KR100991460B1 - Dc power storage device - Google Patents

Abstract

Without increasing the size and cost of the DC power storage device, it is possible to suppress the voltage drop of the external line, to absorb the regenerative power of the electric vehicle, and to prevent the regeneration of the electric vehicle.

The terminal voltage (standby voltage) of the electric double layer capacitor EDLC is set near the upper limit voltage of the rated voltage range of the external line at no load and normal load of the supply system.

If the external line voltage exceeds the upper limit voltage of the rated voltage range, the regenerative power is absorbed by the double layer capacitor, and at the same time the electric vehicle is subjected to the regenerative current squeegee operation, indicating that the terminal voltage of the electric double layer capacitor exceeds its maximum voltage. Suppress it (prevent regeneration). When the external line voltage falls below the lower limit voltage of the rated voltage range, the device may step down and step up the step-up chopper, discharge power from the electric double layer capacitor, and set the external line voltage to the lower limit of the rated voltage range. Maintain so as not to be less than (voltage drop suppression).

Electric power regeneration

Description

DC power storage device {DC POWER STORAGE DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct current power storage device that is connected in parallel to an external line of an electric railway and supplies power to an electric vehicle during a retrograde driving operation and absorbs electric power during a regenerative operation. In particular, it relates to a charge and discharge control system and / or method for controlling a power storage medium for countermeasures against voltage drops of external lines, countermeasures for regenerative power absorption of electric vehicles, and countermeasures against regenerative stabilization of electric vehicles.

In direct current supply systems, rail transport power substations (DCVRs) are installed such that they are relatively long distances apart. Therefore, for the distance from the nearest substation to the electric railway car, since the voltage drop of the external line is large at a time when a large current flows, for example, at start-up, the fantagraph point voltage can be lowered below the prescribed value. To compensate for this voltage drop, rail transport power substations are provided, or notch suppression is performed on the electric vehicle.

In addition, on a quiet or infrequent railway, there is little opportunity for the electric vehicle in the regenerative operation mode to absorb the regenerative energy absorbed by the other electric vehicle as the power for retrograde electric power, which is likely to cause regenerative failure (electric braking impossibility). . Moreover, even when the railway is frequent or active, regeneration failure may occur due to a sudden decrease in load when the electric vehicle in the regenerative driving mode and the retrograde driving operation among other electric vehicles are finished.

If this regeneration fails or is canceled, the electric vehicle stops the regenerative operation and changes the braking mode from electric braking to mechanical braking. This braking mode change operation causes a braking delay, which prevents the electric vehicle from stopping at a predetermined point and shortens the life due to wear between the wheel and the brake shoe due to rapid braking of the mechanical braking. In order to prevent such regenerative failure, the following methods of absorbing regenerative power have been proposed.

(1) Regenerative method of supplying regenerative power to AC power by an inverter

As shown in FIG. 4A, the DC power regenerated by the electric vehicle 1 is converted into an AC power of a voltage and a controlled frequency controlled by an inverter 2 and an inverter transformer 3 connected to an external line as a DC source. AC power is supplied to the AC power source side.

 This method requires an AC load to absorb the regenerative power, and also requires an inverter transformer, an AC circuit breaker, an inverter, a DC circuit breaker, and the like, resulting in a high overall system cost.

(2) Regenerative method of supplying regenerative power to the regenerative resistor device by the chopper

As shown in Fig. 4B, the chopper device 4 converts the DC power regenerated by the electric vehicle 1 into DC power of a controlled voltage, and the regenerative resistor 5 absorbs this DC power as heat.

This method cannot use the regenerative power effectively because all regenerative power is absorbed by heat by the regenerative resistor device, and this method requires a large resistance device. In addition, this method requires ventilation equipment and heat radiation equipment to dissipate heat generated in the resistance device, which includes a chopper, which is relatively expensive.

