JP2003220859A - Power accumulation unit for dc electrical equipment and railway electrical system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To utilize a revived power at the time of reducing a speed at the station without increasing an electric car weight. <P>SOLUTION: The power accumulation unit is equipped with a power converter and an energy accumulation factor connected with a dc power source through the power converter, and controls a power from the power converter to the energy accumulation factor to reduce a difference between the reference voltage and the voltage at the dc power source side of the power converter. Since the power accumulation unit is not necessarily mounted on the electric car but can be installed on the ground, the weight of the electric car is not increased. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electric railway power feeding system.

[0002]

2. Description of the Related Art With the widespread use of drive systems that combine an AC motor and an inverter as a train drive system, it has become possible to efficiently convert kinetic energy into electric energy during braking and regenerate it into overhead lines. The regenerated electric power is used as part of the electric power consumed by other trains that are running.

Japanese Unexamined Patent Publication No. 2000-4507 discloses that a train is equipped with a capacitor and regenerative power is stored in the capacitor.
There is a disclosure of the method to use at the next powering operation. Also,
Japanese Unexamined Patent Publication No. 9-289703 discloses a method of arranging a condenser in an overhead line circuit in a long distance steep wiring section. Further, JP-A-11-27874 discloses a power storage system using a secondary battery.

[0004]

In the above prior art, when there is no other train running on power, the regenerative electric power is consumed by resistance or the like, or the regenerative operation is stopped and the brake is switched to the frictional force. Then, the regenerative power cannot be effectively used. Further, if there is a distance between the train during the regenerative operation and the train during the powering operation, a loss on the overhead line occurs.

Further, the method of mounting a capacitor or the like on a train disclosed in the above-mentioned Japanese Patent Laid-Open No. 2000-4507 leads to an increase in train weight and power consumption. Further, in the case of the method of disposing the electric storage device in the long-distance steep slope line section disclosed in JP-A-9-289703, with respect to the regenerative electric power at the time of deceleration at the station where the generated electric power becomes the largest,
It has no effect. Further, the method described in Japanese Patent Laid-Open No. 11-27874 requires cooperation with a substation, and the structure is complicated.

An object of the present invention is to effectively utilize the regenerative electric power at the time of deceleration at a station without increasing the train weight.

[0007]

A power storage device of the present invention comprises a power converter and an energy storage element connected to a DC power supply via the power converter, and has a reference voltage and a DC power supply for the power converter. Power to the energy storage element is controlled by controlling the power from the power converter to the energy storage element so that the difference with the voltage on the side is reduced, and using the fact that the overhead line voltage rises when regenerative energy is excessive. Therefore, it is not necessary to detect the power regeneration state of the train. Therefore, the power storage device of the present invention does not need to be mounted on a train and can be installed on the ground, and thus the weight of the train is not increased.

Further, in the railroad mechanic system of the present invention, an electric power storage device for collecting regenerative electric power during deceleration when stopping at a station and supplying electric power necessary for accelerating when starting is installed near the station. As a result, the loss due to power transmission can be reduced and the regenerative power can be effectively used.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

(Embodiment 1) This embodiment will be described with reference to FIGS. 1, 2 and 3. In FIG. 1, 1 is an AC power source, 2
Is a transformer, 3 is a rectifier, 4 is an overhead wire, 5 is a track, 6 is a vehicle, 7 is a power storage device, 100 is a first terminal, 101 is a second terminal, 102 is a first voltage detector, and 103. Is a power converter, 104 is a second voltage detector, 105 is a capacitor, 106 is a voltage commander, 107 is a subtractor, 108 is a voltage controller, 109 is a charge amount calculator, and 110 is a current command limiter. .

The AC power supply 1 is, for example, a power system, and the voltage of the AC power supply 1 is transformed by a transformer 2 so as to have a desired voltage, and is converted into a DC voltage by a rectifier 3 composed of a diode bridge circuit. The DC voltage of the rectifier 3 is Es0 when power is supplied from the rectifier 3 to the overhead wire side. Also,
When the voltage on the overhead wire side is higher than Es0, a reverse voltage is applied to all the diodes of the rectifier 3, so that no current flows in the rectifier 3. The converted DC voltage is transmitted by the overhead wire 4 and the track 5. The vehicle 6 travels using the DC voltage supplied from the overhead wire 4 and the track 5.

