JP7443167B2 - Power storage devices, electric vehicle control devices, and railway systems - Google Patents

Description

Embodiments of the present invention relate to a power storage device, an electric vehicle control device, and a railway system.

The electric vehicle includes an inverter and an electric motor. The inverter receives power from a power supply line such as an overhead wire or a third rail, and uses the received power to supply power to an electric motor and various equipment of the electric vehicle. The electric motor is, for example, a permanent magnet synchronous electric motor in which a permanent magnet is used in the rotor. The inverter supplies alternating current power to the electric motor, thereby rotating the shaft of the electric motor and powering the electric vehicle. Further, the inverter performs regeneration that recovers the kinetic energy of rotation of the shaft of the electric motor as electrical energy.

In the above configuration, the running of the electric vehicle by the electric motor is controlled by the difference (slip) between the frequency of AC power from the inverter and the frequency of rotation of the shaft of the electric motor. For example, if the slip is positive, a positive torque (acceleration torque) is applied that accelerates the electric motor. Further, for example, if the slip is negative, a negative torque (regenerative torque) that decelerates the electric motor is applied. Further, when regenerative torque is applied to the electric motor, electric power (regenerative electric power) is generated in the electric motor, and regenerative operation (regenerative braking) is performed in which electric power is returned from the electric motor to the inverter.

The maximum value (or effective value) of the AC voltage applied to the motor from the inverter is determined by the voltage of the filter capacitor that supplies power to the inverter. The filter capacitor is connected in parallel with the inverter between the feed line and the ground line. That is, the voltage of the filter capacitor is determined by the voltage of the feeder line. Further, the relationship between the rotational speed of the shaft of the electric motor and the regenerative torque (constant torque characteristic) is determined by the configuration of the electric motor and the voltage of the power supply line. For example, when the voltage of the power supply line becomes low and the rotational speed of the shaft of the electric motor becomes high, there is a problem that the performance of the regenerative operation may deteriorate.

Japanese Patent Application Publication No. 2005-328618

The problem to be solved by the present invention is to provide a power storage device, an electric vehicle control device, and a railway system that can increase regenerated power.

The power storage device according to the embodiment is a power storage device connected to an electric vehicle that includes an electric motor and a first power conversion device that receives DC power from a power supply line and supplies AC power to the electric motor, and includes a storage battery and A second power conversion device and a control circuit are provided. The second power converter receives DC power from the power supply line and performs a charging operation of supplying the DC power to the storage battery, and a discharging operation of supplying DC power to the power supply line using DC power from the storage battery. do. The control circuit causes the second power conversion device to perform a discharging operation when the first power conversion device is performing a regeneration operation , and when the voltage of the power supply line is equal to or higher than a preset regeneration narrowing voltage, The second power converter is caused to perform a charging operation, and when the voltage of the feeder line is less than a preset regeneration narrowing voltage, the second power converter is caused to perform a discharging operation, and the regenerative power generated by the regenerative operation is When the difference in physical deceleration energy of the electric motor is less than a preset threshold, and the voltage of the power supply line is less than a preset regeneration throttling voltage, the second power conversion device is caused to perform a discharging operation. make it happen

FIG. 1 is an explanatory diagram for explaining an example of a railway system according to a first embodiment. FIG. 2 is an explanatory diagram for explaining an example of the operation of the railway system according to the first embodiment. FIG. 3 is an explanatory diagram for explaining an example of the operation of the railway system according to the first embodiment. FIG. 4 is an explanatory diagram for explaining an example of the operation of the railway system according to the first embodiment. FIG. 5 is an explanatory diagram for explaining an example of the operation of the railway system according to the first embodiment. FIG. 6 is an explanatory diagram for explaining an example of the railway system according to the second embodiment.

Hereinafter, embodiments will be described with reference to the drawings.
(First embodiment)
FIG. 1 is an explanatory diagram showing a configuration example of a railway system 1 according to the first embodiment. The railway system 1 includes an overhead wire 2, a feeding device 3, an electric car 4, a track 5, and the like.

The overhead line 2 is a power supply line for electrically connecting the power feeding device 3 and the electric car 4. The overhead wire 2 is, for example, an overhead contact line. Moreover, a third rail or the like may be used instead of the overhead wire 2.

