U.S. patent application number 15/532601 was filed with the patent office on 2017-11-16 for supercharging system, control device for supercharging system, and method for operating supercharging system.
This patent application is currently assigned to MITSUBISHI HEAVY INDUSTRIES, LTD.. The applicant listed for this patent is MITSUBISHI HEAVY INDUSTRIES, LTD.. Invention is credited to Mitsufumi GOTO, Hiroyoshi KUBO, Musashi SAKAMOTO, Yukio YAMASHITA.
Application Number | 20170328271 15/532601 |
Document ID | / |
Family ID | 56542745 |
Filed Date | 2017-11-16 |
United States Patent
Application |
20170328271 |
Kind Code |
A1 |
YAMASHITA; Yukio ; et
al. |
November 16, 2017 |
SUPERCHARGING SYSTEM, CONTROL DEVICE FOR SUPERCHARGING SYSTEM, AND
METHOD FOR OPERATING SUPERCHARGING SYSTEM
Abstract
A supercharging system includes: a first supercharger including
a first compressor for compressing air to be supplied to an engine
and a motor for driving the first compressor; a leakage current
measuring part for measuring a leakage current of the motor; and a
first controller for controlling the first supercharger. The first
controller includes a motor control part configured to, when a
measurement result by the leakage current measuring part is not
less than a first threshold, set an upper limit value of an output
command value for the motor to be lower than when the measurement
result is less than the first threshold, and to control an output
of the motor within a range which does not exceed the upper limit
value.
Inventors: |
YAMASHITA; Yukio; (Tokyo,
JP) ; KUBO; Hiroyoshi; (Tokyo, JP) ; GOTO;
Mitsufumi; (Tokyo, JP) ; SAKAMOTO; Musashi;
(Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MITSUBISHI HEAVY INDUSTRIES, LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
MITSUBISHI HEAVY INDUSTRIES,
LTD.
Tokyo
JP
|
Family ID: |
56542745 |
Appl. No.: |
15/532601 |
Filed: |
January 30, 2015 |
PCT Filed: |
January 30, 2015 |
PCT NO: |
PCT/JP2015/052659 |
371 Date: |
June 2, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02T 10/12 20130101;
F02B 39/10 20130101; F02B 37/14 20130101; G01R 19/165 20130101;
F02B 37/004 20130101; F02B 37/013 20130101; F02B 37/24
20130101 |
International
Class: |
F02B 37/24 20060101
F02B037/24; F02B 39/10 20060101 F02B039/10; F02B 37/013 20060101
F02B037/013; G01R 19/165 20060101 G01R019/165; F02B 37/00 20060101
F02B037/00 |
Claims
1. A supercharging system, comprising: a first supercharger
including a first compressor for compressing air to be supplied to
an engine and a motor for driving the first compressor; a leakage
current measuring part for measuring a leakage current of the
motor; and a first controller for controlling the first
supercharger, wherein the first controller includes a motor control
part configured to, if a measurement result by the leakage current
measuring part is not less than a first threshold, set an upper
limit value of an output command value for the motor to be lower
than when the measurement result is less than the first threshold,
and to control an output of the motor within a range which does not
exceed the upper limit value.
2. The supercharging system according to claim 1, wherein the motor
control part is configured to: set, if the measurement result is
not less than the first threshold and less than a second threshold
which is greater than the first threshold, the upper limit value of
the output command value for the motor to be greater than zero and
smaller than when the measurement result is less than the first
threshold; and set, if the measurement result is not less than the
second threshold, the upper limit value of the output command value
for the motor to zero.
3. The supercharging system according to claim 1, wherein the first
supercharger further includes: a first turbine configured to be
capable of being rotary driven by exhaust gas from the engine and
by the motor; and a first nozzle vane configured to adjust a flow
path area of the exhaust gas flowing into the first turbine,
wherein the first controller further includes a first vane control
part for controlling an opening degree of the first nozzle vane on
the basis of a measurement result of the leakage current measuring
part, and wherein the first vane control part is configured to, if
the measurement result by the leakage current measuring part is not
less than the first threshold, control an opening degree of the
first nozzle vane so as to reduce the flow path area compared to
when the measurement result is less than the first threshold, in
response to reduction of the upper limit value of the output
command value for the motor by the motor control part.
4. The supercharging system according to claim 3, wherein the first
vane control part is configured to determine a first target opening
degree of the first nozzle vane on the basis of a difference
between a boost pressure by the supercharging system and a target
boost pressure, and to control the opening degree of the first
nozzle vane to the first target opening degree.
5. The supercharging system according to claim 4, wherein the first
vane control part is configured to obtain a first corrected opening
degree by correcting the first target opening degree, corresponding
to a reduction amount of the output command value for the motor by
the upper limit value, and to control the opening degree of the
first nozzle vane to the first corrected opening degree.
6. The supercharging system according to claim 1, further
comprising: a second supercharger including a second compressor for
compressing air to be supplied to the engine, a second turbine
configured to be rotary driven by exhaust gas from the engine to
drive the second compressor, and a second nozzle vane configured to
adjust a flow path area of the exhaust gas flowing into the second
turbine; and a second controller for controlling the second
supercharger, wherein one of the first supercharger or the second
supercharger is a low-pressure stage supercharger, wherein the
other one of the first supercharger or the second supercharger is a
high-pressure stage supercharger configured to further compress air
which is compressed by the compressor of the low-pressure stage
supercharger and to supply the air to the engine, and wherein the
second controller includes a second vane control part configured
to, if the measurement result by the leakage current measuring part
is not less than the first threshold, control an opening degree of
the nozzle vane so as to reduce the flow path area compared to when
the measurement result is less than the first threshold, in
response to reduction of the upper limit value of the output
command value for the motor by the motor control part.
7. The supercharging system according to claim 6, wherein the
second vane control part is configured to determine a second target
opening degree of the second nozzle vane on the basis of a
difference between a boost pressure by the supercharging system and
a target boost pressure, to control the opening degree of the
second nozzle vane to the second target opening degree.
8. The supercharging system according to claim 7, wherein the
second vane control part is configured to obtain a second corrected
opening degree by correcting the second target opening degree
corresponding to a reduction amount of the output command value for
the motor by the upper limit value, and to control the opening
degree of the second nozzle vane to the second corrected opening
degree.
9. The supercharging system according to claim 1, wherein the motor
includes an inverter for converting a direct current voltage from a
battery to a three-phase alternating current voltage and supplying
the three-phase alternating current voltage to a motor winding, and
wherein the leakage current measuring part includes an ammeter
capable of collectively measuring a three-phase alternating current
between the inverter and the motor.
10. The supercharging system according to claim 1, wherein the
motor includes an inverter for converting direct current voltage
from a battery to three-phase alternating current voltage and
supplying the three-phase alternating current voltage to a motor
winding, and wherein the leakage current measuring part includes an
ammeter capable of collectively measuring going and returning
direct current between the battery and the inverter.
11. The supercharging system according to claim 1, wherein the
leakage current measuring part includes an insulation resistance
meter capable of measuring an insulation resistance value of the
motor.
