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 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 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED
2
DESCRIPTION
Technical Field
[0001] The present disclosure relates to a drive control device and a driving
5 apparatus for a railway vehicle.
Background Art
[0002] Some of the driving apparatuses for vehicles that drive railway vehicles
include electric generators and motors. A typical example of such driving apparatuses
for vehicles is disclosed in Patent Literature 1. The driving apparatus for a vehicle
10 disclosed in Patent Literature 1 includes an internal combustion engine, an induction
generator driven by the internal combustion engine, a power converter to drive an
induction motor using electric power generated at the induction generator, and an electric
storage device including a secondary battery. The power generation at the induction
generator driven by the internal combustion engine requires electric power to be fed to
15 the induction generator and excite the induction generator. In this driving apparatus for
a vehicle, the power converter converts direct current (DC) power fed from the electric
storage device into alternating current (AC) power and feeds the AC power to the
induction generator. The fed AC power excites the induction generator, and the
induction generator generates electric power by being driven by the internal combustion
20 engine, and feeds the generated electric power to the power converter. The power
converter then converts the electric power fed from the induction generator into electric
power for driving the induction motor, and feeds the converted electric power to the
induction motor. The fed electric power drives the induction motor, thereby providing
thrust for a railway vehicle.
25 Citation List
Patent Literature
[0003] Patent Literature 1: Unexamined Japanese Patent Application Publication
3
No. 2008-49811
Summary of Invention
Technical Problem
[0004] The electric storage device is required to include a charge-discharge
5 controlling unit to control charge and discharge of the secondary battery, a monitoring
unit to monitor whether an overvoltage of the secondary battery occurs, and a housing to
accommodate components, such as the secondary battery, the charge-discharge
controlling unit, and the monitoring unit, and thus unfortunately has a large size.
[0005] An objective of the present disclosure, which has been accomplished in
10 view of the above situations, is to provide a small drive control device and a small driving
apparatus for a railway vehicle.
Solution to Problem
[0006] In order to achieve the above objective, a drive control device according to
an aspect of the present disclosure includes a self-excited generator, a separately excited
15 generator, a first power converter, and a capacitor. The self-excited generator is coupled
to an internal combustion engine and, by being driven by the internal combustion engine,
generates electric power and outputs the generated electric power. The separately
excited generator is coupled to the internal combustion engine. The separately excited
generator in an excited state is configured to generate electric power and output the
20 generated electric power by being driven by the internal combustion engine. The first
power converter converts electric power fed from the separately excited generator via
primary terminals into DC power and outputs the DC power via secondary terminals, or
converts DC power fed via the secondary terminals into electric power to be fed to the
separately excited generator and outputs the electric power via the primary terminals.
25 The capacitor is connected between the secondary terminals of the first power converter.
The self-excited generator has output terminals connected to the capacitor.
Advantageous Effects of Invention
4
[0007] According to an aspect of the present disclosure, the capacitor connected
between the secondary terminals of the first power converter is also connected to the
output terminals of the self-excited generator. The first power converter thus converts
the DC power, which is fed via the secondary terminals from the capacitor connected to
5 the output terminals of the self-excited generator, into electric power to be fed to the
separately excited generator, and outputs the electric power via the primary terminals.
The electric power fed from the first power converter excites the separately excited
generator. The drive control device therefore requires no electric storage device to feed
electric power for exciting the separately excited generator. This configuration can
10 reduce the size of the drive control device.
Brief Description of Drawings
[0008] FIG. 1 is a block diagram illustrating a configuration of a driving apparatus
for a railway vehicle according to Embodiment 1 of the present disclosure;
FIG. 2 is a timing chart illustrating a process of exciting a separately excited
15 generator executed in the driving apparatus for a railway vehicle according to
Embodiment 1;
FIG. 3 illustrates an example of current flows in the driving apparatus for a railway
vehicle according to Embodiment 1;
FIG. 4 is a block diagram illustrating a configuration of a driving apparatus for a
20 railway vehicle according to Embodiment 2 of the present disclosure;
FIG. 5 is a timing chart illustrating a process of exciting a separately excited
generator executed in the driving apparatus for a railway vehicle according to
Embodiment 2;
FIG. 6 illustrates an example of current flows in the driving apparatus for a railway
25 vehicle according to Embodiment 2;
FIG. 7 is a block diagram illustrating a configuration of a driving apparatus for a
railway vehicle according to Embodiment 3 of the present disclosure;
5
FIG. 8 is a timing chart illustrating a process of exciting a separately excited
generator executed in the driving apparatus for a railway vehicle according to
Embodiment 3; and
FIG. 9 illustrates an example of current flows in the driving apparatus for a railway
5 vehicle according to Embodiment 1.
Description of Embodiments
[0009] A drive control device and a driving apparatus for a railway vehicle
according to embodiments of the present disclosure are described in detail below with
reference to the accompanying drawings. In the drawings, the components identical or
10 corresponding to each other are provided with the same reference symbol.
[0010] Embodiment 1
FIG. 1 illustrates a driving apparatus for a railway vehicle that drives a railway
vehicle by means of electric generators and a motor. A driving apparatus 1 for a railway
vehicle (hereinafter referred to as “driving apparatus 1”) includes an internal combustion
15 engine 2, which is a power source, an engine controller 3 to control the internal
combustion engine 2, a speed sensor 4 to detect a rotation frequency of the internal
combustion engine 2, a drive control device 10 driven by the internal combustion engine
2 to feed generated electric power to a motor 5, and the motor 5 driven by the electric
power fed from the drive control device 10 to provide thrust for the railway vehicle.