The feeding device 3 is configured to supply DC power to the overhead wire 2 . The feeding device 3 includes a transformer 11, a rectifier 12, and the like. The power feeding device 3 converts a DC voltage from a voltage source (not shown) into a voltage according to the specifications of the railway system 1 using a transformer 11. The feeding device 3 supplies the DC voltage transformed by the transformer 11 to the overhead wire 2 via the rectifier 12 . Thereby, a predetermined DC voltage is supplied to the overhead wire 2.

The electric car 4 is a moving body that moves on the track 5. The electric car 4 includes a current collector 21, wheels 22, an electric car control device 23, and the like.

The current collector 21 is configured to receive DC power from a power supply line such as the overhead wire 2 and supply it to the electric vehicle control device 23 . For example, when the power supply line is an overhead line, the current collector 21 is configured as a pantograph or the like. Further, the current collector 21 is configured as a current collector shoe, for example, when the power supply line is a third rail or the like.

The wheels 22 are configured to cause the electric vehicle 4 to travel by being rotated by an electric vehicle control device 23 .

The electric vehicle control device 23 is mounted on a moving body such as the electric vehicle 4, for example. The electric vehicle control device 23 receives DC power from the overhead wire 2 via the current collector 21, converts the received DC power into AC power according to the rating of the motor, and supplies the AC power to the motor. As a result, the electric vehicle control device 23 rotates the rotating shaft of the electric motor, rotates the wheels 22 that are interlocked with the rotating shaft of the electric motor via gears, etc., and causes the electric vehicle to power the electric vehicle on the track.

As shown in FIG. 1, the electric vehicle control device 23 includes a first high-speed circuit breaker 31, a first filter reactor 32, a first filter capacitor 33, an inverter 34, an electric motor 35, a resolver 36, a second high-speed circuit breaker 37, a second filter reactor 38, a second filter capacitor 39, a DCDC converter 40, a storage battery 41, a driver's cab 42, and a control unit 43.

The first high-speed circuit breaker 31 is connected to the current collector 21 . The first high-speed circuit breaker 31 connects the inverter 34 and the current collector 21 by closing (closing) the circuit. The first high-speed circuit breaker 31 switches between closing and opening based on a closing command from the control unit 43.

The first filter reactor 32 is connected between the current collector 21 and a connection point between the inverter 34 and the first filter capacitor 33.

The first filter capacitor 33 is a DC power supply connected in parallel with the inverter 34 when viewed from the first filter reactor 32 . A high voltage side terminal of the first filter capacitor 33 is connected to the first filter reactor 32 and the inverter 34. A low voltage side terminal of the first filter capacitor 33 is connected to an inverter 34. Further, the low voltage side terminal of the first filter capacitor 33 is electrically connected to the track 5 as a ground via the wheels 22 or the like. The first filter capacitor 33 smoothes the power supplied from the current collector 21 via the first filter reactor 32 and the like, and supplies the smoothed power to the inverter 34 .

The inverter 34 is, for example, an inverter circuit such as a variable voltage variable frequency inverter (VVVF inverter). The inverter 34 is a first power conversion device that converts supplied DC power into AC power (three-phase AC power). Inverter 34 supplies the converted AC power to electric motor 35 .

The inverter 34 includes a plurality of legs each made up of a plurality of semiconductor switches forming an upper arm and a lower arm. The inverter 34 includes, for example, three legs. Each leg is connected in parallel to the first filter capacitor 33, respectively. Each leg controls the semiconductor switches of the upper arm and the lower arm to turn on and off based on an inverter operation signal from the control unit 43. Thereby, each leg supplies AC power to the electric motor 35 using the DC voltage from the first filter capacitor 33 . Each leg supplies alternating current power with mutually different phases to the electric motor 35. For example, the inverter 34 supplies the electric motor 35 with three-phase AC power (three-phase AC power) having phases different by 120 degrees from each other.

The electric motor 35 is configured to rotate a rotating shaft using AC power from the inverter 34. The electric motor 35 is configured as, for example, a three-phase permanent magnet synchronous motor (PMSM). The electric motor 35 includes a stator including a plurality of windings connected to each leg of the inverter 34, and a permanent magnet rotor rotatably provided in a space formed in the center of the stator.

The electric motor 35 operates according to three-phase AC power supplied from the inverter 34 to obtain mechanical power. AC power is supplied from each leg of the inverter 34 to each winding at different timings. The interaction between the magnetic field generated in each winding by the current flowing through each winding and the magnetic field of the stator produces mechanical energy that rotates the shaft. When the shaft of the electric motor 35 rotates, driving force is transmitted to the wheels 22 of the electric vehicle 4 through gears connected to the shaft of the electric motor 35, and the electric vehicle 4 runs under power.