(3) Regenerative method using DC power storage device

As shown in FIG. 4C, on the DC side of the rectifier 6, a DC power storage device including a step-up chopper 7 and a DC power storage element 8 is provided. If the external line voltage exceeds the upper limit of the rated voltage range by the regenerative operation of the electric vehicle 1, the voltage reduction control of the chopper 7 adjusts the external line voltage to a low voltage level, and the regenerative power is controlled from the external line. 6 is absorbed into the DC power storage element 8 as a charging current (see Patent Document 1 and Patent Document 2).

When the external line voltage is lower than the lower limit of the rated voltage range by the electric driving operation of the electric vehicle, the external line low pressure is controlled to a higher voltage level by the voltage increase control of the chopper 7, and the power is transferred through the chopper 7 to the DC power storage element. It is supplied from 8 to the external line. Thus, this system can be used as a means for responding to a voltage drop. It can also be used for leveling the load, as seen from the AC power supply side.

5 shows a main circuit configuration of the DC power storage device. Step-up chopper 7 is a high voltage side arm; Low voltage side arm; And reactor L. The high voltage side arm includes a semiconductor switch SW1 having a first end connected to an external line and a second stage and connected to control a charging current flowing from the external line, and a non-parallel diode D1 connected in anti-parallel with the semiconductor switch SW1. . The low voltage side arm has a first end and a second end connected to the second end of the semiconductor switch SW1, and the semiconductor switch SW2 connected in series with the semiconductor switch SW1 in the same direction to control the current with the semiconductor switch SW1, and Non-parallel diode D2 in anti-parallel with semiconductor switch SW2. The reactor L has a first end connected to the second end of the semiconductor switch SW1 and a second end connected to the electric double layer capacitor EDLC.

As shown in Fig. 6, when the external line voltage exceeds the upper limit of the rated voltage range by the regenerative operation of the electric vehicle 1, the power storage system of the above configuration reduces the external line voltage under the control of the chopper. That is, the system controls the switch SW1 to cause the switching operation so that the charging current flows from the external line through the switch SW1 and the reactor L to the EDLC during the on period of the switch SW1, and the EDLC and the reactor L from the reactor L in the off period of the switch SW1. Charge EDLC with circulating current through D2. As such, the system regenerates power as charging power to EDLC.

As shown in Fig. 6, when the external line voltage becomes less than the lower limit of the rated voltage range by the retrograde driving operation of the electric vehicle 1, the power storage system increases the external line voltage under the control of the chopper. That is, the system puts the switch SW2 into the chopping mode, causes short circuiting to flow from the EDLC through the reactor L and the EDLC through the switch SW2 during the ON period of the switch SW2, and accumulates as electron energy in the reactor L, and the switch During the off period of SW2, a discharge current flows from the EDLC through the reactors L and D1 to the external line, thereby suppressing the voltage drop of the external line.

The DC power storage device may include a storage battery in addition to the electric double layer capacitor. The battery is excellent in terms of energy accumulation and accumulation for a long time. However, storage batteries are inferior in terms of rapid charge and discharge characteristics. Therefore, the battery causes a delay in charging the regenerative power that rises rapidly, or a delay in the discharge operation due to the rapid change of the load at the start or acceleration of the electric vehicle, so that the battery may cause a rapid change in the external line voltage or a regenerative failure. It may cause. On the other hand, the electric double layer capacitor is excellent in rapid charge-discharge characteristics, and can appropriately absorb the regenerative energy from the electric vehicle, and can respond quickly to rapid changes in the load.

[Patent Document 1] Japanese Patent Laid-Open No. 2000-233669

[Patent Document 2] Japanese Patent Laid-Open No. 2001-260718

The first task

In order to suppress the voltage drop of the external line using a DC power storage device including an electric double layer capacitor and a step-up chopper, in the configuration of FIG. 5, the terminal voltage (standby voltage) of the electric double layer capacitor It is set to the lower value of the lower limit voltage of the rated voltage range, and prevents discharge to the external line by the path of the reactor L → diode D1 from the electric double layer capacitor. In addition, in order to maximize the amount of power (accumulated power amount) that can be supplied from the electric double layer capacitor, the terminal voltage of the electric double layer capacitor is set to a value close to the lower limit voltage of the rated voltage range of the external line voltage.