20 [0011] The internal combustion engine 2 includes a diesel or gasoline engine, for
example. The internal combustion engine 2 includes a starter. The output shaft of the
internal combustion engine 2 is coupled to the individual input shafts of a self-excited
generator 11 and a separately excited generator 12 included in the drive control device 10,
which are described below. The rotation of the internal combustion engine 2 thus
25 individually drives the self-excited generator 11 and the separately excited generator 12
to generate power.
[0012] The engine controller 3 is fed with a start instruction signal S1 from a start
6
switch provided in a cab, which is not illustrated, and fed with an operation instruction
signal S2 from a master controller provided in the cab. The start instruction signal S1
indicates an instruction for start of the internal combustion engine 2. The start
instruction signal S1 is switched to a low (L) level to stop the internal combustion engine
5 2, and switched to a high (H) level to start the internal combustion engine 2. The
operation instruction signal S2 indicates a power running notch for designating an
acceleration of the railway vehicle, or a braking notch for designating a deceleration of
the railway vehicle, for example.
[0013] The engine controller 3 starts the internal combustion engine 2 in response
10 to switching of the start instruction signal S1 to the H level. In detail, the engine
controller 3 outputs a control signal to the starter and activates the starter in response to
switching of the start instruction signal S1 to the H level. The torque of the starter is
then transmitted to the internal combustion engine 2, thereby starting the internal
combustion engine 2.
15 After the start of the internal combustion engine 2, the engine controller 3 controls
the internal combustion engine 2 on the basis of the target rotation frequency
corresponding to the power running notch indicated by the operation instruction signal S2,
such that the actual rotation frequency of the internal combustion engine 2 acquired from
the speed sensor 4 approaches the target rotation frequency. The engine controller 3
20 preliminarily retains values of target rotation frequencies corresponding to the individual
power running notches.
[0014] The speed sensor 4 includes a pulse generator (PG) mounted on the internal
combustion engine 2. The speed sensor 4 calculates a rotation frequency of the internal
combustion engine 2 from the pulse signal output from the PG, and outputs a signal
25 indicating the rotation frequency of the internal combustion engine 2. Specifically, the
speed sensor 4 counts the number of pulses of the pulse signal in certain time intervals,
and then calculates a rotation frequency of the internal combustion engine 2 from the
7
counted number of pulses within the certain time.
[0015] The motor 5 includes a three-phase induction motor. The motor 5 is driven
by alternating current (AC) power and thus rotates. The AC power is output from a
main inverter 14, which is described below, included in the drive control device 10. The
5 motor 5 is coupled to an axle via a joint, for example, and transmits the torque to the axle.
[0016] The drive control device 10 includes the self-excited generator 11 and the
separately excited generator 12. The self-excited generator 11 is driven by the internal
combustion engine 2 to rotate, and thereby generates direct current (DC) power and
outputs the generated DC power. The separately excited generator 12 is driven by the
10 internal combustion engine 2 to rotate, and thereby generates AC power and outputs the
generated AC power. The drive control device 10 further includes a first power
converter 13 to convert the AC power fed from the separately excited generator 12 via the
primary terminals into DC power and output the DC power via the secondary terminals,
the main inverter 14 to convert the DC power fed from the first power converter 13 via
15 the primary terminals into three-phase AC power and output the three-phase AC power
via the secondary terminals, and a capacitor C1 connected between the secondary
terminals of the first power converter 13.
[0017] The drive control device 10 further includes a first controller 15 to control
the first power converter 13, and an inverter controller 16 to control the main inverter 14.
20 The drive control device 10 further includes a current measurer CT1 connected to the
primary terminals of the first power converter 13 to measure respective values of the U-,
V-, and W-phase currents flowing in the circuitry between the separately excited
generator 12 and the first power converter 13, a current measurer CT2 to measure
respective values of the U-, V-, and W-phase currents flowing from the main inverter 14
25 to the motor 5, and a voltage measurer VT1 connected in parallel to the capacitor C1 to
measure a value of voltage between the terminals of the capacitor C1.
[0018] The self-excited generator 11 includes a DC generator. The input shaft of
8
the self-excited generator 11 is coupled to the output shaft of the internal combustion
engine 2. The self-excited generator 11 generates DC power and outputs the generated
DC power by being driven by the internal combustion engine 2. The output terminals of
the self-excited generator 11 are connected to both ends of the capacitor C1. The DC
5 power output from the self-excited generator 11 thus charges the capacitor C1 while the
separately excited generator 12 is not excited and not generating power.
The self-excited generator 11 preferably has a generation capacity lower than the
generation capacity of the separately excited generator 12.
[0019] The separately excited generator 12 is excited by electric power fed from the
10 first power converter 13. The input shaft of the separately excited generator 12 is
coupled to the output shaft of the internal combustion engine 2. The separately excited
generator 12 in an excited state generates AC power and outputs the generated AC power
by being driven by the internal combustion engine 2.
