U.S. patent application number 11/735819 was filed with the patent office on 2007-08-09 for vehicle rotating electric machine.
This patent application is currently assigned to HITACHI LTD.. Invention is credited to Masamitsu INABA, Masahiro IWAMURA, Keiichi MASHINO, Mutsuhiro MORI, Shinji SHIRAKAWA, Masanori TSUCHIYA, Tatsumi YAMAUCHI.
Application Number | 20070182384 11/735819 |
Document ID | / |
Family ID | 34935020 |
Filed Date | 2007-08-09 |
United States Patent
Application |
20070182384 |
Kind Code |
A1 |
SHIRAKAWA; Shinji ; et
al. |
August 9, 2007 |
Vehicle Rotating Electric Machine
Abstract
An inverter device is mounted on the rotating electric machine
body The inverter device includes a module unit having a converter
circuit and a control unit that controls the operation of the
converter circuit. The converter circuit is configured by
connecting a plurality of the following series circuits in
parallel, each of the series circuits includes a P-channel MOS
semiconductor device disposed at a higher potential side and an
N-channel MOS semiconductor device disposed at a lower potential
side which are electrically connected in series. An electric power
that is supplied from a battery or an electric power that is
supplied to the battery is controlled.
Inventors: |
SHIRAKAWA; Shinji; (Tokyo,
JP) ; MORI; Mutsuhiro; (Tokyo, JP) ; INABA;
Masamitsu; (Tokyo, JP) ; YAMAUCHI; Tatsumi;
(Tokyo, JP) ; IWAMURA; Masahiro; (Tokyo, JP)
; MASHINO; Keiichi; (Tokyo, JP) ; TSUCHIYA;
Masanori; (Ibaraki, JP) |
Correspondence
Address: |
CROWELL & MORING LLP;INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Assignee: |
HITACHI LTD.
6-6, Marunouchi 1-chome Chiyoda-ku
Tokyo
JP
|
Family ID: |
34935020 |
Appl. No.: |
11/735819 |
Filed: |
April 16, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11102627 |
Apr 11, 2005 |
7208918 |
|
|
11735819 |
Apr 16, 2007 |
|
|
|
Current U.S.
Class: |
322/99 |
Current CPC
Class: |
Y02T 10/62 20130101;
H01L 24/36 20130101; H01L 2924/13055 20130101; H01L 24/40 20130101;
F02N 11/04 20130101; H02J 7/1492 20130101; H01L 2224/0603 20130101;
H02M 7/003 20130101; B60W 10/08 20130101; H01L 2924/13091 20130101;
F02N 11/0859 20130101; H01L 2224/4103 20130101; F02N 2011/0896
20130101; F02N 11/0814 20130101; Y02T 10/70 20130101; H01L
2224/73221 20130101; B60K 6/26 20130101; H01L 24/41 20130101; H01L
2224/32225 20130101; H01L 2224/40225 20130101; F02D 2041/2075
20130101; H01L 2924/00014 20130101; B60K 6/48 20130101; H01L
2924/13091 20130101; H01L 2924/00 20130101; H01L 2924/13055
20130101; H01L 2924/00 20130101; H01L 2924/00014 20130101; H01L
2224/37099 20130101; H01L 2924/00014 20130101; H01L 2224/84
20130101 |
Class at
Publication: |
322/099 |
International
Class: |
H02P 9/00 20060101
H02P009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 10, 2005 |
JP |
2004-033760 |
Apr 12, 2004 |
JP |
2004-117027 |
Claims
1. A power converting device comprising: a module unit having a
power control circuit; and a control unit that controls the
operation of the power control circuit, wherein the power control
circuit is configured by connecting a plurality of the following
series circuits in parallel, each of the series circuits includes a
P-channel MOS semiconductor device disposed at a higher potential
side and an N-channel MOS semiconductor device disposed at a lower
potential side which are electrically connected in series, and the
control unit comprises: a control circuit that outputs command
signals for driving the P-channel MOS semiconductor devices and the
N-channel MOS semiconductor devices respectively; and a driver
circuit that outputs drive signals for driving the P-channel MOS
semiconductor devices and the N-channel MOS semiconductor devices
to those MOS semiconductor devices respectively upon receiving the
command signals outputted from the control circuit, wherein the
control circuit comprises a plurality of first electronic circuit
elements and the driver circuit comprises a plurality of second
electronic circuit elements, the plurality of first electronic
circuit elements are integrated and mounted on a first substrate
and the plurality of second electronic circuit elements are
integrated and mounted on a second substrate.
2. A power converting device according to claim 1, wherein the
power control circuit controls a power that is supplied from a
vehicle power supply or a power that is supplied to the vehicle
power supply.
3. A power converting device according to claim 2, wherein the
control circuit has a power source on the basis of the power that
is supplied from the vehicle and operates to output the command
signals for driving the P-channel MOS semiconductor devices and the
N-channel MOS semiconductor devices.
4. A power converting device according to claim 1, wherein the
P-channel MOS semiconductor devices and the N-channel MOS
semiconductor devices are field effect transistors.
5. A power converting device according to claim 4, wherein each
pair of the P-channel semiconductor device and the N-channel MOS
semiconductor device have a drain electrode thereof connected to
conductors of the same potential, and are mounted on the
conductors.
6. A power converting device according to claim 1, wherein the
control unit includes a rewritable memory.
7. A power converting device according to claim 1, wherein the
control unit comprises an adjusting device for adjusting the
operation speeds of the P-channel MOS semiconductor devices and the
N-channel MOS semiconductor devices, and a memory device that
stores information for setting the operation speed therein, and the
adjusting device adjusts the operation speeds of the P-channel MOS
semiconductor devices and the N-channel MOS semiconductor devices
according to the operation speed information from the memory
device.
8. A power converting device according to claim 5, wherein the
conductor has one temperature sensing element for sensing the
temperatures of the P-channel MOS semiconductor devices and the
N-channel MOS semiconductor devices.
Description
CLAIM OF PRIORITY
[0001] The present application is a continuing application of U.S.
application Ser. No. 11/102,627, filed Apr. 12, 2005, which issued
on Apr. 24, 2007, as U.S. Pat. No. 7,208,918.
[0002] The present application also claims priority from Japanese
application serial no. 2004-117027, filed on Apr. 12, 2004, and
serial no. 2005-033760, filed on Feb. 10, 2005, the contents of
which are hereby incorporated by reference into this
application.
BACKGROUND OF THE INVENTION
[0003] The present invention relates to a vehicle rotating electric
machine to be mounted on a vehicle.
[0004] For the purpose of improving fuel consumption and reducing
an exhaust emission including carbon dioxide, in vehicles, there
has been proposed an idling stop system for stopping an engine
temporarily when the automobile are stopping such as waiting at a
red light. The idling stop system provides an engine start system
including, for example, a motor and an inverter device, separately
from a starter. In this type, the motor is disposed in proximity to
the engine, and transmits a driving force to the engine through a
clutch and a belt at the time of restarting the engine. On the
other hand, since the inverter device has a large number of
electronic parts that are low in the durability at high
temperature, it is necessary that the inverter device is separated
and arranged at a position that avoids a high temperature
environment in the vicinity of the engine. For that reason,
additional parts such as the inverter device and the electric cable
that connects the inverter device and the motor are disposed within
an engine room having a limited space, and the idling stop system
cannot be mounted without changing the layout of the interior of
the engine room.
[0005] From the above viewpoint, a motor and an inverter device
able to be simply mounted and low in the costs have been demanded
for spread of the idling stop system. As one solution to the above
demand, there has been proposed an alternator (hereinafter also
referred to as "inverter built-in alternator") which is equipped
with a three-phase bridge converter circuit using MOS (metal oxide
semiconductor) elements and a control circuit for the three-phase
bridge converter circuit to enable motor drive. The inverter
built-in alternator has an inverter circuit in which a rectifier
diode of a normal vehicle alternator is replaced by a MOS element.
Since the inverter built-in alternator can be realized by the
substantially same size as that of the normal vehicle alternator,
the idling stop system can be realized without remarkably changing
the layout of the interior of the engine room even in a small
vehicle having a limited mounting space. Documents of the prior
arts are as follows.
[0006] [Document 1] Japanese Patent Laid-Open No. 2002-89417
[0007] [Document 2] Japanese Patent Laid-Open No.
H6(1994)-225476
[0008] [Document 3] Japanese Patent Laid-Open No.
