FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
ELECTRIC VEHICLE CONTROL DEVICE
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED
AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
2
DESCRIPTION
Field
[0001] The present disclosure relates to an electric
vehicle control device that drives and controls a plurality
5 of electric motors mounted on an electric vehicle.
Background
[0002] An electric vehicle is configured to travel by
rotation of wheels integrally formed with an axle. The
10 axle is driven and rotated by an electric motor mounted on
a truck. As the electric motor, an induction electric
motor or a synchronous electric motor is generally used.
In order to control the electric motor, an electric vehicle
control device including an inverter circuit for supplying
15 power to the electric motor is mounted on a roof or under a
floor of the electric vehicle.
[0003] Electric vehicle drive systems each including an
electric vehicle control device and a plurality of electric
motors are roughly classified into a “collective control
20 system” and an “individual control system” depending on a
connection configuration of an inverter circuit and the
electric motors. The collective control system has a
configuration in which a plurality of induction electric
motors are connected in parallel with one another, and
25 these induction electric motors are collectively driven and
controlled by an inverter circuit. On the other hand, the
individual control system has a configuration in which a
dedicated inverter circuit is provided for each induction
electric motor or each synchronous electric motor to drive
30 and control the electric motor. Although the collective
control system is mainstream, the individual control system
has been increasingly used recently.
[0004] Semiconductor elements constituting an inverter
3
circuit are mounted on a cooler and constitute a power
conversion unit. As a cooling method in the cooler, a
configuration is generally employed in which the
semiconductor elements are cooled by applying traveling air
5 of an electric vehicle to a fin provided in the cooler.
The collective control system generally has a configuration
in which one inverter circuit is disposed on one cooler.
In this configuration, the number of electric motors
controlled by one inverter circuit is generally four, which
10 is the number of electric motors mounted on one vehicle.
On the other hand, regarding the individual control system,
there are a case where one inverter circuit is disposed on
one cooler and a case where a plurality of inverter
circuits are disposed on one cooler. The configuration in
15 which the plurality of inverter circuits are disposed on
one cooler has an advantage in that the power conversion
unit can be downsized.
[0005] In both the collective control system and the
individual control system, outputs of the plurality of
20 electric motors are controlled to be the same during normal
operation. On the other hand, in the case of the
individual control system, outputs of respective axles can
be individually and optimally controlled. Therefore, for
example, when idle running occurs in the wheels, it is
25 possible to adjust the output of the electric motor to be
lowered from a set value transiently depending on the state
of each wheel. Accordingly, the individual control system
can perform more detailed control than the collective
control system.
30 [0006] In the collective control system, when the
inverter circuit fails, the plurality of electric motors
connected in parallel cannot be operated. On the other
hand, in the case of the individual control system, even if
4
an inverter circuit fails, other electric motors than the
electric motor that the failed inverter circuit drives can
be operated. Therefore, the individual control system can
be a system having higher redundancy than the collective
5 control system. These advantages are also a reason for the
increasing use of the individual control system. Patent
Literature 1 described below discloses an electric vehicle
control device applied to such an individual control system.
10 Citation List
Patent Literature
[0007] Patent Literature 1: Japanese Patent Application
Laid-open No. 2004-201500
15 Summary
Technical Problem
[0008] However, the configuration of the individual
control system also has some problems. For example, when a
plurality of inverter circuits are disposed on one cooler
20 for downsizing, it is difficult to efficiently cool the
plurality of inverter circuits. For example, when a region
of the cooler is divided into a windward region and a
leeward region with respect to the traveling air, the
inverter circuit disposed in the windward region of the
25 cooler is easily cooled by efficiently taking in the
traveling air. On the other hand, in the inverter circuit
arranged in the leeward region of the cooler, the traveling
air is less easily taken in, and a temperature tends to
rise due to heat generated by the inverter circuit disposed
30 in the windward region, and thus a cooling condition
becomes severe.
[0009] Accordingly, it is necessary to apply a highperformance cooler using a heat pipe or a large-sized
5
cooler so that sufficient cooling can be performed even in
the inverter circuit disposed in the leeward region.
Consequently, there arise problems in that the size of the
electric vehicle control device increases and manufacturing
5 cost increases.
[0010] There is special operation as an embodiment of
operation different from the normal operation, and relief
operation is one type of the special operation. The relief
operation is an embodiment in which for example, in order
10 to relieve an electric vehicle of another train that has
failed ahead in the traveling direction, an electric
vehicle of a train is propelled from behind. When the
relief operation is performed, it is necessary to increase
the propulsive force of the electric vehicle as compared
15 with that during the normal operation. In that case, there
is a problem in that which inverter circuit should be
increased in output.
[0011] The present disclosure has been made in view of
the above, and an object thereof is to obtain an electric
20 vehicle control device capable of suitably coping with
special operation of an electric vehicle while reducing or
preventing an increase in manufacturing cost.
Solution to Problem
25 [0012] In order to solve the above-described problems
and achieve the object, an electric vehicle control device
according to the present disclosure is an electric vehicle
control device to be mounted on an electric vehicle
including trucks on a front side and a rear side of a
30 vehicle as a first truck and a second truck, respectively,
each of the trucks including a first electric motor that
drives first wheels that are wheels on a front side of the
vehicle and a second electric motor that drives second
6
wheels that are wheels on a rear side of the vehicle. The
electric vehicle control device includes: a plurality of
inverter circuits that individually control the first and
second electric motors; and control units that each control
5 at least one of the plurality of inverter circuits. The
plurality of inverter circuits include: a first inverter
circuit connected to the second electric motor of the first
truck; a second inverter circuit connected to the first
electric motor of the first truck; a third inverter circuit
10 connected to the second electric motor of the second truck;
and a fourth inverter circuit connected to the first
electric motor of the second truck. The first and second
inverter circuits are disposed in this order from the front
towards the rear of the vehicle. The third and fourth
15 inverter circuits are disposed in this order from the front
towards the rear of the vehicle. The control units are
each configured to be capable of controlling an output of
the second electric motor to be a value larger than an
output of the first electric motor.