[0020] The primary terminals of the first power converter 13 are connected to the
15 separately excited generator 12, while the secondary terminals are connected to the main
inverter 14. The first power converter 13 operates under the control of the first
controller 15. The first power converter 13 is fed with DC power via the secondary
terminals from the capacitor C1 charged immediately after the start of the internal
combustion engine 2, converts the DC power into AC power, feeds the AC power via the
20 primary terminals to the separately excited generator 12, and thus excites the separately
excited generator 12. After the excitation of the separately excited generator 12, the
rotation of the internal combustion engine 2 causes the separately excited generator 12 to
start power generation. After the start of power generation at the separately excited
generator 12, the first power converter 13 converts the AC power fed from the separately
25 excited generator 12 via the primary terminals into DC power, and feeds the DC power to
the main inverter 14 via the secondary terminals, under the control of the first controller
15.
9
[0021] The main inverter 14 converts the DC power output from the secondary
terminals of the first power converter 13 into three-phase AC power, and outputs the
three-phase AC power to the motor 5, under the control of the inverter controller 16.
The motor 5 is thus driven by the three-phase AC power output from the main inverter 14
5 and rotates. The main inverter 14 includes a variable voltage variable frequency
(VVVF) inverter.
[0022] A speed sensor 17 includes a PG mounted on the motor 5. The speed
sensor 17 calculates a rotation frequency of the motor 5 from the pulse signal output from
the PG and outputs a signal indicating the rotation frequency of the motor 5, like the
10 speed sensor 4.
[0023] The first controller 15 is fed with the start instruction signal S1 and the
operation instruction signal S2. The first controller 15 acquires a voltage between the
terminals of the capacitor C1 from the voltage measurer VT1. The first controller 15
also acquires respective values of the U-, V-, and W-phase currents flowing in the
15 circuitry between the separately excited generator 12 and the first power converter 13
from the current measurer CT1.
In accordance with the start instruction signal S1 and the operation instruction
signal S2, the first controller 15 outputs a switching control signal S3 for controlling
timings of turning on and off a plurality of switching elements of the first power
20 converter 13. Specifically, the first controller 15 causes the first power converter 13 to
function as a DC-AC converter or an AC-DC converter. The DC-AC converter
converts the DC power, which is fed from the capacitor C1 charged with the DC power
generated at the self-excited generator 11, into AC power. The AC-DC converter
converts the AC power fed from the separately excited generator 12 into DC power.
25 [0024] Specifically, the first controller 15 stops the first power converter 13 when
the start instruction signal S1 is at the L level and the operation instruction signal S2
indicates a braking instruction.
10
When the start instruction signal S1 is at the H level and the voltage between the
terminals of the capacitor C1 reaches a threshold voltage EFC1, the first controller 15
controls the first power converter 13. The first controller 15 causes the first power
converter 13 to convert the DC power, which is fed from the capacitor C1 charged with
5 the DC power generated at the self-excited generator 11, into AC power and to feed the
AC power to the separately excited generator 12. The fed AC power excites the
separately excited generator 12. The threshold voltage EFC1 is defined as a voltage that
can achieve excitation of the separately excited generator 12. The first controller 15
preliminarily retains the value of the threshold voltage EFC1.
10 [0025] The first controller 15 determines whether the amplitude of the phase
currents measured at the current measurer CT1 is at least a threshold amplitude. When
the amplitude of the phase currents measured at the current measurer CT1 is at least the
threshold amplitude, the separately excited generator 12 is deemed to be in an excited
state. The threshold amplitude is defined to be lower than the possible amplitude of
15 currents output from the separately excited generator 12 in an excited state. The first
controller 15 preliminarily retains the value of the threshold amplitude.
[0026] When the amplitude of the phase currents measured at the current measurer
CT1 is at least the threshold amplitude and the operation instruction signal S2 indicates a
power running notch, the first controller 15 controls the timings of turning on and off the
20 switching elements of the first power converter 13 on the basis of the voltage output from
the separately excited generator 12 and the target voltage corresponding to the power
running notch indicated by the operation instruction signal S2, such that the voltage
output from the first power converter 13 approaches the target voltage. The first
controller 15 preliminarily retains the values of target voltages corresponding to the
25 individual power running notches.
[0027] The inverter controller 16 is fed with the operation instruction signal S2.
The inverter controller 16 acquires a rotation frequency of the motor 5 from the speed
11
sensor 17. The inverter controller 16 also acquires values of the phase currents flowing
in the motor 5 from the current measurer CT2. In accordance with the operation
instruction signal S2, the rotation frequency of the motor 5, and the phase currents
flowing in the motor 5, the inverter controller 16 outputs a switching control signal S4 for
5 controlling timings of turning on and off a plurality of switching elements of the main
inverter 14.
[0028] Specifically, the inverter controller 16 calculates a target torque of the motor
5, on the basis of the power running notch indicated by the operation instruction signal S2
and the rotation frequency of the motor 5 acquired from the speed sensor 17. The
10 inverter controller 16 also calculates an actual torque of the motor 5 from the values of
the phase currents measured at the current measurer CT2. The inverter controller 16
then controls the switching elements of the main inverter 14 such that the actual torque of
the motor 5 approaches the target torque.
[0029] An operation of the driving apparatus 1 having the above-described
15 configuration is described below with reference to the timing chart in the sections (A) to
(F) of FIG. 2.