The resolver 36 is a speed detection means that detects the rotation of the shaft of the electric motor 35. The resolver 36 detects the rotation speed of the shaft of the electric motor 35 and supplies the detection result to the control unit 43.

The second high-speed circuit breaker 37 is connected to the current collector 21 . The second high-speed circuit breaker 37 connects the DCDC converter 40 and the current collector 21 by closing (turning on). The second high-speed circuit breaker 37 switches between closing and opening based on a closing command from the control unit 43.

The second filter reactor 38 is connected between the current collector 21 and the connection point between the DCDC converter 40 and the second filter capacitor 39.

The second filter capacitor 39 is a DC power supply connected in parallel with the DCDC converter 40 when viewed from the second filter reactor 38 . A high voltage side terminal of the second filter capacitor 39 is connected to the second filter reactor 38 and the DCDC converter 40. A low voltage side terminal of the second filter capacitor 39 is connected to a DCDC converter 40. Further, the low voltage side terminal of the second filter capacitor 39 is electrically connected to the track 5 as a ground via the wheels 22 or the like. The second filter capacitor 39 smoothes the power supplied from the current collector 21 via the second filter reactor 38 and the like, and supplies the smoothed power to the DC/DC converter 40 .

The DCDC converter 40 is, for example, a second power conversion device that converts the DC power supplied from the second filter capacitor 39 into DC power according to the rated power of the storage battery 41. The DCDC converter 40 performs a charging operation of supplying the converted DC power to the storage battery 41 and a discharging operation of discharging the power from the storage battery 41 to the overhead wire 2 .

The storage battery 41 is configured, for example, as a lithium ion secondary battery including an electrode group in which a positive electrode and a negative electrode are stacked with a separator interposed therebetween. Further, the storage battery 41 may be configured as a large capacity capacitor. The storage battery 41 is charged with DC power supplied from the DCDC converter 40. Further, the storage battery 41 discharges DC power under the control of the DCDC converter 40. The DCDC converter 40 and the storage battery 41 are configured as a power storage device that charges DC power from the overhead wire 2 and discharges the DC power to the overhead wire 2.

The driver's cab 42 is configured to output various commands to the control unit 43. The driver's cab 42 outputs an inverter operation command and various other commands to the control unit 43 in response to operations using a notch or the like.

The control unit 43 is a control circuit that closes and opens the first high-speed circuit breaker 31 and the second high-speed circuit breaker 37, controls the inverter 34, and controls the DCDC converter 40. That is, the control unit 43 outputs a closing command to the first high-speed circuit breaker 31 and the second high-speed circuit breaker 37, an inverter operation signal to the inverter 34, and a charging and discharging control signal to the DCDC converter 40. Do each.

The control unit 43 acquires the detection result of the voltage of the overhead wire 2, which is a power supply line. For example, the control unit 43 may include a voltage detector that detects the voltage of the overhead wire 2, the first filter capacitor 33, or the second filter capacitor 39. Further, the control unit 43 may be configured to acquire the detection result of the voltage of the first filter capacitor 33 or the second filter capacitor 39 from the inverter 34 or the DC/DC converter 40.

Furthermore, the control unit 43 calculates the rotation speed of the shaft of the electric motor 35 based on the detection result from the resolver 36. Furthermore, the control unit 43 calculates the vehicle speed (vehicle speed) of the electric car 4 based on the rotational speed of the shaft of the electric motor 35.

The control unit 43 sends an inverter operation signal to the inverter 34 and an inverter operation signal to the DCDC converter 40 based on the inverter operation command from the driver's cab 42, the detection result of the voltage of the overhead wire 2, and the rotation speed of the shaft of the electric motor 35. generates charging and discharging control signals, etc.

The control unit 43 is configured, for example, as a logic circuit that generates a pulse signal. The control unit 43 also includes a processor, which is an arithmetic element that executes arithmetic processing, and a memory that stores programs and data used in the programs. ) may be configured to generate.

The electric vehicle control device 23 also includes a brake controller (not shown) and the like. Based on the control of the control unit 43, the brake controller applies brakes, such as an air brake, to gears or wheels that are interlocked with the rotating shaft of the electric motor 35.

FIG. 2 is an explanatory diagram for explaining control by the control unit 43 of the inverter 34 and the DCDC converter 40 during regenerative operation.