The power storage device 7 is connected to the overhead wire 4 and the track 5 via a first terminal 100 and a second terminal 101, respectively. The power storage device 7 includes a first terminal 100 and a second terminal 100.
Terminal 101, first voltage detector 102, power converter 1
03, a second voltage detector 104, a capacitor 105, a voltage command unit 106, a subtractor 107, a voltage controller 108, a charge amount calculator 109, and a current command limiter 110.

The first voltage detector 102 includes an overhead line 4 and a track 5.
The DC voltage applied to and is detected and the overhead wire voltage Es is output.
The power converter 103 is a capacitor from the power converter 103.
The capacitor 105 is charged and discharged so that the current Ic flowing through 105 and the second current command Ic2 * match. It is assumed that the capacitor 105 is charged when the second current command Ic2 * is positive, and the capacitor 105 is discharged when the second current command Ic2 * is negative. Further, since the capacitor 105 needs to store the regenerative electric power generated by the vehicle 6, an electric double layer capacitor that can obtain a large capacity is used.

The second voltage detector 104 is the capacitor 10
The voltage of 5 is detected and the capacitor voltage Ec is output. The voltage command device 106 commands the voltage command Es * which is a voltage higher than the DC voltage converted by the rectifier 3. Voltage command E
The voltage deviation ΔEs, which is the difference between s * and the overhead wire voltage Es, is obtained by the subtractor 107, and the voltage controller 108 further determines the voltage deviation ΔEs.
Based on s, the first current command Ic1 * is calculated and output using the equation (1).

[0015]

[Equation 1] In the equation (1), Kp and Ki are control gains,
s is a Laplace operator.

The charge amount calculator 109 obtains the charge amount Qc of the capacitor 105 based on the equation (2).

[0017]

## EQU00002 ## Qc = C.Ec (2) In the equation (2), C is the capacitance of the capacitor 105.

The current command limiter 110 includes the capacitor 10
In order to properly maintain the charge amount Qc of No. 5, the first current command Ic
Limit 1 * and output the second current command Ic2 *.
When the charge amount Qc is less than or equal to the lower limit value QL, the capacitor 1
The second current command Ic2 so that 05 does not discharge any more.
Limit the minimum value of * to 0. On the contrary, when the charge amount Qc is the upper limit value QH or more, the maximum value of the second current command Ic2 * is limited to 0 so that the capacitor 105 is not charged any more. When the charge amount Qc is larger than the lower limit value QL and smaller than the upper limit value QH, the first current command Ic1 * and the second current command Ic2 * match. Here, the lower limit value QL of the charge amount is, for example, 5% of the maximum charge amount of the capacitor 105.
And the upper limit value QH of the charge amount is, for example,
This is 95% of the maximum charge of No. 5.

With the above configuration, the power storage device 7 does not need to detect the power running regeneration state of the vehicle. Therefore, it is not necessary to mount it on the vehicle and can be installed on the ground.

Next, a first operation example of this embodiment will be described with reference to FIG. The four time charts shown in FIG. 2 are respectively the overhead wire voltage Es, the load current Is flowing in the vehicle 6, the second current command Ic2 *, and the charge amount Qc of the capacitor 105.
Shows the change of. The sign of the load current Is is positive when the vehicle 6 is in the power running mode and is negative when the vehicle 6 is in the regenerative mode.
2 shows that the vehicle 6 starts braking at time T1, performs regenerative operation during period A, stops at time T2, stops during period B, departs at time T3, and powers during period C. The case where the vehicle is operated and the coasting operation is performed from time T4 is shown.

At time T1, when the vehicle 6 starts the regenerative operation, the overhead wire voltage Es becomes higher than Es0, so that no current flows through the rectifier 3. At this time, since the overhead wire voltage Es is smaller than the overhead wire voltage command Es *, the voltage deviation ΔEs and the first current command Ic1 * become negative. However, since the charge amount Qc is a value equal to or smaller than the lower limit value QL, the second current command Ic2 * is limited to 0. Therefore, the charge amount Q
c does not change. On the other hand, the overhead wire voltage Es increases.