As illustrated in the sections (A) and (B) of FIG. 2, the start instruction signal S1 is
at the L level and the operation instruction signal S2 indicates a braking notch B1, during
stop of the internal combustion engine 2. As illustrated in the section (C) of FIG. 2, the
20 rotation frequency of the internal combustion engine 2 in the stop mode is defined as
RPM0. As illustrated in the section (D) of FIG. 2, the self-excited generator 11 is
stopped during stop of the internal combustion engine 2. As illustrated in the section (E)
of FIG. 2, the capacitor C1 is in a discharged state during stop of the internal combustion
engine 2, and the voltage between the terminals of the capacitor C1 in the discharged
25 state is defined as EFC0. As illustrated in the section (F) of FIG. 2, the separately
excited generator 12 is stopped during stop of the internal combustion engine 2. In the
examples described below, the timing of switching of the start instruction signal S1 from
12
the L level to the H level is defined as time T1.
[0030] As illustrated in the section (C) of FIG. 2, the engine controller 3 starts the
internal combustion engine 2, in response to switching of the start instruction signal S1
from the L level to the H level at the time T1. The rotation frequency of the internal
5 combustion engine 2 thus starts to rise from the rotation frequency RPM0. The rotation
frequency of the internal combustion engine 2 then reaches a rotation frequency RPM1.
RPM1 indicates a rotation frequency of the internal combustion engine 2 when the
operation instruction signal S2 indicates a braking notch after start of the internal
combustion engine 2.
10 [0031] As illustrated in the section (D) of FIG. 2, the self-excited generator 11
driven by the internal combustion engine 2 starts power generation in accordance with an
increase in the rotation frequency of the internal combustion engine 2. Accordingly, a
current flows from the self-excited generator 11 to the capacitor C1 as represented by the
solid-line arrow A1 in FIG. 3, thereby charging the capacitor C1. As illustrated in the
15 section (E) of FIG. 2, the electric power generated at the self-excited generator 11 charges
the capacitor C1, and the voltage EFC between the terminals of the capacitor C1 starts to
rise from the voltage EFC0. As illustrated in the section (F) of FIG. 2, the separately
excited generator 12 has not been excited and thus does not start power generation
regardless of being driven by the internal combustion engine 2.
20 [0032] The first controller 15 is monitoring the voltage between the terminals of the
capacitor C1 on the basis of the signal output from the voltage measurer VT1. As
illustrated in the section (E) of FIG. 2, the first controller 15 determines that the voltage
EFC between the terminals reaches the threshold voltage EFC1 at a time T2. When
determining that the voltage EFC between the terminals of the capacitor C1 reaches the
25 threshold voltage EFC1, the first controller 15 starts to control the on and off states of the
switching elements of the first power converter 13, and causes the first power converter
13 to convert the DC power fed from the capacitor C1 into AC power and feed the AC
13
power to the separately excited generator 12. Accordingly, a current flows from the first
power converter 13 to the separately excited generator 12 as represented by the solid-line
arrow A2 in FIG. 3, thereby exciting the separately excited generator 12. As illustrated
in the section (F) of FIG. 2, after the excitation of the separately excited generator 12 at
5 the time T2, the separately excited generator 12 driven by the internal combustion engine
2 starts power generation. The separately excited generator 12 then feeds the generated
AC power to the first power converter 13.
[0033] The first controller 15 is monitoring the amplitude of currents flowing
between the separately excited generator 12 and the first power converter 13, on the basis
10 of the signal output from the current measurer CT1. After the excitation of the
separately excited generator 12 at the time T2, the amplitude of the phase currents
measured at the current measurer CT1 becomes at least the threshold amplitude. When
determining that the amplitude of the phase currents measured at the current measurer
CT1 is at least the threshold amplitude, the first controller 15 controls the switching
15 elements of the first power converter 13, and thereby causes the first power converter 13
to convert the AC power fed from the separately excited generator 12 into DC power and
feed the DC power to the main inverter 14.
[0034] Then, a power running notch is input from the master controller, and the
operation instruction signal S2 thus starts to indicate a power running notch N1. This
20 timing is defined as time T3. After the time T3, the engine controller 3 controls the
internal combustion engine 2 such that the rotation frequency of the internal combustion
engine 2 approaches a rotation frequency RPM2 corresponding to the power running
notch N1. This control increases the rotation frequency to the rotation frequency RPM2,
as illustrated in the section (C) of FIG. 2. The increase in the rotation frequency of the
25 internal combustion engine 2 also raises the rotation frequencies and output voltages of
the self-excited generator 11 and the separately excited generator 12.
[0035] In response to the operation instruction signal S2 indicating the power
14
running notch N1, the first controller 15 controls the on and off states of the switching
elements of the first power converter 13 such that the voltage output from the first power
converter 13 approaches a voltage EFC2. The voltage EFC2 is a constant voltage
corresponding to the power running notch N1 and is 600 V, for example. In detail, the
5 first controller 15 calculates a voltage output from the separately excited generator 12, on
the basis of the rotation frequency of the internal combustion engine 2 acquired from the
speed sensor 4 and the values of the phase currents acquired from the current measurer
CT1. The first controller 15 then controls the conduction ratios of the switching
elements of the first power converter 13 on the basis of the voltage output from the
10 separately excited generator 12 and the target voltage corresponding to the power running
notch indicated by the operation instruction signal S2, such that the voltage output from
the first power converter 13 approaches the target voltage.
