FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
DRIVE CONTROL DEVICE AND DRIVE DEVICE FOR RAILROAD CARS;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

DESCRIPTION
Technical Field
[0001] The present disclosure relates to a drive control device and a railway vehicle
driving apparatus.

Background Art
[0002] Some types of vehicle driving apparatuses for driving a railway vehicle
employ a generator and an electric motor. Patent Literature 1 discloses an example of
such a vehicle driving apparatus. The vehicle driving apparatus disclosed in Patent
Literature 1 includes an internal combustion engine, an induction generator driven by the
internal combustion engine, a converter, an inverter that drives an induction electric
motor, and a power storage device. Since the internal combustion engine cannot
perform self-starting, this vehicle driving apparatus, when starting the internal
combustion engine, uses the converter to convert direct current (DC) power supplied
from the power storage device into alternating current (AC) power and to supply the AC
power to the induction generator. This causes the induction generator attached to the
internal combustion engine to operate as an electric motor to apply a torque from the
induction generator, thereby causing the internal combustion engine to start.
Citation List
Patent Literature
[0003] Patent Literature 1: Unexamined Japanese Patent Application Publication
No. 2014-91504
Summary of Invention
Technical Problem
[0004] To start the internal combustion engine in the manner as described above,
the power storage is required to store sufficient power. Thus the vehicle driving
apparatus disclosed in Patent Literature 1, after the internal combustion engine is started,
charges the power storage device using AC power that is output from the induction
generator driven by the internal combustion engine, in order to enable the next starting of
the internal combustion engine. Specifically, the converter included in the vehicle
driving apparatus converts the AC power output from the induction generator into DC
power suitable for charging of the power storage device and supplies the 5 DC power to the
power storage device. When the charging of the power storage device ends, the vehicle
driving apparatus converts the AC power output from the induction generator into DC
power suitable for driving of the induction electric motor by the inverter and supplies the
DC power to the inverter. An output voltage of the converter when supplying power to
the power storage device is lower than an output voltage of the converter when supplying
power to the inverter. Thus, according to the vehicle driving apparatus, power is not
supplied to the inverter during a period in which power is supplied to the power storage
device. In other words, even after the internal combustion engine is started, the railway
vehicle cannot run during a period in which the power storage device is being charged.
This causes a problem in that the railway vehicle cannot run immediately after the
internal combustion engine is started.
[0005] The present disclosure is made in view of the above-described
circumstances, and an objective of the present disclosure is to provide a drive control
device and a railway vehicle driving apparatus that enable running of a railway vehicle
after an internal combustion engine is started and during charging of a power storage
device.
Solution to Problem
[0006] To achieve the aforementioned objective, a drive control device according to
the present disclosure is a drive control device for controlling a railway vehicle driving
apparatus for driving a railway vehicle using, as a motive power source, an internal
combustion engine, and includes a main converter, a first inverter, a step-down circuit,
and a converter controller. The main converter converts alternating current (AC) power
supplied from a generator to a primary terminal thereof into direct current (DC) power
and outputs the DC power from a secondary terminal thereof, the internal combustion
engine driving the generator to generate and output the AC power, or converts DC power
supplied to the secondary terminal into AC power and supplies the AC power to the
generator. The first inverter converts the DC power output from the 5 secondary terminal
of the main converter into AC power and outputs the AC power to an electric motor.
The step-down circuit steps down a voltage of the DC power output from the secondary
terminal of the main converter and supplies the stepped-down DC power to a power
storage device. The converter controller controls power conversion performed by the
main converter. The main converter, when the converter controller acquires a start
command providing instruction for starting of the internal combustion engine, converts
DC power supplied from the power storage device into AC power and supplies the AC
power to the generator. The main converter, after the internal combustion engine is
started, converts the AC power output by the generator into DC power and supplies the
DC power to the first inverter and the step-down circuit.
Advantageous Effects of Invention
[0007] According to the present disclosure, the step-down circuit steps down an
output voltage of the main converter and supplies power to the power storage device with
the stepped down output voltage. Thus, the output voltage of the main converter can be
set, after the internal combustion engine is started, at a voltage that is higher than a
voltage suitable for charging of the power storage device and is suitable for driving of the
electric motor by the first inverter. This enables driving of the electric motor while
charging the power storage device with a stepped down output voltage of the main
converter, and thus enables running of the railway vehicle after the internal combustion
engine is started and during charging of the power storage.
Brief Description of Drawings
[0008] FIG. 1 is a block diagram illustrating configuration of a railway vehicle
driving apparatus according to Embodiment 1 of the present disclosure;
FIG. 2 is a timing chart illustrating an operation of processing of starting an
internal combustion engine that is performed by the railway vehicle driving apparatus
according to Embodiment 1;
FIG. 3 illustrates an example flow of an electric current in the 5 railway vehicle
driving apparatus according to Embodiment 1;
FIG. 4 illustrates an example flow of an electric current in the railway vehicle
driving apparatus according to Embodiment 1;
FIG. 5 illustrates an example flow of an electric current in the railway vehicle
driving apparatus according to Embodiment 1;
FIG. 6 is a block diagram illustrating configuration of a railway vehicle driving
apparatus according to Embodiment 2 of the present disclosure;
FIG. 7 is a block diagram illustrating configuration of a railway vehicle driving
apparatus according to Embodiment 3 of the present disclosure;
FIG. 8 is a block diagram illustrating configuration of a railway vehicle driving
apparatus according to Embodiment 4 of the present disclosure;
FIG. 9 is a timing chart illustrating an operation of processing of starting an
internal combustion engine that is performed by the railway vehicle driving apparatus
according to Embodiment 4;
FIG. 10 illustrates an example flow of an electric current in the railway vehicle
driving apparatus according to Embodiment 4;
FIG. 11 illustrates an example flow of an electric current in the railway vehicle
driving apparatus according to Embodiment 4; and
FIG. 12 illustrates an example flow of an electric current in the railway vehicle
driving apparatus according to Embodiment 4.