The control unit 43 first detects voltage (step S11). That is, the control unit 43 acquires the detection result of the voltage of the overhead wire 2, which is the power supply line. In this example, the control unit 43 will be described as one that detects the voltage of the first filter capacitor 33.

Control unit 43 calculates regenerated power (step S12). For example, the control unit 43 calculates the regenerative power generated in the regenerative operation by the inverter 34 based on the detection result of the voltage of the overhead wire 2 and the rotational speed of the shaft of the electric motor 35.

The control unit 43 acquires a brake command value (step S13). The brake command value is information indicating the degree of deceleration (deceleration). The control unit 43 acquires a brake command value based on an inverter operation command from the driver's cab 42, for example.

The control unit 43 calculates physical deceleration energy (step S14). The physical deceleration energy is deceleration energy calculated from the mass of the electric car 4, the current speed of the train (that is, the rotational speed of the shaft of the electric motor 35), the brake command value (deceleration), and the like. For example, physical deceleration energy is calculated from the product of mass, speed, and brake command value (deceleration).

The control unit 43 determines whether (physical deceleration energy)−(regenerated power)<threshold value Pth (step S15).The threshold value Pth is a preset value. Note that the control unit 43 may be configured to determine whether physical deceleration energy<regenerated power.

If the control unit 43 determines that (physical deceleration energy) - (regenerative power) < threshold value Pth (step S15, YES), it controls the inverter 34 to continue the regenerative operation, and performs the operation in FIG. end.

If (physical deceleration energy)−(regenerated power)<threshold value Pth, the regenerated power is sufficient for the physical deceleration energy. That is, the control unit 43 determines that deceleration is possible through regenerative operation. For this reason, the control unit 43 controls the inverter 34 to reduce the speed by regenerative operation.

Further, if the control unit 43 determines that (physical deceleration energy) - (regenerated power) < threshold value Pth (step S15, NO), the detection result of the voltage of the first filter capacitor 33 is set in advance. It is determined whether or not it is less than the regenerative narrowing voltage (step S16).

If (physical deceleration energy)−(regenerated power)≧threshold value Pth, the regenerated power is insufficient with respect to the physical deceleration energy. That is, the control unit 43 determines that the deceleration due to the regenerative operation is insufficient. Therefore, the control unit 43 determines whether it is possible to increase the regenerative power generated by the regenerative operation.

The regenerative throttling voltage is a value determined by the performance of the inverter 34 of the vehicle and various configurations of the railway system 1. For example, when a high-speed circuit breaker is opened in another train and the load is removed from the overhead wire 2, the voltage on the overhead wire 2 increases rapidly. For this reason, in the railway system 1, the upper limit of the voltage of the overhead wire 2 that increases due to the regenerative operation is set as the regenerative narrowing voltage. The control unit 43 controls the regeneration operation by the inverter 34 so as not to exceed the regeneration narrowing voltage. That is, when the detection result of the voltage of the first filter capacitor 33 is less than the preset regeneration narrowing voltage, the control unit 43 increases the voltage of the overhead wire 2, that is, the voltage of the first filter capacitor 33, thereby It is determined that regenerative power can be increased.

When the control unit 43 determines that the detection result of the voltage of the first filter capacitor 33 is less than the regeneration narrowing voltage (step S16, YES), the control unit 43 controls the DCDC converter 40 to perform a discharging operation (step S17). ). When the DC/DC converter 40 receives a control signal instructing discharge from the control unit 43 , the DC/DC converter 40 discharges DC power from the storage battery 41 to the overhead wire 2 . In this way, the control unit 43 can increase the voltage of the overhead wire 2 by causing the DCDC converter 40 and the storage battery 41 to perform a discharging operation.

Note that the control unit 43 may gradually increase the amount of discharge from the storage battery 41 while detecting the voltage of the first filter capacitor 33, or may discharge a predetermined amount of power from the storage battery 41. Further, the control unit 43 may be configured to perform PI control based on the detection result of the voltage of the first filter capacitor 33 to control the amount of discharge from the storage battery 41.

Further, when the control unit 43 determines that the detection result of the voltage of the first filter capacitor 33 is not less than the regeneration narrowing voltage (step S16, NO), the control unit 43 controls the DCDC converter 40 to perform the charging operation ( Step S18). When receiving a control signal instructing charging from the control unit 43, the DCDC converter 40 charges the storage battery 41 with the DC power supplied from the overhead wire 2 via the second filter capacitor 39. In this way, the control unit 43 can charge the storage battery 41 with the DC power of the overhead wire 2.