[0036] The inverter controller 16 calculates an actual torque of the motor 5 on the
basis of the values of the phase currents flowing in the motor 5, which are acquired from
15 the current measurer CT2. The inverter controller 16 then controls the on and off states
of the switching elements of the main inverter 14 such that the actual torque approaches
the target torque corresponding to the power running notch N1. Accordingly, after the
time T3, the motor 5 is driven in response to the operation instruction signal S2 and thus
provides thrust for the railway vehicle. The inverter controller 16 preliminarily retains
20 the values of target torques corresponding to the individual power running notches.
[0037] As described above, in the drive control device 10 according to Embodiment
1, the first power converter 13 converts the DC power, which is fed from the capacitor C1
charged with the electric power generated at the self-excited generator 11, into AC power
and feeds the AC power to the separately excited generator 12, leading to excitation of
25 the separately excited generator 12. The drive control device 10 therefore requires no
electric storage device to excite the separately excited generator 12. This configuration
can reduce the sizes of the drive control device 10 and the driving apparatus 1.
15
In the case where the self-excited generator 11 has a generation capacity lower
than the generation capacity of the separately excited generator 12, the self-excited
generator 11 may be such a small generator that can generate at least electric power for
exciting the separately excited generator 12. This configuration can further reduce the
5 sizes of the drive control device 10 and the driving apparatus 1.
[0038] Embodiment 2
The drive control device 10 may have any circuit configuration provided that the
capacitor C1 can be charged with electric power generated at the self-excited generator
11 and the electric power fed from the capacitor C1 can excite the separately excited
10 generator 12. A drive control device 20 according to Embodiment 2 illustrated in FIG.
4 further includes a contactor Q1 having an end connected to one of the output terminals
of the self-excited generator 11, a resistor R1 having an end connected to the other end of
the contactor Q1 and having the other end connected to one end of the capacitor C1, and
a contactor controller 18 to control the contactor Q1. The drive control device 20 has
15 the structure identical to that of the drive control device 10, except for the contactor Q1,
the resistor R1, and the contactor controller 18.
[0039] The contactor Q1 includes a DC electromagnetic contactor. The contactor
Q1 is controlled by the contactor controller 18.
When the contactor controller 18 closes the contactor Q1, the one and other ends
20 of the contactor Q1 are connected to each other. The resistor R1 is thus electrically
connected to the self-excited generator 11. The capacitor C1 is then charged with the
electric power generated at the self-excited generator 11. The resistor R1 can suppress
an inrush current flowing into the capacitor C1 at the time of closing of the contactor Q1.
When the contactor controller 18 opens the contactor Q1, the one and other ends of
25 the contactor Q1 are insulated from each other. The resistor R1 is thus electrically
disconnected from the self-excited generator 11.
[0040] The contactor controller 18 outputs a contactor control signal S5 to the
16
contactor Q1 and thereby closes or opens the contactor Q1. The contactor controller 18
acquires the actual rotation frequency of the internal combustion engine 2 from the speed
sensor 4. When the actual rotation frequency of the internal combustion engine 2
reaches a threshold rotation frequency, the contactor controller 18 closes the contactor Q1.
5 The threshold rotation frequency is defined as the rotation frequency of the internal
combustion engine 2 when the self-excited generator 11 is driven by the internal
combustion engine 2 to start power generation after the start of the internal combustion
engine 2, for example.
[0041] The contactor controller 18 also acquires the voltage EFC between the
10 terminals of the capacitor C1 from the voltage measurer VT1. After the closing of the
contactor Q1, when the voltage EFC between the terminals of the capacitor C1 becomes
at least the threshold voltage EFC1 that can achieve excitation of the separately excited
generator 12, then the contactor controller 18 opens the contactor Q1. This
configuration can suppress the electric power output from the self-excited generator 11
15 disturbing the output from the first power converter 13 provided by converting the AC
power generated at the separately excited generator 12 into DC power.
[0042] An operation of the driving apparatus 1 having the above-described
configuration is described below with reference to the timing chart in the sections (A) to
(G) of FIG. 5. The sections (A) to (F) of FIG. 5 correspond to the respective sections
20 (A) to (F) of FIG. 2. As in FIG. 2, the start instruction signal S1 is switched from the L
level to the H level at the time T1.
As illustrated in the section (C) of FIG. 5, the engine controller 3 starts the internal
combustion engine 2 in response to switching of the start instruction signal S1 from the L
level to the H level at the time T1. The rotation frequency of the internal combustion
25 engine 2 thus starts to rise from the rotation frequency RPM0. As illustrated in the
section (D) of FIG. 5, the self-excited generator 11 driven by the internal combustion
engine 2 starts power generation in accordance with an increase in the rotation frequency
17
of the internal combustion engine 2. As illustrated in the section (G) of FIG. 5, the
contactor controller 18 closes the contactor Q1 at the time T1 in order to charge the
capacitor C1 with electric power generated at the self-excited generator 11.
Accordingly, a current flows from the self-excited generator 11 via the contactor Q1 to
5 the capacitor C1 as represented by the solid-line arrow A3 in FIG. 6, thereby charging the
capacitor C1. As illustrated in the section (E) of FIG. 5, the electric power generated at
the self-excited generator 11 charges the capacitor C1, and the voltage EFC between the
terminals of the capacitor C1 starts to rise from the voltage EFC0. As illustrated in the
section (F) of FIG. 5, the separately excited generator 12 has not been excited and thus
10 does not start power generation regardless of being driven by the internal combustion
engine 2.