Description of Embodiments
[0009] Hereinafter, a railway vehicle driving apparatus according to embodiments
of the present disclosure is described in detail with reference to the drawings. In the
drawings, the same or similar components are denoted by the same reference signs.
[0010] Embodiment 1
As described in Embodiment 1 below, a railway vehicle driving apparatus 1
(hereinafter referred to as "the driving apparatus") includes: an internal 5 combustion
engine 2 that serves as a motive power source; an internal-combustion-engine controller 3
that controls the internal combustion engine 2; a speed sensor 4 that detects an engine
speed of the internal combustion engine 2; a generator 11 that rotates by being driven by
the internal combustion engine 2 to output alternating current (AC) power or rotates by
that serves as an electric power source in starting the internal combustion engine 2; an
electric motor 15 that generates railway-vehicle motive power; and a drive control device
that controls various elements included in the railway vehicle driving apparatus 1.
[0011] Further, a start command signal S1 is supplied to the driving apparatus 1
from a starting switch arranged in a non-illustrated driver cab, and an operation command
signal S2 is supplied to the driving apparatus 1 from a master controller arranged in the
driver cab. The start command signal S1 is a signal that provides an instruction for
starting of the internal combustion engine 2. The start command signal S1 is set at a
low (L) level when the internal combustion engine 2 is to be stopped, and the start
command signal S1 is set at a high (H) level when the internal combustion engine 2 is to
be started. The operation command signal S2 is a signal that indicates one of a power
running notch that provides instruction for an acceleration for a railway vehicle and a
brake notch that provides instruction for a deceleration for the railway vehicle. The
driving apparatus 1, when the start command signal S1 is set at the H level, starts the
internal combustion engine 2. The internal combustion engine 2, after being started, is
controlled by the internal-combustion-engine controller 3.
[0012] The internal combustion engine 2 includes a diesel engine, a gasoline engine,
or the like. The internal combustion engine 2 includes an output shaft that is connected
to an input shaft of the generator 11 and drives the generator 11 to generate electricity.
Since the internal combustion engine 2 cannot perform self-starting, the generator 11
operates as an electric motor and rotates to start the internal combustion engine 2. The
internal-combustion-engine controller 3, after the internal combustion engine 5 2 is started,
controls the engine speed of the internal combustion engine 2.
[0013] The operation command signal S2 is supplied to the
internal-combustion-engine controller 3. The internal-combustion-engine controller 3
calculates a target engine speed of the internal combustion engine 2 corresponding to the
operation command signal S2 and controls the internal combustion engine 2 to bring an
actual engine speed of the internal combustion engine 2 acquired from the speed sensor 4
close to the target engine speed.
[0014] The speed sensor 4 includes a pulse generator (PG) attached to the internal
combustion engine 2 and outputs a signal indicating the engine speed of the internal
combustion engine 2 obtained from a pulse signal output by the PG.
[0015] The generator 11 is connected to the internal combustion engine 2, is driven
by the internal combustion engine 2 to generate AC power, and supplies the AC power to
the drive control device 10. Further, the generator 11, when causing the internal
combustion engine 2 to start, rotates by receiving AC power from the drive control
device 10, thereby starting the internal combustion engine 2.
The electric motor 15 includes a three-phase induction motor and rotates by being
driven by AC power output from a first inverter 14. The electric motor 15 is connected
to an axle via, for example, a coupling, in order to transmit a torque to the axle.
[0016] The power storage device 16 includes a secondary battery having multiple
battery cells and stores power for driving of the generator 11 to start the internal
combustion engine 2.
[0017] The drive control device 10 controls (i) an operation of starting the internal
combustion engine 2 by driving the generator 11 using the power stored in the power
storage device 16 and (ii) an operation of, after the internal combustion engine 2 is started,
using the power generated by the generator 11, rotating the electric motor 15 to generate
the railway-vehicle motive power while storing power in the power storage device 16.
[0018] The drive control device 10 includes: a main converter 12 5 that converts AC
power supplied to primary terminals thereof into direct current (DC) power and outputs
the DC power from secondary terminals thereof, or converts DC power supplied to the
secondary terminals into AC power and supplies the AC power to the generator 11; a first
inverter 14 that converts the DC power output from the secondary terminals of the main
converter 12 into AC power and outputs the AC power; a filter capacitor 13 for
smoothening that is arranged in a circuit between the main converter 12 and the first
inverter 14; a speed sensor 24 for obtaining a rotational speed of the electric motor 15; a
step-down circuit 17 that steps down an output voltage of the main converter 12 and
supplies power to the power storage device 16 with the stepped-down output voltage; a
converter controller 18 that controls the power conversion performed by the main
converter 12; an inverter controller 19 that controls the first inverter 14; and a step-down
circuit controller 20 that controls the step-down circuit 17.
[0019] The primary terminals of the main converter 12 are connected to the
generator 11, and the secondary terminals of the main converter 12 are connected to the
first inverter 14. The main converter 12 operates in accordance with control by the
converter controller 18. The main converter 12, when causing the internal combustion
engine 2 to start, converts DC power that is supplied from the filter capacitor 13 charged
with power supplied from the power storage device 16 to the secondary terminals into
AC power, and supplies the AC power from the primary terminals to the generator 11 to
rotate the generator 11. The rotation of the generator 11 causes rotation of the internal
combustion engine 2, thereby starting the internal combustion engine 2. Further, the
main converter 12, after the internal combustion engine 2 is started, in accordance with
control by the converter controller 18, converts AC power supplied from the generator 11
to the primary terminals into DC power and supplies the DC power from the secondary
terminals to the first inverter 14 and the power storage device 16.
[0020] The first inverter 14, in accordance with control by the inverter controller 19,
converts the DC power output from the secondary terminals of the main 5 converter 12 into
AC power and outputs the AC power to the electric motor 15. The electric motor 15
rotates by being driven by the AC power output by the first inverter 14.