Next, the relationship between vehicle speed and regenerated power, and the relationship between voltage and regenerated power will be explained.
FIG. 3 is an explanatory diagram for explaining the relationship between vehicle speed and regenerated power. The vertical axis in FIG. 3 indicates regenerative power, which is energy generated by regenerative operation. The horizontal axis in FIG. 3 indicates the speed of the electric vehicle 4 (vehicle speed). Note that the horizontal axis may be the rotational speed of the shaft of the electric motor 35.

As shown in FIG. 3, there is a constant torque characteristic between the vehicle speed and the regenerated power in which the regenerated power is constant regardless of the vehicle speed until the vehicle speed reaches a predetermined speed. FIG. 3 shows constant torque characteristics when the storage battery 41 is not discharging the overhead wire 2. That is, FIG. 3 shows an example of constant torque characteristics when the voltage of the first filter capacitor 33 is a certain value lower than that during the discharging operation.

The regenerated power changes depending on the speed range of the vehicle speed. Specifically, the regenerated power remains constant until the vehicle speed reaches a predetermined value (hereinafter referred to as constant torque region terminal speed). Furthermore, the regenerated power gradually decreases when the vehicle speed exceeds the constant torque region terminal speed.

For example, at point A in FIG. 3, the vehicle speed (first speed) is less than the constant torque region terminal speed. Therefore, a sufficient amount of regenerated power is generated. On the other hand, at point B in FIG. 3, the vehicle speed (second speed) is equal to or higher than the constant torque region terminal speed. For this reason, sufficient regenerative power is not obtained.

FIG. 4 is an explanatory diagram for explaining the relationship between the voltage of the first filter capacitor 33 and regenerated power. The vertical axis in FIG. 4 indicates regenerated power. The horizontal axis in FIG. 3 indicates the voltage of the first filter capacitor 33.

As shown in FIG. 4, the regenerated power changes depending on the voltage of the DC power supplied to the inverter 34, that is, the voltage of the first filter capacitor 33. Specifically, the regenerative power is constant until the voltage of the first filter capacitor 33 reaches a predetermined value (the above-mentioned regenerative narrowing voltage), and gradually decreases when the voltage of the first filter capacitor 33 exceeds the voltage. .

For example, at point C in FIG. 4, the voltage of the first filter capacitor 33 is less than the regeneration narrowing down voltage (regeneration narrowing down starting voltage). Therefore, a sufficient amount of regenerated power is generated. On the other hand, at point D in FIG. 4, the voltage of the first filter capacitor 33 is equal to or higher than the regeneration narrowing down voltage (regeneration narrowing starting voltage). For this reason, regeneration is narrowed down and sufficient regenerative power is not obtained.

As mentioned above, torque performance changes depending on the speed range and also changes depending on the overhead wire voltage. Specifically, the constant torque region terminal speed depends on the overhead line voltage, that is, the voltage of the first filter capacitor 33 that supplies DC power to the inverter 34. For example, when the voltage of the first filter capacitor 33 decreases, the constant torque region terminal speed also decreases. As a result, regenerative torque in the high-speed range also decreases. As a result, regenerative power generated during regenerative operation is reduced.

However, as shown in FIG. 2 above, if the detection result of the voltage of the first filter capacitor 33 is less than the regenerative narrowing voltage, the control unit 43 controls the DCDC converter 40 to perform a discharging operation. As a result, the voltage of the overhead wire 2 increases due to discharge from the storage battery 41.

FIG. 5 is an explanatory diagram for explaining the relationship between vehicle speed and regenerated power. The vertical axis in FIG. 5 indicates regenerative power, which is energy generated by regenerative operation. The horizontal axis in FIG. 5 indicates the speed of the electric vehicle 4 (vehicle speed).

Graph 51 in FIG. 5 shows normal constant torque characteristics. Graph 51 in FIG. 5 is the same as the constant torque characteristic in FIG. 3. That is, the graph 51 in FIG. 5 shows constant torque characteristics when the storage battery 41 is not discharging the overhead wire 2. The constant torque region terminal speed of graph 51 is referred to as the first constant torque region terminal speed.