12. A control device for the supercharging system according to
claim 1, the control device comprising a first controller which
includes a motor control part configured to, if a measurement
result by the leakage current measuring part is not less than a
first threshold, set an upper limit value of an output command
value for the motor to be lower than when the measurement result is
less than the first threshold, to control an output of the motor
within a range which does not exceed the upper limit value.
13. A method of operating a supercharging system which comprises a
first supercharger including a first compressor for compressing air
to be supplied to an engine and a motor for driving the first
compressor, the method comprising: a leakage current measuring step
of measuring a leakage current of the motor; an output
upper-limit-value setting step of setting, if a measurement result
in the leakage current measuring step is not less than a first
threshold, set an upper limit value of an output command value for
the motor to be lower than when the measurement result is less than
the first threshold; and an output control step of controlling an
output of the motor within a range which does not exceed the upper
limit value set in the output upper-limit-value setting step.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a supercharging system, a
control device for the supercharging system, and a method for
operating the supercharging system.
BACKGROUND ART
[0002] It is known that occurrence of insulation degradation of
winding, which is a typical example of malfunction of a motor,
causes an increase in a leakage electric current with development
of the insulation degradation.
[0003] To detect such a leakage current, Patent Document 1
discloses an electric leakage detection system for detecting a
presence or absence of electric leakage when an inverter motor is
supplied with voltage, provided for a motor compressor system for
air conditioning. In this electric leakage detection system,
electric leakage is detected by an electric leakage detection
sensor. If electric leakage is detected, power supply to the
inverter motor is immediately stopped to stop operation of the
inverter motor.
CITATION LIST
Patent Literature
[0004] Patent Document 1: JP2000-298220A
SUMMARY
Problems to be Solved
[0005] Meanwhile, known motored superchargers include, for
instance, an electric supercharger equipped with a motor-driven
compressor, and an electric-assisted turbocharger equipped with a
compressor which is driven by engine exhaust and also assisted by a
motor. For such a motored supercharger, stopping operation of the
motor immediately upon detection of electric leakage as described
above may lead to deterioration of drivability due to a rapid
decrease in the engine output and the vehicle speed.
[0006] In view of the above, an object of at least one embodiment
of the present invention is to provide a supercharging system
whereby it is possible to mitigate deterioration of drivability due
to malfunction of a motor.
Solution to the Problems
[0007] (1) A supercharging system according to at least one
embodiment of the present invention comprises: a first supercharger
including a first compressor for compressing air to be supplied to
an engine and a motor for driving the first compressor; a leakage
current measuring part for measuring a leakage current of the
motor; and a first controller for controlling the first
supercharger. The first controller includes a motor control part
configured to, if a measurement result by the leakage current
measuring part is not less than a first threshold, set an upper
limit value of an output command value for the motor to be lower
than when the measurement result is less than the first threshold,
and to control an output of the motor within a range which does not
exceed the upper limit value.
[0008] If insulation degradation of winding occurs in a motor,
leakage current increases with development of the insulation
degradation.
[0009] With the above configuration (1), if the measurement result
of the leakage current of the motor is not less than the first
threshold, i.e., when the motor is malfunctioning or is about to
malfunction, the upper limit value of the output command value for
the motor is set to be lower than when it is otherwise, and the
output of the motor is controlled in the range of the upper limit
value. Thus, compared to a case in which the motor is stopped
immediately after the motor is determined to be malfunctioning, the
output of the motor is reduced gradually, which mitigates
deterioration of drivability. Further, insulation degradation of
the motor occurs depending on the temperature of the wire of the
motor (motor winding or wire that leads to outside from the motor),
and is more likely to develop when the temperature of the wire is
higher. In this regard, with the above configuration (1), reducing
the output of the motor as described above also reduces the wire
temperature of the motor, and thereby it is possible to suppress
development of insulation degradation of the motor.
[0010] (2) In some embodiments, in the above configuration (1), the
motor control part is configured to: set, if the measurement result
is not less than the first threshold and less than a second
threshold which is greater than the first threshold, the upper
limit value of the output command value for the motor to be greater
than zero and smaller than when the measurement result is less than
the first threshold; and set, if the measurement result is not less
than the second threshold, the upper limit value of the output
command value for the motor to zero.
[0011] With the above configuration (2), the upper limit value of
the output command value for the motor is reduced to a value larger
than zero if the leakage current of the motor increases to at least
the first threshold, and the upper limit value of the output
command value for the motor is set to zero when the leakage current
is at least the second threshold which is greater than the first
threshold. Accordingly, the upper limit value of the output command
value for the motor is reduced in stages with an increase in the
leakage current of the motor. Thus, compared to a case in which the
motor is stopped immediately after the motor is determined to be
malfunctioning, the output of the motor is reduced gradually, which
mitigates deterioration of drivability.
[0012] (3) In some embodiments, in the above configuration (1) or
(2), the first supercharger further includes: a first turbine
configured to be capable of being rotary driven by exhaust gas from
the engine and by the motor; and a first nozzle vane configured to
adjust a flow path area of the exhaust gas flowing into the first
turbine. The first controller further includes a first vane control
part for controlling an opening degree of the first nozzle vane on
the basis of a measurement result of the leakage current measuring
part. The first vane control part is configured to, if the
measurement result by the leakage current measuring part is not
less than the first threshold, control an opening degree of the
first nozzle vane so as to reduce the flow path area compared to
when the measurement result is less than the first threshold, in
response to reduction of the upper limit value of the output
command value for the motor by the motor control part.
[0013] With the above configuration (3), when the leakage current
of the motor increases and the upper limit value of the output
command value for the motor is reduced, the opening degree of the
nozzle vane is reduced in response to a decrease in the output
command value. That is, the opening degree of the nozzle vane is
reduced to increase the boost pressure in response to a decrease in
the boost pressure due to a decrease in the output command value
for the motor, and thereby it is possible to ensure a boost
pressure by the supercharging system while performing a control by
the motor control part.
[0014] (4) In some embodiments, in the above configuration (3), the
first vane control part is configured to determine a first target
opening degree of the first nozzle vane on the basis of a
difference between a boost pressure by the supercharging system and
a target boost pressure, and to control the opening degree of the
first nozzle vane to the first target opening degree.
[0015] With the above configuration (4), a feedback control is
performed on the first nozzle vanes so as to achieve a target
opening degree determined on the basis of a difference between the
boost pressure by the supercharging system and the target boost
pressure, and thereby it is possible to bring the boost pressure
closer to the target boost pressure while performing a control by
the motor control part.
[0016] (5) In some embodiments, in the above configuration (4), the
first vane control part is configured to obtain a first corrected
opening degree by correcting the first target opening degree,
corresponding to a reduction amount of the output command value for
the motor by the upper limit value, and to control the opening
degree of the first nozzle vane to the first corrected opening
degree.