For example, in a 1500 V system, if the external line voltage is below 1200 V (the lower limit of the rated voltage range of the external line voltage) and power is supplied from the electric double layer capacitor, the terminal voltage (standby voltage) of the electric double layer capacitor Is set to 1200 V or less, and the system is provided to suppress the voltage drop of the external line voltage by the step-up control by the chopper.

In the configuration of Fig. 5, since the terminal voltage of the electric double layer capacitor is set below the lower limit voltage of the rated voltage range of the external line voltage, the amount of accumulated power of the electric double layer capacitor is limited. In order to increase the accumulated power amount, it is possible to increase the number of parallel elements of the electric double layer capacitor and to increase the controllable current capacity of the step-up chopper. However, this method increases the size of the DC power storage device and increases the cost.

Second task

When a direct current power storage device is used for suppressing voltage drop and absorbing regenerative power, and when the voltage of an external line is lowered, the systems of the above patent documents use terminals of an electric double layer capacitor by a chopper in a voltage increase (or boost) control mode. The voltage is increased to suppress the voltage drop, and when the voltage of the external line is increased, the external line voltage is reduced by the chopper in the voltage reduction (or step-down) control mode to absorb the regenerative power.

In this case, for the use of both the means for the voltage drop and the means for absorbing regenerative power, the same voltage range of the terminal voltage (standby voltage) of the electric double layer capacitor is used during discharge operation to suppress the voltage drop. It is used during charging operation for regenerative power absorption. However, in the operation for suppressing the voltage drop, the system can more efficiently suppress the voltage drop in a state where the electric double layer capacitor is fully charged and its terminal voltage is high. Upon regenerative power absorption, the system can absorb more energy with the amount of charged energy lower than in the electric double layer capacitor, and at its lower terminal voltage. Therefore, since the amount of discharged electric energy supplied and the amount of charged energy absorbed are used in the same voltage range, the amount of energy performing both the voltage drop suppression function and the regenerative power absorption function is at least equal to the amount of energy in the fully charged state. Compared to the amount of energy in the charged state, the system cannot satisfy both functions at the same time.

Therefore, in order to secure the amount of charge / discharge energy that satisfies the two functions of voltage drop suppression and regenerative power absorption function, as in the above-mentioned first task, the parallel number of the electric double layer capacitors is increased and the voltage is increased at the same time. It is necessary to increase the chopper's controllable current capacity. As a result, this technique increases the size of the DC power storage device and increases the cost.

In order to increase the amount of charge / discharge energy, a first DC power storage element having a low terminal voltage (standby voltage) for voltage drop function and a second DC power storage element having a high terminal voltage for regenerative power absorption function are included. Dual system can be adopted. However, this dual system adds to the size and cost of the system.

Third task

When a power storage medium such as an electric double layer capacitor is fully charged, the systems of the above-mentioned patent documents do not absorb the regenerative power, and regenerative failure occurs when the electric vehicle performs a regenerative operation. Therefore, it is necessary to provide a resistive device for regenerative power absorption. In addition, the power storage medium remains fully charged until several electric vehicles start the retrograde driving operation. Therefore, when the regenerative operation of the electric vehicle is continuous, the regenerative effectiveness occurs continuously.

SUMMARY OF THE INVENTION An object of the present invention is to provide a DC power storage device or system suitable for increasing the sum of the amount of power supplied to an external line and the amount of absorbed power, as compared to conventional devices, without increasing the size and cost of the DC power storage device. More specifically, the present invention improves the voltage drop suppression function and the regenerative power absorption of the external line, and enables the regenerative stabilization prevention.

