FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
POWER CONVERTER FOR RAILWAY VEHICLE;
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
TITLE OF THE INVENTION:
POWER CONVERTER FOR RAILWAY VEHICLE
5
Field
[0001] The present disclosure relates to a power
converter for a railway vehicle. The power converter is
installed in a railway vehicle and performs required power
conversion.10
Background
[0002] As one of the power converters for railway
vehicles, there is an inverter that supplies power to a
plurality of driving motors mounted on trucks of an15
electric motor vehicle. Further, in a power converter for
a railway vehicle that travels in an alternating-current
section, a converter is added for once converting
alternating-current power, which is received from an
alternating-current overhead contact line, into a direct20
current and supplying the direct current to an inverter.
[0003] Furthermore, as described in Patent Literature 1,
in order to reduce the size and weight of the device, the
mainstream cooling system of a power converter for a
railway vehicle is a forced air cooling system that25
circulates the external air with a cooling blower, which is
provided for cooling purpose, to cool an inverter and a
converter.
Citation List30
Patent Literature
[0004] Patent Literature 1: Japanese Patent Application
Laid-open No. 2006-025556
3
Summary of Invention
Problem to be solved by the Invention
[0005] Conventionally, as a cooling blower provided for
cooling purpose and used for an inverter in a power5
converter for railway vehicle, a constant speed type
cooling blower that rotates at a constant rotational speed
is employed. The cooling blower with sufficient
performance is selected to ensure that a junction
temperature of switching elements included in the inverter10
does not exceed a specified value. However, in the cooling
blower of this kind of constant speed type, the inverter is
excessively cooled when the inverter is not in operation.
Therefore, there is a problem in that a temperature
fluctuation range of the switching elements becomes large15
and heat stress that the switching elements are subjected
to becomes large.
[0006] The present disclosure has been made in view of
the above, and an object of the present disclosure is to
obtain a power converter for a railway vehicle capable of20
reducing the heat stress that switching elements are
subjected to.
Means to Solve the Problem
[0007] In order to solve the above-described problem and25
achieve the object, a power converter for a railway vehicle
according to the present disclosure is installed in a
railway vehicle and performs required power conversion.
The power converter for a railway vehicle includes: an
inverter that converts direct-current power into30
alternating-current power for a driving motor; and a
control unit that controls operation of the inverter. The
inverter includes: a power module on which a plurality of
4
switching elements are mounted; a cooler that cools the
power module; and a cooling blower that supplies cooling
air to the cooler. The control unit controls rotational
speed of the cooling blower on the basis of first
information relating to an increase in temperature of the5
power module.
Effects of the Invention
[0008] The power converter for a railway vehicle
according to the present disclosure can obtain an effect10
whereby the heat stress that the switching elements are
subjected to can be reduced.
Brief Description of Drawings
[0009] FIG. 1 is a diagram illustrating an exemplary15
configuration of a power converter for a railway vehicle
according to a first embodiment.
FIG. 2 is a flowchart provided for describing
operation of a control unit in the first embodiment.
FIG. 3 is a diagram illustrating an example of a20
variation of an input circuit unit illustrated in FIG. 1.
FIG. 4 is a diagram illustrating an exemplary
configuration of a power converter for a railway vehicle
according to a second embodiment.
FIG. 5 is a first diagram provided for describing25
operation of a calculation unit in the second embodiment.
FIG. 6 is a second diagram provided for describing the
operation of the calculation unit in the second embodiment.
FIG. 7 is a diagram illustrating an exemplary
configuration of a power converter for a railway vehicle30
according to a third embodiment.
FIG. 8 is a first diagram provided for describing
operation of a calculation unit in the third embodiment.
5
FIG. 9 is a second diagram provided for describing the
operation of the calculation unit in the third embodiment.
FIG. 10 is a block diagram illustrating an example of
a hardware configuration that implements functions of
control units in the first to third embodiments.5
FIG. 11 is a block diagram illustrating another
example of a hardware configuration that implements the
functions of the control units in the first to third
embodiments.