[0017] With the above configuration (5), the target opening degree
of the first nozzle vanes in the feedback control is corrected
corresponding to the amount of reduction of the output command
value for the motor by the upper limit value, and thus it is
possible to bring the boost pressure closer to the target boost
pressure quickly compared to a case in which the target opening
degree is not corrected.
[0018] (6) In some embodiments, in any one of the above
configurations (1) to (5), the supercharging system further
comprises: a second supercharger including a second compressor for
compressing air to be supplied to the engine, a second turbine
configured to be rotary driven by exhaust gas from the engine to
drive the second compressor, and a second nozzle vane configured to
adjust a flow path area of the exhaust gas flowing into the second
turbine; and a second controller for controlling the second
supercharger. One of the first supercharger or the second
supercharger is a low-pressure stage supercharger. The other one of
the first supercharger or the second supercharger is a
high-pressure stage supercharger configured to further compress air
which is compressed by the compressor of the low-pressure stage
supercharger and to supply the air to the engine. The second
controller includes a second vane control part configured to, if
the measurement result by the leakage current measuring part is not
less than the first threshold, control an opening degree of the
nozzle vane so as to reduce the flow path area compared to when the
measurement result is less than the first threshold, in response to
reduction of the upper limit value of the output command value for
the motor by the motor control part.
[0019] With the above configuration (6), when the leakage current
of the motor of the first supercharger increases and the upper
limit value of the output command value of the motor is reduced,
the opening degree of the nozzle vane of the second supercharger is
reduced in response to a decrease in the output command value. That
is, the pressure ratio of the second supercharger is increased in
response to a decrease in the pressure ratio of the first
supercharger, and thereby it is possible to ensure a boost pressure
by the supercharging system while performing a control by the motor
control part.
[0020] (7) In some embodiments, in the above configuration (6), the
second vane control part is configured to determine a second target
opening degree of the second nozzle vane on the basis of a
difference between a boost pressure by the supercharging system and
a target boost pressure, to control the opening degree of the
second nozzle vane to the second target opening degree.
[0021] With the above configuration (7), a feedback control is
performed on the second nozzle vanes so as to achieve a target
opening degree determined on the basis of a difference between the
boost pressure by the supercharging system and the target boost
pressure, and thereby it is possible to bring the boost pressure
closer to the target boost pressure while performing a control by
the motor control part.
[0022] (8) In some embodiments, in the above configuration (7), the
second vane control part is configured to obtain a second corrected
opening degree by correcting the second target opening degree
corresponding to a reduction amount of the output command value for
the motor by the upper limit value, and to control the opening
degree of the second nozzle vane to the second corrected opening
degree.
[0023] With the above configuration (8), the target opening degree
of the second nozzle vane in the feedback control is corrected
corresponding to the amount of reduction of the output command
value for the motor by the upper limit value, and thus it is
possible to bring the boost pressure closer to the target boost
pressure quickly compared to a case in which the target opening
degree is not corrected.
[0024] (9) In some embodiments, in any one of the above
configurations (1) to (8), the motor includes an inverter for
converting a direct current voltage from a battery to a three-phase
alternating current voltage and supplying the three-phase
alternating current voltage to a motor winding. The leakage current
measuring part includes an ammeter capable of collectively
measuring a three-phase alternating current between the inverter
and the motor.
[0025] With the above configuration (9), it is possible to measure
a leakage current of the motor by measuring a zero-phase current of
a three-phase alternating current between the inverter and the
motor.
[0026] (10) In some embodiments, in any one of the above
configurations (1) to (9), the motor includes an inverter for
converting direct current voltage from a battery to three-phase
alternating current voltage and supplying the three-phase
alternating current voltage to a motor winding, and the leakage
current measuring part includes an ammeter capable of collectively
measuring going and returning direct current between the battery
and the inverter.
[0027] With the above configuration (10), it is possible to measure
a leakage current of the motor by measuring the total of going and
returning direct current between the inverter and the motor.
[0028] (11) In some embodiments, in any one of the above
configurations (1) to (10), the leakage current measuring part
includes an insulation resistance meter capable of measuring an
insulation resistance value of the motor.
[0029] With the above configuration (11), it is possible to detect
a leakage current of the motor from a decrease in the insulation
resistance value of the motor. Further, an insulation resistance
value of the motor can be measured even when the motor is not
supplied with power from the battery, and thus, a leakage current
of the motor can be detected through the above configuration (11)
even when the motor is not in operation.
[0030] (12) A control device according to at least one embodiment
of the present invention is for the supercharging system having the
configuration of any one of the above (1) to (11), and comprises a
first controller which includes a motor control part configured to,
if a measurement result by the leakage current measuring part is
not less than a first threshold, set an upper limit value of an
output command value for the motor to be lower than when the
measurement result is less than the first threshold, to control an
output of the motor within a range which does not exceed the upper
limit value.
[0031] If insulation degradation of winding occurs in a motor,
leakage current increases with development of the insulation
degradation.
[0032] With the above configuration (12), if the measurement result
of the leakage current of the motor is not less than the first
threshold, i.e., when the motor is malfunctioning or is about to
malfunction, the upper limit value of the output command value for
the motor is set to be lower than when it is otherwise, and the
output of the motor is controlled in the range of the upper limit
value. Thus, compared to a case in which the motor is stopped
immediately after the motor is determined to be malfunctioning, the
output of the motor is reduced gradually, which mitigates
deterioration of drivability. Further, insulation degradation of
the motor occurs depending on the temperature of the wire of the
motor (motor winding or wire that leads to outside from the motor),
and is more likely to develop when the temperature of the wire is
higher. In this regard, with the above configuration (12), reducing
the output of the motor as described above also reduces the wire
temperature of the motor, and thereby it is possible to suppress
development of insulation degradation of the motor.
[0033] (13) A method of operating a supercharging system which
comprises a first supercharger including a first compressor for
compressing air to be supplied to an engine and a motor for driving
the first compressor, according to at least one embodiment of the
present invention, comprises: a leakage current measuring step of
measuring a leakage current of the motor; an output
upper-limit-value setting step of setting, if a measurement result
in the leakage current measuring step is not less than a first
threshold, set an upper limit value of an output command value for
the motor to be lower than when the measurement result is less than
the first threshold; and an output control step of controlling an
output of the motor within a range which does not exceed the upper
limit value set in the output upper-limit-value setting step.
[0034] If insulation degradation of winding occurs in a motor,
leakage current increases with development of the insulation
degradation.
[0035] According to the above method (13), if the measurement
result of the leakage current of the motor is not less than the
first threshold, i.e., when the motor is malfunctioning or is about
to malfunction, the upper limit value of the output command value
for the motor is set to be lower than when it is otherwise, and the
output of the motor is controlled within the range of the upper
limit value. Thus, compared to a case in which the motor is stopped
immediately after the motor is determined to be malfunctioning, the
output of the motor is reduced gradually, which mitigates
deterioration of drivability. Further, insulation degradation of
the motor occurs depending on the temperature of the wire of the
motor (motor winding or wire that leads to outside from the motor),
and is more likely to develop when the temperature of the wire is
higher. In this regard, according to the above method (1), reducing
the output of the motor as described above also reduces the wire
temperature of the motor, and thereby it is possible to suppress
development of insulation degradation of the motor.