To solve the aforementioned technical problems, the DC power storage device or system of the present invention includes a DC / DC converter such as a step-up chopper, connected between an external line and a power storage medium such as an electric double layer capacitor. . When the external line voltage exceeds the upper limit of the rated voltage range of the external line, the external line voltage increases from no load to the rectifier no load voltage exceeding the upper limit, so the device of the present invention creates a charge conduction path, thereby The power storage medium is charged up to the no-load voltage of the rectifier. As a means for absorbing regenerative power, when the external line voltage (voltage at the terminal connecting the chopper and the external line) exceeds the upper limit voltage, the apparatus of the present invention creates the conduction path, so that the power storage medium has a regenerative difference. Absorbs the regenerative power as charging energy. When the fantagraph point voltage of the regenerative car increases, the apparatus of the present invention uses the regenerative current squeegeeing function of the electric vehicle to prevent the regenerative failure of the electric vehicle. As a means for the voltage drop, when the external line voltage is less than the lower limit voltage of the rated voltage range of the external line, the apparatus of the present invention performs step-down control or step-up control of the terminal voltage of the power storage medium, thereby Discharge can be performed in a line, thereby maintaining the external line voltage at the lower limit voltage. The DC power storage device or system of the present invention has the following configuration.

(1) The direct current power storage device includes a direct current / direct current converter connected between the power storage medium and an external line. The electrical DC / DC converter forms a conductive connection between the external line and the electrical power storage medium when the external line voltage exceeds the upper limit voltage of the rated voltage range of the external line to charge or discharge the power storage medium. And regenerative power control means or region for interrupting the discharge path from the electric power storage medium to the external line when the external line voltage is less than the upper limit voltage; and the lower limit voltage of the rated voltage range of the external line. And when the terminal voltage of the electric power storage medium exceeds the external line voltage, discharging the power storage medium in an external line direction while stepping down the terminal voltage of the power storage medium, and the external line voltage. Is below the lower limit voltage, and the terminal voltage of the power storage medium is When a voltage less than, while boosting the terminal voltage of the energy storage medium includes a voltage drop suppression means or section for discharging the energy storage medium to an external line direction.

(2) If the upper limit voltage is exceeded by absorption of regenerative power from an electric vehicle, and the external line voltage rises due to the connection between the electric power storage medium and an external line, the regenerative power adjusting means or region is determined by the electric vehicle. With the regenerative current squeegeeing operation of the regenerative current squeeze function, the terminal voltage of the electric power storage medium is suppressed below the maximum voltage of the terminal voltage.

(3) The DC / DC converter connects the external line and the power storage medium at no load of the external line, thereby charging the power storage medium so that the terminal voltage of the power storage medium reaches the no-load voltage of the rectifier. do.

(4) In the DC / DC converter, when the external line becomes above the lower limit voltage of the rated voltage range and the terminal voltage of the power storage medium becomes below the upper limit voltage of the rated voltage range, the terminal voltage becomes the external line voltage. Less than the external line voltage to charge the power storage medium from the external line side, and if the terminal voltage exceeds the external line voltage, the power storage medium is charged from the external line side while boosting the external line voltage. Means or apparatus.

(5) The DC / DC converter includes a discharge control switch that controls or blocks a discharge current from the power storage medium to the external line side when the terminal voltage of the power storage medium exceeds the external line voltage.

(6) DC / DC converters include the main circuit. The main circuit includes a semiconductor switch SW1 including a first end and a second end connected to an external line, and a diode D1 in anti-parallel connection with the semiconductor switch SW1 and provided in a direction for controlling charging current flowing from an external line. A low voltage side arm provided in a direction of the high voltage side arm, a semiconductor switch SW2 connected in series with a second end of the semiconductor switch SW1, and a diode D2 in anti-parallel connection with the semiconductor switch SW2; A boosting chopper including a reactor including a first end and a second end connected to a second end of the semiconductor switch SW1; And a semiconductor switch SW3 connected between the second end of the reactor L and the power storage medium, the semiconductor switch SW3 provided in a direction to control the discharge current from the power storage medium, and a diode D3 connected in anti-parallel to the semiconductor switch SW3. And a discharge control switch.