20
Advantageous Effects of Invention
[0013] The electric vehicle control device according to
the present disclosure achieves an effect that it is
possible to suitably cope with special operation of an
25 electric vehicle while reducing or preventing an increase
in manufacturing cost.
Brief Description of Drawings
[0014] FIG. 1 is a diagram illustrating an example
30 configuration of an electric vehicle drive system including
an electric vehicle control device according to a first
embodiment.
FIG. 2 is a top view illustrating an example in which
7
the electric vehicle control device according to the first
embodiment is mounted on a vehicle which is an electric
vehicle.
FIG. 3 is a diagram illustrating an example of control
5 performed by the electric vehicle control device according
to the first embodiment.
FIG. 4 is a top view illustrating an example in which
an electric vehicle control device according to a
modification of the first embodiment is mounted on a
10 vehicle.
FIG. 5 is a block diagram illustrating an example of a
hardware configuration that realizes functions of an
integrated control unit in the first embodiment.
FIG. 6 is a block diagram illustrating another example
15 of the hardware configuration that realizes the functions
of the integrated control unit in the first embodiment.
FIG. 7 is a diagram illustrating an example
configuration of an electric vehicle drive system including
an electric vehicle control device according to a second
20 embodiment.
FIG. 8 is a flowchart illustrating a control operation
performed by the electric vehicle control device according
to the second embodiment.
FIG. 9 is a diagram illustrating an example of control
25 performed by the electric vehicle control device according
to the second embodiment.
Description of Embodiments
[0015] Hereinafter, an electric vehicle control device
30 according to each embodiment of the present disclosure will
be described in detail with reference to the accompanying
drawings. In the accompanying drawings, scales of the
components and distance between the components may be
8
different from actual scales. The same applies to scales
among the drawings. In the following descriptions,
electrical connection and physical connection will not be
distinguished from each other and will be simply referred
5 to as “connection”.
[0016] First Embodiment.
FIG. 1 is a diagram illustrating an example
configuration of an electric vehicle drive system 500
including an electric vehicle control device 100 according
10 to a first embodiment. The electric vehicle drive system
500 is configured as an individual control system.
[0017] As illustrated in FIG. 1, the electric vehicle
drive system 500 includes a switch 10, a reactor 11, the
electric vehicle control device 100, and electric motors
15 201 to 204. The electric vehicle control device 100
includes a positive terminal P and a negative terminal N.
The positive terminal P is connected to the reactor 11.
The negative terminal N is connected to rails 6 via wheels
2. The electric vehicle control device 100 includes power
20 conversion units 81 and 82 and an integrated control unit
30. The power conversion units 81 and 82 receive directcurrent power from an overhead contact line 1 via a current
collector 5, the switch 10, the reactor 11, and the
positive terminal P. In the configuration of FIG. 1, the
25 switch 10 and the reactor 11 may be included in the
electric vehicle control device 100. Although FIG. 1
illustrates the example configuration in a case where
direct-current power is received from the overhead contact
line 1, a configuration may be employed in which
30 alternating-current power is received. In a case of the
configuration in which alternating-current power is
received, an alternating-current to direct-current
conversion circuit is provided in a stage preceding the
9
power conversion units 81 and 82.
[0018] The power conversion unit 81 includes a control
unit 31 which is a first control unit, and inverter
circuits 61 and 62. The power conversion unit 82 includes
5 a control unit 32 which is a second control unit, and
inverter circuits 63 and 64. The power conversion units 81
and 82 have the same configuration. Hereinafter, a
description will be given using the power conversion unit
81.
10 [0019] The inverter circuit 61 is a power conversion
circuit that supplies three-phase alternating-current power
to the electric motor 202. The inverter circuit 61
includes a capacitor 50 that holds a direct-current voltage.
In the inverter circuit 61, the capacitor 50 operates as a
15 voltage source. The inverter circuit 61 converts the
direct-current voltage of the capacitor 50 into a threephase alternating-current voltage of any frequency having
any voltage value and applies the three-phase alternatingcurrent voltage to the electric motor 202. The capacitor
20 50 may be disposed outside the power conversion unit 81.
[0020] As illustrated in FIG. 1, the inverter circuit 61
includes six semiconductor elements 60U, 60V, 60W, 60X, 60Y,
and 60Z. The semiconductor elements 60U, 60V, 60W, 60X,
60Y, and 60Z are bridge-connected to constitute a three25 phase bridge circuit.
[0021] In the inverter circuit 61, the semiconductor
elements 60U, 60V, and 60W are each referred to as a
positive arm, and the semiconductor elements 60X, 60Y, and
60Z are each referred to as a negative arm. In addition, a
30 set of the positive arm and the negative arm connected in
series is referred to as a leg. The semiconductor elements
60U and 60X constitute a U-phase leg, the semiconductor
elements 60V and 60Y constitute a V-phase leg, and the
10
semiconductor elements 60W and 60Z constitute a W-phase leg.
[0022] As the semiconductor elements 60U, 60V, 60W, 60X,
60Y, and 60Z, as illustrated in the figure, an insulated
gate bipolar transistor (IGBT) element including an
5 antiparallel diode is suitable. Note that instead of the
IGBT element, a metal-oxide-semiconductor field-effect
transistor (MOSFET) may be used.