Advantageous Effects
[0036] According to at least one embodiment of the present
invention, provided is a supercharging system whereby it is
possible to mitigate deterioration of drivability due to
malfunction of a motor.
BRIEF DESCRIPTION OF DRAWINGS
[0037] FIG. 1 is a configuration diagram of a supercharging system
according to an embodiment.
[0038] FIG. 2 is a configuration diagram of a supercharging system
according to an embodiment.
[0039] FIG. 3 is a schematic cross-sectional view of a turbine of a
supercharger according to an embodiment.
[0040] FIG. 4 is a configuration diagram of a control device for a
supercharging system according to an embodiment.
[0041] FIG. 5 is a flowchart of a method for operating a
supercharging system according to an embodiment.
[0042] FIG. 6 is a flowchart of a nozzle-vane opening degree
control according to an embodiment.
[0043] FIG. 7 is a flowchart of a nozzle-vane opening degree
control according to an embodiment.
[0044] FIG. 8 is a control block diagram of a supercharging system
according to an embodiment.
[0045] FIG. 9 is a configuration diagram of a supercharging system
according to an embodiment.
[0046] FIG. 10 is a configuration diagram of a supercharging system
according to an embodiment.
[0047] FIG. 11 is a configuration diagram of a supercharging system
according to an embodiment.
[0048] FIG. 12 is a configuration diagram of a supercharging system
according to an embodiment.
[0049] FIG. 13 is a configuration diagram of a control device for a
supercharging system according to an embodiment.
[0050] FIG. 14 is a flowchart of a method for operating a
supercharging system according to an embodiment.
DETAILED DESCRIPTION
[0051] Embodiments of the present invention will now be described
in detail with reference to the accompanying drawings. It is
intended, however, that unless particularly specified, dimensions,
materials, shapes, relative positions and the like of components
described in the embodiments shall be interpreted as illustrative
only and not intended to limit the scope of the present
invention.
[0052] FIGS. 1, 2, and 9 to 12 are each a configuration diagram of
a supercharging system according to an embodiment. As depicted in
FIGS. 1, 2, and 9 to 12, the supercharging system 1 includes a
first supercharger 2 configured to compress a pressure of air to be
supplied to an engine 8 mounted to a vehicle or the like, a leakage
current measuring part 4, and a control device 100. The first
supercharger 2 includes a first compressor 10 for compressing air
to be supplied to the engine 8, and a motor 12 for driving the
first compressor 10. The leakage current measuring part 4 is
configured to measure a leakage current of the motor 12. Further,
the control device 100 includes a first controller 110 for
controlling the first supercharger 2.
[0053] The first supercharger 2 depicted in FIGS. 1, 9, and 10 is
an electric supercharger in which the first compressor 10 is driven
by the motor 12. The motor 12 includes an inverter 28 for
converting direct-current voltage from a battery 30 into
three-phase alternating current voltage and supplying the
alternating current voltage to a motor winding. The motor 12 is
configured to be supplied with electric power from the battery 30
via the inverter 28, and to generate rotational energy. The first
compressor 10 is connected to the motor 12 via a rotational shaft
11, and is rotary driven as the rotational energy generated by the
motor 12 rotates the rotational shaft 11, and thereby intake air
flowing into the first compressor 10 is compressed.
[0054] The first supercharger 2 depicted in FIGS. 2, 11, and 12 is
an electric-assist turbocharger further including a first turbine
14 which is rotary driven by exhaust gas from the engine 8, and the
motor 12 assists the rotary driving of the first turbine 14 by
exhaust gas. In other words, the first turbine can be rotary driven
by exhaust gas from the engine 8 and by the motor 12. In the first
supercharger 2, the first turbine 14 is connected to the first
compressor 10 via the rotational shaft 11, and can rotate about the
same axis with the first compressor 10. In the first supercharger,
the first turbine 14 is rotary driven through inflow of exhaust gas
from the engine 8, which causes the first compressor 10 to be
coaxially driven via the rotational shaft 11, and thereby intake
air flowing into the first compressor 10 is compressed.
[0055] In the first supercharger 2 depicted in FIGS. 2, 11, and 12,
the motor 12 includes, similarly to the first supercharger 2
depicted in FIGS. 1 and so on, the inverter 28 for converting
direct-current voltage from the battery 30 into three-phase
alternating current voltage and supplying the alternating current
voltage to a motor winding. The motor 12 is configured to be
supplied with electric power from the battery 30 via the inverter
28, and to generate rotational energy. Further, the motor 12
assists rotation of the rotational shaft 11 or rotary driving of
the first compressor 10.
[0056] The first supercharger 2 depicted in FIG. 2 further includes
a first nozzle vane 16 configured to adjust the flow-path area of
exhaust gas from the engine 8 flowing into the first turbine
14.
[0057] With reference to FIG. 3, adjustment of the flow-path area
of exhaust gas by the nozzle vane will be described. FIG. 3 is a
schematic cross-sectional view of a turbine (herein, the first
turbine 14) of a supercharger according to an embodiment. As
depicted in FIG. 3, the first turbine 14 includes a turbine rotor
54 with a plurality of rotor blades 56 mounted thereto, inside a
turbine casing 50. The turbine rotor 54 is connected to the first
compressor 10 via the rotational shaft 11. As exhaust gas from the
engine 8 flows into the first turbine 14, the rotor blades 56
receive a flow of exhaust gas and the turbine rotor 54 rotates, and
thereby the first compressor 10 is rotary driven. A plurality of
nozzle vanes 16 are disposed on the outer peripheral side of the
turbine rotor 54, the nozzle vanes 16 being configured rotatable
about support shafts 17 that serve as rotational shafts.
[0058] The opening degree of the plurality of nozzle vanes 16 can
be changed by rotating the support shafts 17 with an actuator (not
depicted). In FIG. 3, nozzle vanes 16a indicated by the dotted line
have a larger opening degree than the nozzle vanes 16 indicated by
the solid line. In other words, the distance D2 between the nozzle
vanes 16a indicated by the dotted line is greater than the distance
D1 between the nozzle vanes 16 indicated by the solid line. Thus,
the flow-path area of exhaust gas is larger when the opening degree
is large than when the opening degree is small.
[0059] With the opening degree of the nozzle vanes 16 reduced (i.e.
the flow path area of exhaust gas is reduced), the inflow velocity
of exhaust gas to the first turbine 14 increases, and thus it is
possible to increase the boost pressure by the supercharging system
1. Furthermore, with the opening degree of the nozzle vanes 16
expanded (i.e. the flow path area of exhaust gas increased), the
inflow velocity of exhaust gas to the first turbine 14 decreases,
and thus it is possible to decrease the boost pressure by the
supercharging system 1. Accordingly, it is possible to adjust the
boost pressure by the supercharging system 1 by adjusting the
opening degree of the nozzle vanes 16.