10
Description of Embodiments
[0010] Hereinafter, a power converter for a railway
vehicle according to embodiments of the present disclosure
will be described in detail with reference to the
accompanying drawings. Note that the embodiments described15
below are examples, and the scope of the present disclosure
is not limited to the following embodiments. In addition,
in the following description, physical connection and
electrical connection are not distinguished from each
other, and are simply referred to as “connection”. That20
is, the term “connection” includes both a case where
constituent elements are directly connected to each other
and a case where constituent elements are indirectly
connected to each other via another constituent element.
[0011] First Embodiment.25
FIG. 1 is a diagram illustrating an exemplary
configuration of a power converter 100 for a railway
vehicle according to a first embodiment. The power
converter 100 for a railway vehicle according to the first
embodiment includes an inverter 3 and a control unit 8 that30
controls the operation of the inverter 3. In FIG. 1, the
inverter 3 has an input end connected to an input circuit
unit 2 and an output end connected to at least one driving
6
motor 6.
[0012] The input circuit unit 2 includes at least a
switch, a filter capacitor, and a filter reactor. The
input circuit unit 2 has one end connected to an overhead
contact line 10 via a power collector 11 and another end5
connected to rails 12 at the ground potential via wheels
13. Direct-current power or alternating-current power
supplied from the overhead contact line 10 is input to the
one end of the input circuit unit 2 via the power collector
11. A direct-current voltage of the direct-current power10
generated at an output end of the input circuit unit 2 is
applied to the inverter 3.
[0013] The inverter 3 includes a power module 31, a
cooler 32, and a cooling blower 34. A plurality of
switching elements 33 are mounted on the power module 31.15
The switching elements 33 generate heat by a switching
operation. As a result, the temperature of the power
module 31 increases. The cooler 32 cools the power module
31, the temperature of which has increased. The cooling
blower 34 supplies cooling air to the cooler 32 to cool the20
cooler 32.
[0014] The control unit 8 generates a gate signal for
switching-driving the switching elements 33 on the basis of
a known control configuration, and outputs the gate signal
to the inverter 3. The switching elements 33 perform the25
switching operation in accordance with the gate signal.
The current flowing through the switching elements 33 is
intermittently controlled by the switching operation of the
switching elements 33. As a result, the direct-current
power supplied from the input circuit unit 2 is converted30
into alternating-current power for the driving motor 6.
The driving motor 6 is driven by the alternating-current
power supplied from the inverter 3, and gives a propulsive
7
force to a train including one or more railway vehicles
(not illustrated).
[0015] In addition, the control unit 8 includes a
calculation unit 81. Speed information and notch
information are input to the control unit 8. A torque5
command value used in the control unit 8 is input to the
calculation unit 81. The speed information can be obtained
from a tachometer generator or a train information managing
apparatus (not illustrated) mounted on a railway vehicle.
In addition, the notch information can be obtained from a10
master controller or the train information managing
apparatus (not illustrated) mounted on the railway vehicle.
[0016] The cooling blower 34 is configured such that the
rotational speed of the cooling blower 34 can be changed by
a control voltage output from the control unit 8. The15
calculation unit 81 calculates the control voltage on the
basis of the speed information and the notch information.
Note that the torque command value used when the gate
signal is generated may be used instead of the notch
information. In this case, the calculation unit 8120
calculates the control voltage on the basis of the speed
information and the torque command value.
[0017] The notch information is input to the control
unit 8 as information relating to an increase in
temperature of the power module. In addition, the torque25
command value is input to the calculation unit 81 as
information relating to the increase in temperature of the
power module. Note that, in the present specification, the
information relating to the increase in temperature of the
power module is collectively referred to as “first30
information” in some cases.