At time T1 'in FIG. 2, when the overhead wire voltage Es reaches the overhead wire voltage command Es *, the first current command Ic1 * is obtained.
Becomes positive, the second current command Ic2 * coincides with the first current command Ic1 *, and becomes positive. As a result, the capacitor 1
The charging of 05 starts, and the charge amount Qc starts increasing. Further, the overhead line voltage Es is controlled so as to match the overhead line voltage command Es *. That is, the kinetic energy of the vehicle 6 is regenerated and accumulated in the capacitor 105.

At time T2 in FIG. 2, when the vehicle 6 stops, the load current Is becomes 0, and the first current command Ic1 * and the second current command Ic1 *
Current command Ic2 * becomes 0, and the increase in the charge amount Qc of the capacitor 105 stops.

At time T3 in FIG. 2, when the vehicle 6 starts and starts a powering operation, the load current Is becomes positive and the overhead wire voltage Es is reached.
To decrease, the first current command Ic1 * and
The second current command Ic2 * becomes negative and the capacitor 10
The discharge of 5 starts, and the charge amount Qc starts to decrease. Also,
The overhead line voltage Es is controlled so as to match the overhead line voltage command Es *. That is, the electric energy stored in the capacitor 105 is converted into the kinetic energy of the vehicle 6.

At time T3 'in FIG. 2, when the charge amount Qc becomes equal to or lower than the lower limit value QL, the lower limit of the second current command Ic2 * becomes 0.
Therefore, the second current command Ic2 * becomes 0, and the decrease in the charge amount Qc stops. As a result, the overhead wire voltage Es starts to decrease. When the overhead wire voltage Es becomes equal to or lower than Es0, a current flows from the overhead wire to the rectifier 3, and the rectifier 3 supplies power to the vehicle 6. In FIG. 2, the overhead wire voltage Es is lower than Es0 because of the voltage drop due to the resistance of the overhead wire.

At time T4 in FIG. 2, when the vehicle 6 starts coasting, the load current Is becomes zero and the voltage drop in the overhead wire disappears, so the overhead wire voltage Es becomes Es0.

Thus, the charge amount Q of the capacitor 105
When c is between the upper limit value QH and the lower limit value QL, the overhead wire voltage is controlled to Es *. At this time, when the vehicle 6 is performing regenerative operation, the regenerative energy is stored in the capacitor 10
If the vehicle 6 is performing a power running operation,
Energy is supplied from the capacitor 105. Therefore, regenerative energy can be effectively used. Also, the vehicle 6
If the energy stored in the capacitor 105 is exhausted during the power running operation, the rectifier 3 supplies the energy, so that the operation of the vehicle is not hindered.

Next, a second operation example of this embodiment will be described with reference to FIG. FIG. 3 illustrates a case where the energy that can be stored in the capacitor 105 is smaller than the regenerative energy that is regenerated when the vehicle 6 is stopped.

The four time charts shown in FIG. 3 are shown in FIG.
Similarly, the overhead line voltage Es, the load current Is, the second current command Ic2 *, and the charge amount Qc of the capacitor 105. Figure 3
At time T5, vehicle 6 starts braking, performs regenerative operation during period D, and stops at time T6. From time T5 to time T5 ', the operation is similar to that of FIG.

At time T5 'in FIG. 3, the charge amount Qc of the capacitor 105 reaches the upper limit value QH. That is, the vehicle 6
Is a state in which the regenerative energy regenerated has reached the upper limit energy that can be stored in the capacitor 105. Charge Q
Since c becomes the upper limit value QH or more, the second current command Ic2
* Becomes 0. As a result, the charge amount Q of the capacitor 105
It is prevented that the increase of c stops and the capacitor 105 is overcharged. At this time, since the destination of the regenerative energy from the vehicle 6 disappears, the overhead wire voltage Es starts to increase.