1 is a circuit diagram illustrating a DC power storage device according to an embodiment of the present invention.

FIG. 2 is a graph showing regenerative current squeegeeing characteristics of an electric vehicle to which the DC power storage device of FIG. 1 is applied.

FIG. 3 is a voltage waveform diagram showing operations of the DC storage device of FIG. 1 for preventing regenerative failure and suppressing voltage drop. FIG.

4 is a conceptual diagram illustrating three other examples of a conventional power regenerative system.

5 shows a circuit diagram of a conventional DC power storage device.

FIG. 6 is a waveform diagram illustrating an operation of the DC power storage device of FIG. 5.

<Description of the symbols for the main parts of the drawings>

1: electric car, 6: rectifier

7: step-up chopper, 8: electric double layer capacitor

9: discharge control switch, SW1 ~ SW3: semiconductor switch

D1 ~ D3: Diode, L: Reactor

1 shows a circuit diagram of a DC power storage device or system according to an embodiment of the present invention. The main circuit region of FIG. 1 is almost similar to the circuit shown in FIG. However, unlike the circuit shown in FIG. 5, the circuit shown in FIG. 1 further includes a discharge control switch 9, connected between the second stage of reactor L and the power storage medium. The discharge control switch 9 comprises a semiconductor switch SW3 provided in a direction for controlling the discharge current from the electric power storage medium, and a diode D3 connected in anti-parallel with the semiconductor switch SW3.

The control element or control device 10 functions to control the step-up voltage and the step-down voltage of the chopper 7. In addition, the control device 10 functions to control the switching operation and the conduction / off of the discharge control switch 9. The control device 10 performs various control operations mentioned below according to various voltage setting conditions and voltage detection signals. Thus, the control device 10 includes the following control means.

In the specification and drawings of the present application, "external line" refers to the DC side of rectifier 6 of the supply substation, the output side supply line, supply line, overhead wire and trolley wire of the power storage device.

(a) An electric double layer capacitor is a double layer capacitor having a charge voltage range whose upper limit is greater than or equal to the maximum voltage that can be generated in an external line by regenerative power of an electric vehicle. In the no-load state of the external line, the double layer capacitor is charged up to the no-load voltage of the rectifier above the upper limit of the rated voltage range of the external line.

(b) The DC power storage device or system provides the regenerative power absorbing means and the regenerative failure preventing means in the following manner. When the external line voltage exceeds the upper limit of the rated voltage range, the switches SW1 and SW3 are turned on (in conduction state) to connect the external line and the electric double layer capacitor, and the electric double layer capacitor converts the regenerative power into the charging power. Let it absorb. With this power absorption, the system prevents the regenerative failure of the electric vehicle due to the sudden voltage rise of the external line voltage, and discharges the regenerative energy absorbed from the electric double layer capacitor to the electric vehicle performing the reverse operation to effectively use the regenerative power. Can be.

If the external line voltage continues to rise due to this power absorption, the system cooperates with the regenerative current squeegeeing operation by the regenerative current squeegeeing function of the electric vehicle to control the terminal voltage and the external line voltage of the double layer capacitor, thereby increasing the maximum voltage. Do not increase to an excess. At the same time, the system suppresses the regeneration ineffective by the regenerative current squeegeeing control of the electric vehicle even in this state.