H7(1995)-75262
[0009] [Document 4] Japanese Patent Laid-Open No. 2003-70256
[0010] In the inverter circuit equipped in the inverter built-in
alternator, downsizing of the device and having the durability at a
high temperature are required to enable to arrange the device
concerning the inverter in a high temperature environment in the
vicinity of the engine. However, because the conventional large
current output inverter has the three-phase bridge converter
circuit made up of an N-channel MOSFET (metal oxide semiconductor
field effect transistor) which is low in the on-resistance, there
is provided a wiring layout in which the MOSFET at the higher side
and the MOSFET at the lower side are connected to conductor plates
that are different in the potential. As a result, because the two
conductor plates thus insulated are required, the inverter circuit
is prevented from being downsized. Also, because the potential of
the output terminal of the bridge circuit fluctuates roughly from
the power potential to the ground potential according to the on/off
states of the semiconductor switches at the higher side and the
lower side, a power supply that provides a reference potential as
the output terminal potential is required in the driver circuit of
the MOSFET at the higher side in each of the phases (refer to FIG.
15). A large-capacity electrolytic capacitor is essential for the
power supply of the driver circuit of the high-side MOSFET in order
to hold the voltage. However, the electrolytic capacitor is larger
in the volume than other electronic parts, and has such a
characteristic that the electrostatic capacity is reduced and the
deterioration such as an increase of the internal resistor is
liable to occur under the high temperature environment. As a
result, it is difficult to realize the inverter built-in alternator
that requires the downsizing and the high-temperature durability in
the inverter circuit that requires the electrolytic capacitor.
[0011] Also, the inverter built-in alternator requires the driver
circuit, the minimum control circuits, a protector circuit and
power supplies for those circuits in addition to the field current
control circuit that is equipped in the conventional alternator
having only a power generating function. However, in the case where
the respective circuits are made up of the individual parts, it is
very difficult from the viewpoint of sizes to realize that those
circuits are equipped in the inverter built-in alternator. In
addition, there is required that each of those circuits is made up
of a circuit or a power supply which does not require the
electrolytic capacitor from the viewpoint of the high-temperature
resistant durability.
SUMMARY OF THE INVENTION
[0012] The present invention provides a vehicle rotating electric
machine that is capable of realizing that a power converter device
is mounted on a rotating electric machine body by about the same
built-structure as the conventional one.
[0013] In order to provide the vehicle rotating electric machine,
the present invention improves the property of mounting the power
converter device onto the rotating electric machine body. As one of
specific solving means, the power control circuit is configured by
connecting a plurality of the following series circuits in
parallel, each of the series circuits includes a P-channel MOS
semiconductor device disposed at a higher potential side and an
N-channel MOS semiconductor device disposed at a lower potential
side which are electrically connected in series.
[0014] Also, the present invention integrates a plurality of
electronic circuit elements that constitute a control circuit and a
driver circuit in a control unit that controls the operation of the
power control circuit.
[0015] According to the present invention, since the inverter
device can be downsized, there can be realized the vehicle rotating
electric machine in which the inverter device is mounted on the
rotating electric machine body by the substantially about same size
as that of the general vehicle alternator. As a result, even in the
small vehicle having a limited mounted space, the idling stop
function can be provided without remarkably changing the layout of
the interior of an engine room.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a plan view showing a semiconductor device
mounting structure of a converter circuit in an inverter device
that is integrally mounted on a motor-alternator which is an
embodiment of the present invention.
[0017] FIG. 2 is a plan view showing a mounting structure of the
inverter device that is integrally mounted on the motor-alternator
which is the embodiment of the present invention.
[0018] FIG. 3 is a cross-sectional view showing the entire
structure of the motor-alternator according to the embodiment of
the present invention.
[0019] FIG. 4 is a block diagram showing the system structure of
the motor-alternator according to the embodiment of the present
invention.
[0020] FIG. 5 is a block diagram showing the functional structure
of a control circuit shown in FIG. 4.
[0021] FIG. 6 is a block diagram showing the functional structure
of a driver circuit shown in FIG. 4.
[0022] FIG. 7 is a block diagram showing the circuit structure of a
converter circuit shown in FIG. 4.
[0023] FIG. 8 is a block diagram showing the circuit structure of a
field circuit shown in FIG. 4.
[0024] FIG. 9 is a circuit structural diagram showing the circuit
structure of a driver unit of the driver circuit shown in FIG.
6.
[0025] FIG. 10 is a block diagram showing the structure of a power
train of an automobile on which the motor-alternator that is the
embodiment of the present invention is mounted.
[0026] FIG. 11 is a flowchart showing the operation of the
motor-alternator according to the embodiment of the present
invention.
[0027] FIG. 12 is a plan view showing the semiconductor device
mounting structure of a converter circuit in an inverter device
according to a comparative example.
[0028] FIG. 13 is an explanatory diagram showing a system of
driving a motor by subjecting the switching semiconductor device to
one on/off operation in one cycle.
[0029] FIG. 14 is a circuit diagram showing the inverter device
according to the embodiment of the present invention.
[0030] FIG. 15(1) is a circuit diagram in a case where an n-MOS and
an n-MOS are combined together, and FIG. 15(2) is a circuit diagram
in a case where a p-MOS and an n-MOS are combined together.
DETAILED DESCRIPTION OF THE INVENTION
[0031] Hereinafter, embodiments of the present invention will be
described with reference to FIGS. 1 to 11. A motor-alternator 100
according to an embodiment of the present invention is a so-called
inverter built-in vehicle rotating electric machine in which an
inverter device 50 is integrated with a rotating electric machine
body 1, and constitutes an electric power train of an automobile
200.
[0032] The automobile 200 to which the motor-alternator 100 of the
present invention is applied is a so-called hybrid automobile
having both of an engine power train with an internal combustion
engine as a power source and an electric power train with the
motor-alternator 100 as a power source, as shown in FIG. 10. The
engine power train is mainly used for a driving power source of the
automobile 200. The electric power train is mainly used for the
power source to make starting of the engine 120, and used for the
electric power supply for the automobile 200. The automobile 200
having such an electric power train, when the automobile stops such
that the automobile waits at a red light in a state where the
ignition key is on, the engine 120 automatically stops, and when
the automobile starts, the electric power train automatically makes
the engine start for starting of the vehicle. Thereby the
automobile makes it possible to perform so-called idling stop
driving which enables the fuel consumption of the automobile 200 to
be improved and the exhaust emission to be reduced.
[0033] As shown in FIG. 10, a front axle 115 is rotatably supported
at a front side of a vehicle body. Front wheels 111 and 112 are
disposed at both ends of the front axle 115. A rear axle 116 is
rotatably supported at a rear side of the vehicle body. Rear wheels
113 and 114 are disposed at both ends of the rear axle 116. A
differential gear 117 that is a power sharing mechanism is disposed
in the center of the front axle 115. The differential gear 117
shares a rotational driving force, which has been transmitted
through a transmission 130 from the engine 120, to the right and
left axle members of the front axle 115. The transmission 130
varies the rotational driving force of the engine 120 and transmits
the varied driving force to the differential gear 117. The driving
of the engine 120 is controlled by controlling the operations of
accessories such as an injector that is a fuel control mechanism
and a throttle valve that is an air flow rate control mechanism
with an engine control device 140.
[0034] The motor-alternator 100 is arranged within the engine room
at the front of the vehicle body 110 together with the engine 120,
and mounted to the side of the engine 120 and mechanically
connected to the engine 120. The mechanical connection can be
realized by looping a belt 170 over a pulley 120a disposed on a
crank shaft of the engine 120 and a pulley 100a disposed on the
rotary shaft of the motor-alternator 100. As a result, the
motor-alternator 100 can transmit the rotational driving force to
the engine 120, and can receive the rotational driving force from
the engine 120.
[0035] The electric power train of the automobile 200 is
electrically connected to a 14 V vehicle power supply comprising a
battery 150 as shown in FIGS. 4 and 10, and gives a power generated
by itself to the battery or receives a power from the 14 V vehicle
power supply. The 14 V vehicle power supply is electrically
connected with a starter as a starting device of the engine 120,
and vehicle accessories machinery such as lamps, a car radio, and
direction indicators not shown. A lead battery of an output voltage
of about 12 V is used for the battery 150.