[0021] The speed sensor 24 includes a PG arranged in the electric motor 15 and
outputs a signal indicating the rotational speed of the electric motor 15 that is obtained
from a pulse signal output by the PG.
[0022] The step-down circuit 17 is arranged in a circuit between the secondary
terminals of the main converter 12 and the power storage device 16, and when the output
voltage of the main converter 12 is higher than a charging voltage of the power storage
device 16, steps down the output voltage of the main converter 12 and applies the
stepped-down voltage to the power storage device 16. The step-down circuit 17
includes contactors Q1, Q2, and Q3 that are connected in series, a voltage dividing
resistor R1 connected in parallel to the contactor Q1, and a voltage dividing resistor R2
connected in parallel to the contactor Q2. The voltage dividing resistor R1 preferably
has a resistance value that is sufficiently smaller than a resistance value of the voltage
dividing resistor R2. Specifically, the resistance value of the voltage dividing resistor
R1 is preferably several ohms (Ω), and the resistance value of the voltage dividing
resistor R2 is preferably several hundred Ω. The step-down circuit controller 20
controls conductivity/non-conductivity of the contactors Q1, Q2, and Q3. Different
combinations of conductivity/non-conductivity of the contactors Q1, Q2, and Q3 result in
different resistance values of the step-down circuit 17.
[0023] The start command signal S1 and the operation command signal S2 are
supplied to the converter controller 18. The converter controller 18 operates in
accordance with the start command signal S1 and the operation command signal S2 and
controls on/off timings of multiple switching elements included in the main converter 12,
thereby causing the main converter 12 to operate as a DC-AC converter to convert DC
power supplied from the power storage device 16 into AC power, or as an AC-DC
converter to convert the AC power supplied from the generator 11 into 5 DC power. The
converter controller 18 controls the on/off timings of the multiple switching elements
included in the main converter 12 by sending switching control signals S3 to the multiple
switching elements.
[0024] Specifically, when the start command signal S1 is set at the L level and the
operation command signal S2 indicates a braking command, the converter controller 18
stops the main converter 12.
[0025] Further, when the start command signal S1 is set at the H level and a voltage
of the filter capacitor 13 that is detected by a voltage detector 22 reaches a threshold
voltage EFC1 suitable for starting of the internal combustion engine 2, the converter
controller 18 controls the main converter 12 to cause the main converter 12 to convert
DC power supplied from the power storage device 16 into AC power and to supply the
AC power to the generator 11. In this case, the converter controller 18 calculates, based
on a current detected by a current detector 21 and flowing from the main converter 12 to
the generator 11, an actual torque of the generator 11 that operates as an electric motor.
Then the converter controller 18 controls on/off operation of the multiple switching
elements included in the main converter 12 such that the actual torque of the generator 11
approaches a target torque suitable for starting of the internal combustion engine 2. The
converter controller 18 holds in advance the target torque suitable for starting of the
internal combustion engine 2.
[0026] The converter controller 18, after causing the main converter 12 to start
supplying of AC power to the generator 11 and then upon determination based on an
output signal of the speed sensor 4 that the engine speed of the internal combustion
engine 2 reaches a reference engine speed Th1 that enables independent rotation of the
internal combustion engine 2, determines that the internal combustion engine 2 is started.
The converter controller 18 holds in advance a value of the reference engine speed Th1.
The current detector 21 connected to the primary terminals of the main converter 12
detects a phase current for each of a U-phase, V-phase and W-phase that 5 flows through a
circuit between the generator 11 and the main converter 12. The converter controller 18,
after the internal combustion engine 2 is started, calculates an output voltage of the
generator 11 based on (i) the engine speed of the internal combustion engine 2 that is
acquired from the speed sensor 4 and (ii) the current values that are acquired from the
current detector 21.
The converter controller 18, when the operation command signal S2 indicates a
power running notch after the internal combustion engine 2 is started, controls on/off
timings of the multiple switching elements included in the main converter 12 based on
the output voltage of the generator 11 and a target voltage corresponding to the power
running notch indicated by the operation command signal S2, in order to bring the output
voltage of the main converter 12 close to the target voltage.
[0027] The operation command signal S2 is supplied to the inverter controller 19.
The inverter controller 19 calculates a target torque of the electric motor 15 based on (i)
the power running notch indicated by the operation command signal S2 and (ii) the
rotational speed of the electric motor 15 that is acquired from the speed sensor 24.
Further, the inverter controller 19 calculates an actual torque of the electric motor 15
based on current values acquired from a current detector 23. The current detector 23
detects a phase current for each of U-phase, V-phase and W-phase that flows from the
first inverter 14 to the electric motor 15. The inverter controller 19, in order to bring the
actual torque of the electric motor 15 close to the target torque, controls multiple
switching elements included in the first inverter 14. The inverter controller 19 controls
on/off timings of the multiple switching elements included in the first inverter 14 by
sending switching control signals S4 to the multiple switching elements.
[0028] The step-down circuit controller 20, as described later, opens and closes the
contactors Q1, Q2, and Q3 based on the start command signal S1, the engine speed of the
internal combustion engine 2 that is acquired from the speed sensor 4, and a voltage value
acquired from the voltage detector 22, thereby changing a resistance 5 value of a circuit
between the secondary terminals of the main converter 12 and the power storage device
[0029] Next, an operation of the driving apparatus 1 having the above-described
configuration is described with reference to the timing chart illustrated in FIG. 2.
During a period in which the railway vehicle is stopped, the start command signal
S1 is at the L level and the operation command signal S2 indicates a brake notch B1, as
illustrated in (A) and (B) of FIG. 2. Hereinafter, a timing at which the start command
signal S1 changes from the L level to the H level is referred to as the "time T1".