(c) The direct current power storage device or system performs the means for voltage drop in the following manner. When the external line voltage is less than the lower limit voltage of the rated voltage range, the system controls the semiconductor switch SW3 of the discharge control switch 9 to the switching control mode when the terminal voltage of the electric double layer capacitor exceeds the external line voltage. Due to this switching control of the semiconductor switch SW3, the system step-down-controls the terminal voltage of the electric double layer capacitor, and discharges the electric double layer capacitor in the external line direction. Due to the discharge from the electric double layer capacitor, the system maintains the external line voltage above the lower limit of its rated voltage range. In addition, when such a discharge causes the terminal voltage of the electric double layer capacitor to be less than the external line voltage, the system puts the semiconductor switch SW3 in an on (conduction) control state and controls the semiconductor switch SW2 of the chopper 7 in the switching control mode. Due to these control state transitions of SW3 and SW2, the system continues to discharge from the double layer capacitor during step-up control of the terminal voltage of the electric double layer capacitor to maintain the external line voltage above the lower limit of its rated voltage range. .

Squeegeeing of regenerative current is a function provided in existing electric vehicles. In this squeegeeing control, the system monitors the fantagraph point voltage of the electric vehicle. When the fantagraph point voltage is above the preset voltage, the system squeezes the regenerative current from 100% to 0%, thereby preventing excessive increase in the fantagraph point voltage. In general, for an electric vehicle of a DC 1500V system, as shown in FIG. 2, when the Fantagonist point voltage is DC 1600V or less, the squeeze ratio is equal to 1.0 (0% squeeze amount), and the pantograph point voltage is DC1800V. If it is above, a squeeze ratio will become equal to 0 (100% of squeeze amount). Between 1600 V and 1800 V, the squeeze ratio decreases to zero linearly proportional to the voltage. The system suppresses the regenerative current in this way. The surplus braking energy generated by this squeegeeing control of the regenerative current is absorbed by mechanical braking.

Hereinafter, when the control operations for the voltage drop countermeasure means, the regenerative power absorption countermeasure means, and the regenerative stabilization countermeasure means are applied to the 1500V system, a detailed example will be described.

(1) Operation conditions of the supply system:

The rated voltage range of the external line is DC 1600V (upper limit) to 1200V (lower limit), and the no-load voltage of rectifier 6 of the supply substation is DC 1620V. The maximum charge voltage of the electric double layer capacitor EDLC is DC 1800V.

(2) no-load operation:

When the external line voltage is 1600 V or more, the controller 10 controls the semiconductor switch SW1 of the chopper 7 to the on (conduction) control state. If the electric double layer capacitor EDLC is less than 1600 V, charge the electric double layer capacitor EDLC from rectifier 6 of the supply substation until its charge voltage reaches 1620 V of the no-load voltage of rectifier 6.

(3) normal load operation:

When the electric vehicle is operated in the retrograde mode and the external line voltage is below the rectifier no-load voltage (1620 V), the control device 10 equipped in parallel with the supply from the rectifier 6 supplies the power supply from the electric double layer capacitor EDLC, Since the external line voltage and the terminal voltage of the electric double layer capacitor EDLC are in equilibrium, the discharge control switch 9 performs on (conduction) control. However, if the external line voltage is less than 1600 V (but not less than 1200 V), the control device 10 turns off the discharge control switch 9. In this case, therefore, back energy is supplied from the rectifier 60,000 within the rated voltage range of the external line.

(4) regenerative power absorbing means and regenerative invalidation means:

As shown in Fig. 3, when the external line voltage increases due to the regenerative power from the electric vehicle, and the external line voltage exceeds the upper limit (1600 V) of the rated voltage range (time t1), the controller 10 The semiconductor switch SW1 of the step-up chopper 7 is turned on, and the semiconductor switch SW3 is turned on. In this case, since the terminal voltage of the electric double layer capacitor EDLC is also 1600 V, the system causes the charging current to flow from the external line to the electric double layer capacitor EDLC by the on control of the semiconductor switch SW1. Thereby, the system absorbs regenerative power in this charging operation.