[0018] Next, operation of a main portion in the first
embodiment will be described with reference to FIGS. 1 and
8
2. FIG. 2 is a flowchart provided for describing operation
of the control unit 8 in the first embodiment. Note that
in the following description related to FIG. 2, the term
“notch information” may be read as the “torque command
value”.5
[0019] First, in step S11, the control unit 8 receives
the speed information and the notch information from the
outside. The speed information is information relating to
the speed of the train driven by the driving motor 6.
Next, in step S12, the control unit 8 determines whether or10
not the train is stopped on the basis of the speed
information. In a case where the control unit 8 determines
that the train is stopped (step S12, Yes), the process
proceeds to step S15. In step S15, control to stop the
rotation of the cooling blower 34 is performed. Any method15
may be used for the control to stop the rotation of the
cooling blower 34. The control may be achieved by shutting
off an input power supply to the cooling blower 34, by
shutting off the control voltage to the cooling blower 34,
or by setting the control voltage to zero.20
[0020] In a case where the control unit 8 determines
that the train is not stopped (step S12, No), the process
proceeds to step S13. In step S13, the control unit 8
determines whether or not the train is in a state of
coasting operation on the basis of the notch information.25
In a case where the control unit 8 determines that the
train is in a state of coasting operation (step S13, Yes),
the process proceeds to step S15 and the processing
described above is performed. In a case where the control
unit 8 determines that the train is not in a state of30
coasting operation (step S13, No), the process proceeds to
step S14. In step S14, control to maintain the current
rotational speed of the cooling blower 34, that is, control
9
to rotate the cooling blower 34 at the commanded rotational
speed is performed.
[0021] Next, the above processing will be supplemented,
and effects of the processing in the first embodiment will
be described. As described above, in the power converter5
100 for a railway vehicle, the cooling blower 34 with
sufficient performance is selected to ensure that a
junction temperature of the switching elements 33 included
in the inverter 3 does not exceed a specified value. On
the other hand, in a case where the train is stopped or the10
train is in a state of coasting operation, a torque
current, which is a current that generates torque, does not
flow through the driving motor 6. In this case, when the
cooling blower 34 is operated similarly to a case where the
train is in a state of power running operation, the15
switching elements 33 are excessively cooled. On the other
hand, as in the first embodiment, by stopping the operation
of the cooling blower 34 in a case where the train is in a
stopped state or in a coasting operation state, excessive
cooling of the switching elements 33 can be prevented. As20
a result, a fluctuation range of the junction temperature
of the switching elements 33 can be reduced, so that the
heat stress that the switching elements 33 are subjected to
can be reduced. As a result, a decrease in the life of the
switching elements 33 can be reduced, so that the life of25
the switching elements 33 can be extended.
[0022] Although the rotation of the cooling blower 34 is
stopped in the process of step S15 described above, the
cooling blower 34 may be rotated at a rotational speed
lower than the specified value such that the switching30
elements 33 are not excessively cooled. Even in this case,
the effects described above can be obtained.
[0023] In addition, in the processing in the first
10
embodiment, the rotation of the cooling blower 34 is
stopped during the coasting operation that occupies a
relatively large amount of time in a train operation.
Accordingly, an effect can be obtained that the power
consumption can be reduced as compared with the case of5
using a conventional cooling blower of a constant speed
type.
[0024] FIG. 3 is a diagram illustrating an example of a
variation of the input circuit unit 2 illustrated in FIG.
1. In FIG. 3, an input circuit unit 2A is illustrated as10
an example of a case in which the overhead contact line 10
is an alternating-current overhead contact line. The input
circuit unit 2A includes a traction transformer 21, a
converter 22, and a filter capacitor 23. The traction
transformer 21 steps down an alternating-current voltage15
received via the power collector 11 and applies the
alternating-current voltage to the converter 22. The
converter 22 converts the stepped-down alternating-current
voltage into a direct-current voltage and applies the
direct-current voltage to the inverter 3. The filter20
capacitor 23 smooths the direct-current voltage output from
the converter 22 so as to reduce a ripple of the voltage
applied to the inverter 3.