[0036] As described above, the motor-alternator 100 is structured
such that the inverter device 50 is integrated with the rotating
electric machine 1. In the motor-alternator 100, the rotating
electric machine 1 is made up in common with conventional
alternators mounted on the automobile as shown in FIG. 3. More
specifically, the rotating electric machine 1 comprises a stator 2
having a stator winding 5 and a rotor 3 having a field winding 8 as
shown in FIG. 4. A specific structure of the rotating electric
machine body 1 will be described later with reference to FIG. 3. A
three-phase alternating power, which is controlled by the inverter
device 50, is supplied to the stator winding 5. A field current,
which is also controlled by the inverter device 50, is supplied to
the field winding 8. In the motor-alternator 100, a rotating
magnetic field is generated by such three-phase alternating power
and field current, and the rotor 3 rotates with respect to the
stator 2. As a result, the motor generator 100 operates as an
electric motor, and generates a rotational driving force for
starting the engine 120. On the other hand, in the motor-alternator
100, when a field current is supplied to the field winding 8, and
the rotor 3 rotates by the rotational driving force of the engine
120, a voltage is induced in the stator winding 5. As a result, the
motor-alternator 100 operates as an alternator, and generates a
three-phase alternating power to charge the battery 150. In this
embodiment, a synchronous alternating rotating electric machine is
used for the motor-alternator 100. However, an inductive
alternating rotating electric machine may be used as the
motor-alternator 100.
[0037] The inverter device 50 is a power converter device that
converts a DC power supplied from the battery 150 into a
three-phase AC power, or converts a three-phase AC power obtained
by the power generation of the motor-alternator 100 into a DC
power. More specially, the inverter device 50 comprises a module
unit 52 and a control unit 51 as shown in FIG. 4. The mounting
structure of the inverter device 50 will be described later with
reference to FIG. 1. The module unit 52 has a converter circuit 55
and a field circuit 56. The converter circuit 55 is a power control
circuit that converts a DC power supplied from the battery 150 into
a three-phase AC power, or converts a three-phase AC power supplied
from the stator winding 5 into a DC power. The field circuit 56 is
a field current control circuit that controls the field current
supplied to the field winding 8 from the battery 150. The control
unit 51 has a control circuit 53 and a driver circuit 54. The
control circuit 53 is a control logic circuit that outputs, to the
driver circuit 54, command signals to control the operation of the
converter circuit 55 and the field circuit 56 according to a
command signal from a host control device, for example, the engine
control device 140, and various detection signals (feedback
signals) related to a phase voltage of the motor-alternator 100 or
the terminal voltage of the battery 150. Upon receiving the command
signal from the control circuit 53, the driver circuit 54 outputs
the driving signals to operate the converter circuit 55 and the
field circuit 56 to the converter circuit 55 and the field circuit
56. In order to improve the mounting property of the inverter
device 50 on the rotating electric machine body 1, in this
embodiment, a voltage adjuster that has been mounted on the vehicle
alternator up to now is integrated with the inverter device 50 to
ensure a space where which the inverter device 50 is mounted.
[0038] The respective structures of the control circuit 53, the
driver circuit 54, the converter circuit 55 and the field circuit
56 in the inverter device 50 will be described in more detail.
[0039] The converter circuit 55 converts the DC power into the
three-phase AC power or the three-phase AC power into the DC power
by the switching (on/off) operation of the switching semiconductor
device. The switching semiconductor device may be MOSFETs (MOS
field effect transistor) that are MOS (metal oxide semiconductor)
elements, or an IGBT (insulated gate bipolar transistor). In this
embodiment, MOSFETs in which respective diodes are incorporated are
used for the switching semiconductor device. As shown in FIG. 7,
the converter circuit 55 is configured with a bridge circuit of 6
phases (3 phases.times.the number of stator windings:2) in which
each thereof has a P-channel MOSFET and a N-channel MOSFET. In each
(arms) of the 6 phases, a drain electrode of the P-channel MOSFET
64 and a drain of the N-channel MOSFET 65 are electrically
connected to each other in series, on condition that the P-channel
MOSFET 64 is disposed at a higher potential pole (positive pole)
side, and the N-channel MOSFET 64 is disposed at a lower potential
pole (negative pole) side. And by connecting the respective phases
(series circuits: arms) to each other in parallel, the bridge
circuit of 6 Phases is configured for converter. A source electrode
of the P-channel MOSFET 64 is electrically connected to the higher
potential pole (positive pole) side in both poles of the battery
150. A source electrode of the N-channel MOSFET 65 is electrically
connected to the lower potential pole (negative pole) side in both
poles of the battery 150. Phase windings of the stator winding 5
respectively are electrically connected between the drain
electrodes of the P-channel MOSFET 64 and the N-channel MOSFET 65.
That is, a U-phase winding on one side of the stator winding 5 is
electrically connected between the drain electrodes of the
P-channel MOSFET 64U.sub.1 and the N-channel MOSFET 65U.sub.1. A
U-phase winding on the other side of the stator winding 5 is
electrically connected between the drain electrodes of the
P-channel MOSFET 64U.sub.2 and the N-channel MOSFET 65U.sub.2. The
same structure as the U phase is applied to a V-phase and a
W-phase. Corresponding driving signals A to L are inputted from the
control unit 51 to the gate electrodes of the P-channel MOSFET 64
and the N-channel MOSFET 65. A voltage between the drain electrodes
of the P-channel MOSFET 64 and the N-channel MOSFET 65 is inputted
to the control unit 51 as a phase voltage signal. A voltage at a
higher potential pole (positive pole) side in both poles of the
battery 150 is inputted to the control unit 51 as a battery
positive pole voltage signal.
[0040] The field circuit 56 controls a field current that flows
into the field winding 8 from the battery 150 due to the switching
(on/off) operation of the switching semiconductor device. An
N-channel MOSFET 69 is used for the switching element. The drain
electrode of the N-channel MOSFET 69 is electrically connected to a
negative pole end of the field winding 8 (a side opposite to the
positive pole end connected to the higher potential (positive pole)
side of the battery 150). A source electrode of the N-channel
MOSFET 69 is electrically connected to the lower potential
(negative pole) side of the battery 150. A driving signal T from
the control unit 51 is inputted to a gate electrode of the
N-channel MOSFET 69. A diode 68 is electrically connected between
the drain electrodes of the N-channel MOSFET 69 and the higher
potential (positive pole) side of the battery 150. The diode 68 is
made up of a P-channel MOSFET which is in a forward direction
toward the higher potential (positive pole) side of the battery 150
from the drain electrode side of the N-channel MOSFET 69.
[0041] The control circuit 53 is a circuit that operates by a
driving voltage of about 5 V, and includes plural control units as
shown in FIG. 5. The driving voltage is applied from the driver
circuit 54 which will be described later, and the driving voltage
results from stepping down the voltage (about 12 V) of the battery
150. The control circuit 53 inputs a command signal from the engine
control device 140 that is a host control device. The command
signal from the engine control device 140 is a signal for operating
the motor-alternator 100 as a motor, or a signal for operating the
motor-alternator 100 as an alternator. Those signals are outputted
according to the operation state of the vehicle. For example, in
the case of starting the engine 120 to start the vehicle from a
stopping state of the vehicle, such a mode of changing from the
idle stop to starting of the engine 120, the engine control device
140 outputs a start signal for operating the motor-alternator 100
as the motor to the control circuit 53 when the off of the brake is
detected.
[0042] The transmission of the command signal from the engine
control device 140 to the control circuit 53 is conducted by means
of an LIN (local interconnect network) system which is one of the
serial communication systems. The command signal from the engine
control device 140 to the control circuit 53 through a LIN is
inputted to a microprocessor (hereinafter referred to as "MP") 53d
through an interface circuit 53f. The MP 53d judges the operation
mode of the motor-alternator 100 based on an inputted command
signal, and outputs the operation commands to the respective
control units according to the operation mode so that the
respective control units execute given processing corresponding to
the operation mode. Also, the MP 53d reads program or data
corresponding to the operation mode from a RAM 53m that is a memory
device that can rewrite the stored information or a ROM 53n that is
a memory device that can read the stored information, or writes the
data in the RAM 53m. In addition, the MP 53d has an A/D converter
53k and a timer/counter 53e. The AD converter 53k converts an
analog quantity such as a voltage or temperature inputted to the MP
53d into a digital quantity. A timer/counter 531 is used to, for
example, measure a time width at which the command value is
sequentially changed by the control program and a time interval in
which the LIN communication is conducted. As a result, the MP 53d
can detect the rotation speed of the motor-alternator 100, and can
output the predetermined operation commands to the respective
control units by comparing the sensed rotation speed with a
predetermined rotation speed. The signal transmission between the
engine control device 140 and the control circuit 53 is executed by
using the LIN, thereby making it possible to reduce the number of
communication lines between the engine control device 140 and the
control circuit 53.