[0030] As illustrated in (C), (D), and (E) of FIG. 2, the step-down circuit controller
20, in response to the start command signal S1 and the operation command signal S2,
keeps all of the contactors Q1, Q2, and Q3 open until the time T1. Then in response to a
change at the time T1 in the start command signal S1 from the L level to the H level, the
step-down circuit controller 20, while keeping the contactor Q1 open, closes the
contactors Q2 and Q3 to charge the filter capacitor 13 using the power storage device 16
as an electric power source. Upon closing of the contactors Q2 and Q3, current flows
from the power storage device 16 to the filter capacitor 13 through the contactors Q3 and
Q2 and the voltage dividing resistor R1, as illustrated in FIG. 3 using a solid arrow. The
flow of current to the filter capacitor 13 via the voltage dividing resistor R1 prevents an
inrush current from flowing to the filter capacitor 13.
[0031] As current flows from the power storage device 16 to the filler capacitor 13,
an amount of power stored in the secondary battery included in the power storage device
16 gradually decreases from a maximum power amount W2 as illustrated in (H) of FIG. 2,
and a both-ends voltage that is a voltage between both ends of the filter capacitor 13
gradually increases from a voltage EFC0 as illustrated in (F) of FIG. 2.
[0032] The step-down circuit controller 20 monitors the both-ends voltage of the
filter capacitor 13 using an output signal from the voltage detector 22 and detects, at a
time T2, reach of the both-ends voltage EFC to the threshold voltage 5 EFC1. Then the
step-down circuit controller 20 closes the contactor Q1 as illustrated in (C) of FIG. 2, in
order to start the internal combustion engine 2 using the power storage device 16 as an
electric power source.
[0033] The converter controller 18, in response to (i) the start command signal S1 at
the H level, (ii) the operation command signal S2 indicating the brake notch B1, and (iii)
the output signal from the voltage detector 22 indicating that the both-ends voltage EFC
of the filter capacitor 13 reaches the threshold voltage EFC1, starts controlling on/off
operation of the multiple switching elements included in the main converter 12, thereby
causing the main converter 12 to convert DC power supplied from the power storage
device 16 into AC power and to supply the AC power to the generator 11. This leads to
flowing of current from the power storage device 16 to the main converter 12 through the
contactors Q3, Q2, and Q1, as illustrated in FIG. 4 using a solid arrow.
More specifically, the converter controller 18, based on the current flowing from
the main converter 12 to the generator 11 and detected by the current detector 21,
calculates the actual torque of the generator 11 that operates as an electric motor. Then
the converter controller 18 controls on/off timings of the multiple switching elements
included in the main converter 12, in order to bring the actual torque close to the target
torque suitable for starting of the internal combustion engine 2. The target torque
suitable for starting of the internal combustion engine 2 is determined based on
characteristics of the internal combustion engine 2. The converter controller 18
performs the above-described control, thereby causing the main converter 12 to convert
DC power supplied from the power storage device 16 to the secondary terminals into AC
power and to supply the AC power from the primary terminals to the generator 11. This
allows the generator 11 to operate as an electric motor and to rotate the internal
combustion engine 2 and thus causes, as illustrated in (G) of FIG. 2, gradual increase in
the engine speed of the internal combustion engine 2 on and after the time T2.
[0034] A timing at which the engine speed of the internal combustion 5 engine 2
reaches the reference engine speed Th1 that enables independent rotation of the internal
combustion engine 2 is referred to as a "time T3". In other words, the internal
combustion engine 2 is started and starts independent rotation at the time T3.
[0035] The converter controller 18, when detecting based on the output signal from
the speed sensor 4 that the engine speed of the internal combustion engine 2 reaches the
reference engine speed Th1, controls on/off operation of the multiple switching elements
included in the main converter 12, thereby causing the main converter 12 to convert AC
power that the generator 11 driven by the internal combustion engine 2 supplies to the
primary terminals into DC power and to output the DC power from the secondary
terminals. As illustrated in (F) of FIG. 2, the converter controller 18 controls
conduction ratios of the multiple switching elements included in the main converter 12
such that the main converter 12 outputs the DC power with the threshold voltage EFC1.
[0036] The step-down circuit controller 20, when detecting based on the output
signal from the speed sensor 4 that the engine speed of the internal combustion engine 2
reaches the reference engine speed Th1, opens the contactors Q1 and Q2 while keeping
the contactor Q3 closed, as illustrated in (C), (D), and (E) of FIG. 2, in order to, on and
after a time T4 described later, (i) step down, using the step-down circuit 17, the voltage
that is output by the main converter 12 from the secondary terminals and is higher than a
voltage suitable for charging of the power storage device 16 and (ii) supply power to the
power storage device 16 with the stepped-down voltage.
[0037] Thereafter, the power running notch is input from the master controller, and
thus the operation command signal S2 indicates a power running notch N1. This timing
is referred to as a time T4. On and after the time T4, the internal-combustion-engine
controller 3 controls the internal combustion engine 2 to bring the engine speed of the
internal combustion engine 2 close to an engine speed corresponding to the power
running notch N1, thereby increasing the engine speed of the internal combustion engine
2 as illustrated in (G) of FIG. 2. In accordance with the increase in the 5 engine speed of
the internal combustion engine 2, a rotational speed of the generator 11 and the output
voltage of the generator 11 increase.
[0038] Then the converter controller 18, in response to the operation command
signal S2 indicating the power running notch N1, starts performing on/off control
operation for the multiple switching elements included in the main converter 12, in order
to bring the output voltage of the main converter 12 close to a fixed voltage
corresponding to the power running notch N1, for example, to 600V. Specifically, the
converter controller 18 calculates the output voltage of the of the generator 11 based on
(i) the engine speed of the internal combustion engine 2 that is acquired from the speed
sensor 4 and (ii) the current values that are acquired from the current detector 21. Then
the converter controller 18, based on the output voltage of the generator 11 and a target
voltage corresponding to the power running notch indicated by the operation command
signal S2, controls the conduction ratios of the multiple switching elements included in
the main converter 12, in order to bring the output voltage of the main converter 12 close
to the target voltage.