[0025] Similarly to the inverter 3, the converter 22 is
a power converter including a power module on which a25
plurality of switching elements are mounted. In addition,
as described above, the mainstream cooling system of the
converter 22 is a forced air cooling system that cools a
power module with a cooling blower, similarly to the
inverter 3. Furthermore, the converter 22 is a power30
converter that supplies operation power to the inverter 3.
Accordingly, the temperature of the switching elements
increases in a case where the train is in a state of power
11
running operation and the temperature of the switching
elements decreases in a case where the train is in a
stopped state or in a coasting operation state. Therefore,
by applying the control method described above also to the
converter 22, the effects similar to those of the inverter5
3 can be obtained. Note that, in the present
specification, the power module of the converter 22 is
referred to as a “second power module” in some cases in
order to distinguish the power module of the converter 22
from the power module 31 of the inverter 3. In addition,10
speed information and notch information used to control the
operation of the cooling blower that cools the second power
module are referred to as “second information” in some
cases. That is, the second information is information
relating to an increase in temperature of the second power15
module.
[0026] As has been described above, according to the
power converter for a railway vehicle of the first
embodiment, the control unit that controls the operation of
the cooling blower controls the rotational speed of the20
cooling blower in order to reduce the heat stress that the
switching elements are subjected to on the basis of the
first information relating to the increase in temperature
of the power module. As a result, a decrease in the life
of the switching elements can be reduced, which enables the25
life of the switching elements to be extended.
[0027] Note that the above control can be implemented by
stopping the rotation of the cooling blower when the train
is in a coasting operation or in a stopped state. The
junction temperature of the switching elements increases30
when the train is in power running during which a torque
current flows, and decreases when the train is in a
coasting operation and in a stopped state during each of
12
which a torque current does not flow. Therefore, by
stopping the rotation of the cooling blower when the train
is in a coasting operation and in a stopped state, the
temperature fluctuation range is reduced by an amount of
the decrease in junction temperature of the switching5
elements. As a result, the heat stress that the switching
elements are subjected to can be reduced, which enables the
life of the switching elements to be extended.
[0028] Second Embodiment.
FIG. 4 is a diagram illustrating an exemplary10
configuration of a power converter 100A for a railway
vehicle according to a second embodiment. As compared with
the power converter 100 for a railway vehicle illustrated
in FIG. 1, in FIG. 4, the inverter 3 is replaced with an
inverter 3A, and the control unit 8 is replaced with a15
control unit 8A. In the inverter 3A, a temperature sensor
35 is added. A detection value detected by the temperature
sensor 35 is input to the control unit 8A as temperature
information. In addition, in the control unit 8A, the
calculation unit 81 is replaced with a calculation unit20
81A. Other configurations are identical or equivalent to
those in the power converter 100 for a railway vehicle, and
the constituent elements identical or equivalent to those
in the power converter 100 are denoted by like reference
numerals and detailed description thereof will be omitted.25
[0029] An example of the temperature sensor 35 is a
thermistor. The temperature sensor 35 detects a
temperature of the power module 31, a temperature of the
cooler 32, or the ambient temperature thereof. The
calculation unit 81A calculates the control voltage on the30
basis of the speed information, the notch information, and
the temperature information. The temperature information
is another example of the first information. Note that the
13
torque command value may be used instead of the notch
information. In this case, the calculation unit 81A
calculates the control voltage on the basis of the speed
information, the torque command value, and the temperature
information.5
[0030] Next, operation of a main portion in the second
embodiment will be described with reference to FIGS. 5 and
6. FIG. 5 is a first diagram provided for describing
operation of the calculation unit 81A in the second
embodiment. FIG. 6 is a second diagram provided for10
describing the operation of the calculation unit 81A in the
second embodiment.