At time T5 "in FIG. 3, when the overhead wire voltage Es reaches the reference voltage Es1, the vehicle 6 switches the regenerative brake to a mechanical brake or causes the mounted resistor to consume the regenerative energy, and Regeneration is not performed, that is, the operation is performed so that the load current Is = 0. As a result, the increase of the overhead wire voltage Es is stopped.
Therefore, the overhead wire voltage command Es * needs to be set to a value lower than the reference voltage Es1.

As shown in the second operation example described above,
Even if the energy that can be stored in the capacitor 105 is smaller than the energy regenerated when the vehicle 6 is stopped, the capacitor 105 will not be overcharged.

However, since the kinetic energy of the vehicle 6 that cannot be stored in the capacitor 105 is lost due to frictional heat and heat generated by the resistor, in order to effectively use the regenerative energy, the energy that can be stored in the capacitor 105 is It is desirable that 6 is larger than the regenerative energy that can be generated during braking.

Here, to show specific examples of Es0, reference voltage Es1 and overhead line voltage command Es *, the nominal voltage of the overhead line is 1
In case of 500V, Es0 is 1500V, reference voltage Es1
Is 1800V, and the overhead wire voltage command Es * is 1700V.

Although an electric double layer capacitor is used as the capacitor in the above description, another type of capacitor may be used as long as the required capacitance can be obtained. Further, instead of the capacitor, another energy storage element may be used. For example, as the energy storage element, there is a flywheel or a secondary battery that stores energy as kinetic energy of a rotating body. When using the flyhole, the charge amount Qc may be replaced with the kinetic energy of the flywheel.

Next, the installation location of the power storage device 7 of this embodiment will be described with reference to FIG. FIG. 4 is a schematic plan view around a railway station. In FIG. 4, 7 is a power storage device, 301 is a first orbit, 302 is a second orbit, 303
Is the first home, 304 is the second home, 310, 31
1, 312 and 313 are area lines.

The first platform 30 is in contact with the first track 301 and the second track 302 on which the railroad car runs, respectively.
3 and the second home 304 are installed. The passengers of the railway vehicle are the first home 303 or the second home 30.
By 4 the boarding / alighting of the railway car is performed. The area lines 310 and 311 represent the boundaries of the first area having a radius of 3 km or less from the midpoint of the side of the first platform that contacts the railroad track. Further, the area lines 312 and 313 represent the boundaries of the second area having a radius of 3 km or less from the midpoint of the side of the second platform which contacts the line. The power storage device 7 is installed in the first area or the second area indicated by the diagonal lines in FIG. In other words, 3km from the midpoint of the side of the track on a certain platform
It will be installed at the following distances.

Since the railway vehicle stops near the platform except for the transit station, it decelerates toward the platform, stops, and accelerates again. When decelerating, regenerative energy is generated, stored in the power storage device 7, and when accelerated again, the stored energy is released from the power storage device 7. At this time, if the distance between the power storage device 7 and the railway vehicle is long, the loss in the overhead line becomes large. Therefore, by minimizing this distance, the loss can be reduced. In this embodiment, this distance is within 3 km, for example.

(Embodiment 2) This embodiment will be described with reference to FIG. The same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The present embodiment is different from the first embodiment in that the power storage device is mounted on a vehicle so as to be movable. In FIG. 5, 400 is a vehicle body, 401 is a current collector, 4
02 is a wheel. The electric power storage device 7 is mounted on the vehicle body 400, and the current collector 401 and the wheels 402 are further attached. The current collector 401 is electrically connected to the first terminal 100 of the power storage device 7, and is connected to the wheel overhead wire 4 and the second terminal 101 of the power storage device 7. The current collector 401 is in sliding contact with the overhead wire 4.
On the other hand, the wheel 402 is also in contact with the track 5. Therefore, since the power storage device 7 is electrically connected to the overhead wire 4 and the track 5, the power storage device 7 operates similarly to the first embodiment.

In this embodiment, the current collector 401 and the wheels 40
Since the power storage device 7 is connected via 2 and can be moved on the track, for example, a lead-in line or a siding line in the station premises,
Further, a vehicle equipped with the power storage device 7 of the present embodiment can be arranged near a station similar to that of the first embodiment to regenerate energy. In this case, an electric motor may be mounted on the vehicle body 400 and the wheels may be driven to move, or the locomotive may be towed to move. Further, a plurality of power storage devices 7 of this embodiment may be arranged according to the scale of regenerative energy.