[0023] The inverter circuit 61 illustrated in FIG. 1 has
a three-phase two-level circuit configuration, but the
10 configuration is not limited to thereto. The inverter
circuit 61 may have a three-phase three-level circuit
configuration.
[0024] A connection conductor 91 for supplying the
three-phase alternating-current voltage generated by the
15 inverter circuit 61 to the electric motor 202, is disposed
in a stage subsequent to the inverter circuit 61. As the
connection conductor 91, an electric wire such as a cable,
a conductor plate subjected to insulation treatment, or the
like is used. Connection conductors 92 to 94 are
20 configured similarly thereto.
[0025] As described above, the power conversion unit 81
includes the inverter circuit 62. Since the internal
configuration of the inverter circuit 62 is the same as
that of the inverter circuit 61, the description thereof is
25 omitted here. A three-phase alternating-current voltage
generated by the inverter circuit 62 is supplied to the
electric motor 201 by the connection conductor 92. In FIG.
1, the connection conductors 91 and 92 are collectively
referred to as a first connection conductor 95.
30 [0026] The control unit 31 receives an input of a
control signal HA from the integrated control unit 30. The
control signal HA includes at least first to third signals.
The first signal is a signal serving as an output command
11
of the inverter circuits 61 and 62. The second signal is a
signal related to an operation state of the electric
vehicle, such as “acceleration”, “deceleration”, and
“coasting”. The third signal is a signal serving as a
5 command of the magnitude and direction of an output or a
torque generated by each of the electric motors 201 and 202.
On the basis of the input signal, the control unit 31
generates and outputs a signal for turning on and off the
switching elements of the inverter circuits 61 and 62 so
10 that the outputs generated by the electric motors 201 and
202 have desired values.
[0027] Although the control unit 31 which is the first
control unit is configured to control both the inverter
circuits 61 and 62 in FIG. 1, the configuration is not
15 limited thereto. The control unit 31 may be configured to
be partitioned into two control units that individually
control the inverter circuits 61 and 62. The same applies
to the control unit 32 which is the second control unit.
[0028] As described above, the power conversion unit 82
20 is configured similarly to the power conversion unit 81.
In the power conversion unit 82, the inverter circuit 63
applies a three-phase alternating-current voltage to the
electric motor 204 by the connection conductor 93. The
inverter circuit 64 applies a three-phase alternating25 current voltage to the electric motor 203 by the connection
conductor 94. In FIG. 1, the connection conductors 93 and
94 are collectively referred to as a second connection
conductor 96.
[0029] The integrated control unit 30 receives, from a
30 host control unit (not illustrated), an input of a command
signal CMD including an acceleration/deceleration command,
an operation direction command, and a special operation
command. The integrated control unit 30 controls the
12
control units 31 and 32 on the basis of the command signal
CMD. Examples of the host control unit include a
controller in a cab and a train control device. The
special operation is as described above. The special
5 operation command is a command for increasing the
propulsive force of the electric vehicle during the special
operation as compared with the propulsive force during the
normal operation usually performed.
[0030] When the special operation command is input from
10 the host control unit, the integrated control unit 30
outputs, to the control units 31 and 32 using the control
signal HA, a command to increase a motoring torque of each
of the electric motors 201 to 204 by a set value from that
in the normal time.
15 [0031] FIG. 2 is a top view illustrating an example in
which the electric vehicle control device 100 according to
the first embodiment is mounted on a vehicle 4 which is an
electric vehicle. Trucks 3a and 3b and the electric
vehicle control device 100 are mounted on the vehicle 4.
20 [0032] As illustrated in FIG. 2, the truck 3a is
installed further on a forward side with respect to a
traveling direction, that is, on a front side in the
traveling direction. The truck 3b is installed further on
a rearward side with respect to the traveling direction,
25 that is, on a rear side in the traveling direction. The
electric vehicle control device 100 is mounted on a central
portion of the vehicle 4 so as to be sandwiched between the
truck 3a and the truck 3b along the traveling direction.
[0033] The truck 3a includes wheels 2a and 2b and the
30 electric motors 201 and 202. In the truck 3a, the wheels
2a are wheels located on the front side in the traveling
direction, and the wheels 2b are wheels located on the rear
side in the traveling direction. The electric motor 201
13
drives the wheels 2a, and the electric motor 202 drives the
wheels 2b. Three-phase alternating-current power is
supplied to the electric motor 201 via the connection
conductor 92, and three-phase alternating-current power is
5 supplied to the electric motor 202 via the connection
conductor 91.
[0034] Similarly, the truck 3b includes wheels 2c and 2d
and the electric motors 203 and 204. In the truck 3b, the
wheels 2c are wheels located on the front side in the
10 traveling direction, and the wheels 2d are wheels located
on the rear side in the traveling direction. The electric
motor 203 drives the wheels 2c, and the electric motor 204
drives the wheels 2d. Three-phase alternating-current
power is supplied to the electric motor 203 via the
15 connection conductor 94, and three-phase alternatingcurrent power is supplied to the electric motor 204 via the
connection conductor 93.
[0035] The power conversion units 81 and 82 are mounted
in a housing 101 of the electric vehicle control device 100.
20 In the power conversion unit 81, the inverter circuits 61
and 62 are mounted on a cooler 71. The cooler 71 is made
of aluminum or copper, and includes fins 73 thermally
connected to the inverter circuits 61 and 62. The fins 73
are arranged outside the housing 101. The inverter
25 circuits 61 and 62 are cooled by the traveling air of the
vehicle 4 hitting the fins 73. The power conversion unit
82 has a similar configuration, and the inverter circuits
63 and 64 are cooled by the traveling air of the vehicle 4
hitting fins 74 of a cooler 72.