[0043] The control unit has a motor control unit 53a, an alternator
(synchronous rectifier) control unit 53b, and a filed control unit
53h.
[0044] When the motor-alternator 100 operates as the motor, the
motor control unit 53a outputs voltage command signals to control
the operation of the P-channel MOSFETs 64 and the N-channel MOSFETs
65 of the converter circuit 55. An operation command signal from
the MP 53d, a rotation speed signal from the rotation speed
calculating circuit 53e, and phase voltage signals c to h from the
converter circuit 55 are inputted to the motor control 53a through
the driver circuit 54. The rotation speed signal is calculated
based on a sensed signal b from a rotation sensor 73. The motor
control unit 53a outputs voltage command signals for controlling
the operation of the P-channel MOSFETs 64 and the N-channel MOSFETs
65 according to the operation command signal from the MP 53d and
based on the sensed signal b from the rotation sensor 73. The
voltage command signals are to control the MOSFETs 64, 65 so that
the motor-alternator 100 reaches a target rotation speed. In the
voltage command signals from the motor control unit 53a, the
voltage command signals related to the P-channel MOSFETs 64 at the
higher potential side are inputted to a switching circuit 53j. The
voltage command signals related to the N-channel MOSFETs 65s at the
lower potential side are inputted to a switching circuit 53i.
[0045] When the motor-alternator 100 operates as the alternator,
the alternator (synchronous rectifier) control unit 53b outputs
voltage command signals to control the operation of the P-channel
MOSFETs 64 and the N-channel MOSFETs 65 of the converter circuit
55. The operation command signal from the MP 53d, the phase voltage
signals c to h from the converter circuit 55 via the driver circuit
54, a battery higher potential side voltage signal i from the
converter circuit 55 via the driver circuit 54, and a battery lower
potential side voltage signal j from the driver circuit 54, are
inputted to the alternator (synchronous rectifier) control unit
53b. The alternator (synchronous rectifier) control unit 53b
outputs voltage command signals for controlling of the operation of
the P-channel MOSFETs 64 and the N-channel MOSFETs 65, in order to
synchronously rectify the three-phase AC power from the
motor-alternator 100 and convert the AC power into a DC power
according to the operation command of the MP 53d. In this case, the
alternator control unit 53b compares a voltage across both ends of
the battery 150 with the inputted phase voltage values of the
respective phases (in the case where the phase voltage is positive,
the phase voltage value is compared with the battery higher
potential side voltage, whereas in the case where the phase voltage
is negative, the phase voltage value is compared with the battery
lower potential side voltage). Then, the alternator (synchronous
rectifier) control unit 53b outputs voltage command signals for
controlling the operation of the P-channel MOSFETs 64 and the
N-channel MOSFETs 65 according to the comparison result being equal
to or more than a predetermined voltage (forward voltage drop of
the diode: about 0.7 V), or less. In the voltage command signals
from the alternator (synchronous rectifier) control unit 53b, the
voltage command signals related to the P-channel MOSFETa 64 at the
higher potential side are inputted to the switching circuit 53j.
The voltage command signals related to the N-channel MOSFET 65 at
the lower potential side are inputted to the switching circuit
53i.
[0046] When the motor-alternator 100 operates as the motor or the
alternator, the field control unit 53h outputs a voltage command
signal to control the operation of the N-channel MOSFET 69. The
N-channel MOSFET is used to pass a field current through a winding
8 of the field circuit 56. The operation command signal from the MP
53d and an abnormality signal from a detector/protector circuit
unit 53c that will be described later, are inputted to the field
control unit 53h. When the motor-alternator 100 operates as the
motor, the field control unit 53h calculates a field current value
based on the operation command from the MP 53d so that a
predetermined torque is outputted from the motor-alternator 100.
And the field control unit 53h calculates a voltage command value
based on the calculated field current value; then, it outputs the
voltage command value as a voltage command signal for controlling
the operation of the N-channel MOSFET 69. When the motor-alternator
100 operates as the alternator, the field control unit 53h
calculates a field current value according to the operation command
of the MP 53d so that a predetermined electrical energy is
outputted from the motor-alternator 100. And the control unit 53h
calculates the voltage command value based on the calculated field
current value; then, the field control unit 53h outputs the voltage
command value as the voltage command signal for controlling the
operation of the N-channel MOSFET 69. Also, when a damp surge
voltage or the like is detected by the detector/protector circuit
unit 53c, the field control unit 53h outputs the voltage command
signal to control the operation of the N-channel MOSFET 69 based on
the abnormality signal from the detector/protector circuit unit 53c
so that the amount of current flowing in the winding 8 is
decreased. A voltage command signal x from the field control unit
53h is inputted to the driver circuit 54.
[0047] The detector/protector circuit unit 53c is used to detect
the generation of an over-voltage such as a damp surge voltage, an
over-current or an over-temperature, and protect a switching
element of the converter circuit 55 or the field circuit 56 from
such over-voltage, over-current or over-temperature. An operation
command signal from the MP 53d, phase voltage signals c to h from
the converter circuit 55 via the driver circuit 54, a battery
higher potential side voltage signal i from the converter circuit
55 via the driver circuit 54, and a battery lower potential side
voltage signal j from the driver circuit 54, are inputted to the
detector/protector circuit unit 53c. The detector/protector circuit
unit 53c executes various abnormality detections on the basis of
the operation command signal from the MP 53d. As a result, if there
is an abnormality, the detector/protector circuit unit 53c outputs
the abnormality signal to the MP 53d and the field control unit
53h. For example, in the case where the damp surge voltage is
detected by the detector/protector circuit unit 53, the operation
command signal is outputted to the switching circuit 53i so that
the N-channel MOSFET 65 at the lower potential side of the
converter circuit 55 should be turned off.
[0048] The switching circuit 53j switches between the voltage
command signals from the motor control unit 53a and the voltage
command signals from the alternator (synchronous rectifier) control
unit 53b according to the operation mode of the motor-alternator
100; and the switched signals are outputted. Those voltage command
signals are used for controlling the operation of the P-channel
MOSFET 64. The operation command signal from the MP 53d and the
voltage command signals from the motor control unit 53a or the
alternator (synchronous rectifier) control unit 53b, are inputted
to the switching circuit 53j. The switching circuit 53j switches
the outputs of the voltage command signals for the P-channel MOSFET
64 according to the operation command signal from the MP 53d, and
outputs the switched voltage command signals to the driver circuit
54 as the voltage command signals j to q.
[0049] The switching circuit 53i switches between the voltage
command signals from the motor control unit 53a and the alternator
(synchronous rectifier) control unit 53b according to the operation
mode of the motor-alternator 100; and the switched signals are
outputted. Those voltage command signals are used for controlling
the operation of the N-channel MOSFET 65. The operation command
signal from the MP 53d and the voltage command signals from the
motor control unit 53a or the alternator (synchronous rectifier)
control unit 53b, are inputted to the circuit 53i. The switching
circuit 53i switches the outputs of the voltage command signals for
the N-channel MOSFET 65 according to the operation command signal
from the MP 53d, and outputs the voltage command signals to the
driver circuit 54 as the voltage command signals r to w.
[0050] In this embodiment, as shown in FIG. 5, the motor control
unit 53a, the alternator (synchronous rectifier) control unit 53b,
and the detector/protector circuit unit 53c are surrounded by a
dotted line. This indicates that the phase voltage signals c to h,
the battery high potential side voltage signal i, and the battery
low potential side voltage signal j, are commonly inputted to the
motor control unit 53a, the alternator (synchronous rectifier)
control unit 53b, and the detector/protector circuit unit 53c in
the control circuit 53. Arrows indicative of signals that are
commonly inputted to the motor control unit 53a, the alternator
(synchronous rectifier) control unit 53b and the detector/protector
control unit 53c are inputted to the box indicated by the dotted
line. Also, the number of arrows of the voltage command signals
from the motor control unit 53a and the alternator (synchronous
rectifier) control unit 53b, respectively, is equal to the number
of P-channel MOSFETs 64 and N-channel MOSFETs 65, that is 12. In
this embodiment, for simplification of the drawing, those arrows
are indicated by one arrow. In addition, in this embodiment, in
order to distinguish between power flows and signal flows, the
power flows are indicated by solid lines, and the signal flows are
indicated by dotted lines, respectively.