[0039] As illustrated in (G) of FIG. 2, the output voltage of the main converter 12,
that is, the voltage of the filter capacitor 13, increases on and after the time T4. As a
result, current flows from the main converter 12 to the power storage device 16 through
the voltage dividing resistors R1 and R2 and the contactor Q3 to charge the power
storage device 16, as illustrated in FIG. 5 using a solid arrow. Thus, on and after the
time T4, the amount of power stored in the power storage device 16 gradually increases
from a power amount W1 to the maximum power amount W2. The flow of current
through the voltage dividing resistors R1 and R2 leads to applying of a voltage to the
power storage device 16 at, for example, about 300V. In other words, the step-down
circuit 17 steps down the voltage that is output by the main converter 12 and is higher
than the voltage suitable for charging of the power storage device 16, and the power
storage device 16 is charged with the voltage suitable for charging of 5 the power storage
device 16.
[0040] Furthermore, the inverter controller 19 calculates the target torque of the
electric motor 15 based on the power running notch N1 and the rotational speed of the
electric motor 15 that is acquired from the speed sensor 24. Further, the inverter
controller 19 calculates the actual torque of the electric motor 15 based on current values
that are detected for the currents flowing in the phases of the electric motor 15 and are
acquired from the current detector 23. Further, the inverter controller 19, in order to
bring the actual torque close to the target torque, controls on/off operation of the multiple
switching elements included in the first inverter 14. Thus, the electric motor 15 is
driven in response to the operation command signal S2 on and after the time T4, to
generate the railway-vehicle motive power. This enables running of the railway vehicle
while charging the power storage device 16.
[0041] As described above, the drive control device 10 according to Embodiment 1
enables, while charging the power storage device 16 after the internal combustion engine
2 is started, driving of the electric motor 15.
[0042] Embodiment 2
In Embodiment 1, the first inverter 14 that drives the electric motor 15 is connected
to the secondary terminals of the main converter 12. However, a device other than the
electric motor 15 that is to be supplied power may be supplied power by connecting
another inverter to the secondary terminals of the main converter 12 and supplying power
from the other inverter to the device. As illustrated in the example of FIG. 6, a drive
control device 10 according to Embodiment 2 includes, in addition to the elements
included in the drive control device 10 according to Embodiment 1, a second inverter 31
connected to the secondary terminals of the main converter 12 and an inverter controller
32 that controls the second inverter 31. The second inverter 31 converts DC power
supplied from the main converter 12 to primary terminals thereof into AC power and
supplies, from secondary terminals thereof, the AC power to a load device 5 33 installed in
the railway vehicle. The load device 33 may be any electronic devices installed in the
railway vehicle, such as an air conditioner, a lightning device, and a blower. The
inverter controller 32 controls on/off operation of multiple switching elements included in
the second inverter 31. An output voltage of the second inverter 31 may be a value
different from that of the output voltage of the secondary terminals of the first inverter 14.
[0043] The inverter controller 32 calculates output power of the second inverter 31
based on current values acquired from a current detector 34. Then the inverter
controller 32 controls on/off operation of the multiple switching elements included in the
second inverter 31, in order to bring the output power of the second inverter 31 close to a
target voltage suitable for power consumption by the load device 33. The inverter
controller 32 controls on/off timings of the multiple switching elements included in the
second inverter 31 by sending switching control signals S5 to the multiple switching
elements. The current detector 34 detects a phase current for each of the U-phase,
V-phase and W-phase that flows from the second inverter 31 to the load device 33.
[0044] The contactors Q1, Q2, and Q3 are closed and opened at timings similar to
those in Embodiment 1. The converter controller 18, by performing control similar to
that in Embodiment 1, causes the first inverter 14 to drive the electric motor 15 and
causes the second inverter 31 to run the load device 33, after the internal combustion
engine 2 is started and during charging of the power storage device 16.
[0045] As described above, the drive control device 10 according to Embodiment 2
enables, while charging the power storage device 16 after the internal combustion engine
2 is started, driving of the electric motor 15 and running of the load device 33.
[0046] Embodiment 3
The step-down circuit 17 may include any circuit that can step down the voltage of
the DC power output by the main converter 12 and can supply the stepped-down DC
power to the power storage device 16. As illustrated in the example of FIG. 7, the
step-down circuit 17 included in a driving apparatus 1 according 5 to Embodiment 3
includes a diode D1 as a substitute for the contactor Q2 of the step-down circuits 17
included in the driving apparatuses 1 according to Embodiment 1 and 2. The anode of
the diode D1 is connected to the power storage device 16 via the contactor Q3. The
cathode of the diode D1 is connected to the secondary terminals of the main converter 12
via the contactor Q1. The voltage dividing resistor R2 is connected in parallel to the
diode D1.
[0047] The contactors Q1 and Q3 are closed and opened at timings similar to those
in Embodiment 1. Upon closing of the contactor Q3 in response to the start command
signal S1 at the H level, current flows from the power storage device 16 to the main
converter 12 through the contactor Q3, the diode D1, and the voltage dividing resistor R1.
Further, upon closing of the contactor Q1 in response to the output signal from the
voltage detector 22 indicating that the both-ends voltage EFC of the filter capacitor 13
reaches the threshold voltage EFC1, current flows from the power storage device 16 to
the main converter 12 through the contactor Q3, the diode D1, and the contactor Q1.
Then, after the internal combustion engine 2 is started and the contactor Q1 is opened,
current flows from the main converter 12 to the power storage device 16 through the
voltage dividing resistors R1 and R2 and the contactor Q3, thereby charging the power
storage device 16. The converter controller 18, by performing control similar to that in
Embodiment 1, causes the first inverter 14 to drive the electric motor 15, after the internal
combustion engine 2 is started and during charging of the power storage device 16.