[0060] In the supercharging system 1 depicted in FIGS. 1, 2, and 9
to 12, air (intake air) introduced into the intake pipe 32 flows
into the first compressor 10 of the first supercharger 2, and is
compressed by rotation of the first compressor 10. The intake air
compressed by the first compressor 10 is cooled by an intercooler
34, the amount of the intake air is adjusted by a throttle valve
(not depicted), and the intake air is supplied to each cylinder of
the engine 8 via an intake manifold 36. Compressed gas and fuel are
supplied to each cylinder of the engine 8 to combust and generate
exhaust gas, which is discharged to the exhaust pipe 40 via an
exhaust manifold 38.
[0061] In the intake pipe 32, a pressure sensor 5 for measuring a
pressure of air to be supplied to the engine 8 (boost pressure) may
be disposed, on the further upstream side of the intake manifold
36.
[0062] In the supercharging system 1 depicted in FIG. 2, exhaust
gas from the engine 8 flows into the first turbine 14 of the first
supercharger 2, and exhaust gas having performed work in the first
turbine 14 is discharged to the exhaust pipe 40.
[0063] A bypass pipe 42 bypassing the first turbine 14 may be
connected to the exhaust pipe 40, and a waste-gate valve 43 may be
disposed in the bypass pipe 42. By adjusting the opening degree of
the waste-gate valve 43, it is possible to adjust the flow rate of
exhaust gas that flows into the first turbine 14 and the flow rate
of exhaust gas that flows through the bypass pipe 42, and thereby
it is possible to control the rotation speed of the first turbine
14 and the rotation speed of the first compressor 10 coaxially
driven with the first turbine 14. The opening degree of the
waste-gate valve 43 may be controlled by the control device
100.
[0064] FIG. 4 is a configuration diagram of a control device for a
supercharging system according to an embodiment. As depicted in
FIG. 4, the control device 100 for the supercharging system 1
according to an embodiment includes a first controller 110 for
controlling the first supercharger 2. In an embodiment, the first
controller 110 includes a motor control part 112 and a first vane
control part 114.
[0065] The control device 100 may be an ECU for controlling the
supercharging system 1. Further, the control device 100 may be an
ECU provided independently from an engine ECU for controlling the
engine 8.
[0066] The control device 100 may be a microcomputer comprising a
central processing unit (CPU), a random access memory (RAM), a read
only memory (ROM), and an I/O interface.
[0067] A method for operating the supercharging system 1 using the
control device 100 according to an embodiment now will be described
along the flowchart of FIG. 5. FIG. 5 is a flowchart of a method
for operating a supercharging system according to an
embodiment.
[0068] Leakage current of the motor 12 for driving the first
compressor is measured (S2). Leakage current of the motor 12 is
measured by using the leakage current measuring part 4 (described
below).
[0069] If insulation degradation of winding, which is a typical
example of malfunction of the motor 12, occurs in the motor 12,
leakage current increases with development of the insulation
degradation. In other words, a leakage current value indicates the
stage of progress of malfunction of the motor 12.
[0070] A measurement value obtained by the leakage current
measuring part 4 is sent to the first controller 110 as an electric
signal.
[0071] Next, it is determined whether the measurement result of the
leakage current of the motor 12 in S2 is greater than the first
threshold set in advance (S4). The first controller 110 may include
a storage part (memory), and the first threshold may be stored in
the storage part in advance. Further, the first controller 110 may
be configured to compare the first threshold stored in the storage
part and a measurement value sent from the leakage current
measuring part 4.
[0072] If it is determined in S4 that the measurement result of the
leakage current of the motor 12 is less than the first threshold
(No in S4), the flow is just ended. Alternatively, the flow may
return to S2 and perform the step of measuring the leakage
current.
[0073] If it is determined in S4 that the measurement result of the
leakage current of the motor 12 is not less than the first
threshold (YES in S4), the motor control part 112 sets an upper
limit value of the output command value for the motor 12 to be
lower than when the measurement result of the leakage current is
less than the first threshold, and controls the output of the motor
12 to be within a range that does not exceed the upper limit value
(S8 or S10).
[0074] As described above, if the measurement result of the leakage
current of the motor 12 is not less than the first threshold, i.e.,
when the motor 12 is malfunctioning or is about to malfunction, the
upper limit value of the output command value for the motor 12 is
set to be lower than when it is otherwise, and the output of the
motor 12 is controlled in the range of the upper limit value. Thus,
compared to a case in which the motor 12 is stopped immediately
after the motor 12 is determined to be malfunctioning, the output
of the motor 12 is reduced gradually, which mitigates deterioration
of drivability. Further, insulation degradation of the motor 12
occurs depending on the temperature of the wire of the motor 12
(motor winding or wire that leads to outside from the motor), and
is more likely to develop when the temperature of the wire is
higher. In this regard, reducing the output of the motor 12 as
described above also reduces the wire temperature of the motor 12,
and thereby it is possible to suppress development of insulation
degradation of the motor 12.
[0075] To control the output of the motor 12, the motor control
part 112 may control the voltage that the inverter 28 applies to
the motor 12 so as to obtain a desired output from the motor
12.
[0076] As described above, if it is determined in S4 that the
measurement result of the leakage current of the motor 12 is not
less than the first threshold (Yes in S4), it may be further
determined whether the measurement result of the leakage current
exceeds a second threshold which is greater than the first
threshold (S6). If it is determined in S6 that the measurement
result of the leakage current of the motor 12 is less than the
second threshold (No in S6), the motor control part 112 sets the
upper limit value of the output command value for the motor 12 to
be larger than zero and smaller than when the measurement result of
the leakage current is less than the first threshold, and controls
the output of the motor 12 to be within the range not exceeding the
upper limit value (S8). If it is determined in S6 that the
measurement result of the leakage current of the motor 12 is not
less than the second threshold (Yes in S6), the motor control part
112 sets an upper limit value of the output command value for the
motor 12 to zero, and controls the output of the motor 12 to become
zero (S10).
[0077] In this case, the upper limit value of the output command
value for the motor 12 is reduced in stages with an increase in the
leakage current of the motor 12. Thus, compared to a case in which
the motor 12 is stopped immediately after the motor 12 is
determined to be malfunctioning, the output of the motor 12 is
reduced gradually, which mitigates deterioration of
drivability.
[0078] The second threshold may be stored in advance in the storage
part of the first controller 110. Further, the first controller 110
may be configured to compare the second threshold stored in the
storage part and a measurement value sent from the leakage current
measuring part 4.
[0079] If the first supercharger 2 has the first turbine 14 and the
first nozzle vanes 16 for adjusting the flow-path area of exhaust
gas that flows from the engine 8 into the first turbine 14, the
first vane control part 114 may control the opening degree of the
first nozzle vanes 16 (S12) to ensure a boost pressure by the
supercharging system 1. More specifically, when the measurement
result by the leakage current measuring part 4 is not less than the
first threshold (Yes in S4), the first vane control part 114
controls the opening degree of the first nozzle vanes 16 so that
the flow path area of exhaust gas flowing into the first turbine 14
is smaller than when the measurement result of the leakage current
is less than the first threshold, in response to reduction of the
upper limit value of the output command value for the motor 12 by
the motor control part 112 in S8 and S10.