[0043] As illustrated in the section (E) of FIG. 5, when the voltage EFC between
the terminals reaches the threshold voltage EFC1 at the time T2, the first controller 15
starts to control the on and off states of the switching elements of the first power
15 converter 13, and causes the first power converter 13 to convert the DC power fed from
the capacitor C1 into AC power and feed the AC power to the separately excited
generator 12. Accordingly, a current flows from the first power converter 13 to the
separately excited generator 12 as represented by the solid-line arrow A4 in FIG. 6,
thereby exciting the separately excited generator 12. As illustrated in the section (F) of
20 FIG. 5, after the excitation of the separately excited generator 12 at the time T2, the
separately excited generator 12 driven by the internal combustion engine 2 starts power
generation. The separately excited generator 12 then feeds the generated AC power to
the first power converter 13.
[0044] When the voltage EFC between the terminals reaches the threshold voltage
25 EFC1 at the time T2, the contactor controller 18 opens the contactor Q1 as illustrated in
the section (G) of FIG. 5. The following steps are identical to those in Embodiment 1.
[0045] As described above, in the drive control device 20 according to Embodiment
18
2, the first power converter 13 converts the DC power, which is fed from the capacitor C1
charged with the electric power generated at the self-excited generator 11, into AC power
and feeds the AC power to the separately excited generator 12, leading to excitation of
the separately excited generator 12. The drive control device 20 therefore requires no
5 electric storage device to excite the separately excited generator 12. This configuration
can reduce the sizes of the drive control device 20 and the driving apparatus 1.
In the case where the self-excited generator 11 has a generation capacity lower
than the generation capacity of the separately excited generator 12, the self-excited
generator 11 may be such a small generator that can generate at least electric power for
10 exciting the separately excited generator 12. This configuration can further reduce the
sizes of the drive control device 20 and the driving apparatus 1.
[0046] Embodiment 3
The drive control devices 10 and 20 may have any circuit configuration provided
that the capacitor C1 can be charged with electric power generated at the self-excited
15 generator 11 and the electric power fed from the capacitor C1 can excite the separately
excited generator 12. A drive control device 30 according to Embodiment 3 illustrated
in FIG. 7 includes a self-excited generator 21. The drive control device 30 further
includes a second power converter 22 and a second controller 23 to control the second
power converter 22, in addition to the configuration of the drive control device 20. The
20 second power converter 22 has primary terminals connected to the self-excited generator
21 and secondary terminals one of which is connected to one end of the contactor Q1.
The second power converter 22 converts the AC power fed from the self-excited
generator 21 into DC power and outputs the DC power. The drive control device 30 has
the structure identical to that of the drive control device 20, except for the self-excited
25 generator 21, the second power converter 22, and the second controller 23.
[0047] The self-excited generator 21 includes an AC generator. The input shaft of
the self-excited generator 21 is coupled to the output shaft of the internal combustion
19
engine 2. The self-excited generator 21 generates AC power and outputs the generated
AC power by being driven by the internal combustion engine 2. The output terminals of
the self-excited generator 21 are connected to the primary terminals of the second power
converter 22.
5 [0048] The second power converter 22 converts the AC power fed from the
self-excited generator 21 via the primary terminals into DC power and outputs the DC
power via the secondary terminals. The electric power output from the second power
converter 22 charges the capacitor C1.
[0049] The second controller 23 outputs a switching control signal S6 to the second
10 power converter 22, and thus controls the timings of turning on and off a plurality of
switching elements of the second power converter 22. Specifically, the second
controller 23 acquires the actual rotation frequency of the internal combustion engine 2
from the speed sensor 4. When the actual rotation frequency of the internal combustion
engine 2 reaches a threshold rotation frequency, the second controller 23 controls the
15 timings of turning on and off the switching elements of the second power converter 22,
and thus causes the second power converter 22 to start the power conversion process of
converting the AC power fed via the primary terminals into DC power. The threshold
rotation frequency is defined as the rotation frequency of the internal combustion engine
2 when the self-excited generator 11 is driven by the internal combustion engine 2 to start
20 power generation after the start of the internal combustion engine 2, for example.
[0050] The second controller 23 also acquires the voltage EFC between the
terminals of the capacitor C1 from the voltage measurer VT1. When the voltage EFC
between the terminals of the capacitor C1 becomes at least the threshold voltage EFC1,
the second controller 23 outputs a switching control signal S6 for turning off the
25 switching elements of the second power converter 22, and thereby stops the second
power converter 22.
[0051] An operation of the driving apparatus 1 having the above-described
20
configuration is described below with reference to the timing chart in the sections (A) to
(H) of FIG. 8. The sections (A) to (G) of FIG. 8 correspond to the respective sections
(A) to (G) of FIG. 5. As in FIG. 5, the start instruction signal S1 is switched from the L
level to the H level at the time T1.
5 As illustrated in the section (C) of FIG. 8, the engine controller 3 starts the internal
combustion engine 2 in response to the switching of the start instruction signal S1 from
the L level to the H level at the time T1. The rotation frequency of the internal
combustion engine 2 thus starts to rise from the rotation frequency RPM0. As
illustrated in the section (D) of FIG. 8, the self-excited generator 21 starts power
10 generation in accordance with the increase in the rotation frequency of the internal
combustion engine 2. Accordingly, a current flows from the self-excited generator 21 to
the second power converter 22 as represented by the solid-line arrow A5 in FIG. 9.