[0048] As described above, the drive control device 10 according to Embodiment 3
enables driving by the first inverter 14 of the electric motor 15 while achieving power
supply to the power storage device 16 with a stepped-down voltage that is obtained by
stepping down the voltage of the DC power output by the main converter 12 using the
step-down circuit 17 having simple configuration by inclusion of the diode D1 and the
voltage dividing resistor R2. That is to say, running of the railway vehicle can be
achieved after the internal combustion engine 2 is started and during 5 charging of the
power storage device 16. Employment of the diode D1 as a substitute for the contactor
Q2 enables simplification in configuration of the step-down circuit 17.
[0049] Embodiment 4
The step-down circuit 17 may include any circuits that can step down the voltage
of the DC power output by the main converter 12 and can supply the stepped-down DC
power to the power storage device 16. As illustrated in the example of FIG. 8, the
step-down circuit 17 included in a driving apparatus 1 according to Embodiment 4 does
not include the voltage dividing resistor R2 included in the step-down circuits 17
according to Embodiments 1 and 2 and includes a contactor Q4 and a DC-DC converter
35. The drive control device 10 further includes a step-down circuit controller 36 that
controls power conversion performed by the DC-DC converter 35. Specifically, the
step-down circuit controller 36 controls multiple switching elements included in the
DC-DC converter 35. The step-down circuit controller 36, after the internal combustion
engine 2 is started, controls on/off operation of the multiple switching elements included
in the DC-DC converter 35 to bring the output voltage of the DC-DC converter 35 that is
acquired from a voltage detector 37 close to the target voltage suitable for charging of the
power storage device 16, in response to the operation command signal S2 indicating the
power running notch. The step-down circuit controller 36 controls the on/off operation
of the multiple switching elements included in the DC-DC converter 35 by sending
switching control signals S6 to the multiple switching elements. The step-down circuit
controller 36 controls the on/off operation of the multiple switching elements included in
the DC-DC converter 35 as described above, thereby causing the DC-DC converter 35 to
step down the voltage of the DC power output by the main converter 12 and to supply the
stepped-down DC power to the power storage device 16.
[0050] An operation of the driving apparatus 1 having the above-described
configuration is described with reference to the timing chart illustrated in FIG. 9.
Similarly to Embodiment 1, during a period in which the railway vehicle 5 is stopped, the
start command signal S1 is at the L level and the operation command signal S2 indicates
the brake notch B1, as illustrated in (A) and (B) of FIG. 9. Hereinafter, a timing at
which the start command signal S1 changes from the L level to the H level is referred to
as the "time T1".
As illustrated in (C), (D), (E), and (I) of FIG. 9, the step-down circuit controller 20,
in response to the start command signal S1 and the operation command signal S2, keeps
all of the contactors Q1, Q2, Q3, and Q4 open until the time T1. Then in response to a
change at the time T1 in the start command signal S1 from the L level to the H level, the
step-down circuit controller 20, while keeping the contactors Q1 and Q4 open, closes the
contactors Q2 and Q3 to charge the filter capacitor 13 using the power storage device 16
as an electric power source. Upon closing of the contactors Q2 and Q3, current flows
from the power storage device 16 to the filter capacitor 13 through the contactors Q3 and
Q2 and the voltage dividing resistor R1, as illustrated in FIG. 10 using a solid arrow.
Flow of current to the filter capacitor 13 via the voltage dividing resistor R1 prevents an
inrush current from flowing to the filter capacitor 13.
As current flows from the power storage device 16 to the filler capacitor 13, the
amount of power stored in the secondary battery included in the power storage device 16
gradually decreases from a maximum power amount W2 as illustrated in (H) of FIG. 9,
and the both-ends voltage of the filter capacitor 13 gradually increases from a voltage
EFC0 as illustrated in (F) of FIG. 9.
[0051] The step-down circuit controller 20 monitors the both-ends voltage of the
filter capacitor 13 using the output signal from the voltage detector 22 and detects, at a
time T2, reach of the both-ends voltage EFC to the threshold voltage EFC1. Then the
step-down circuit controller 20 closes the contactor Q1 while keeping the contactor Q4
open as illustrated in (C) of FIG. 9, in order to start the internal combustion engine 2
using the power storage device 16 as an electric power source.
[0052] Similarly to Embodiment 1, the converter controller 18, in response 5 to (i) the
start command signal S1 at the H level, (ii) the operation command signal S2 indicating
the brake notch B1, and (iii) the output signal from the voltage detector 22 indicating that
the both-ends voltage EFC of the filter capacitor 13 reaches the threshold voltage EFC1,
starts controlling on/off operation of the multiple switching elements included in the main
converter 12, thereby causing the main converter 12 to convert DC power supplied from
the power storage device 16 into AC power and to supply the AC power to the generator
11. This leads to flow of current from the power storage device 16 to the main
converter 12 through the contactors Q3, Q2, and Q1, as illustrated in FIG. 11 using a
solid arrow.
The converter controller 18 performs the above-described control, thereby causing
the main converter 12 to convert DC power supplied from the power storage device 16 to
the secondary terminals into AC power and to supply the AC power from the primary
terminals to the generator 11. This allows the generator 11 to operate as an electric
motor and to rotate the internal combustion engine 2 and thus causes, as illustrated in (G)
of FIG. 9, gradual increase in the engine speed of the internal combustion engine 2 on
and after the time T2.
[0053] A timing at which the engine speed of the internal combustion engine 2
reaches the reference engine speed Th1 is referred to as a "time T3". In other words, the
internal combustion engine 2 is started and starts independent rotation at the time T3.
[0054] The converter controller 18, when detecting based on the output signal from
the speed sensor 4 that the engine speed of the internal combustion engine 2 reaches the
reference engine speed Th1, controls on/off operation of the multiple switching elements
included in the main converter 12, thereby causing the main converter 12 to convert AC
power that the generator 11 driven by the internal combustion engine 2 supplies to the
primary terminals into DC power and to output the DC power from the secondary
terminals. As illustrated in (F) of FIG. 9, the converter controller 18 controls
conduction ratios of the multiple switching elements included in the 5 main converter 12
such that the main converter 12 outputs the DC power with the threshold voltage EFC1.