[0051] The control circuit 53 is provided with a temperature sensor
53g. Also, a thermistor 57 is disposed in the converter circuit 55,
a sensing signal from the termistor 57 is inputted to the control
circuit 53. In the control circuit 53, any signal of the sensing
signal from the temperature sensor 53g and the sensing signal from
the thermistor 57 is selected and inputted to an A/D converter 53k.
Then, the signal is converted into a digital signal and inputted to
the MP 53d.
[0052] The driver circuit 54 operates at an output voltage (about
12 V) of the battery 150, and as shown in FIG. 6, comprises driver
units 54d.sub.1 to 54d.sub.12, 54e, level converter circuits 54b,
54c, and a control power supply 54a. The control power supply 54a
is electrically connected between both poles of the battery 150,
and outputs a driving power of the control circuit 53. The control
power supply 54a supplies a control power k resulting from stepping
down the output voltage (about 12 V) of the battery 150 to about 5
V to the control circuit 53. The driver units 54d.sub.1 to
54d.sub.6 output driving signals to drive the P-channel MOSFET 64
corresponding to the converter circuit 55. The driver unit
54d.sub.7 to 54d.sub.12 output driving signals to turn on/off the
N-channel MOSFET 65 corresponding to the converter circuit 55. The
driver unit 54e outputs a driving signal to drive the N-channel
MOSFET 65 of the field circuit 56. The voltage command signals 1 to
q among the voltage command signals outputted from the control
circuit 53, are increased in the potential level by the level
converter circuit 54d and then inputted to the corresponding driver
units 54d.sub.1 to 54d.sub.6. Likewise, the voltage command signals
r to w are increased in the potential level by the level converter
circuit 54d and then inputted to the corresponding driver units
54d.sub.7 to 54d.sub.12. The voltage command signal x from the
control circuit 53 is increased in the potential level by the level
converter circuit 54c and then inputted to the driver unit 54e. The
driver units 54d.sub.1 to 54d.sub.6 output the driving signals A to
F to the gate electrode of the corresponding P-channel MOSFET 64
according to the inputted voltage command signals 1 to q. The
driver units 54d.sub.7 to 54d.sub.12 output the driving signals G
to L to the gate electrode of the corresponding N-channel MOSFET 65
according to the inputted voltage command signals r to w. The
driver unit 54e outputs the driving signal T to the gate electrode
of the corresponding N-channel MOSFET 65 according to the inputted
voltage command signal x. The level converter circuit 54d drops the
potential levels of the phase voltage signals M to R and the
battery higher potential side voltage signal S from the converter
circuit 55, and then output those signals to the control circuit 53
as the phase voltage signals c to h and the battery higher
potential side voltage signal i. In addition, the level converter
circuit 54b takes in the lower potential side voltage of the
battery 150 as the battery lower potential side voltage signal,
drops the potential level and outputs the voltage to the control
circuit 53 as the battery lower potential side voltage signal
j.
[0053] Each of the driver units 54d.sub.1 to 54d.sub.12 is made up
of a circuit including a transistor and a resistor, as shown in
FIG. 9. In this example, there is shown a structure of a driver
unit for one arm which consists of a P-channel MOSFET 64 and an
N-channel MOSFET 65. The driver unit for driving the P-channel
MOSFET 64 is made up of the following an off-circuit and an
on-circuit. The off-circuit comprises a series circuit of a
transistor 401 and a resistor 407, a series circuit of a transistor
402 and a resistor 408, and a series circuit of a transistor 403
and a resistor 409; and the off-cut circuit is formed by connecting
these series circuits in parallel. The on-circuit is formed with a
series circuit of a transistor 413 and a resistor 414. The driver
unit for driving the N-channel MOSFET 65 is made up of the
following an off-circuit and an on-circuit. The off-circuit
comprises a series circuit of a transistor 404 and a resistor 410,
a series circuit of a transistor 405 and a resistor 411, and a
transistor 406 and a resistor 412; and the off-circuit is formed by
connecting these series circuits in parallel. The on-circuit is
formed with the series circuit of a transistor 415 and a resistor
416. In the off-circuit of the P-channel MOSFET 64, each emitter
electrode of the transistors 401-403 is electrically connected to a
source electrode side of the P-channel MOSFET 64, and each end of
the resistors 407-409 opposite to each collector electrode of the
transistors 401-403 is electrically connected to a gate electrode
side of the P-channel MOSFET 64. In the on-circuit of the P-channel
MOSFET 64, an emitter electrode of the transistor 413 is connected
to a source electrode side of the N-channel MOSFET 65, and end of
the resistor 414 opposite to a collector electrode of the
transistor 413 is connected to a gate electrode side of the
P-channel MOSFET 64. In the off circuit of the N-channel MOSFET 65,
each emitter electrode of the transistors 404-406 is electrically
connected to a source electrode side of the N-channel MOSFET 65,
and each end of the resistors 410-412 opposite to each collector
electrode side of the transistor 404-406 is electrically connected
to a gate electrode side of the N-channel MOSFET 65. In the on
circuit of the N-channel MOSFET 65, an emitter electrode side of
the transistor 415 is electrically connected to a source electrode
side of the P-channel MOSFET 64, and an end of the resistor 416
opposite to a collector electrode side of the transistor 415 is
electrically connected to a gate electrode side of the N-channel
MOSFET 65.
[0054] In the driver unit thus structured according to this
embodiment, by changing the off signal applied to the base
electrodes of the transistors 401 to 403 (off circuit of each
P-channel MOSFET 64 switch), it possible to control a speed of
drawing out the electric charges of the gate electrode of the
P-channel MOSFET 64 according to the resistances of the resistors
407 to 409. For example, when it is assumed that the resistances of
the resistors 407 to 409 are 10.OMEGA., 20.OMEGA. and 40Q, the
resistances in the off circuit of the P-channel MOSFET 64 can be
adjusted in a wide range of about 6 to 40.OMEGA.. According to this
embodiment, when the MOS elements for the converter circuit 55 are
changed, the switching speed of that element can be readily
changed. Also, according to this embodiment, since the control
circuit 53 has the MP 53d, the RAM 53m and the ROM 53n, the off
signal supplied to the base electrode of the transistors 401 to
403(off circuit of the P-channel MOSFET 64) can be readily changed
over by changing of the variable of the memory. In addition,
according to this embodiment, by changing the program of the
switching timing of the off signal that is applied to the base
electrode of the transistors 401 to 403, it possible to perform
soft switching for changing a speed depend on time at which the
gate electric charges of the transistors 401 to 403 is drawn out.
The same is applied to the N-channel MOSFET 65 side.
[0055] Subsequently, the actual structure of the motor-alternator
100 according to this embodiment will be described with reference
to FIGS. 1 to 3. First, the structure of the rotary electric
machine body 1 will be described.
[0056] In FIG. 3, reference numeral 2 denotes a stator. The stator
2 has a stator core 6 and a stator winding 5 installed on the
stator core 6. The stator core 6 is formed of a cylindrical
lamination core resulting from forming a plurality of annular core
plates each of which is obtained by punching a thin silicon steel
plate. The thickness of each of the core plates laminated at both
ends of the lamination core in the axial direction is thicker than
the core plates laminated in the middle portion in the axial
direction. A core back (not shown) is formed on the outer
peripheral portion of the stator core 6 is formed with. The core
back is formed of a cylindrical core portion that is formed
continuously in the circumferential direction, and is held between
a front bracket 12 and a rear bracket 13 from both sides thereof in
the axial direction. With the above structure, the stator 2 is
supported at the inner side of the brackets. Plural teeth (not
shown) are formed on the inner circumferential side of the core
back which is an inner circumferential portion of the stator core
6. The teeth are dentate core portions that are so formed as to
project toward an inner center side in the radial direction from
the inner circumferential surface of the core back, and formed
continuously in the axial direction along the inner circumferential
surface of the core back. The plural teeth are at given intervals
in the circumferential direction along the inner circumferential
surface of the core back. Slots (not shown) of the same number as
that of the teeth are formed between the respective adjacent teeth.