Graph 52 in FIG. 5 shows constant torque characteristics during discharge operation. As described above, when the storage battery 41 discharges electricity from the overhead wire 2, the voltage of the overhead wire 2 increases. When the voltage of the overhead wire 2 increases, the voltage applied from the first filter capacitor 33 to the inverter 34 increases. When the voltage of the first filter capacitor 33 increases, as shown in graphs 51 and 52 of FIG. 5, the constant torque region terminal speed in the constant torque characteristic changes from the first constant torque region terminal speed to the second constant torque region terminal speed. increases to

Point E indicates the regenerated power generated when the discharge operation is not performed and the regeneration operation is performed at the first speed. In the example of point E, the vehicle speed (first speed) is less than the first constant torque region terminal speed. Therefore, the example at point E is in a state where sufficient regenerative power is generated.

Point F indicates regenerated power generated when a discharge operation is not performed and a regeneration operation is performed at a second speed faster than the first speed. In the example of point F, the vehicle speed (second speed) is equal to or higher than the first constant torque region terminal speed. Therefore, the example of point F is in a state where sufficient regenerative power is not generated.

Point G indicates the regenerated power generated when the discharge operation is performed and the regeneration operation is performed at the second speed. In the example of point G, the vehicle speed (second speed) is less than the second constant torque region terminal speed. Therefore, the example of point G is in a state where sufficient regenerative power is generated.

As described above, the control unit 43 controls the DC/DC converter so that the storage battery 41 discharges to the overhead wire 2 when the voltage detection result of the first filter capacitor is less than the regenerative narrowing voltage. As a result, the voltage of the overhead wire 2 increases, and the constant torque region terminal speed in the constant torque characteristic increases. As a result, it is possible to increase the regenerative power generated by the regenerative operation when the electric vehicle 4 is traveling at high speed.

(Second embodiment)
FIG. 6 is an explanatory diagram showing a configuration example of a railway system 1A according to the second embodiment. In addition, the same reference numerals are given to the same structure as 1st Embodiment, and detailed description is abbreviate|omitted. In the first embodiment, the configuration is such that discharge is performed from the storage battery mounted on the electric vehicle 4 to the overhead wire 2 . On the other hand, the second embodiment differs from the first embodiment in that discharge is performed from a stationary power storage device provided on the ground to the overhead wire 2.

The railway system 1A includes an overhead wire 2, a feeding device 3, an electric car 4, a track 5, a stationary power storage device 6A, and the like.

The stationary power storage device 6A is a device that charges with DC power from the overhead wire 2 and discharges to the overhead wire 2. The stationary power storage device 6A includes a DCDC converter 40, a storage battery 41, and a control unit 43.

The DCDC converter 61A is, for example, a power converter (second power converter) that converts DC power supplied from the overhead wire 2 via a filter capacitor (not shown) into DC power according to the rated power of the storage battery 62A. The DCDC converter 61A performs a charging operation of supplying the converted DC power to the storage battery 62A and a discharging operation of discharging the power from the storage battery 62A to the overhead wire 2.

The storage battery 62A is configured, for example, as a lithium ion secondary battery including an electrode group in which a positive electrode and a negative electrode are stacked with a separator in between. Further, the storage battery 62A may be configured as a large capacity capacitor. The storage battery 62A is charged with DC power supplied from the DCDC converter 61A. Further, the storage battery 62A discharges DC power under the control of the DCDC converter 61A.

The control unit 63A controls the DCDC converter 61A. That is, the control unit 63A outputs a control signal for instructing the DCDC converter 61A to charge or discharge.

The control unit 63A acquires the detection result of the voltage of the overhead wire 2, which is a power supply line. For example, the control unit 63A may include a voltage detector that detects the voltage of a filter capacitor provided between the overhead wire 2 or the DC/DC converter 61A and the overhead wire 2. Further, the control unit 63A may be configured to acquire the voltage detection result from the DC/DC converter 61A.

The control unit 63A determines whether to cause the DCDC converter 40 to perform charging or discharging, based on the detection result of the voltage of the overhead wire 2. For example, similarly to the first embodiment, the control unit 63A determines whether the detection result of the voltage of the overhead wire 2 is less than a preset regeneration narrowing voltage. When the control unit 63A determines that the voltage detection result is less than the regeneration narrowing voltage, the control unit 63A controls the DCDC converter 61A to perform a discharging operation.

The DCDC converter 61A discharges DC power from the storage battery 62A to the overhead wire 2 when receiving a control signal instructing discharge from the control unit 63A. In this way, the control unit 63A can increase the voltage of the overhead wire 2 by causing the DCDC converter 61A and the storage battery 62A to perform a discharging operation.

