formed. As
illustrated in FIG. 9, the direct current positive wire 315A is
connected to the conductive plate 315, and the direct current
negative wire 319A is connected to the conductive plate 319, and
the alternate current wire 320A is connected to the conductive
plate 320.
[0085] As illustrated in FIG. 6, outside of the module case 37,
further, the metallic signal wires 324U, 324L, 326 for electrically
connecting to the driver circuit 174 are provided, and at the end
portions thereof, a signal terminal 325U (154), a signal terminal
325L (164), and a signal terminal 327 (155, 165) are respectively
formed. As illustrated in FIG. 9, the signal wire 324U is connected
to the IGBT 328, and the signal wire 324L is connected to the IGBT
330.
[0086] As illustrated in FIG. 6, the direct current positive wire
315A, the direct current negative wire 319A, alternate current wire
320A, the signal wire 324U and the signal wire 324L are integrally
formed as the supporting mold body 600 while being insulated from
each other by a wire insulating unit 608 formed by resin material.
The wire insulating unit 608 also serves as a support member for
supporting each wire, and the resin material used for this is
preferably thermosetting resin or thermoplastics resin having
insulating property. In the present embodiment, polyphenylene
sulfide (PPS) which is thermoplastics resin is employed.
Accordingly, this can ensure insulating property between the direct
current positive wire 315A, the direct current negative wire 319A,
the alternate current wire 320A, and the signal wire 324U and the
signal wire 324L, and high density wires can be made.
[0087] As illustrated in FIG. 6, the direct current positive wire
315A and the direct current negative wire 319A are laminated to
face each other with the wire insulating unit 608 interposed
therebetween to form a shape extending substantially parallel to
each other. With such arrangement and shape, the electric currents
flowing momentarily during switching operation of the power
semiconductor device flow facing each other and in the opposite
directions. Therefore, the magnetic field generated by the electric
currents cancel each other, and with this action, low inductance
can be achieved. It should be noted that the alternate current wire
320A and the signal wires 324U, 324L also extend in the same
directions as the direct current positive wire 315A and direct
current negative wire 319A.
[0088] As illustrated in FIG. 8, the supporting mold body 600 is
joined and integrated with the module primary encapsulant body 302
at the connection unit 389 by metal junction. The metal junction of
the module primary encapsulant body 302 and the supporting mold
body 600 at the connection unit 389 may use, for example, TIG
welding and the like.
[0089] The direct current positive wire 315A, the direct current
negative wire 319A, the alternate current wire 320A, and supporting
mold body side connection terminal 386 of each of the signal wire
324U and the signal wire 324L are arranged in a row at the side of
the supporting mold body 600 of the connection unit 389. On the
other hand, the direct current positive wire 315A, the direct
current negative wire 319A, the alternate current wire 320A, and
the device side connection terminal 383 of each of the signal wire
324U and the signal wire 324L are arranged in a row at the side of
the module primary encapsulant body 302 of the connection unit 389.
The supporting mold body side connection terminal is formed on each
of the wires 319A, 320A, 324U, 324L is formed, but for the sake of
convenience, the same reference numerals are attached. The same
reference numerals are also attached to the device side connection
terminal.
[0090] FIG. 11 is a perspective view illustrating how the module
primary encapsulant body 302 is inserted into the module case 37.
As illustrated in FIG. 11, the supporting mold body 600 penetrates
through the hole 608e provided in the wire insulating unit 608, and
is fixed to the mole case 37 by the screw 309 attached to the screw
hole 382e of the module case 37. The wire insulating unit 608 is
provided with a positioning pin 601 capable of engaging with the
positioning hole 382c of the module case 37 explained later, in
such a manner that the positioning pin 601 protrudes downward.
[0091] As illustrated in FIG. 7, the connection unit 389 where the
module primary encapsulant body 302 and the supporting mold body
600 are connected by metal joint is sealed in the module case 37 by
the second sealing resin 351. Accordingly, the insulating distance
required between the connection unit 389 and the module case 37 can
be ensured in a stable manner, and therefore, as compared with a
case where no sealing is used, the size of the power module 300a
can be reduced.
[0092] Subsequently, the configuration of the module case 37 will
be explained with reference to FIGS. 11 to 14. FIG. 12 is a cross
sectional schematic view illustrating the module case 37. FIG. 13
is an exploded perspective view illustrating the module case
37.