[0052] As illustrated in the section (H) of FIG. 8, the second controller 23 starts to
control the timings of turning on and off the plurality of switching elements of the second
15 power converter 22 at the time T1, and thus causes the second power converter 22 to
convert the AC power generated at the self-excited generator 21 into DC power, in order
to charge the capacitor C1 with electric power generated at the self-excited generator 11.
As illustrated in the section (G) of FIG. 8, the contactor controller 18 closes the contactor
Q1 at the time T1. Accordingly, a current flows from the second power converter 22 to
20 the capacitor C1 as represented by the solid-line arrow A6 in FIG. 9, thereby charging the
capacitor C1. As illustrated in the section (E) of FIG. 8, the electric power generated at
the self-excited generator 11 charges the capacitor C1, and the voltage EFC between the
terminals of the capacitor C1 starts to rise from the voltage EFC0. As illustrated in the
section (F) of FIG. 8, the separately excited generator 12 has not been excited and thus
25 does not start power generation regardless of being driven by the internal combustion
engine 2.
[0053] As illustrated in the section (E) of FIG. 8, when the voltage EFC between
21
the terminals reaches the threshold voltage EFC1 at the time T2, the first controller 15
starts to control the on and off states of the switching elements of the first power
converter 13, and thus causes the first power converter 13 to convert the DC power fed
from the capacitor C1 into AC power and feed the AC power to the separately excited
5 generator 12. Accordingly, a current flows from the first power converter 13 to the
separately excited generator 12 as represented by the solid-line arrow A7 in FIG. 9,
thereby exciting the separately excited generator 12. As illustrated in the section (F) of
FIG. 8, after the excitation of the separately excited generator 12 at the time T2, the
separately excited generator 12 driven by the internal combustion engine 2 starts power
10 generation. The separately excited generator 12 then feeds the generated AC power to
the first power converter 13.
[0054] When the voltage EFC between the terminals reaches the threshold voltage
EFC1 at the time T2, as illustrated in the section (H) of FIG. 8, the second controller 23
turns off the switching elements of the second power converter 22, and thereby stops the
15 second power converter 22. As illustrated in the section (G) of FIG. 8, the contactor
controller 18 opens the contactor Q1 at the time T2.
The stop of the second power converter 22 preferably precedes the opening of the
contactor Q1. In this case, the contactor controller 18 may acquire the switching control
signal S6 and detect that the second controller 23 has stopped the second power converter
20 22, and then open the contactor Q1.
The following steps are identical to those in Embodiment 1.
[0055] As described above, in the drive control device 30 according to Embodiment
3, the first power converter 13 converts the DC power, which is fed from the capacitor C1
charged with electric power generated at the self-excited generator 21 including an AC
25 motor, into AC power and feeds the AC power to the separately excited generator 12,
leading to excitation of the separately excited generator 12. The drive control device 30
therefore requires no electric storage device to excite the separately excited generator 12.
22
The self-excited generator 21 may be such a small generator that can generate at least
electric power for exciting the separately excited generator 12. This configuration can
reduce the sizes of the drive control device 30 and the driving apparatus 1.
[0056] The above-described embodiments are not to be construed as limiting the
5 scope of the present disclosure. The above-described circuit configurations of the drive
control devices 10, 20, and 30 are mere examples. The drive control devices 10, 20, and
30 may have any circuit configuration provided that the electric power generated at the
self-excited generator 11 or 21 can excite the separately excited generator 12.
In one example, the drive control device 30 may exclude the contactor Q1, like the
10 drive control device 10.
The device to which the driving apparatus 1 feeds electric power, in other words,
the load connected to the secondary terminals of the main inverter 14 is not necessarily
the motor 5 and may be an in-vehicle device, such as air conditioner or lighting
equipment. In this case, the main inverter 14 may include a constant voltage constant
15 frequency (CVCF) inverter.
[0057] The drive control devices 20 and 30 may include any element to electrically
connect the capacitor C1 to the self-excited generator 11 or 21, or electrically disconnect
the capacitor C1 from the self-excited generator 11 or 21, instead of the contactor Q1.
[0058] The drive control device 30 may include a diode bridge for full-wave
20 rectification of the AC power output from the self-excited generator 21, instead of the
second power converter 22.
[0059] The above-described control by the first controller 15 is a mere example.
In another example, the first controller 15 may adjust the switching elements of the first
power converter 13 by means of feedback of the current output from the first power
25 converter 13. The above-described control by the inverter controller 16 is a mere
example. The drive control devices 10, 20, and 30 may exclude the speed sensor 17,
and the inverter controller 16 may acquire the rotation frequency of the motor 5 from an
23
automatic train control (ATC). The inverter controller 16 may then execute sensorless
vector control for estimating a rotational speed of the motor 5.
[0060] The above-described control by the contactor controller 18 is a mere
example. In another example, the contactor controller 18 may close the contactor Q1
5 after the lapse of a predetermined period since the actual rotation frequency of the internal
combustion engine 2 reaches the threshold rotation frequency. Alternatively, the
contactor controller 18 may acquire the start instruction signal S1, and close the contactor
Q1 after the lapse of a predetermined period since the start instruction signal S1 is
switched to the H level.