The slots are space portions for receiving the winding conductors
that constitute the stator winding 5, and formed continuously in
the axial direction as with the teeth portion. Plural slots are
arranged at predetermined intervals in the circumferential
direction. Also, a side opposite to the core back of each slot is
opened, and both ends of the slot in the axial direction are also
opened. Each of the slots receives the winding conductor that
constitutes the stator winding 5. Each of the winding conductors is
formed by a rectangular wire or a circular wire. Each of the
winding conductors projects outward from both ends of the stator
core 6 in the axial direction to be connected to obtain a star
connection. In this embodiment, the stator winding 5 is formed of
two three-phase windings that are electrically independent from
each other.
[0057] The rotor 3 is so disposed as to face the inner
circumferential side of the stator 2 with a gap. A rotary shaft 9
is disposed on the center axis of the rotor 3. One end side of the
rotary shaft 9 is supported rotatably by a bearing 14 at the center
portion of the front bracket 12, and the other end side is
supported by a bearing 15 at the center portion of the rear bracket
13. A portion of the rotary shaft 9 which faces the inner
circumferential side of the stator 2 is fixed into a rotor core 7.
The rotor core 7 is structured so that a pair of unguiform magnetic
pole cores face each other in the axial direction. The unguiform
magnetic pole cores have plural unguiform magnetic poles that
extend toward the centrifugal side in the radial direction from the
cylindrical core portion, and have triangular or trapezoidal
leading ends folded at right angles in directions along which those
leading ends face each other. The unguiform magnetic poles are
arranged at given intervals in the rotational direction. In the
case where the unquiform magnetic poles face each other in the
axial direction, the unguiform magnetic poles are arranged between
the respective unguiform magnetic poles of the unguiform magnetic
pole cores that face each other. One of the unguiform magnetic pole
cores forms an N pole. The other magnetic pole forms an S pole.
With the above structure, the rotor 3 has plural magnetic poles
formed in such a manner that the polarity is alternately different
in the rotational direction, that is, the N pole and the S pole are
alternate. The field winding 8 is disposed on the outer
circumference of the core portions which face the inner
circumferential side of the leading portions of the unguiform
magnetic poles. One end of the rotary shaft 9 in the axial
direction (end portion of the front bracket 12 side) extends toward
the outer side in the axial direction farther than the bearing 14.
A pulley 100a is disposed on a portion that extends toward the
outer side in the axial direction farther than the bearing 14 on
one end of the rotary shaft 9. The pulley 100a is connected to a
pulley 120a of the engine 120 through a belt (not shown). The other
end of the rotary shaft 9 in the axial direction (the end portion
on the rear bracket 13 side) extends toward the outer side in the
axial direction farther than the bearing 15. A slip ring 17 is
disposed on the outer circumferential surface of the portion that
extends toward the outer side in the axial direction farther than
the bearing 15 on the other end of the rotary shaft 9. The slip
ring 17 is electrically connected to the field winding 8. The slip
ring 17 is slidable in contact with a brush 16. The brush 16
supplies a field current to be supplied to the field winding 8 to
the slip ring 17. A front fan 11 is attached onto one end of the
unguiform magnetic pole core (end portion on the front bracket 12
side) in the axial direction. A rear fan 10 is attached onto the
other end of the unguiform magnetic pole core (end portion on the
rear bracket 13 side) in the axial direction. The front fan 11 and
the rear fan 10 rotate together with the rotation of the rotor 3 so
that an outside air to be a cooling medium is introduced into the
interior of the machine from the exterior and then circulated
within the machine, and the outside air that has finished the
cooling function is exhausted toward the exterior from the interior
of the machine. In order to achieve the above operation, plural
through-holes are provided at the front bracket 12 and the rear
bracket 13 in order to introduce the outside air into the interior
of the machine from the exterior and to exhaust the outside air
toward the exterior from the interior of the machine.
[0058] A space defined by module cases 62 and 63 is formed on one
side of a side surface of the rear bracket 13 (a side opposite to
the front bracket 12 side). An inverter device 50 is installed in
the space. The module case 63 serves as a brush holder that holds
the brush 16. A communication terminal 60 and a battery terminal 18
are exposed from the module case 62 toward the external. The rear
bracket 13 is electrically connected to a chassis of the automobile
200. A positive pole side of the inverter device 50 is electrically
connected to the battery terminal 18, and a negative pole (ground)
side is electrically connected to the rear bracket 13. The above
structure has the compatibility with the general vehicle
alternator.
[0059] Now, a specific arrangement structure of the inverter device
50 will be described. Concerning the structure of the control
circuit 53 including the converter circuit 55 and the control power
supply 54a, there are considerable two types. One of the converter
circuits 55 may be formed of P-channel MOSFETs 64 and N-channel
MOSFETs 65. Another may be formed of only the N-channel MOSFETs 65.
Herein both types thereof will be described in comparison. In the
inverter for outputting a large current, the N-channel
semiconductor device is mainly used in order to reduce the loss of
the semiconductor device at the on time. However, in this
embodiment, the control circuit 53 including the converter circuit
55 and the control power supply 54 is structured as shown in FIG. 1
for the purposes of the downsizing and the high-temperature
durability in order to mount the inverter device 50 integrally with
the rotary electric machine body 1. The structure of the control
circuit 53 including the converter circuit 55 and the control power
supply 54a as in the latter is shown in FIG. 12.
[0060] When the circuits in FIGS. 1 and 12 are compared with each
other, in the circuit shown in FIG. 12, in order to drive an
N-channel MOSFET 65a on the higher potential side, there is
required a high side power supply 300 relative to a potential of an
output terminal 76 which fluctuates due to the rotation of the
motor-alternator 100. However, in the circuit of this embodiment
shown in FIG. 1, in MOSFETs of the higher potential side, a
potential between the higher potential and the lower potential can
be supplied to the gate electrodes of each MOSFET relative to the
higher potential side of the battery 150; and in MOSFETs of the
lower potential side, the potential between the higher potential
and each lower potential can be supplied to the gate electrodes of
each MOSFET relative to the lower potential side (ground potential)
of the battery 150; thereby making it possible to drive the
respective MOSFETs. This means that, in order to drive the
three-phase alternating motor, the high side power supply 300 for
driving the MOSFET on the higher potential side is not required in
the circuit shown in FIG. 1, whereas at least three high side power
supplies 300 are required in the circuit shown in FIG. 12.
Moreover, an electrolyte capacitor that is relatively large in the
electrostatic capacity is required in the high side power supply
300 in order to hold the voltage. The electrolyte capacitor suffers
from a problem on the reliability under the high-temperature
environment. A relationship between the lifetime of the electrolyte
capacitor and the temperature is frequently expressed by the
following relational expression that applies the Arrhenius law.
L=Lc*A.sup.((TC-T)/10) where L is the lifetime at the used
temperature T, Lc is the lifetime at a reference temperature
T.sub.c, T is the used temperature, T.sub.c is the reference
temperature, and A is a temperature acceleration coefficient. The
lifetime of the electrolyte capacitor means an increase in the
internal resistance and a decrease in the capacitance. For example,
in the case of A=2, the lifetime becomes 1/2 when the used
temperature T is higher than the reference temperature T.sub.c by
10.degree. C. As described above, the electrolyte capacitor
exponentially deteriorates the performance under the
high-temperature environments. Also, it is impossible to make the
electrolyte capacitor IC-compatible, and the electrolyte capacitor
is improper for downsizing the circuit. From this viewpoint, there
is required a structure in which the electrolyte capacitor is not
used in the rotating electric machine that mounts the inverter
device 50 integrally with the rotating electric machine body 1. On
the other hand, because the control power supply 54a for only the
necessary control circuit 53 in the circuit of this embodiment
shown in FIG. 1 steps down the output voltage of the battery 150 to
generate the reference voltage, there can be provided the power
supply circuit that does not require the electrolyte capacitor.
From this viewpoint, in order to constitute the inverter device
that improves the heat resistance using no electrolyte capacitor,
it is understood that the circuit of this embodiment shown in FIG.
1 is effective. Also, there are a large number of MOSFETs that are
driven by a power supply of about 10 V to 14 V. From this
viewpoint, since the circuit structure of this embodiment shown in
FIG. 1 can use the 14 V power supply mounted on a large number of
vehicles as it is, the MOSFET is proper for the inverter built-in
rotating electric machine that is applied to the 14 V power supply
vehicle.