[0093] As illustrated in FIGS. 11 and 12, the module case 37 is a
CAN-type cooling device in a cylindrical shape having a bottom but
of which upper surface is open. As illustrated in FIGS. 12 and 13,
the module case 37 according to the present embodiment is formed as
follows. The frame body 380 and the first heat sink 371 and the
second heat sink 372 arranged to face each other are manufactured
individually by cold forging operation, die cast, and cutting
operation, and each of the first and second heat sinks 371, 372 are
welded to the frame body 380 by solid-state welding. In the present
embodiment, from the perspective of mass production, reduction of
weight, and improvement of heat radiation performance, the first
heat sink 371 and the second heat sink 372 are formed with pure
aluminum material having a heat conductivity higher than the frame
body 380, and the frame body 380 is formed with aluminum alloy
material having a higher degree of rigidity than the first heat
sink 371 and the second heat sink 372.
[0094] As illustrated in FIGS. 12 and 13, the first heat sink 371
and the second heat sink 372 respectively include the first fin
base 373 and the second fin base 374 in rectangular flat plate
shape, and one surface of the first and second fin bases 373, 374
is arranged with multiple pin fins in a staggered manner.
[0095] As illustrated in FIGS. 12 and 13, at the center of the
first heat sink 371, a heat radiation fin unit 371f is provided.
Multiple pin fins are vertically installed on the heat radiation
fin unit 371f. At the external peripheral edge of the first heat
sink 371, a protruding matching unit 371b, which is a joint portion
with the frame body 380, is provided. Between the protruding
matching unit 371b and the heat radiation fin unit 371f, a thin fin
peripheral edge unit 371p is provided to enclose the heat radiation
fin unit 371f.
[0096] Although riot shown in FIG. 13, a heat radiation fin unit
372f is also provided at the center of the second heat sink 372.
Multiple pin fins are vertically installed on the heat radiation
fin unit 372f. On the external peripheral edge of the second heat
sink 372, a protruding matching unit 372b, which is a joint portion
with the frame body 380, is provided. Between the protruding
matching unit 372b and the heat radiation fin unit 372f, a fin
peripheral edge unit 372p is provided to enclose the heat radiation
fin unit 372f. As explained later, the protruding matching unit
372b is formed to be thinner than the fin peripheral edge unit
372p, and the external peripheral edge of the second fin base 374
is in a step like shape.
[0097] As illustrated in FIG. 12, the first heat sink 371 is formed
such that the material thickness t1 of the fin peripheral edge unit
371p is thinner than the material thickness tf1 of the base of the
heat radiation fin unit 371f (t1<tf1), and the material
thickness tb1 of the protruding matching unit 371b is the same
thickness as the material thickness t1 of the fin peripheral edge
unit 371p (tb1=t1).
[0098] The second heat sink 372 is formed such that the material
thickness t2 of the fin peripheral edge unit 372p is the same
thickness as the material thickness tf2 of the base of the heat
radiation fin unit 372f (t2=tf2), and the material thickness tb2 of
the protruding matching unit 372b is thinner than the material
thickness t2 of the fin peripheral edge unit 372p (tb2<t2).
[0099] The material thickness tf1 of the base of the heat radiation
fin unit 371f is configured to be the same thickness as the
material thickness tf2 of the base of the heat radiation fin unit
372f (tf1=tf2), so that the heat radiation effects of the first
heat sink 371 and the second heat sink 372 become the same. The
material thickness tb1 of the protruding matching unit 371b of the
first heat sink 371 is configured to be the same thickness as the
material thickness tb2 of the protruding matching unit 372b of the
second heat sink 372 (tb1=tb2), so that the first heat sink 371 and
the second heat sink 372 can be joined to the frame body 380 under
the same condition.
[0100] As described above, t1<tf1=tf2 holds, and t2=tf2=tf1
holds, and therefore, the thickness t1 of the fin peripheral edge
unit 371p of the first heat sink 371 is configured to be thinner
than the thickness t2 of the fin peripheral edge unit 372p of the
second heat sink 372 (t1<t2).
[0101] FIG. 14 is a cross sectional schematic view illustrating the
frame body 380. As illustrated in FIG. 14, the frame body 380
includes a frame portion 381 and a flange portion 382, and is
integrally formed by pressing and the like. As illustrated in FIGS.