30 [0036] Next, a relationship between a mounting position
of each of the electric motors 201 to 204 and that of each
of the inverter circuits 61 to 64 will be described.
[0037] In the truck 3a, the electric motor 201 on the
14
front side in the traveling direction is connected to the
inverter circuit 62. In the truck 3b, the electric motor
203 on the front side in the traveling direction is
connected to the inverter circuit 64. The inverter circuit
5 62 is disposed on the rear side in the traveling direction
in the power conversion unit 81. The inverter circuit 64
is disposed on the rear side in the traveling direction in
the power conversion unit 82. That is, each of the
inverter circuits 62 and 64 is disposed on the leeward side
10 of the traveling air.
[0038] In the truck 3a, the electric motor 202 on the
rear side in the traveling direction is connected to the
inverter circuit 61. In the truck 3b, the electric motor
204 on the rear side in the traveling direction is
15 connected to the inverter circuit 63. The inverter circuit
61 is disposed on the front side in the traveling direction
in the power conversion unit 81. The inverter circuit 63
is disposed on the front side in the traveling direction in
the power conversion unit 82. That is, each of the
20 inverter circuits 61 and 63 is disposed on the windward
side of the traveling air.
[0039] As apparent from FIG. 2, a relationship between
the electric motor 201 and the electric motor 204, a
relationship between the electric motor 202 and the
25 electric motor 203, a relationship between the inverter
circuit 61 and the inverter circuit 64, and a relationship
between the inverter circuit 62 and the inverter circuit 63
are line-symmetric with respect to an axis in a direction
orthogonal to the traveling direction in the central
30 portion of the vehicle 4. Therefore, when the traveling
direction is opposite to the illustrated direction, the
inverter circuits that drive the electric motors on the
front side in the traveling direction are located on the
15
rear side in the traveling direction, that is, on the
leeward side. In addition, the inverter circuits that
drive the electric motors on the rear side in the traveling
direction are located on the front side in the traveling
5 direction, that is, on the windward side.
[0040] Since the electric motors 201 to 204 have the
above relationship, hereinafter, the wheels on the front
side in the traveling direction may be referred to as
“first wheels”, and the wheels on the rear side in the
10 traveling direction may be referred to as “second wheels”.
The truck on the front side in the traveling direction may
be referred to as a “first truck”, and the truck on the
rear side in the traveling direction may be referred to as
a “second truck”. In each of the trucks 3a and 3b, the
15 electric motor on the front side in the traveling direction
may be referred to as a “first electric motor”, and the
electric motor on the rear side in the traveling direction
may be referred to as a “second electric motor”. The power
conversion unit on the front side in the traveling
20 direction may be referred to as a “first power conversion
unit”, and the power conversion unit on the rear side in
the traveling direction may be referred to as a “second
power conversion unit”. In each of the power conversion
units 81 and 82, the inverter circuit on the front side in
25 the traveling direction may be referred to as a “first
inverter circuit”, and the inverter circuit on the rear
side in the traveling direction may be referred to as a
“second inverter circuit”.
[0041] The integrated control unit 30 is disposed
30 between the power conversion unit 81 and the power
conversion unit 82. With this placement, an interval of
about 1 m can be ensured between the power conversion unit
81 and the power conversion unit 82. Consequently,
16
regarding the power conversion unit 82 on the rear side in
the traveling direction, it is possible to cause
practically sufficient cooling air for cooling the inverter
circuits 63 and 64 to hit the cooler 72.
5 [0042] Advantages obtained from the electric motors 201
to 204 and from the mounting position relationship of the
electric motors 201 to 204 described as above will be
described later.
[0043] FIG. 3 is a diagram illustrating an example of
10 control performed by the electric vehicle control device
100 according to the first embodiment. In FIG. 3, the
horizontal axis represents time. The vertical axis
represents the magnitude of a torque which is an output of
each of the electric motors 201 to 204.
15 [0044] FIG. 3 illustrates how the torque of each of the
electric motors 201 to 204 changes when the operation
transitions from the normal operation to the special
operation. During the normal operation, each of the
electric motors 201 to 204 is controlled so as to output a
20 torque of 100% which is a prescribed torque. The
prescribed torque is a value determined on the basis of an
acceleration/deceleration request indicated from the host
control unit.
[0045] An instruction to perform the special operation
25 is issued from the host control unit under an operating
condition requiring a propulsion capacity higher than usual.
In the example in FIG. 3, when the instruction to perform
the special operation is issued, only the torques of the
electric motors 202 and 204 on the rear side in the
30 traveling direction are controlled to be larger than the
torque during the normal operation. With this control, the
torque of the entirety of the electric motors 201 to 204
can be increased. Consequently, it is possible to increase
17
the propulsive force of the entire electric vehicle as
compared with that during the normal operation. Note that
the torque here may be rephrased as output.
[0046] In the control in FIG. 3, when the amount of
5 increase or the ratio of increase in the torque of the
electric motor 202 is made equal to the amount of increase
or the ratio of increase in the torque of the electric
motor 204, the total torque of the electric motor 201 and
the electric motor 202 is equal to the total torque of the
10 electric motor 203 and the electric motor 204. The total
torque of the electric motor 201 and the electric motor 202
is the torque of the entirety of the truck 3a on the front
side in the traveling direction. The total torque of the
electric motor 203 and the electric motor 204 is the torque
15 of the entirety of the truck 3b on the rear side in the
traveling direction.
[0047] When the electric vehicle is accelerating,
centroids move to the wheels 2b and 2d on the rear side in
the traveling direction in the trucks 3a and 3b. Therefore,
20 a larger load is applied to the wheels 2b and 2d on the
rear side than to the wheels 2a and 2c on the front side.