The control unit 63A may gradually increase the amount of discharge from the storage battery 62A while detecting the voltage of the overhead wire 2, or may discharge a predetermined amount of power from the storage battery 62A. Further, the control unit 63A may be configured to perform PI control based on the detection result of the voltage of the overhead wire 2 and control the amount of discharge from the storage battery 62A.

Moreover, when the control unit 63A determines that the detection result of the voltage of the overhead wire 2 is not less than the regeneration narrowing voltage, the control unit 63A controls the DC/DC converter 61A to perform a charging operation.

When the DC/DC converter 61A receives a control signal instructing charging from the control unit 63A, the DC/DC converter 61A charges the storage battery 62A with the DC power supplied from the overhead wire 2. In this way, the control unit 63A can charge the storage battery 62A with the DC power of the overhead wire 2.

As described above, the stationary power storage device 6A can discharge electricity from the storage battery 62A to the overhead wire 2 based on the detection result of the voltage of the overhead wire 2, thereby increasing the overhead wire voltage. As a result, in the electric vehicle 4 existing in the section where the overhead wire voltage has increased, the constant torque region terminal speed in the constant torque characteristic increases. As a result, it is possible to increase the regenerative power generated by the regenerative operation when the electric vehicle 4 is traveling at high speed.

Note that the railway system 1 may include a plurality of electric cars 4. Furthermore, each of the plurality of electric cars 4 may have a current collector 21, wheels 22, electric car control device 23, and the like. Further, at least one of the plurality of electric cars 4 connected to the overhead wire 2 may be configured as an electric car control device 23 including an inverter 34 , an electric motor 35 , a DC/DC converter 40 , a storage battery 41 , and a control unit 43 . That is, an electric vehicle that is not equipped with the DC/DC converter 40 and the storage battery 41 may be connected to the overhead wire 2 .

Note that the functions described in each of the above-described embodiments are not limited to being configured using hardware, but can also be realized using software by loading a program in which each function is described into a computer. Further, each function may be configured by selecting either software or hardware as appropriate.

Although several embodiments of the invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention, as well as within the scope of the invention described in the claims and its equivalents.

DESCRIPTION OF SYMBOLS 1... Railway system, 1A... Railway system, 2... Overhead line, 3... Power feeding device, 4... Electric car, 5... Track, 6A... Stationary power storage device, 11... Transformer, 12... Rectifier, 21... Current collector, 22... Wheels, 23... Electric vehicle control device, 31... First high speed circuit breaker, 32... First filter reactor, 33... First filter capacitor, 34... Inverter, 35... Electric motor, 36... Resolver, 37... Second High-speed circuit breaker, 38... Second filter reactor, 39... Second filter capacitor, 40... DCDC converter, 41... Storage battery, 42... Cab, 43... Control unit, 51... Graph, 52... Graph, 61A... DCDC converter , 62A...Storage battery, 63A...Control unit.

Claims (3)

A power storage device connected to an electric vehicle that includes an electric motor and a first power conversion device that receives DC power from a power supply line and supplies AC power to the electric motor,
storage battery and
a second power conversion device that performs a charging operation that receives DC power from the power supply line and supplies the DC power to the storage battery; and a discharge operation that supplies DC power to the power supply line using the DC power from the storage battery; ,
a control circuit that causes the second power converter to perform a discharging operation when the first power converter is performing a regenerative operation;
Equipped with
The control circuit includes:
When the voltage of the power supply line is equal to or higher than a preset regeneration throttling voltage, causing the second power conversion device to perform a charging operation, and when the voltage of the power supply line is lower than a preset regeneration throttling voltage, causing the second power converter to perform a discharging operation,
If the difference between the regenerative power generated by the regenerative operation and the physical deceleration energy of the electric motor is less than a preset threshold, and the voltage of the feeder line is less than the preset regeneration throttling voltage, the second power conversion is performed. A power storage device that causes the device to perform a discharge operation . The power storage device according to claim 1;
electric motor and
a first power conversion device that receives DC power from the power supply line and supplies AC power to the electric motor;
An electric vehicle control device comprising: a feeding device that supplies DC power to the feeder;
The power storage device according to claim 1;
an electric vehicle control device comprising: an electric motor; and a first power converter that receives DC power from the power supply line and supplies AC power to the electric motor;
A railway system equipped with