11 and 12, the frame portion 381 is joined with the first and
second heat sinks 371, 372, thus forming a cylindrical unit 390 in
a cylindrical shape having a bottom in which the module primary
encapsulant body 302 is accommodated.
[0102] As illustrated in FIGS. 13 and 14, the frame portion 381
includes a pair of side plates 381s1, 381s2 (see FIG. 13), a bottom
plate 381u connecting the lower portions of the pair of side plates
381s1, 381s2, and a pair of upper portion side plate 381t1, 381t2
connecting the upper portions of the pair of side plates 381s1,
381s2 (see FIG. 14), and has an overall shape in which rectangular
opening portions 381h1, 381h2 are formed on the pair of wide
surfaces of the cylindrical body having the bottom.
[0103] At the peripheral edge of the rectangular opening portion
381h1 of the frame portion 381, a step portion 382a engaging with
the first heat sink 371 is provided. Likewise, at the peripheral
edge of the rectangular opening portion 381h2 of the frame portion
381, a step portion 382b engaging with the second heat sink 372 is
provided (see FIG. 14).
[0104] As illustrated in FIG. 12, when the protruding matching unit
371b of the first heat sink 371 is engaged with the step portion
382b, the end surface 371b1 of the protruding matching unit 371b
comes into contact with the side wall of the step portion 382a.
When the rotation tool is rotated and moved along the contact
surface (protruding matching unit), the frictional heat is
generated between the metal member and the rotation tool, and
accordingly, the protruding matching unit of the frame portion 381
and the first heat sink 371 is heated and soften, whereby plastic
flow is caused by the ration of the rotation tool, so that the
protruding matching units are welded by solid-state welding, and
the first heat sink 371 is fixed to the frame portion 381.
Likewise, when the protruding matching unit 372b of the second heat
sink 372 is engaged with the step portion 382b, the end surface
372b2 of the protruding matching unit 372b comes into contact with
the side wall of the step portion 382b, and when the rotation tool
is rotated and moved along the contact surface (protruding matching
unit), the protruding matching units of the frame portion 381 and
the second heat sink 372 are welded by solid-state welding, and the
second heat sink 372 is fixed to the frame portion 381. As
described above, the first heat sink 371 and the second heat sink
372 are joined to close the rectangular opening portions 381h1,
381h2 of the frame portion 381 by Friction Stir Welding.
[0105] As illustrated in FIG. 12, the flange portion 382 is
provided in such a manner that it protrudes from the insertion
opening 306 to the outside so as to enclose the insertion opening
306 of the cylindrical unit 390. As illustrated in FIG. 11, the
flange portion 382 is provided with a screw hole 382e to which the
screw 309 for attaching the supporting mold body 600 is attached, a
positioning hole 382c engaged with the positioning pin 601, and a
hole 382d through which a screw (not shown) for attaching the
flange portion 382 to the channel forming body 12 is inserted.
[0106] The method for making the power module by accommodating and
integration the module primary encapsulant body 302 in the module
case 37 will be explained in detail with reference to FIGS. 15 and
16. FIG. 15 is a cross sectional schematic view illustrating how
the module primary encapsulant body 302 is inserted into the module
case 37. FIG. 16 is a cross sectional schematic view illustrating
the first and second heat sinks 371, 372 brought into pressurized
into contact with the module primary encapsulant body 302 by
pressurizing the wide surface of the module case 37 from the
outside.
[0107] As illustrated in FIG. 15, the module primary encapsulant
body 302 is inserted into the module case 37 while sandwiched by
the insulating sheet 333. During insertion, the positioning pin 601
of the supporting mold body 600 is inserted into the positioning
hole 382c of the flange portion 382, and positioning is achieved by
bringing the wide surface of the module primary encapsulant body
302 into the second heat sink 372 constituting the inner surface of
the module case 37. Thereafter, with the screw 309 (see FIGS. 6 and
11), the supporting mold body 600 is mechanically fixed to the
module case 37. Accordingly, the external leads of the signal
terminals 325U, 325L, 327, and the like can be easily attached to
predetermined position of the driver circuit board 22 and the like.
At this occasion, the first heat sink 371 is arranged to face the
conductive plates 318, 319, and the second heat sink 372 is
arranged to face the conductive plates 315, 320. The second heat
sink 372 is in contact with the module primary encapsulant body 302
with the insulating sheet 333 interposed therebetween, but there is
space between the first heat sink 371 and the module primary
encapsulant body 302.