In that case, idling is likely to occur in the wheels 2a
and 2c on the front side. Accordingly, as in the example
of the control in FIG. 3, the torque of each of the
25 electric motors 202 and 204 on the rear side is increased
to thereby increase the driving force of each of the wheels
2b and 2d on the rear side. In this way, it is possible to
efficiently accelerate the electric vehicle while
preventing idling of the wheels.
30 [0048] Note that a control method is also possible in
which the torque of the entirety of the truck 3b is made
larger than the torque of the entirety of the truck 3a in
consideration of the movement of a centroid of the vehicle
18
4 as a whole. In this control method, in consideration
that the traveling direction is reversed, the control needs
to be changed depending on the traveling direction, and
thereby the control becomes complicated, which is a
5 disadvantage. In a case where the control method is
implemented by utilizing the connection between the
inverter circuits 61 to 64 and the electric motors 201 to
204 without changing the control depending on the traveling
direction, there occurs an intersection of the connection
10 conductors, an increase in connection conductor length, and
the like. Consequently, an underfloor structure of the
electric vehicle becomes complicated, which leads to an
increase in a space occupied thereby. Therefore, it is not
necessarily appropriate to determine a connection
15 configuration between the inverter circuits 61 to 64 and
the electric motors 201 to 204 in consideration of the
shift of the centroid of the vehicle 4 as a whole.
[0049] Note that increasing the torque of each of the
electric motors 202 and 204 on the rear side in the
20 traveling direction is equivalent to increasing a current
flowing through each of the inverter circuits 61 and 63.
Therefore, generation loss in each of the inverter circuits
61 and 63 increases as compared with that during the normal
operation. Thus, in the electric vehicle control device
25 100 according to the first embodiment, the inverter
circuits 61 and 63 are disposed on the front side in the
traveling direction, that is, on the windward side. With
this placement, cooling performance can be improved as
compared with that of the inverter circuits 62 and 64. In
30 addition, with such a configuration, it is possible to cope
with a request for increasing the driving force during the
special operation without increasing the size or
performance of the fins 73 and 74 and the coolers 71 and 72.
19
Consequently, the electric vehicle control device 100 can
be reduced in size and weight, and can be configured to be
inexpensive.
[0050] According to the electric vehicle control device
5 100 of the first embodiment, as illustrated in FIG. 2, the
first connection conductor 95 including the connection
conductors 91 and 92 and the second connection conductor 96
including the connection conductors 93 and 94 can be
disposed in the vehicle 4 so as not to intersect.
10 Supplementally, the diameters of cross sections required by
the first connection conductor 95 and the second connection
conductor 96 are each about 20 cm. Therefore, if the first
connection conductor 95 and the second connection conductor
96 are disposed to intersect, not only an excessive space
15 is required under the floor of the vehicle 4, but also
there is a disadvantage that the shape of wiring ducts that
accommodate the first connection conductor 95 and the
second connection conductor 96 becomes complicated, and
thus it is not necessarily an appropriate configuration.
20 [0051] As described above, in the electric vehicle
control device 100 according to the first embodiment, an
interval of about 1 m can be ensured between the power
conversion unit 81 and the power conversion unit 82.
Therefore, the power conversion unit 81 can be brought
25 closer to the truck 3a as much as possible, and the power
conversion unit 82 can be brought closer to the truck 3b as
much as possible. With this placement, it is possible to
further shorten the lengths of the first connection
conductor 95 and the second connection conductor 96 while
30 optimizing the longitudinal dimension, that is, the length
in the traveling direction, of the electric vehicle control
device 100. Consequently, the weight of the cable can be
reduced. In addition, since the laying of the cable and
20
the routing of the cable under the floor of the vehicle 4
can be simplified, workability and maintainability can be
improved.
[0052] FIG. 4 is a top view illustrating an example in
5 which an electric vehicle control device 100A according to
a modification of the first embodiment is mounted on a
vehicle 4A. The electric vehicle control device 100 in the
configuration of the example of mounting on the vehicle 4
illustrated in FIG. 2 is replaced with the electric vehicle
10 control device 100A in FIG. 4. The power conversion unit
82 is replaced with a power conversion unit 82A in the
electric vehicle control device 100A.
[0053] In the power conversion unit 82A, the cooler 72
is attached such that a protruding direction of the fins 74
15 is opposite to that in FIG. 2 in the direction orthogonal
to the traveling direction. Other arrangements and
connection relationships are the same as those in FIG. 2,
and redundant descriptions thereof will be omitted.
[0054] In FIGS. 2 and 4, the control units 31 and 32 are
20 not illustrated. In the configuration of FIG. 4, the
control units 31 and 32 can be disposed using a space above
or below the power conversion units 81 and 82A,
respectively. In the configuration of FIG. 4, the
traveling air to the fins 74 of the cooler 72 arranged on
25 the leeward side is not blocked by the fins 73 of the
cooler 71 disposed on the windward side. Therefore, there
is an advantage that the traveling air can be taken in more
efficiently than in the configuration of FIG. 2.
[0055] In FIG. 4, the power conversion unit 82A is
30 disposed to be shifted to the rear side in the traveling
direction with respect to the power conversion unit 81, but
the configuration is not limited thereto. For example, the
power conversion unit 82A may be disposed side by side with
21
the power conversion unit 81 without being shifted to the
rear side in the traveling direction. If a space in a
direction orthogonal to the traveling direction cannot be
ensured in this configuration, the power conversion unit 81
5 and the power conversion unit 82A may be disposed to be
shifted in the vertical direction. In any of these
configurations, the effect of the electric vehicle control
device 100 described above can be obtained.