[0031] In FIGS. 5 and 6, the horizontal axis indicates a
detected temperature that is a detection value of the
temperature sensor 35, and the vertical axis indicates the15
control voltage that changes according to the detected
temperature. As illustrated in FIGS. 5 and 6, the control
voltage takes a minimum value at an initial temperature,
and increases up to a maximum value as the detected
temperature increases. The initial temperature is an20
initial value of the detected temperature, which is
detected when the inverter 3A stars its operation at the
start of the day. FIG. 5 is an example in summer when the
initial temperature is high, and FIG. 6 is an example in
winter when the initial temperature is low. In the example25
in summer illustrated in FIG. 5, the initial temperature is
made to correspond to a minimum rotational speed, and
initial temperature+ΔT is made to correspond to a maximum
rotational speed. In addition, in the example in winter
illustrated in FIG. 6, the initial temperature is made to30
correspond to the minimum rotational speed, and initial
temperature+ΔT is made to correspond to the maximum
rotational speed. Here, ΔT represents an optional
14
temperature.
[0032] Japan is a country with large differences in
temperature change depending on the seasons. In addition,
Japan has an elongated land extending in the north-south
direction, so that differences in temperature change are5
also large depending on the regions. Therefore, if the
change rate at the time of increasing or decreasing the
rotational speed is fixed, a large difference occurs in
temperature fluctuation range of the cooler 32 due to
differences in temperature change between seasons or10
between regions. On the other hand, as the examples in
FIGS. 5 and 6, by determining the change rate at the time
of increasing or decreasing the rotational speed of the
cooling blower 34 on the basis of the initial temperature,
dependency on differences in temperature change between15
seasons and between regions can be reduced.
[0033] Note that, in FIGS. 5 and 6, examples are
illustrated in each of which the initial temperature is
made to correspond to the minimum rotational speed of the
cooling blower 34, but the present disclosure is not20
limited to these examples. In a case where an operation
time is long like an electric railcar in the city, a first
temperature that is an optional temperature higher than the
initial temperature may be defined and the first
temperature may be made to correspond to the minimum25
rotational speed of the cooling blower 34.
[0034] As has been described above, according to the
power converter for a railway vehicle of the second
embodiment, the inverter includes the temperature sensor
that detects the temperature of the power module or the30
cooler. The control unit determines the change rate at the
time of increasing or decreasing the rotational speed of
the cooling blower on the basis of the initial value of the
15
temperature information detected by the temperature sensor.
In this way, dependency on differences in temperature
change between seasons and between regions can be reduced.
[0035] Third Embodiment.
FIG. 7 is a diagram illustrating an exemplary5
configuration of a power converter 100B for a railway
vehicle according to a third embodiment. As compared with
the power converter 100A for a railway vehicle illustrated
in FIG. 4, in FIG. 7, the control unit 8A is replaced with
a control unit 8B. In the control unit 8B, the calculation10
unit 81A is replaced with a calculation unit 81B. Load
compensation information is input to the control unit 8B.
Other configurations are identical or equivalent to those
in the power converter 100 for a railway vehicle, and the
constituent elements identical or equivalent to those in15
the power converter 100 are denoted by like reference
numerals and detailed description thereof will be omitted.
[0036] The load compensation information is information
relating to the weight of each of one or more railway
vehicles included in a train. The control unit 8B receives20
the load compensation information as passenger-load-factor
information. By using the load compensation information,
the passenger load factor of each vehicle in the train can
be obtained by calculation. The calculation unit 81B
generates the control voltage on the basis of the speed25
information, the notch information, the temperature
information, and the passenger-load-factor information.
Note that the torque command value may be used instead of
the notch information. In this case, the calculation unit
81B generates the control voltage on the basis of the speed30
information, the torque command value, the temperature
information, and the passenger-load-factor information.
[0037] Next, operation of a main portion in the third
16
embodiment will be described with reference to FIGS. 8 and
9. FIG. 8 is a first diagram provided for describing
operation of the calculation unit 81B in the third
embodiment. FIG. 9 is a second diagram provided for
describing the operation of the calculation unit 81B in the5
third embodiment.