[0108] While the contact plate (not shown) is brought into contact
with the second heat sink 372 from the outer side, the first heat
sink 371 is pressed from the external side toward the inner side of
the module case 37. As described above, the first heat sink 371 has
the thin fin peripheral edge unit 371p thinner than the base of the
heat radiation fin unit 371f, and therefore when the first heat
sink 371 is pressed, the thin fin peripheral edge unit 371p is
deformed preferentially as illustrated in FIG. 16, and the first
heat sink 371 constituting the inner surface of the module case 37
is crimped to the other wide surface of the module primary
encapsulant body 302, and at the same time the second heat sink 372
is also crimped to the wide surface of the module primary
encapsulant body 302.
[0109] When The first heat sink 371 is pressed against the side of
the second heat sink 372, the pressure is also applied to the
second heat sink 372 supported by the contact plate toward the
inner side in the module case 37 from the external side. However,
the material thickness t2 of the fin peripheral edge unit 372p of
the second heat sink 372 is thinner than the material thickness t1
of the material thickness t1 of the fin peripheral edge unit 371p
of the first heat sink 371 (see FIG. 12), and the second heat sink
372 is not deformed.
[0110] The frame body 380 has a higher degree of rigidity than the
first and second heat sinks 371, 372, and therefore, the frame body
380 is not deformed. As described above, when the module case 37 is
pressurized, only the peripheral edge unit 371p of the first heat
sink 371 is deformed with a high degree of priority, and therefore,
at a position where the module primary encapsulant body 302 and the
supporting mold body 600 is positioned, the module case 37 can be
crimped to the module primary encapsulant body 302 with the
insulating sheet 333 interposed therebetween.
[0111] When the second sealing resin 351 is filled in the module
case 37, the space remaining in the module case 37 is filled, and
the module case 37 is sealed as illustrated in FIG. 7.
[0112] As illustrated in FIG. 4, the power module 300a formed as
described above is inserted from the opening unit 400a of the
channel forming body 12 so that it crosses the flow direction of
the coolant, and the flange portion 382 (see FIG. 6) is attached to
the channel forming body 12, so that the opening unit 400a at the
upper surface side of the channel forming body 12 is sealed.
Accordingly, even if the module case 37 is inserted into the
cooling channel 19 in which the coolant flows, the seal for the
coolant can be obtained with the flange portion 382, and therefore,
this prevents the coolant from entering into the inside of the
module case 37.
[0113] The first heat sink 371 and the second heat sink 372 are
arranged such that the wide surface is arranged along the flow
direction of the coolant, and the pin fin protrudes in the
direction perpendicular to the flow direction of the coolant. The
first heat radiation member 371 and the second heat radiation
member 372 exchange heat with the coolant flowing in the cooling
channel 19. The heat from the power semiconductor device is
transmitted via the conductive plate and the like to the external
surface of the module case 37 including the pin fins of the first
and second heat sinks 371, 372, and the heat is radiated to the
coolant.
[0114] As illustrated in FIGS. 2 and 6, the signal terminals 325U
(154), 325L (164), 327 (155, 165) protruding from the power module
300a are connected with the driver circuit 174, and the direct
current positive/negative terminals 315B (157), 319B (158) are
connected to the electric power providing bus bar, and the
alternate current terminal 320B (159) is connected to the alternate
current bus bar 802.
[0115] According to the present embodiment explained above, the
following actions and effects can be achieved.
[0116] (1) The frame body 380 and the first heat sink 371 and the
second heat sink 372 are individually formed, and the first and
second heat sinks 371, 372 are joined with the frame body 380, so
that the module case 37 is formed. Accordingly, the material can be
selected in accordance with the function of the constituent
component, and the material is selected for the frame body 380 with
the rigidity being regarded as important, and the material can be
selected for the first heat sink 371 and the second heat sink 372
with the heat radiation performance being regarded as
important.
[0117] As a result, the power modules 300a to 300c and the power
conversion apparatus 200 using the same can be selected while
achieving riot only high degree of rigidity but also high heat
radiation performance.