[0056] As described above, according to the electric
10 vehicle control device of the first embodiment, the
plurality of inverter circuits include the first inverter
circuit connected to the second electric motor of the first
truck, the second inverter circuit connected to the first
electric motor of the first truck, a third inverter circuit
15 connected to the second electric motor of the second truck,
and a fourth inverter circuit connected to the first
electric motor of the second truck. The first and second
inverter circuits are disposed in this order from the front
towards the rear of the vehicle, and the third and fourth
20 inverter circuits are disposed in this order from the front
towards the rear of the vehicle. When the electric vehicle
is accelerating, the centroids shift to the wheels on the
rear side in the traveling direction of the first and
second trucks, so that a larger load is applied to the
25 wheels on the rear side than to the wheels on the front
side. With respect to this operation aspect, the electric
vehicle control device according to the first embodiment
can control the output of the second electric motor to a
value larger than the output of the first electric motor.
30 Consequently, it is possible to efficiently accelerate the
electric vehicle while reducing or preventing idling of the
wheels even during the special operation in which an
operating condition requiring a propulsion capacity higher
22
than usual is imposed. That is, it is possible to suitably
cope with the special operation of the electric vehicle.
[0057] According to the electric vehicle control device
of the first embodiment, the first inverter circuit and the
5 third inverter circuit out of the first to fourth inverter
circuits are always located on the windward side. The
first inverter circuit is an inverter circuit connected to
the second electric motor whose torque or output is
increased during the special operation. The third inverter
10 circuit is an inverter circuit connected to the fourth
electric motor whose torque or output is increased during
the special operation. That is, the first and third
inverter circuits whose losses increase during the special
operation are always located on the windward side.
15 Accordingly, the first and third inverter circuits have
more improved cooling performance than the second and
fourth inverter circuits. Therefore, it is not necessary
to increase the size or performance of the coolers, so that
an increase in manufacturing cost can be reduced or
20 prevented. Consequently, it is possible to respond to the
request for increasing the driving force during the special
operation while reducing or preventing an increase in
manufacturing cost.
[0058] According to the electric vehicle control device
25 of the first embodiment, the first connection conductor and
the second connection conductor can be disposed in the
vehicle so as not to intersect. The first connection
conductor here is a group of connection conductors in which
the connection conductor connecting the first inverter
30 circuit and the second electric motor of the first truck,
and the connection conductor connecting the second inverter
circuit and the first electric motor of the first truck,
are bundled. The second connection conductor here is a
23
group of connection conductors in which the connection
conductor connecting the third inverter circuit and the
second electric motor of the second truck, and the
connection conductor connecting the fourth inverter circuit
5 and the first electric motor of the second truck, are
bundled. Consequently, the lengths of the first and second
connection conductors can be shortened, so that the weight
of the cable including the first and second connection
conductors can be reduced. In addition, since the laying
10 of the cable and the routing of the cable under the floor
of the vehicle can be simplified, workability and
maintainability can be improved.
[0059] Next, a hardware configuration for implementing
functions of the integrated control unit 30 in the first
15 embodiment will be described with reference to FIGS. 5 and
6. FIG. 5 is a block diagram illustrating an example of a
hardware configuration that implements the functions of the
integrated control unit 30 in the first embodiment. FIG. 6
is a block diagram illustrating another example of the
20 hardware configuration that implements the functions of the
integrated control unit 30 in the first embodiment.
[0060] In a case of realizing a part or all of the
functions of the integrated control unit 30 in the first
embodiment, a configuration can be employed which includes
25 a processor 300 that performs calculation, a memory 302
that stores a program read by the processor 300, and an
interface 304 that inputs/outputs signals, as illustrated
in FIG. 5.
[0061] The processor 300 may be an arithmetic means such
30 as an arithmetic device, a microprocessor, a microcomputer,
a central processing unit (CPU), or a digital signal
processor (DSP). Examples of the memory 302 include a nonvolatile or volatile semiconductor memory such as a random
24
access memory (RAM), a read only memory (ROM), a flash
memory, an erasable programmable ROM (EPROM), or an
electrically EPROM (EEPROM (registered trademark)), a
magnetic disk, a flexible disk, an optical disk, a compact
5 disc, a mini disk, and a digital versatile disc (DVD).
[0062] The memory 302 stores a program for executing the
functions of the integrated control unit 30 in the first
embodiment. Necessary information is transmitted and
received via the interface 304, a program stored in the
10 memory 302 is executed by the processor 300, and a table
stored in the memory 302 is referred to by the processor
300, and thereby the processor 300 can perform the abovedescribed process. A result of calculation by the
processor 300 can be stored in the memory 302.
15 [0063] In a case where a part of the functions of the
integrated control unit 30 in the first embodiment is
implemented, a processing circuit 303 illustrated in FIG. 6
can also be used. The processing circuit 303 corresponds
to a single circuit, a composite circuit, an application
20 specific integrated circuit (ASIC), a field programmable
gate array (FPGA), or a combination thereof. Information
input to the processing circuit 303 and information output
from the processing circuit 303 can be obtained via the
interface 304.
25 [0064] Note that some processes in the integrated
control unit 30 may be performed by the processing circuit
303, and processes not performed by the processing circuit
303 may be performed by the processor 300 and the memory
302.
30 [0065] Second Embodiment.