[0080] Accordingly, the opening degree of the first nozzle vanes 16
is reduced to increase the boost pressure in response to a decrease
in the boost pressure due to a decrease in the output command value
for the motor 12, and thereby it is possible to ensure a boost
pressure by the supercharging system 1 while performing a control
by the motor control part 112.
[0081] FIGS. 6 and 7 are each a flowchart of a step of controlling
the opening degree of the first nozzle vanes (S12) according to an
embodiment. In an embodiment, as depicted in FIG. 6, to control the
first nozzle vanes 16, the first vane control part 114 determines
the first target opening degree of the first nozzle vanes 16 on the
basis of a difference between the boost pressure by the
supercharging system 1 and the target boost pressure (S14), and
controls the opening degree of the first nozzle vanes 16 to the
first target opening degree (S16).
[0082] Accordingly, a feedback control (e.g. PI control or PID
control) is performed on the first nozzle vanes 16 so as to achieve
a target opening degree determined on the basis of a difference
between the boost pressure by the supercharging system 1 and the
target boost pressure, and thereby it is possible to bring the
boost pressure closer to the target boost pressure while performing
a control by the motor control part 112.
[0083] Further, the boost pressure by the supercharging system 1
may be measured by the pressure sensor 5 and sent to the first
controller 110 as an electric signal.
[0084] In an embodiment, as depicted in FIG. 7, the first vane
control part 114 determines the first target opening degree of the
first nozzle vanes 16 on the basis of a difference between the
boost pressure by the supercharging system 1 and the target boost
pressure (S18), obtains the first corrected opening degree by
correcting the first target opening degree of the first nozzle
vanes 16 corresponding to the reduction amount of the output
command value for the motor 12 by the upper limit value set in S8
or S10 (S20), and controls the opening degree of the first nozzle
vanes 16 to the first corrected opening degree (S22).
[0085] Accordingly, the target opening degree of the first nozzle
vanes 16 in the feedback control is corrected corresponding to the
amount of reduction of the output command value for the motor 12 by
the upper limit value, and thus it is possible to bring the boost
pressure closer to the target boost pressure quickly compared to a
case in which the target opening degree is not corrected.
[0086] FIG. 8 is a control block diagram of a supercharging system
according to an embodiment. The control block diagram shows the
above described flow of control computation by the motor control
part 112 and the first vane control part 114.
[0087] In the control block diagram depicted in FIG. 8, a command
value calculation part 102 calculates a motor output command value
P.sub.m* and a nozzle vane opening degree command value (first
target opening degree) O.sub.V* for achieving a target boost
pressure P.sub.B* in the supercharging system 1, on the basis of
the target boost pressure P.sub.B* and an actual boost pressure
P.sub.B by the supercharging system 1 measured by the pressure
sensor 5. Calculation of the motor output command value P.sub.m*
and the nozzle vane opening degree command value (first target
opening degree) O.sub.V* may be performed taking account of vehicle
velocity, engine rotation speed, accelerator step-in amount, for
instance, in addition to the boost pressure P.sub.B and the target
boost pressure P.sub.B*.
[0088] In the motor control part 112, an upper limit value
determination part 104 determines the upper limit value of the
output command value for the motor 12 on the basis of the value of
a leakage current I.sub.L measured by the leakage current measuring
part 4. For instance, if the measurement result by the leakage
current measuring part 4 is not less than the above described first
threshold, the upper limit of the output command value for the
motor 12 is set to be lower than when the measurement result of the
leakage current is less than the first threshold. Further, a
limiter 106 imposes a limit on the motor output command value
P.sub.m* to be not greater than the set upper limit value of the
output command value, and thereby P.sub.m is obtained. P.sub.m
obtained as described above is used to control the output of the
motor 12 as a motor output command value.
[0089] In the first vane control part 114, a correction part 108
corrects the first target opening degree O.sub.V* of the first
nozzle vane 16, and thereby the first corrected opening degree (the
first nozzle vane opening degree command value) O.sub.V is
obtained.
[0090] The correction part 108 corrects the first target opening
degree of the first nozzle vanes 16 corresponding to a reduction
amount of the output command value for the motor 12, that is, a
difference between the target boost pressure P.sub.B* calculated by
the command value calculation part 102 and the motor output command
value P.sub.m whose upper limit value is limited by the limiter
106, and thereby the first corrected opening degree (the first
nozzle vane opening degree command value) O.sub.V is obtained.
O.sub.V obtained as described above is used to control the opening
degree of the first nozzle vanes 16 as the first corrected opening
degree (the first nozzle vane opening degree command value).
[0091] The supercharging system 1 according to the embodiment
depicted in FIGS. 9 to 12 further includes a second supercharger 6,
and a second controller 120 for controlling the second supercharger
6.
[0092] The second supercharger 6 is a turbocharger including a
second compressor 20 for compressing air to be supplied to the
engine 8, and a second turbine 24 configured to be rotary driven by
exhaust gas from the engine 8 to drive the second compressor 20.
The second supercharger 6 includes a second nozzle vane 26
configured to adjust the flow-path area of exhaust gas flowing into
the second turbine 24.
[0093] The first supercharger 2 and the second supercharger 6 are
disposed in series in the supercharging system 1, and one of the
first supercharger 2 or the second supercharger 6 is a low-pressure
stage supercharger (90) that is disposed on the low pressure side
(that is, a side closer to the inlet of intake air). The other one
of the first supercharger 2 or the second supercharger 6 is a
high-pressure stage supercharger (92) configured to further
compress air that is compressed by the compressor (the first
compressor 10 or the second compressor 20) of the low-pressure
stage compressor (90) and to supply the air to the engine 8.
[0094] In the supercharging system 1 depicted in FIGS. 9 and 10,
the first supercharger 2 is an electric supercharger in which the
first compressor 10 is driven by the motor 12 as described above.
In the supercharging system 1 depicted in FIG. 9, the first
supercharger 2, which is an electric supercharger, is the
low-pressure stage supercharger 90, and the second supercharger 6,
which is a turbocharger having nozzle vanes, is the high-pressure
stage supercharger 92. In the supercharging system 1 depicted in
FIG. 10, the second supercharger 6, which is a turbocharger with
nozzle vanes, is the low-pressure stage supercharger 90, and the
first supercharger 2, which is an electric supercharger, is the
high-pressure stage supercharger 92.
[0095] In the supercharging system 1 depicted in FIGS. 11 and 12,
the second supercharger 6 is an electric-assist turbocharger
including the first turbine 14 which is rotary driven by exhaust
gas from the engine 8, and the rotary driving of the first turbine
14 by exhaust gas is assisted by the motor 12, as described above.