[0118] (2) Further, the surfaces of the first heat sink 371 and the
second heat sink 372 constituting the inner surface of the module
case 37 can be made into a desired degree of surface precision in
advance. In the conventional technique in which the module case is
integrally formed, the adhesive surface of the insulating sheet 333
may be undulated, and there is a problem in that the heat radiation
surface of the conductive plate is only in contact with only a part
via the insulating sheet 333. However, according to the present
embodiment, as described above, the surface precision of the inner
surface of the module case 37 can be improved, and the contact
surface with the conductive plate in contact with the insulating
sheet 333 can be increased. As a result, the heat generated from
the power semiconductor device can be efficiently transmitted to
the first heat sink 371 and the second heat sink 372.
[0119] (3) The material thickness t1 of the fin peripheral edge
unit 371p is configured to be thinner than the material thickness
t2 of the fin peripheral edge unit 372p (t1<t2), so that the
bending rigidity of the fin peripheral edge unit 371p of the first
heat sink 371 is lower than the bending rigidity of the fin
peripheral edge unit 372p of the second heat sink 372. Accordingly,
in a step of pressurizing the module case 37 and crimping the
module case 37 to the module primary encapsulant body 302, the fin
peripheral edge unit 371p of the first heat sink 371 is
preferentially deformed.
[0120] Therefore, when the module primary encapsulant body 302 is
positioned so that the wide surface of the module primary
encapsulant body 302 is in contact with the second heat sink 372
constituting the inner surface of the module case 37, the second
heat sink 372 is not deformed during pressurizing process, and
therefore, the positions of the module primary encapsulant body 302
and the supporting mold body 600 are deviated, and the module case
37 can be crimped to the module primary encapsulant body 302. As a
result, the signal terminals 325U, 325L, 327 and the like are
arranged at predetermined positions of the driver circuit board 22
and the like, and can be easily connected to predetermined
portions.
[0121] In contrast, the material thicknesses of both of the fin
peripheral edge units of the first and second heat sinks are formed
to be thin, and the module primary encapsulant body 302 is arranged
at the center of the module case, and the following problem occurs
when the power module is made by applying external pressure to the
first and second heat sinks. More specifically, because there is
difference in the amount of deformation of both of the first and
second heat sinks, the position of the module primary encapsulant
body 302 is deviated, and it may be difficult to appropriately join
the driver circuit board 22 and the like and the signal terminals
325U, 325L, 327 and the like.
[0122] (4) The frame body 380 and the first heat sink 371, and the
frame body 380 and the second heat sink 372 are joined by
solid-state welding. Accordingly, this ensures the sealing property
of the joint surface between the frame body 380 and the first heat
sink 371 and the joint surface between the frame body 380 and the
second heat sink 372, and each of the first and second heat sinks
371, 372 can be firmly fixed to the frame body 380.
[0123] (5) In the present embodiment, the frame body 380 and the
first and second heat sinks 371, 372 are individually manufactured,
and the three components are joined, and therefore, the power
module having a high degree of rigidity and having a less number of
components can be provided, as opposed to the configuration for
holding the pair of heat sinks by adhering the bottom case, the top
case, and the pair of side cases with adhesive which is a
conventional technique.
[0124] (6) In the present embodiment, the frame body 380 integrally
formed has a high degree of rigidity, and therefore, this can
ensure sufficient level of durability against deformation, and,
deformation by creep, fatigue fracture, and the like when the power
module is mechanically fixed to the case of the power conversion
apparatus.
[0125] The following modifications are also within the scope of the
present invention, and one or more of modification can also be
combined with the above embodiment.
[0126] (1) The present invention is not limited to the case where
the material thickness t1 of the fin peripheral edge unit 371p of
the first heat sink 371 is configured to be thinner than the
material thickness t2 of the fin peripheral edge unit 372p of the
second heat sink 372. The fin peripheral edge units 371p, 372p may
be of the same thickness, and the first and second heat sinks 371,
372 may be pressurized from the external side toward the inside of
the module case 37, so that both of the fin peripheral edge units
371p, 372p may be deformed, and the module case 37 may be crimped
to the module primary encapsulant body 302. As described above,
when one of the fin peripheral edge units 371p, 372p is
preferentially deformed, the deviation of the position of the
module primary encapsulant body 302 is prevented, and therefore, it
is preferable to preferentially deform one of the fin peripheral
edge units 371p, 372p.