FIG. 7 is a diagram illustrating an example
configuration of an electric vehicle drive system 500B
including an electric vehicle control device 100B according
25
to a second embodiment. The electric vehicle control
device 100 in the configuration of the electric vehicle
drive system 500 according to the first embodiment
illustrated in FIG. 1, is replaced with the electric
5 vehicle control device 100B in the electric vehicle drive
system 500B according to the second embodiment. The
control units 31 and 32 are replaced with control units 31B
and 32B, respectively, in the electric vehicle control
device 100B. Signals indicating respective temperatures T1
10 and T2 of the inverter circuits 61 and 62 are input to the
control unit 31B. Although not illustrated, signals
indicating respective temperatures of the inverter circuits
63 and 64 are input to the control unit 32B, as well. The
other configurations are the same as or equivalent to those
15 in FIG. 1. The same or equivalent components are denoted
by the same reference numerals, and redundant descriptions
thereof will be omitted.
[0066] The control unit 31B adjusts the output
distribution in the inverter circuits 61 and 62, that is,
20 the torque distribution in the electric motors 202 and 201,
on the basis of the temperature T1 of the inverter circuit
61 and the temperature T2 of the inverter circuit 62.
[0067] Next, an operation of a main part of the electric
vehicle control device 100B according to the second
25 embodiment will be described. FIG. 8 is a flowchart
illustrating a control operation performed by the electric
vehicle control device 100B according to the second
embodiment.
[0068] The control unit 31B compares the temperatures T1
30 and T2 (step S11). The temperature T1 is a temperature of
the inverter circuit 61 located on the windward side. The
temperature T2 is a temperature of the inverter circuit 62
located on the leeward side.
26
[0069] The control unit 31B determines a temperature
difference condition (step S12). Specifically, if the
temperature T2 is equal to or lower than the temperature T1,
or a temperature difference T2-T1 is equal to or smaller
5 than a preset prescribed value Tc (Step S12, No), the
control unit 31B determines that the temperature difference
condition is unsatisfied, and performs the torque
distribution as usual without changing the torque
distribution (step S13). On the other hand, if the
10 temperature T2 is higher than the temperature T1 and the
temperature difference T2-T1 is larger than the prescribed
value Tc (Step S12, Yes), the control unit 31B determines
that the temperature difference condition is satisfied, and
changes the torque distribution (step S14).
15 [0070] As an example in which the temperature difference
T2-T1 is larger than the prescribed value Tc, it is assumed
that the traveling speed of the electric vehicle is slower
than that during the normal operation due to disruption of
the train schedule or the like, and thereby the air volume
20 of the traveling air is reduced and the cooling performance
of the coolers becomes insufficient.
[0071] Although the control operation of the control
unit 31B has been described with reference to the flowchart
of FIG. 8, the control unit 32B also performs similar
25 control. The detail thereof is overlapping, and therefore
will not be described here.
[0072] Next, a more specific control operation will be
described with reference to FIG. 9. FIG. 9 is a diagram
illustrating an example of control performed by the
30 electric vehicle control device 100B according to the
second embodiment. In FIG. 9, the horizontal axis
represents time. The vertical axis represents the
magnitude of a torque which is an output of each of the
27
electric motors 201 to 204.
[0073] FIG. 9 illustrates how the torque of each of the
electric motors 201 to 204 changes when the temperature
difference condition transitions from unsatisfaction to
5 satisfaction. In a case of the unsatisfaction of the
temperature difference condition, each of the electric
motors 201 to 204 is controlled so as to output a torque of
100% which is a prescribed torque. The prescribed torque
is a value determined on the basis of an
10 acceleration/deceleration request indicated from the host
control unit.
[0074] In the example in FIG. 9, when the temperature
difference condition is satisfied, the torque of the
electric motor 201 driven and controlled by the inverter
15 circuit 62 at a higher temperature is continuously changed
from 100% to 90%. In addition, the torque of the electric
motor 202 driven and controlled by the inverter circuit 61
at a lower temperature is continuously changed from 100% to
110%. With this control, the loss of the inverter circuit
20 61 at a lower temperature can be increased, and the loss of
the inverter circuit 62 at a higher temperature can be
reduced. Since the total torque of the electric motor 201
and the electric motor 202 remains unchanged, the operation
of the electric vehicle is not hindered.
25 [0075] By performing the above control, the temperature
difference T2-T1 that is a difference between the
temperature T2 of the inverter circuit 62 and the
temperature T1 of the inverter circuit 61 can be reduced to
be within the prescribed value Tc. Consequently, it is no
30 longer necessary for the cooler 71 or the fins 73 to have
performance for eliminating the temperature difference
between the windward side and the leeward side. Therefore,
the performance of the cooler 71 and the fins 73 can be
28
optimized. As a result, the electric vehicle control
device 100B can be configured to be small, lightweight, and
inexpensive.
[0076] In the above, the control operation has been
5 described in which the torque distribution in the electric
motors 201 and 202 is changed on the basis of the
temperature difference expressed as T2-T1 between the
temperature T2 of the inverter circuit 62 located on the
leeward side and the temperature T1 of the inverter circuit
10 61 located on the windward side, but the configuration is
not limited thereto. A control operation may be employed
in which the torque distribution in the electric motors 201
and 202 is changed on the basis of a temperature ratio
T2/T1 which is a ratio between the temperature T2 and the
15 temperature T1.
[0077] It is important that the control is only required
to be performed so that the temperature T2 of the inverter
circuit 62 located on the leeward side and the temperature
T1 of the inverter circuit 61 located on the windward side
20 are equalized. As long as such control is achieved, the
torques or outputs of the electric motors 201 and 202 may
be controlled in any way.