In the supercharging system 1 depicted in FIG. 11, the first
supercharger 2, which is an electric-assist turbocharger, is the
low-pressure stage supercharger 90, and the second supercharger 6,
which is a turbocharger with nozzle vanes, is the high-pressure
stage supercharger 92. In the supercharging system 1 depicted in
FIG. 10, the second supercharger 6, which is a turbocharger with
nozzle vanes, is the low-pressure stage supercharger 90, and the
first supercharger 2, which is an electric-assisted turbocharger,
is the high-pressure stage supercharger 92.
[0096] The supercharging system 1 depicted in FIGS. 9 to 12
includes a recirculation passage 46 connecting the upstream side
and the downstream side of the compressor (20 or 10) of the
high-pressure stage supercharger 92 so as to bypass the compressor
(20 or 10), disposed in the intake pipe 32 in which the compressor
(10 or 20) of the low-pressure stage supercharger 90 and the
compressor (20 or 10) of the high-pressure stage supercharger 92
are disposed, and a recirculation valve 47 disposed in the
recirculation passage 46. To suppress surging in the supercharging
system 1, a part of air introduced into the intake pipe 32 and
compressed by the compressor (10 or 20) of the low-pressure stage
supercharger 90 and the compressor (20 or 10) of the high-pressure
stage supercharger 92 can be returned to the inlet of the
compressor (20 or 10) of the high-pressure stage supercharger 92
through the recirculation passage 46 via the recirculation valve
47.
[0097] In the supercharging system 1 depicted in FIGS. 9 and 10,
exhaust gas from the engine 8 flows into the second turbine 24 of
the second supercharger 6, and exhaust gas having performed work in
the second turbine 24 is discharged to the exhaust pipe 40.
[0098] A bypass pipe 42 bypassing the second turbine 24 may be
connected to the exhaust pipe 40, and a waste-gate valve 43 may be
disposed in the bypass pipe 42. By adjusting the opening degree of
the waste-gate valve 43, it is possible to adjust the flow rate of
exhaust gas that flows into the second turbine 24 and the flow rate
of exhaust gas that flows through the bypass pipe 42, and thereby
it is possible to control the rotation speed of the second turbine
24 and the rotation speed of the second compressor 20 coaxially
driven with the second turbine 24. The opening degree of the
waste-gate valve 43 may be controlled by the control device
100.
[0099] In the supercharging system 1 depicted in FIGS. 11 and 12,
exhaust gas from the engine 8 flows into the turbine (24 or 14) of
the high-pressure stage supercharger 92 and to the turbine (14 or
24) of the low-pressure stage supercharger 90 in this order, and
exhaust gas having performed work in the turbine (14 or 24) of the
low-pressure stage supercharger 90 is discharged to the exhaust
pipe 40.
[0100] A bypass pipe 42 bypassing the turbine (14 or 24) of the
low-pressure stage supercharger 90 may be connected to the exhaust
pipe 40, and a waste-gate valve 43 may be disposed in the bypass
pipe 42. By adjusting the opening degree of the waste-gate valve
43, it is possible to adjust the flow rate of exhaust gas that
flows into the turbine (14 or 24) of the low-pressure stage
supercharger 90 and the flow rate of exhaust gas that flows through
the bypass pipe 42, and thereby it is possible to control the
rotation speed of the turbine (14 or 24) of the low-pressure stage
supercharger 90 and the rotation speed of the compressor (10 or 20)
of the low-pressure stage supercharger 90 coaxially driven with the
turbine (14 or 24). The opening degree of the waste-gate valve 43
may be controlled by the control device 100.
[0101] Further, a second bypass flow passage 48 is connected to the
exhaust pipe 40 and the exhaust manifold 38 so as to bypass the
turbine (24 or 14) of the high-pressure stage supercharger 92. A
part of exhaust gas from the engine 8 can flow into the turbine (14
or 24) of the low-pressure stage supercharger 90 without passing
through the turbine (24 or 14) of the high-pressure stage
supercharger 92 via a bypass valve 45 disposed in the second bypass
flow passage 48. By adjusting the opening degree of the bypass
valve 45, it is possible to adjust the flow rate of exhaust gas
that flows into the turbine (24 or 14) of the high-pressure stage
supercharger 92 and the turbine (14 or 24) of the low-pressure
stage supercharger 90, and thereby it is possible to control the
rotation speed of the turbine (24 or 14) of the high-pressure stage
supercharger 92 and the turbine (14 or 24) of the low-pressure
stage supercharger 90, as well as the rotation speed of the
compressor (20 or 10) of the high-pressure stage supercharger 92
and the compressor (10 or 20) of the low-pressure stage
supercharger 90 coaxially driven with the turbine (24 or 14) and
the turbine (14 or 24). The opening degree of the bypass valve 45
may be controlled by the control device 100.
[0102] FIG. 13 is a configuration diagram of a control device for a
supercharging system according to an embodiment. As depicted in
FIG. 13, the control device 100 used in the supercharging system 1
according to an embodiment includes a first controller 110 for
controlling the first supercharger 2 and a second controller 120
for controlling the second supercharger 6. In an embodiment, the
first controller 110 includes a motor control part 112 and a first
vane control part 114, and the second controller 120 includes a
second vane control part. Each of the first controller 110 and the
second controller 120 may be a microcomputer comprising a central
processing unit (CPU), a random access memory (RAM), a read only
memory (ROM), and an I/O interface.
[0103] The supercharging system 1 depicted in FIGS. 9 to 12 can be
controlled by using the control device 100 depicted in FIG. 13, for
instance.
[0104] A method for operating the supercharging system 1 using the
control device 100 including the first controller 110 and the
second controller 120 will be described along the flowchart of FIG.
14. FIG. 14 is a flowchart of a method for operating a
supercharging system according to an embodiment.
[0105] Herein, S32, S34, S36, S38, and S40 in FIG. 14 are the same
as S2, S4, S6, S8, and S10 in the flowchart of FIG. 5, and thus not
described in detail.
[0106] In S34, when it is determined that the measurement result of
the leakage current of the motor 12 is not less than the first
threshold (Yes in S34), the second vane control part 122 may
control the opening degree of the second nozzle vanes 26 (S42) to
ensure the boost pressure by the supercharging system 1. More
specifically, when the measurement result by the leakage current
measuring part 4 is not less than the first threshold (Yes in S34),
the second vane control part 122 controls the opening degree of the
second nozzle vanes 26 so that the flow path area of exhaust gas
flowing into the second turbine 24 becomes smaller than when the
measurement result of the leakage current is less than the first
threshold, in response to reduction of the upper limit value of the
output command value for the motor 12 by the motor control part 112
in S38 or S40.
[0107] Accordingly, the opening degree of the second nozzle vanes
26 is reduced to increase the boost pressure in response to a
decrease in the boost pressure due to a decrease in the output
command value for the motor 12, and thereby it is possible to
ensure a boost pressure by the supercharging system 1 while
performing a control by the motor control part 112.
[0108] The opening degree of the second nozzle vanes 26 in S42 can
be controlled in accordance with the flowchart depicted in FIG. 6
or 7 described above, for instance.