[0127] (2) In the above embodiment, the material thicknesses of the
fin peripheral edge unit 371p of the first heat sink 371 and the
fin peripheral edge unit 372p of the second heat sink 372 is
changed, so that the bending rigidity is changed, and when the
first and second heat sinks 371, 372 are pressurized, one of them
is preferentially deformed. However, the present invention is not
limited thereto. The bending rigidities of the cross sectional
shapes of the fin peripheral edge unit 372p of the second heat sink
372 and the fin peripheral edge unit 371p of the first heat sink
371 may be changed, and one of the fin peripheral edge unit 372p of
the second heat sink 372 and the fin peripheral edge unit 371p of
the first heat sink 371 may be preferentially deformed. The
thicknesses of the fin peripheral edge unit 371p of the first heat
sink 371 and the fin peripheral edge unit 372p of the second heat
sink 372 may be configured to be the same, and a beam which is a
separate member is attached to one of them to increase the bending
rigidity. Both of the material thicknesses of the fin peripheral
edge unit 371p of the first heat sink 371 and the fin peripheral
edge unit 372p of the second heat sink 372 may be increased, and
multiple cut outs may be made in one of them to reduce the bending
rigidity. As described above, according to various kinds of modes,
the bending rigidities of both of the fin peripheral edge units
371p, 372p are changed, so that one of the fin peripheral edge
units 371p, 372p can be preferentially deformed.
[0128] (3) The heat radiation fin is not limited to the case where
the pin shaped members are employed. Various kinds of shapes such
as flat plate-like fins may be employed. The shape and the number
of fins are determined on the basis of the cooling performance and
the pressure drop required.
[0129] (4) The present invention is not limited to the case where
the frame body 380 and the first heat sink 371, and the frame body
380 and the second heat sink 372 are joined by solid-state welding.
Alternatively, the frame body 380 and the first heat sink 371, and
the frame body 380 and the second heat sink 372 may be joined by
fused junction.
[0130] (5) In order to improve the adhesive property of the
insulating sheet 333, an adhesive layer may be provided on the
surface of the insulating sheet 333 in advance.
[0131] (6) In the above embodiment, the insulating sheet 333 is a
resin sheet made by dispersing ceramics particles in the epoxy
resin. However, the present invention is not limited thereto. The
insulating sheet 333 may employ ceramics sheet such as aluminum
oxide, silicon nitride, aluminum nitride having better heat
conductivity than resin, and the heat radiation grease may be
applied to both surfaces of the ceramics sheet.
[0132] (7) In the above embodiment, the insulating sheet 333 is
used, but the present invention is not limited thereto. Instead of
the insulating sheet 333, grease, compound, and the like having
insulating property may be used.
[0133] (8) In the above embodiment, the material thickness tb1 of
the protruding matching unit 371b of the first heat sink 371 is of
the same thickness as the material thickness t1 of the fin
peripheral edge unit 371p. However, the present invention is not
limited thereto. The material thickness tb1 of the protruding
matching unit 371b may be configured to be thicker than the
material thickness t1 of the fin peripheral edge unit 371p.
[0134] (9) The above embodiment employs the configuration in which
the first heat sink 371, the second heat sink 372, and the frame
body 380 are individually formed and assembled, and employs the
both-sides cooling method for providing the power module 300a in
the cooling channel 19 and cooling both of the first heat sink 371
and the second heat sink 372. However, the present invention is not
limited thereto. Alternatively, it may be possible to employ one
side cooling method for using a wide surface of the module case as
the heat radiation surface arranged in the cooling channel, and the
module case may be constituted by one heat sink and a frame
body.
[0135] (10) The power conversion apparatus can be used as a vehicle
power supply apparatus for other electric vehicles such as railroad
vehicles such as a hybrid train, cargo vehicles such as a truck,
and an industrial vehicle such as a battery forklift truck.
[0136] (11) The power conversion apparatus may be applied to a
power conversion apparatus constituting a power supply apparatus
other than an electric vehicle, such as uninterruptible power
systems used for computer systems and server systems, and power
supply apparatuses used for private power generation
facilities.
[0137] As long as the features of the present invention are not
lost, the present invention is not limited to the above embodiment.
Other modes that can be conceived of within the scope of the
technical concept of the present invention are also included within
the scope of the present invention.
[0138] The contents disclosed in the following priority basis
application are incorporated herein by reference.
[0139] Japanese Patent Application No. 2011-128304 (filed on Jun.
8, 2011)
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