[0055] The step-down circuit controller 20, when detecting based on the output
signal from the speed sensor 4 that the engine speed of the internal combustion engine 2
reaches the reference engine speed Th1, opens the contactors Q1 and Q2 and closes the
contactor Q4 while keeping the contactor Q3 closed, as illustrated in (C), (D), (E), and (I)
of FIG. 9, in order to, on and after a time T4 described later, (i) step down, using the
step-down circuit 17, the voltage that is output by the main converter 12 from the
secondary terminals and is higher than a voltage suitable for charging of the power
storage device 16 and (ii) supply power to the power storage device 16 with the
stepped-down voltage. The step-down circuit controller 36 controls on/off operation of
the switching elements included in the DC-DC converter 35, thereby charging the power
storage device 16 with the output voltage of the DC-DC converter 35.
[0056] Thereafter, the power running notch is input from the master controller, and
thus the operation command signal S2 indicates the power running notch N1. This
timing is referred to as a time T4. On and after the time T4, the
internal-combustion-engine controller 3 controls the internal combustion engine 2 to
bring the engine speed of the internal combustion engine 2 close to an engine speed
corresponding to the power running notch N1, thereby increasing the engine speed of the
internal combustion engine 2 as illustrated in (G) of FIG. 9. In accordance with the
increase in the engine speed of the internal combustion engine 2, a rotational speed of the generator 11 and the output voltage of the generator 11 increase.
Then the converter controller 18, in response to the operation command signal S2
indicating the power running notch N1, starts performing on/off control operation for the
multiple switching elements included in the main converter 12, in order to bring the
output voltage of the main converter 12 close to a fixed voltage corresponding to the
power running notch N1.
[0057] The step-down circuit controller 36, on and after the time T4, 5 controls on/off
operation of the multiple switching elements included in the DC-DC converter 35. As a
result, the DC-DC converter 35 steps down the voltage of the DC power output by the
main converter 12 and supplies the stepped-down DC power to the power storage device
16. Then the step-down circuit controller 36 controls conduction ratios of the multiple
switching elements included in the DC-DC converter 35, in order to bring the output
voltage of the DC-DC converter 35 acquired from the voltage detector 37 close to the
target voltage suitable for charging of the power storage device 16.
[0058] On and after the time T4, the output voltage of the main converter 12 that is,
the voltage of the filter capacitor 13, increases as illustrated in (G) of FIG. 9, and the
step-down circuit controller 36 controls the multiple switching elements included in the
DC-DC converter 35. As a result, current flows from the main converter 12 to the
power storage device 16 through the contactor Q4, the DC-DC converter 35, and the
contactor Q3 to charge the power storage device 16, as illustrated in FIG. 12 using a solid
arrow. Thus, on and after the time T4, the amount of power stored in the power storage
device 16 gradually increases from a power amount W1 to the maximum power amount
W2. Processing by the DC-DC converter 35 leads to applying of a voltage to the power
storage device 16 at, for example, about 300V. In other words, the DC-DC converter 35
steps down the voltage that is output by the main converter 12 and is higher than the
voltage suitable for charging of the power storage device 16, and the power storage
device 16 is charged with the voltage suitable for charging of the power storage device
[0059] Furthermore, the inverter controller 19 calculates the target torque of the
electric motor 15 based on the power running notch N1 and the rotational speed of the
electric motor 15 that is acquired from the speed sensor 24. Further, the inverter
controller 19 calculates the actual torque of the electric motor 15 based on current values
that are detected for the currents flowing in the phases of the electric motor 15 and are
acquired from the current detector 23. Further, the inverter controller 5 19, in order to
bring the actual torque close to the target torque, controls on/off operation of the multiple
switching elements included in the first inverter 14. Thus, the electric motor 15 is
driven in response to the operation command signal S2 on and after the time T4, to
generate the railway-vehicle motive power. This enables running of the railway vehicle
while charging the power storage device 16.
[0060] As described above, the drive control device 10 according to Embodiment 4
enables driving of the electric motor 15 after the internal combustion engine 2 is started.
[0061] Embodiments of the present disclosure are not limited to the aforementioned
embodiments. Any of the embodiments described above may be combined. For
example, the drive control devices 10 according to Embodiments 3 and 4 may further
include the second inverter 31. Further, the drive control device 10 may further include
another inverter that is connected to the secondary terminals of the main converter via a
step-up circuit or a step-down circuit.
[0062] Circuit configurations of the driving apparatus 1 and the drive control device
10 are not limited to the above-described examples, and any circuit configurations may
be employed. For example, the step-down circuit 17 may include a variable resistor.
Setting a resistance value of the variable resistor after starting of the internal combustion
engine 2 sufficiently larger than a resistance value of the variable resistor before starting
of the internal combustion engine 2 enables stepping down of the voltage of the DC
25 power output by the main converter 12 and supplying of the stepped-down DC power to
the power storage device 16. Further, any step-down circuit can be arranged as the
step-down circuit 17. For example, a switching regulator may be arranged. Moreover,
the resistance values of the voltage dividing resistors R1 and R2 in the aforementioned
embodiments are examples, and these values may be appropriately determined based on
the output voltage of the main converter 12 and characteristics of the power storage
device 16.
[0063] The control performed by the converter controller 18 is 5 not limited to the
above-described example. For example, by feedback of the output current of the main
converter 12, the converter controller 18 may adjust the multiple switching elements
included in the main converter 12. Further, the control performed by the inverter
controller 19 is not limited to the above-described example. The speed sensor 24 may
be omitted from the driving apparatus 1, and the inverter controller 19 may acquire the
rotational speed of the electric motor 15 from an automatic train control (ATC) device.