[0109] That is, in an embodiment, as depicted in FIG. 6, to control
the second nozzle vanes 26, the second vane control part 122
determines the second target opening degree of the second nozzle
vanes 26 on the basis of a difference between the boost pressure by
the supercharging system 1 and the target boost pressure (S14), and
controls the opening degree of the second nozzle vanes 26 to the
second target opening degree (S16).
[0110] Accordingly, a feedback control (e.g. PI control or PID
control) is performed on the second nozzle vanes 26 so as to
achieve a target opening degree determined on the basis of a
difference between the boost pressure by the supercharging system 1
and the target boost pressure, and thereby it is possible to bring
the boost pressure closer to the target boost pressure while
performing a control by the motor control part 112.
[0111] Further, in an embodiment, as depicted in FIG. 7, the second
vane control part 122 determines the second target opening degree
of the second nozzle vanes 26 on the basis of a difference between
the boost pressure by the supercharging system 1 and the target
boost pressure (S18), obtains the second corrected opening degree
by correcting the second target opening degree of the second nozzle
vanes 26 corresponding to the reduction amount of the output
command value for the motor 12 by the upper limit value set in S38
or S40 (S20), and controls the opening degree of the second nozzle
vanes 26 to the second corrected opening degree (S22).
[0112] Accordingly, the target opening degree of the second nozzle
vanes 26 in the feedback control is corrected corresponding to the
amount of reduction of the output command value for the motor 12 by
the upper limit value, and thus it is possible to bring the boost
pressure closer to the target boost pressure quickly compared to a
case in which the target opening degree is not corrected.
[0113] Next, the leakage current measuring part 4 according to some
embodiments will be described.
[0114] In an embodiment, the leakage current measuring part 4 is an
ammeter capable of collectively measuring a three phase alternating
current between the motor 12 and the inverter 28 for converting
direct-current voltage from the battery 30 into three-phase
alternating current voltage and supplying the alternating current
voltage to the motor winding. Such an ammeter includes, for
instance, a clamp meter.
[0115] A clamp meter can be used, for instance, to measure a
leakage current of the motor 12 by collectively measuring a
zero-phase current of a three-phase alternating current between the
inverter 28 and the motor 12. That is, if the total current
obtained by collectively measuring a three-phase alternating
current is zero, it means that there is no problem in insulation of
the winding of the motor 12, and there is no occurrence of leakage
current. In contrast, if the total current obtained by collectively
measuring a three-phase alternating current is not zero, it means
that there is occurrence of leakage current in the motor 12. If the
total current is increasing, it means that insulation degradation
of the winding is in progress.
[0116] In an embodiment, the leakage current measuring part 4 is an
ammeter capable of collectively measuring going and returning
direct current between the battery 30 and the inverter 28. Such an
ammeter includes, for instance, a clamp meter.
[0117] A clamp meter can be used, for instance, to measure a
leakage current of the motor 12 by collectively measuring the total
of going and returning direct current between the battery 30 and
the inverter 28. That is, if the total current obtained by
collectively measuring going and returning direct current between
the battery 30 and the inverter 28 is zero, it means that there is
no problem in insulation of the winding of the motor 12, and there
is no occurrence of leakage current. In contrast, if the total
current obtained by collectively measuring going and returning
direct current between the battery 30 and the inverter 28 is not
zero, it means that there is occurrence of leakage current in the
motor 12. If the total current is increasing, it means that
insulation degradation of the winding is in progress.
[0118] In an embodiment the leakage current measuring part 4 is an
insulation-resistance meter capable of measuring an insulation
resistance value of the motor 12.
[0119] A decrease in the insulation resistance value of the motor
12 means an increase in leakage current of the motor 12. Thus, it
is possible to detect a leakage current of the motor 12 with an
insulation resistance meter for measuring an insulation resistance
value of the motor 12. Further, an insulation resistance value of
the motor 12 can be measured even when the motor 12 is not supplied
with power from the battery 30, and thus, an insulation resistance
meter can detect a leakage current of the motor 12 even when the
motor 12 is not in operation.
[0120] The control device 100 may perform monitoring of leakage
current by the leakage current measuring part 4. Further,
monitoring of leakage current by the leakage current measuring part
4 may be performed not directly by the control device 100 but by an
inverter controller, and maybe sent to the control device 100
through communication (e.g. CAN).
[0121] As described above, before the motor 12 develops a critical
insulation failure, an abnormality is detected from an increase in
leakage current, which is a sign of malfunction of the motor 12,
and the output of the motor 12 is controlled on the basis of the
detection. Accordingly, it is possible to mitigate deterioration of
drivability due to malfunction of the motor 12.
[0122] Embodiments of the present invention were described in
detail above, but the present invention is not limited thereto, and
various amendments and modifications may be implemented.
[0123] Further, in the present specification, an expression of
relative or absolute arrangement such as "in a direction", "along a
direction", "parallel", "orthogonal", "centered", "concentric" and
"coaxial" shall not be construed as indicating only the arrangement
in a strict literal sense, but also includes a state where the
arrangement is relatively displaced by a tolerance, or by an angle
or a distance whereby it is possible to achieve the same
function.
[0124] For instance, an expression of an equal state such as "same"
"equal" and "uniform" shall not be construed as indicating only the
state in which the feature is strictly equal, but also includes a
state in which there is a tolerance or a difference that can still
achieve the same function.
[0125] On the other hand, an expression such as "comprise",
"include", "have", "contain" and "constitute" are not intended to
be exclusive of other components.
DESCRIPTION OF REFERENCE NUMERALS
[0126] 1 Supercharging system [0127] 2 First supercharger [0128] 4
Leakage current measuring part [0129] 5 Pressure sensor [0130] 6
Second supercharger [0131] 8 Engine [0132] 10 First compressor
[0133] 11 Rotational shaft [0134] 12 Motor [0135] 14 First turbine
[0136] 16 First nozzle vane [0137] 17 Support shaft [0138] 20
Second compressor [0139] 24 Second turbine [0140] 26 Second nozzle
vane [0141] 28 Inverter [0142] 30 Battery [0143] 32 Intake pipe
[0144] 34 Intercooler [0145] 36 Intake manifold [0146] 38 Exhaust
manifold [0147] 40 Exhaust pipe [0148] 42 Bypass pipe [0149] 43
Waste-gate valve [0150] 45 Bypass valve [0151] 46 Recirculation
passage [0152] 47 Recirculation valve [0153] 48 Second bypass flow
passage [0154] 50 Turbine casing [0155] 54 Turbine rotor [0156] 56
Rotor blade [0157] 90 Low-pressure stage supercharger [0158] 92
High-pressure stage supercharger [0159] 100 Control device [0160]
102 Command value calculation part [0161] 104 Upper limit value
determination part [0162] 106 Limiter [0163] 108 Correction part
[0164] 110 First controller [0165] 112 Motor control part [0166]
114 First vane control part [0167] 120 Second controller [0168] 122
Second vane control part
* * * * *