[0061] Subsequently, the structures shown in FIGS. 1 and 12 are
compared with each other from the viewpoint of an area in which the
converter circuit is mounted. In FIGS. 1 and 12, an insulating
substrate 66 is formed of a circuit board where electrically
conductive plates 66b to 66d and an insulating plate 66a are put
together. The insulating plate 66a is made of aluminum nitride,
silicon nitride or alumina which is an insulating material that is
excellent in the heat conductance. In the circuit structure shown
in FIG. 12, there is required that the conductive plates 66b and
66d of the insulating substrate 66, which also serve as wirings of
the converter circuit, are divided into two pieces and insulated
from each other in order to fix the MOSFETs at the higher potential
side and the lower potential side. As a result, it is necessary to
provide a predetermined distance between the conductive plates 66b
and 66d for insulation. Also, there is required an area for a
wiring that connects a source electrode of the MOSFET 65a at the
higher potential side to the conductive plate 66d of fixing the
MOSFET 65b at the lower potential side. On the contrary, in the
circuit structure of this embodiment shown in FIG. 1, because the
MOSFET 64 at the higher potential side and the MOSFET 65 at the
lower potential side can be fixed onto the single conductive plate
66b, the mounting area can be reduced more than the circuit
structure shown in FIG. 12 without the above-mentioned restriction.
Also, in the motor-alternator 100 of this embodiment, the
importance of the temperature management of the MOS semiconductor
that is a main heating part is high because the motor-alternator
100 is used under the high-temperature environments. In order to
manage the temperature with higher precision, it is essential to
locate a temperature sensing thermistor 57 on the conductive plate
66b on which the MOS semiconductor is fixed. In the circuit shown
in FIG. 12, two thermistors 57 are required because the conductive
plates on which the MOS semiconductors at the higher potential side
and the lower potential side are fixed are separated from each
other. On the other hand, one thermistor 57 may be provided in the
circuit structure according to this embodiment shown in FIG. 1.
Even if an area necessary to locate the thermistor 57 is not taken
into consideration, the circuit structure of this embodiment shown
in FIG. 1 can reduce the mounting area more than the circuit
structure shown in FIG. 12.
[0062] Accordingly, this embodiment, in which the circuit structure
shown in FIG. 1 is applied, solves problems occurring when the
inverter device 50 is integrally mounted on the rotating electric
machine body 1, that is, problems such as the downsizing and the
high-temperature durability.
[0063] Hereinafter, a specific arrangement structure of the
inverter device 50 will be described with reference to FIG. 2. In
FIG. 2, reference numeral 64 denotes each P-channel MOSFET, 65 is
each N-channel MOSFET, 66 is an insulating substrate, 61 is a
radiation conductive plate, 67 is an output terminal, 70P and 70N
are power supply wirings, 71 is a positive pole side power
terminal, 72 is a control circuit board, and 51 is a control IC
(control unit). Also, reference numeral 60 denotes a communication
terminal, 74 is a wiring for connects the source electrode of the
P-channel MOSFET 64 and the power supply wiring 70P, 75 is a wiring
that connects the source electrode of the N-channel MOSFET 65 and
the radiation conductive plate 61, 76 is a wiring that connects an
electrically conductive plate of the insulating substrate 66 and
the output terminal 67, 73 is a rotation sensor, and 77 is a wiring
that connects a P-channel MOSFET as a diode 68 and the power supply
wiring 70P. Further, reference numeral 78 denotes a wiring that
connects the insulating substrate and the power supply wiring 70N,
69 denotes a wiring that connects the source electrode of the
N-channel MOSFET 69 and the radiation conductive plate 61, 80 is an
aluminum wire for connecting the control circuit board 72 to the
P-channel MOSFET 64 and the N-channel MOSFETs 65, 69,
respectively.
[0064] As shown in FIG. 2, the control unit 51 and the rotation
sensor 73 are disposed in an upper half of a space within the
module cases 62 and 63, and the module unit 52 is disposed in a
lower half of the space. The drain electrodes of the P-channel
MOSFET 64 and the N-channel MOSFET 65 are connected to the
conductive plates of the insulating substrate 66 in which the
conductive plates are bonded to the insulating plate. The source
electrode of the P-channel MOSFET 64 and the power supply wiring
70P are connected by the wiring 74. The source electrode of the
N-channel MOSFET 65 and the radiation conductive plate 61 that also
serves as the ground wiring are connected by the wiring 75. The
conductive plates of the insulating plate 66 and the output
terminal 67 are connected by the wiring 76. With the above
structure, the mounting structural bodies shown in FIG. 1 (arms of
the respective phases which constitute the bridge circuit) are
disposed radially so as to extend in the radial direction in the
lower half of the space within the module cases 62 and 63.
Reference U1, U2, V1, V2, W1 and W2 attached to reference numeral
correspond to the respective phases of the two stator wirings 5. In
this embodiment, the mounting structural bodies shown in FIG. 1 are
arranged in such a manner that the mounting structural bodies of
the same phase are adjacent to each other. The output terminal 67
is connected to a phase winding corresponding to the stator wiring
5. In this embodiment, a description is given of the structure in
which six insulating substrates 66 are mounted, and the stator
windings 5 of two systems are provided. In the case where the
stator winding 5 of one system is provided, the arms of the
respective phases which constitute the bridge circuit may be
disposed in such a manner that the arms of the same phase are
arranged in parallel and connected to the phase windings
corresponding to the stator windings 5.
[0065] The output terminal 67, the power supply terminal 71 and the
power supply wirings 70P, 70N are embedded in the module case 63 so
as to be exposed on the surface of the module case 63. A part of
the module case 63 adheres to the radiation conductive plate
61.
[0066] Plural electronic circuit elements that constitute the
control circuit 53 and the driver circuit 54 in the control unit 51
are integrated into one IC chip. The control IC 51 is disposed on
the control circuit board 72 and electrically connected to the
control circuit board 72. The P-channel MOSFET 64 and the N-channel
MOSFETs 65, 69 in the module unit 52, and the control circuit board
72 are electrically connected to each other by the aluminum wire
80. The control circuit board 72 is also electrically connected
with the communication terminal 60 and the rotation sensor 73. The
communication terminal 60 is used for communication with the engine
control device 140 and connected with an LIN. The rotation sensor
73 detects the rotational speed of the motor-alternator 100 by
sensing the magnetism of a magnetic pole disk 4 that is disposed at
an end of the rotary shaft 9.
[0067] The P-channel MOSFET 68 makes its gate electrode identical
in potential with its source electrode so as to be used as a diode.
As a result, the drain electrode of the P-channel MOSFET 68 and the
drain electrode of the N-channel MOSFET 69 are joined to the
conductive plate of the insulating substrate 66f as the MOSFET of
the converter circuit 55.
[0068] The control IC 51 has the function of the regulator IC of
the conventional vehicle alternator. As a result, the control IC 51
serves as the regulator IC. As described above, it is necessary to
improve the high-temperature durability in the rotating electric
machine on which the inverter device is integrally mounted. In
addition, it is necessary to reduce the heating of the
semiconductor elements that constitute the converter circuit 55 to
suppress a rising temperature of the inverter device. In
particular, in the case where the inverter device is used for
idling stop, a time required for motor driving when the engine 120
is restarted is less than one second, and most of the running time
of the motor-alternator 100 functions as the alternator. From the
above fact, the loss reduction at the time of electric power
generation is effective in suppression of the rising temperature of
the inverter device.
[0069] In the case where the synchronous rectifying function is not
used, rectification is conducted by a diode that is installed in
the MOS semiconductor device of the converter circuit 55. For
example, in the case where a current 50 A passes through into the
diode, a built-in potential of about 1V is required with the result
that heating of 50 A.times.about 1 V=about 50 W occurs. On the
contrary, because the on-resistance of the MOSFET can be set to
about 3 m.OMEGA., the heating in the case where a current of 50 A
passes through the MOSFET becomes about 3 m.OMEGA..times.(square of
50 A)=about 7.5 W. The heating value of the diode is about 7 times
as large as the heating value of the MOSFET. As is understood from
this fact, to conduct synchronous rectification at the time of
electric power generation is every effective in the suppression of
the rising temperature of the inverter device. As another
countermeasure against the case where heating is large, there is a
method of increasing the mounting area of the semiconductor device
in the converter circuit 55. However, taking the heating value of
the diode into consideration, the area of about seven times is
required in order to offset the heating of about seven times, and
this method is improper from the viewpoints of downsizing and the
cost reduction. For the above reasons, in this embodiment, the
synchronous rectifying function is provided to the control IC
51.