[0038] The calculation unit 81B includes a summing
processing block 82 and a set temperature reference table
83. The set temperature reference table 83 is a reference
table for outputting a passenger-load-factor-dependent10
temperature on the basis of the passenger load factor. As
illustrated in FIG. 8, the passenger-load-factor-dependent
temperature is set to be higher as the passenger load
factor increases, and to be lower as the passenger load
factor decreases. In the summing processing block 82, the15
initial temperature and the passenger-load-factor-dependent
temperature are summed, and a value obtained as a result of
the sum is output as a target balanced temperature X.
[0039] FIG. 9 illustrates a concept in which the control
voltage applied to the cooling blower 34 is determined by20
the target balanced temperature X. In the example in FIG.
9, the target balanced temperature X is set to a median
value of a temperature range, and temperature X-a is made
to correspond to the minimum rotational speed and
temperature X+a is made to correspond to the maximum25
rotational speed. That is, the target balanced temperature
X is a reference temperature for defining a speed control
range for the cooling blower 34.
[0040] In general, in the train operation, the motor
torque is changed according to variation in passenger load30
factor of each vehicle, so that the amount of heat
generated by the switching elements also varies according
to the passenger load factor. Therefore, by making the
17
temperature range within which rotational speed is variable
follow the passenger load factor, the temperature
fluctuation range due to the variation in passenger load
factor can be reduced. As a result, an effect can be
obtained that the heat stress that the switching elements5
are subjected to can be reduced.
[0041] Note that, in the example in FIG. 9, the target
balanced temperature X is set to the median value of the
temperature range, but the present disclosure is not
limited to this example. The target balanced temperature X10
may be any set value as long as the value is between the
upper limit value and the lower limit value of the
temperature range.
[0042] As has been described above, according to the
power converter for a railway vehicle of the third15
embodiment, the control unit determines the reference
temperature for defining the speed control range for the
cooling blower on the basis of the initial value of the
temperature information and the passenger-load-factor
information. The control unit defines the speed control20
range on the basis of the reference temperature, and
controls the rotational speed of the cooling blower within
the speed control range. The amount of heat generated by
the switching elements also varies according to the
passenger load factor. Therefore, by defining the speed25
control range for the cooling blower on the basis of the
passenger-load-factor information, the temperature
fluctuation range due to the variation of the passenger
load factor can be reduced. As a result, as compared with
the first and second embodiments, the life of the switching30
elements can be further extended.
[0043] Finally, a hardware configuration for
implementing functions of the above-described control units
18
8, 8A, and 8B will be described with reference to the
drawings of FIGS. 10 and 11. FIG. 10 is a block diagram
illustrating an example of the hardware configuration that
implements the functions of the control units 8, 8A, and 8B
in the first to third embodiments. FIG. 11 is a block5
diagram illustrating another example of the hardware
configuration that implements the functions of the control
units 8, 8A, and 8B in the first to third embodiments.
[0044] In a case where some or all of the functions of
the control units 8, 8A, and 8B in the first to third10
embodiments are implemented, a configuration including a
processor 300, a memory 302, and an interface 304 can be
used as illustrated in FIG. 10. The processor 300 performs
a calculation. The memory 302 stores a program read by the
processor 300. Signals are input and output through the15
interface 304.
[0045] The processor 300 is a calculation means. The
processor 300 may be a calculation means called a
microprocessor, a microcomputer, a central processing unit
(CPU), or a digital signal processor (DSP). In addition,20
examples of the memory 302 include a nonvolatile or
volatile semiconductor memory such as a random 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, a25
flexible disk, an optical disk, a compact disk, a mini
disk, and a digital versatile disc (DVD).
[0046] The memory 302 stores the program for executing
the functions of the control units 8, 8A, and 8B in the
first to third embodiments. The processor 300 can perform30
the above processing by transmitting and receiving
necessary information via the interface 304, executing the
program stored in the memory 302, and referring to a table
19
stored in the memory 302. The calculation result by the
processor 300 can be stored in the memory 302.