Moreover, the inverter controller 19 may perform sensorless vector control by estimating
the rotational speed of the electric motor 15.
[0064] The timings at which the step-down circuit controller 20 closes and opens
the contactors Q1, Q2, and Q3 are not limited to the above-described examples. For
example, the step-down circuit controller 20 may open the contactor Q3 when the power
storage device 16 is sufficiently charged after the time T4. In this case, determination as
to whether the storage device 16 is sufficiently charged may be made based on an
estimated value of an amount of power stored in the power storage device 16 that is
estimated using charging/discharging current, a terminal voltage of the secondary battery
included in the power storage device 16, a temperature of the secondary battery, or the
like. Further, the step-down circuit controller 20 included in the driving apparatus 1
according to Embodiment 4 may close the contactor Q4 when the operation command
signal S2 indicates the power running notch. In other words, the step-down circuit
controller 20 may close the contactor Q4 at the time T4 of FIG. 9.
[0065] Although examples are describe above of detecting a phase current for each
of the U-phase, V-phase and W-phase using the current detectors 21, 23, and 24, phase
currents of at least two phases among the U-phase, V-phase and W-phase may be
detected.
[0066] The foregoing describes some example embodiments for explanatory
purposes. Although the foregoing discussion has presented specific embodiments,
persons skilled in the art will recognize that changes may be made 5 in form and detail
without departing from the broader spirit and scope of the invention. Accordingly, the
specification and drawings are to be regarded in an illustrative rather than a restrictive
sense. This detailed description, therefore, is not to be taken in a limiting sense, and the
scope of the invention is defined only by the included claims, along with the full range of
equivalents to which such claims are entitled.
Reference Signs List
[0067] 1 Railway vehicle driving apparatus
2 Internal combustion engine
3 Internal-combustion-engine controller
15 4, 24 Speed sensor
10 Drive control device
11 Generator
12 Main converter
13 Filter capacitor
20 14 First inverter
15 Electric motor
16 Power storage device
17 Step-down circuit
18 Converter controller
25 19, 32 Inverter controller
20, 36 Step-down circuit controller
21, 23, 34 Current detector
27
22, 37 Voltage detector
31 Second inverter
33 Load device
35 DC-DC converter
5 D1 Diode
Q1, Q2, Q3, Q4 Contactor
R1, R2 Voltage dividing resistor

We Claim:
1. A drive control device for controlling a railway vehicle driving apparatus for
driving a railway vehicle using, as a motive power source, an internal combustion engine,
the drive control device comprising:
a main converter to (i) convert alternating current (AC) power 5 supplied from a
generator to a primary terminal thereof into direct current (DC) power and output the DC
power from a secondary terminal thereof, the internal combustion engine driving the
generator to generate and output the AC power, or (ii) convert DC power supplied to the
secondary terminal into AC power and supply the AC power to the generator;
a first inverter to convert the DC power output from the secondary terminal of the
main converter into AC power and output the AC power to an electric motor;
a step-down circuit to step down a voltage of the DC power output from the
secondary terminal of the main converter and supply the stepped-down DC power to a
power storage device; and
a converter controller to control the power conversion performed by the main
converter, wherein the main converter, when the converter controller acquires a start command providing instruction for starting of the internal combustion engine, converts DC power supplied from the power storage device into AC power and supplies the AC power to the generator, and the main converter, after the internal combustion engine is started, converts the AC power output by the generator into DC power and supplies the DC power to the first inverter and the step-down circuit.
2. The drive control device according to claim 1, wherein the first inverter,
after the internal combustion engine is started and during charging of the power storage
device, drives the electric motor by converting the DC power supplied from the main
converter into AC power and supplying the AC power to the electric motor, the charging
of the power storage device being performed by the step-down circuit (i) stepping down
the voltage of the DC power supplied from the main converter and (ii) supplying the
stepped-down DC power to the power storage device.
3. The drive control device according to claim 1 or 2, wherein the converter
controller, after the internal combustion engine is started by rotation of the generator
receiving the supply of AC power from the main converter, increases the voltage of the
DC power output by the main converter to a voltage for driving of the electric motor.
4. The drive control device according to any one of claims 1 to 3, further
comprising:
a second inverter connected to the secondary terminal of the main converter,
wherein
the main converter, after the internal combustion engine is started, converts the AC
power output by the generator into DC power and supplies the DC power to the first
inverter, the second inverter, and the step-down circuit.
5. The drive control device according to any one of claims 1 to 4, wherein
the step-down circuit includes:
a contactor connected to the power storage device and the main converter;
and a voltage dividing resistor connected in parallel to the contactor,
the drive control device further includes a step-down circuit controller to close and
open the contactor,
the step-down circuit controller closes the contactor when acquiring the start
command, andthe step-down circuit controller, after the internal combustion engine is started,opens the contactor.
6. The drive control device according to any one of claims 1 to 4, wherein
the step-down 5 circuit includes:
a diode that has an anode connected to the power storage device and a
cathode connected to the secondary terminal of the main converter; and
a voltage dividing resistor connected in parallel to the diode.
7. The drive control device according to any one of claims 1 to 4, wherein
the step-down circuit includes a DC-DC converter that steps down the DC power
output from the secondary terminal of the main converter and supplies the stepped-down
DC power to the power storage device,
the drive control device further includes a step-down circuit controller to control
power conversion performed by the DC-DC converter, and
the DC-DC converter, after the internal combustion engine is started, steps down
the DC power output by the main converter and supplies the stepped-down DC power to
the power storage device.
8. A railway vehicle driving apparatus comprising:
the drive control device according to any one of claims 1 to 7;
an internal combustion engine;
a generator to (i) generate and output alternating current (AC) power by being
driven by the internal combustion engine, or (ii) rotate the internal combustion engine by
rotating by receiving AC power; and
a power storage device that is connected to the secondary terminal of the main converter
included in the drive control device via the step-down circuit.