[0070] In order to mount the control circuit 53 on the rotating
electric machine body 1, it is essential to integrate the
electronic circuit elements that constitute the control circuit 53
as with the control IC 51. However, a long developing period of
time and high developing costs are taken for development of the IC.
For that reason, a device that suppresses the developing costs and
flexibly deals with various vehicles is required. Also, it is
desirable that the control IC 51 can also flexibly deal with a
change in the semiconductor device used in the converter circuit 55
and a change in the specification of the stator winding 5 of the
motor-alternator 100. In this embodiment, in order to enhance the
flexibility, an MP 53d, a RAM 53m and a ROM 53n are mounted on the
control IC 51. By rewriting the memory contents in the ROM 53n, it
is possible to change parameters for controlling the power
generation or parameters for controlling the drive current at the
time of starting the motor according to the battery voltage, the
temperature or the engine rotational speed.
[0071] Subsequently, the operation of the motor-alternator 100
according to this embodiment will be described with reference to
FIG. 11. Initial setting is executed in Step S1, and an electric
power generation control routine is executed in Step S2. In the
electric power generation control, the field control executed
through the use of the synchronous rectification control, the
battery voltage, the command battery voltage and the temperature
detected by the temperature sensor circuit. In Step S3, it is
judged whether idling stop, that is, the engine 120 stops, or not,
and if judgment is not the idling stop, processing is advanced to
Step S2, and the electric power generation continues. If the
judgment is the idling stop, a standby state setting for restarting
the engine 120 is executed in Step S4. As one operation of the
standby state setting, there is an operation where a predetermined
field current is allowed to pass through the field winding 8 in
advance so that a torque occurs immediately at the time of restart.
The predetermined field current varies according to the electric
constant of the field winding 8 or the amount of torque necessary
to restart the engine 120. In the control IC 51 that mounts the MP
53d, the RAM 53m and the ROM 53n, the standby state setting can be
dealt with by changing a variable of the memory.
[0072] In Step S5, it is judged whether there is a restart command
of the engine 120, or not. When there is no restart command of the
engine 120, the standby state continues, and when there is the
restart command, the processing is advanced to Step S6. In Step S6,
the motor drive routine is executed. The rotational speed of the
motor-alternator 100 is detected in Step S7, and the detected
rotational speed is compared with a targeted rotational speed Nref.
In the case where the detected rotational speed is equal to or less
than the targeted rotational speed Nref, a set value of the field
current is maintained in Step S9. In the case where the detected
rotational speed exceeds the targeted rotational speed Nref, a
field magnetic current reduction routine is executed in Step S10,
and the field magnetic current is reduced down to a predetermined
value. Then, it is judged whether the engine 120 is restarted, or
not, in Step S11. The restart judgment in Step S11 is made by, for
example, a command signal from the engine control device 140. After
the engine 120 starts, the processing is advanced to the electric
power generation control in Step S2, and when the engine 120 does
not start, the processing is returned to Step S6, and the motor
drive routine continues. If the engine 120 starts at a high
rotational speed while the field current is kept large, and a large
electric power is rapidly generated, a rapid load fluctuation of
the engine 120 occurs. Step S10 is a routine that is executed to
reduce the field current and to prevent from such a rapid load
fluctuation of the engine.
[0073] Also, this embodiment desirably applies not a system of
bringing the switching semiconductor device into operation at a
carrier frequency of several kHz as the PWM control system, but a
system of driving the motor with one on/off operation per one cycle
as the motor drive system.
[0074] In the inverter, a surge voltage dependent on a wiring
inductance of causing a change in turn off speed of a current and a
current value is applied to the switching semiconductor device. As
means for reducing the surge voltage, there is a method of reducing
the wiring inductance by disposing the electrolyte capacitor with
the capacity of about 0.5 mF to 10 mF between the battery and the
ground. However, in this embodiment, it is difficult to use the
electrolyte capacitor with a large capacity from the viewpoints of
the operation environments and downsizing.
[0075] To reduce the surge voltage, there may be proposed that a
turn off speed of the current is made gentle. In this point, in the
case of using the PWM control system, if the turn off speed of the
current is made gentle, the loss in the switching semiconductor
element which occurs every time switching is conducted cannot be
ignored. However, in the system of driving the motor with one
on/off operation per one cycle is applied, the amount of loss
caused by switching per unit time can be reduced.
[0076] The system of driving the motor by bringing the switching
semiconductor device in operation with one on/off per one cycle can
be performed by the following control: controlling the gate voltage
output of the switching semiconductor device in synchronism with
the a hole sensor output that switches to high and low every
180.degree. according to an angle between the rotor windings and
the stator windings of the respective phases as shown in FIG. 3. In
this example, the hole sensor can also serve as the rotation sensor
73. The hole sensor outputs H_U.sub.1, H_V1, and H_W1 shown in FIG.
13 have a relationship different in the phase by 120.degree. with
respect to the respective outputs. Also, a gate signal Ulg1 becomes
a gate off voltage due to the rising of the hole sensor output
H_U1. And the gate voltage is controlled so as to generate the gate
on-state voltage of the switching semiconductor device of the upper
arm of the same phase after a delay time. In this example, the
delay time is provided because the switching semiconductor devices
of the upper and lower arms are prevented from turning on at the
same time.
[0077] The application of the above motor drive system does not
require the arrangement of the capacitor with a large capacity
between the battery and the ground as shown in FIG. 14, and an
inverter circuit can be constituted by provision of only a
capacitor with a small capacity of about 1 .mu.F which filters the
noises from a direct current cable.
[0078] The above-mentioned motor-alternator 100 according to this
embodiment has the following advantages.
[0079] 1) The driving power supply of the MOSFET and the
electrolyte capacitor at the higher potential side are not
required, and the mounting area can be reduced and the high
temperature resistance can be improved (refer to FIG. 15).
[0080] 2) The circuit mounted area of the converter circuit 55 can
be reduced.
[0081] 3) A reduction in the size of the semiconductor devices in
the converter circuit 55 and a reduction in the costs can be
effected by the heating reduction effect of the synchronous
rectification.
[0082] 4) The electronic circuit elements that constitute the
control circuit 53 and the driver circuit 54 are integrated into
the control IC 51, thereby making it possible to reduce the
size.
[0083] 5) The MP 53d, the RAM 53m and the ROM 63n are mounted on
the control IC 51, thereby making it possible to suppress the costs
and to flexibly deal with vehicles with different engines or
different electric power generation systems.
[0084] 6) The electrolyte capacitor with a large capacity which
should be arranged between the battery and the ground is not
required, and the inverter can be constituted by only a capacitor
with a small capacity which filters the noises from a direct
current cable, thereby making it possible to downsize the
device.
[0085] Therefore, according to the motor-alternator 100 of this
embodiment, the integration of the rotating electric machine body 1
with the inverter device 50 can be realized by substantially the
same size as that of the normal vehicle alternator while the costs
are suppressed.
[0086] In the background art of the present specification, there is
described that parts which are simply mounted are necessary in
spread of the idling stop system. The present invention provides
the motor-alternator 100 having the inverter compatible with
existing alternators, as a part necessary for realizing the idling
stop system. The present invention is made to realize the idling
stop system that is substantially identical with the existing
vehicle layout, but when the present invention is considered as the
system, it is necessary to combine the system with a lead battery
that allows a large current output in a short period of time. For
example, a current output from the battery 150 at the time of
restarting the engine is about tenth of several seconds, and
becomes 200 to 400 amperes of the same degree as that in the case
where the engine starts due to the stator. When the battery voltage
becomes equal to or less than 10 V in the battery voltage drop at
the time of outputting a large current, there is a fear that the
stable operation of a device such as an audio device or a car
navigation system is impeded during that period. There is a method
of arranging the lead batteries in parallel in order to prevent the
voltage drop, but there arises a new problem on the assurance of
the mounting space. This problem can be solved by a winding lead
battery that is disclosed in, for example, Japanese Patent
Application No. 2004-133693. The winding lead battery disclosed in
the above Japanese Patent Application No. 2004-133693 has a
performance that can hold the battery voltage to 10 V or higher at
the time of outputting a large current in a short period of time
with a volume that is equal to or less than that of the
conventional lead battery. The combination of the winding lead
battery with the motor-alternator of the present invention can
provide an idling stop system that is substantially identical with
the existing vehicle layout.
[0087] As described above, according to the present invention, even
in a compact vehicle with a limited vehicle mounting space, the
idling stop system can be realized without remarkably changing the
layout within the engine room.
* * * * *