[0047] In addition, in a case where some of the
functions of the control units 8, 8A, and 8B in the first
to third embodiments are implemented, processing circuitry5
303 illustrated in FIG. 11 can also be used. The
processing circuitry 303 corresponds to a single circuit, a
composite circuit, an application specific integrated
circuit (ASIC), a field-programmable gate array (FPGA), or
a combination thereof. Information input to the processing10
circuitry 303 and information output from the processing
circuitry 303 can be obtained via the interface 304.
[0048] Note that some of the processes to be performed
in the control units 8, 8A, and 8B may be performed by the
processing circuitry 303, and processes not performed by15
the processing circuitry 303 may be performed by the
processor 300 and the memory 302.
[0049] The configurations described in the above
embodiments are just examples and can be combined with
other known techniques. The embodiments can be combined20
with each other and the configurations can be partially
omitted and/or modified without departing from the scope of
the present disclosure.
Reference Signs List25
[0050] 2, 2A input circuit unit; 3, 3A inverter; 6
driving motor; 8, 8A, 8B control unit; 10 overhead
contact line; 11 power collector; 12 rail; 13 wheel; 21
traction transformer; 22 converter; 23 filter capacitor;
31 power module; 32 cooler; 33 switching element; 3430
cooling blower; 35 temperature sensor; 81, 81A, 81B
calculation unit; 82 summing processing block; 83 set
temperature reference table; 100, 100A, 100B power
20
converter for railway vehicle; 300 processor; 302 memory;
303 processing circuitry; 304 interface.
21
We Claim :
[Claim 1] A power converter for a railway vehicle to be
installed in a railway vehicle and to perform required
power conversion, the power converter comprising:
an inverter to convert direct-current power into5
alternating-current power for a driving motor; and
a control unit to control operation of the inverter,
wherein
the inverter includes:
a power module on which a plurality of switching10
elements are mounted;
a cooler to cool the power module; and
a cooling blower to supply cooling air to the cooler,
and
the control unit controls rotational speed of the15
cooling blower on a basis of first information relating to
an increase in temperature of the power module.
[Claim 2] The power converter for a railway vehicle
according to claim 1, wherein20
the control unit stops rotation of the cooling blower
when a train including one or more railway vehicles is in a
coasting operation or in a stopped state.
[Claim 3] The power converter for a railway vehicle25
according to claim 1 or 2, wherein
the first information is torque information relating
to torque to be generated in the driving motor, and
the torque information is a torque command value to be
used by the control unit or notch information to be30
indicated to the railway vehicle.
[Claim 4] The power converter for a railway vehicle
22
according to any one of claims 1 to 3, wherein
the inverter includes a temperature sensor to detect a
temperature of the power module or the cooler, and
the first information is temperature information
detected by the temperature sensor.5
[Claim 5] The power converter for a railway vehicle
according to claim 4, wherein
the control unit determines a change rate at a time of
increasing or decreasing the rotational speed of the10
cooling blower on a basis of an initial value of the
temperature information.
[Claim 6] The power converter for a railway vehicle
according to claim 4, wherein15
passenger-load-factor information relating to
passenger load factor of each of one or more railway
vehicles included in a train is input to the control unit,
and
the control unit determines a reference temperature20
for defining a speed control range for the cooling blower
on a basis of an initial value of the temperature
information and the passenger-load-factor information.
[Claim 7] The power converter for a railway vehicle25
according to claim 4 or 5, comprising
a converter to generate the direct-current power and
to supply the direct-current power to the inverter, wherein
the converter includes:
a second power module on which a plurality of30
switching elements are mounted;
a second cooler to cool the second power module; and
a second cooling blower to supply cooling air to the
23
second cooler, and
the control unit controls rotational speed of the
second cooling blower on a basis of second information
relating to an increase in temperature of the second power
module.5