[0078] Although the torque distribution in the electric
motors 201 and 202 has been described above, the torque
25 distribution in the electric motors 203 and 204 can also be
controlled similarly. A lower portion of FIG. 9
illustrates an example in which the torque of the electric
motor 203 driven and controlled by the inverter circuit 64
at a higher temperature is continuously changed from 100%
30 to 90%, and the torque of the electric motor 204 driven and
controlled by the inverter circuit 63 at a lower
temperature is continuously changed from 100% to 110%. The
explanation thereof is overlapping, and therefore will not
29
be described here.
[0079] As described above, according to the electric
vehicle control device of the second embodiment, the first
inverter circuit and the third inverter circuit out of the
5 first to fourth inverter circuits are always located on the
windward side. The control units can change the outputs of
pluralities of the first and second electric motors on the
basis of the temperatures of the first to fourth inverter
circuits, can further control the output of the first
10 inverter circuit to be larger than the output of the second
inverter circuit, and can further control the output of the
third inverter circuit to be larger than the output of the
fourth inverter circuit. Consequently, it is no longer
necessary for the coolers or the fins to have performance
15 for eliminating the temperature difference between the
windward side and the leeward side, and therefore it is
possible to optimize the performance of the coolers and the
fins. As a result, the electric vehicle control device can
be configured to be small, lightweight, and inexpensive.
20 [0080] The configurations described in the above
embodiments are merely examples, and can be combined with
other known technology, the embodiments can be combined
with each other, and part of the configurations can be
omitted or modified without departing from the gist thereof.
25 [0081] Furthermore, the aspects of the invention are
described herein in consideration of application to the
electric vehicle control device, but the application field
thereof is not limited thereto, and it is needless to say
that application to various related fields is possible.
30
Reference Signs List
[0082] 1 overhead contact line; 2, 2a to 2d wheel; 3a,
3b truck; 4, 4A vehicle; 5 current collector; 6 rail; 10
30
switch; 11 reactor; 30 integrated control unit; 31, 31B,
32, 32B control unit; 50 capacitor; 60U, 60V, 60W, 60X,
60Y, 60Z semiconductor element; 61 to 64 inverter
circuit; 71, 72 cooler; 73, 74 fin; 81, 82, 82A power
5 conversion unit; 91 to 94 connection conductor; 95 first
connection conductor; 96 second connection conductor; 100,
100A, 100B electric vehicle control device; 201 to 204
electric motor; 300 processor; 302 memory; 303 processing
circuit; 304 interface; 500, 500B electric vehicle drive
10 system; N negative terminal; P positive terminal.

WE CLAIM:
1. An electric vehicle control device to be mounted on an
electric vehicle including trucks on a front side and a
rear side of a vehicle as a first truck and a second truck,
5 respectively, each of the trucks including a first electric
motor that drives first wheels that are wheels on a front
side of the vehicle and a second electric motor that drives
second wheels that are wheels on a rear side of the vehicle,
the electric vehicle control device comprising:
10 a plurality of inverter circuits to individually
control the first and second electric motors; and
control units to each control at least one of the
plurality of inverter circuits, wherein
the plurality of inverter circuits include:
15 a first inverter circuit connected to the second
electric motor of the first truck;
a second inverter circuit connected to the first
electric motor of the first truck;
a third inverter circuit connected to the second
20 electric motor of the second truck; and
a fourth inverter circuit connected to the first
electric motor of the second truck,
the first and second inverter circuits are disposed in
this order from front towards rear of the vehicle,
25 the third and fourth inverter circuits are disposed in
this order from front towards rear of the vehicle, and
the control units are each configured to be capable of
controlling an output of the second electric motor to be a
value larger than an output of the first electric motor.
30
2. The electric vehicle control device according to claim
1, comprising:
a first power conversion unit including a first cooler
32
that cools the first and second inverter circuits, the
first and second inverter circuits and the first cooler
being mounted on the first power conversion unit;
a second power conversion unit including a second
5 cooler that cools the third and fourth inverter circuits,
the third and fourth inverter circuits and the second
cooler being mounted on the second power conversion unit;
and
an integrated control unit to control the control
10 units on a basis of a command signal, wherein
the first and second inverter circuits are mounted on
the first cooler in this order from front toward rear of
the vehicle,
the third and fourth inverter circuits are mounted on
15 the second cooler in this order from front toward rear of
the vehicle, and
the first power conversion unit, the integrated
control unit, and the second power conversion unit are
disposed on a housing in this order from front toward rear
20 of the vehicle, the housing being disposed under a floor of
the electric vehicle.
3. The electric vehicle control device according to claim
1 or 2, wherein
25 the control units are configured to be capable of
increasing an output of an entirety of pluralities of the
first and second electric motors, and capable of
controlling an output of the first inverter circuit to be
larger than an output of the second inverter circuit, or
30 capable of controlling an output of the third inverter
circuit to be larger than an output of the fourth inverter
circuit, under an operating condition requiring a
propulsion capacity higher than usual.
33
4. The electric vehicle control device according to claim
1 or 2, wherein
the control units are configured to be capable of
5 changing outputs of pluralities of the first and second
electric motors on a basis of temperatures of the first to
fourth inverter circuits, capable of further controlling an
output of the first inverter circuit to be larger than an
output of the second inverter circuit, and capable of
10 further controlling an output of the third inverter circuit
to be larger than an output of the fourth inverter circuit.
5. The electric vehicle control device according to any
one of claims 1 to 4, wherein
15 a first connection conductor including a connection
conductor that connects the first inverter circuit and the
second electric motor of the first truck, and a connection
conductor that connects the second inverter circuit and the
first electric motor of the first truck, and
20 a second connection conductor including a connection
conductor that connects the third inverter circuit and the
second electric motor of the second truck, and a connection
conductor that connects the fourth inverter circuit and the
first electric motor of the second truck,
25 are capable of being disposed on the vehicle so as not
to intersect.