10 In another example, the contactor controller 18 may open the contactor Q1 when
the voltage EFC between the terminals of the capacitor C1 has been at least the threshold
voltage EFC1 for a predetermined time or longer.
[0061] Although the current measurers CT1 and CT2 detect all the U-, V-, and
W-phase currents in the above description, the current measurers CT1 and CT2 are only
15 required to detect at least two of the U-, V-, and W-phase currents.
[0062] The drive control devices 10, 20, and 30 may further include a clutch and a
clutch controller to control the clutch. This clutch mechanically connects the
self-excited generator 11 to the internal combustion engine 2, or mechanically
disconnects the self-excited generator 11 from the internal combustion engine 2. In this
20 case, the clutch controller may acquire the phase currents measured at the current
measurer CT1, and cause the clutch to mechanically disconnect the self-excited generator
11 from the internal combustion engine 2 when the amplitude of the phase currents
becomes at least a threshold current. Thereafter, when the internal combustion engine 2
is stopped and then restarted, the clutch controller may cause the clutch to mechanically
25 connect the self-excited generator 11 to the internal combustion engine 2.
[0063] The foregoing describes some example embodiments for explanatory
purposes. Although the foregoing discussion has presented specific embodiments,
24
persons skilled in the art will recognize that changes may be made 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
5 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
[0064] 1 Driving apparatus for a railway vehicle
2 Internal combustion engine
10 3 Engine controller
4, 17 Speed sensor
5 Motor
10, 20, 30 Drive control device
11, 21 Self-excited generator
15 12 Separately excited generator
13 First power converter
14 Main inverter
15 First controller
16 Inverter controller
20 18 Contactor controller
22 Second power converter
23 Second controller
B1 Braking notch
C1 Capacitor
25 CT1, CT2 Current measurer
EFC Voltage between terminals
EFC0, EFC2 Voltage
25
EFC1 Threshold voltage
N1 Power running notch
Q1 Contactor
R1 Resistor
5 RPM0, RPM1, RPM2 Rotation frequency
S1 Start instruction signal
S2 Operation instruction signal
S3, S4, S6 Switching control signal
S5 Contactor control signal
10 VT1 Voltage measurer
26
We Claim:
1. A drive control device comprising:
a self-excited generator coupled to an internal combustion engine, and configured,
5 by being driven by the internal combustion engine, to generate electric power and output
the generated electric power;
a separately excited generator coupled to the internal combustion engine, the
separately excited generator in an excited state being configured, by being driven by the
internal combustion engine, to generate electric power and output the generated electric
10 power;
a first power converter to convert electric power fed from the separately excited
generator via primary terminals into direct current (DC) power and output the DC power
via secondary terminals, or to convert DC power fed via the secondary terminals into
electric power to be fed to the separately excited generator and output the electric power
15 via the primary terminals; and
a capacitor connected between the secondary terminals of the first power converter,
wherein
the self-excited generator has output terminals connected to the capacitor.
20 2. The drive control device according to claim 1, further comprising:
a first controller to control switching elements included in the first power converter,
wherein
the first controller controls the switching elements, and thereby causes the first
power converter to convert the DC power fed via the secondary terminals from the
25 capacitor into electric power to be fed to the separately excited generator and feed the
electric power to the separately excited generator via the primary terminals, the capacitor
being charged with the electric power output from the self-excited generator, and
27
after the separately excited generator is excited by the electric power fed from the
first power converter, the first controller controls the switching elements, and thereby
causes the first power converter to convert the electric power fed from the separately
excited generator via the primary terminals into DC power and output the DC power via
5 the secondary terminals.
3. The drive control device according to claim 1 or 2, wherein the self-excited
generator has a generation capacity lower than a generation capacity of the separately
excited generator.
10
4. The drive control device according to any one of claims 1 to 3, further
comprising:
a contactor having one end connected to the self-excited generator and the other
end connected to the capacitor; and
15 a contactor controller to control the contactor, wherein
the contactor controller closes the contactor after start of the internal combustion
engine.
5. The drive control device according to claim 4, wherein the contactor
20 controller opens the contactor when a voltage between terminals of the capacitor is
greater than or equal to a threshold voltage.
6. The drive control device according to any one of claims 1 to 5, wherein the
self-excited generator comprises a DC generator coupled to the internal combustion
25 engine, the DC generator being configured, by being driven by the internal combustion
engine, to generate DC power and output the generated DC power.

7. The drive control device according to any one of claims 1 to 5, wherein
the self-excited generator comprises an alternating current (AC) generator coupled
to the internal combustion engine, the AC generator being configured to, by being driven
by the internal combustion engine, generate AC power and output the generated AC
5 power, and
the drive control device further comprises a second power converter to convert the
AC power fed from the self-excited generator into DC power and feed the converted DC
8. A driving apparatus for a railway vehicle, the driving apparatus comprising:
an internal combustion engine;
the drive control device according to any one of claims 1 to 7; and
a main inverter having primary terminals between which the capacitor included in
the drive control device is connected and secondary terminals, the main inverter being
15 configured to (i) convert DC power fed from the capacitor via the primary terminals into
electric power to be fed to a load, and (ii) feed the converted electric power via the
secondary terminals to the load.