[0041]

According to the present invention, the regenerative electric power at the time of deceleration at the station can be effectively used without increasing the weight of the train.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a power storage device according to a first embodiment.

FIG. 2 is a time chart of the operation of the power storage device according to the first embodiment.

FIG. 3 is a time chart of another operation of the power storage device according to the first embodiment.

FIG. 4 is an explanatory diagram of an installation place of the power storage device according to the first embodiment.

FIG. 5 is an explanatory diagram of a power storage device according to a second embodiment.

[Explanation of symbols]

1 ... AC power supply, 2 ... Transformer, 3 ... Rectifier, 4 ... Overhead line, 5
... track, 6 ... vehicle, 7 ... power storage device, 100 ... first terminal, 101 ... second terminal, 102 ... first voltage detector, 103 ... power converter, 104 ... second voltage detector ,
105 ... Capacitor, 106 ... Voltage commander, 107 ... Subtractor, 108 ... Voltage controller, 109 ... Charge amount calculator, 1
10 ... Current command limiter, 301 ... First track, 302 ...
Second track, 303 ... First home, 304 ... Second home, 400 ... Car body, 401 ... Current collector, 402 ... Wheels.

Continued front page    (72) Inventor Motoo Futami             7-1-1, Omika-cho, Hitachi-shi, Ibaraki Prefecture             Inside the Hitachi Research Laboratory, Hitachi Ltd. (72) Inventor Shigeta Ueda             7-1-1, Omika-cho, Hitachi-shi, Ibaraki Prefecture             Inside the Hitachi Research Laboratory, Hitachi Ltd.

Claims (12)

[Claims] 1. A power storage device comprising a power converter and an energy storage element connected to a DC power supply via the power converter, wherein a difference between a reference voltage and a voltage on the DC power supply side of the power converter. A power storage device, characterized in that the power from the power converter to the energy storage element is controlled so as to decrease. 2. The power storage device according to claim 1, further comprising a storage amount detector for detecting or estimating an energy storage amount of an energy storage element, and energy storage from the power converter based on an output of the storage amount detector. A power storage device characterized by limiting power to an element. 3. The method according to any one of claims 1 and 2,
A power storage device, wherein the reference voltage is set to a voltage higher than a voltage of a DC power supply. 4. The power storage device according to claim 1, wherein the energy storage element is an electric double layer capacitor or a secondary battery. 5. The power storage device according to claim 1, wherein the energy storage element is a flywheel. 6. The power storage device according to claim 1, wherein the power storage device can be installed while moving on a track. 7. A railroad mechanic system comprising a vehicle running on electric power, a DC power source, a power transmission means for transmitting electric power to the vehicle, a platform for getting on and off the vehicle, and a track on which the vehicle travels, A power storage device electrically connected to the power transmission means is provided within a radius of 3 km from the center of the platform facing the track, and the power storage means includes a power converter and a DC power source via the power converter. A connected energy storage element, characterized in that it controls the power from the power converter to the energy storage element so that the difference between the reference voltage and the voltage on the DC power supply side of the power converter decreases. A railway mechatronic system. 8. The power storage device according to claim 7, further comprising a storage amount detector for detecting or estimating the amount of energy storage of the energy storage element, and the energy storage from the power converter based on the output of the storage amount detector. A railroad electric power system characterized by limiting the power to the elements. 9. The railway machine power system according to claim 7, wherein the power storage device sets the reference voltage to a voltage higher than the voltage of the DC power supply. 10. The railway machine and electrical system according to claim 8, 9, or 10, wherein the energy storage element of the power storage device is an electric double layer capacitor or a secondary battery. . 11. The railroad mechanic system according to claim 8, 9, or 10, wherein the energy storage element of the power storage device is a flywheel. 12. The railway machine / electric system according to any one of claims 7 to 11, wherein the power storage device can be installed by moving on a track.