With the charging operation of the regenerative power of the electric vehicle, the terminal voltage of the electric double layer capacitor EDLC rises, and the fantagraph point voltage of the electric vehicle also rises together. With this increase in the fantagraph point voltage, the electric vehicle activates the squeegeeing function and reduces the regenerative current. When the regenerative operation of the electric vehicle is finished (as shown in curve A in FIG. 3, when the rise of the external line voltage ends and the external line voltage decreases to the rectifier no-load voltage (1620 V)), the semiconductor switch SW3 is turned on. By control, the terminal voltage of the electric double layer capacitor EDLC spontaneously decreases in order to maintain the voltage balance between the outer line voltage of the region and the outer line voltage of the surrounding region. Then, if the no-load condition is maintained, the terminal voltage of the electric double layer capacitor EDLC is reduced to the rectifier no-load voltage (1620 V). When the external line voltage exceeds the upper limit voltage, when there is an electric vehicle that runs backward, power is supplied from the electric double layer capacitor EDLC to the electric vehicle up to the rectifier no-load voltage. Below the no-load voltage, the electric vehicle is powered from a rectifier and an electric double layer capacitor EDLC equipped in parallel (as shown in curve B of FIG. 3), and the external line voltage is driven by the driving of the electric vehicle driving backwards. It is reduced below the upper limit voltage.

When the terminal voltage of the electric double layer capacitor EDLC falls below the upper limit (1600 V) of the external line rated voltage, the control device 10 stops the discharge operation of the electric double layer capacitor EDLC by the off (blocking) control of the semiconductor switch SW3. . The electric vehicle receives the power supply only from the rectifier 6.

When the regenerative operation of the electric vehicle continues and the terminal voltage of the electric double layer capacitor EDLC reaches the maximum voltage (1800 V) (time t2), the regenerative current from the electric vehicle is reduced to zero by the current squeegeeing operation. The external line voltage also temporarily rises above the rated voltage upper limit (1,600 V) to 1800 V. However, since the regenerative current is zero, there is no further voltage rise and the regenerative failure is prevented.

Therefore, in the regenerative power absorbing means and the regenerative failure preventing means, the external line voltage may temporarily exceed the upper limit (1600 V) of the rated voltage range, but finally the external line voltage is at a level below the rectifier no-load voltage or the upper limit of the rated voltage. Decreases. Thus, the terminal voltage of the electric double layer capacitor EDLC is controlled in the range of 1600 V to 1800 V.

(5) voltage drop corresponding means:

As shown in Fig. 3, when the electric vehicle is operated in the retrograde driving mode and the external line voltage is lower than the lower limit (1200 V) of the rated voltage range (time t3), the controller 10 is switching control of the semiconductor switch SW3, Reduce the terminal voltage of the electric double layer capacitor EDLC, initiate a discharge operation from reactor L and diode D1 from the electric double layer capacitor EDLC, and suppress the voltage drop with power supply from rectifier 6. When the external line voltage returns above the lower limit (1200 V) due to the operation of suppressing the voltage drop (time t4: curve C in FIG. 3), the controller 10 turns off the semiconductor switch SW3 to turn off the electric double layer capacitor EDLC. The discharge is stopped, the step-up chopper is switched to the step-up control, the electric double layer capacitor EDLC is charged (curve Ck in Fig. 3), and the control is stopped in the charged state up to 1600V.

When the external line voltage is kept below the lower limit voltage (1200 V), and the terminal voltage of the electric double layer capacitor EDLC becomes lower than the external line voltage (time t5), the controller 10 turns on the semiconductor switch SW3, and the step-up voltage The semiconductor switch SW2 of the chopper 7 is switched to the switching control mode. Accordingly, the control device 10 increases the terminal voltage, continues to discharge, and suppresses the voltage drop of the external line voltage along with the power supply at the rectifier 6. With this discharge, the terminal voltage of the electric double layer capacitor EDLC decreases below the lower limit voltage (1200 V). By suppressing this voltage drop, when the external line voltage returns to the lower limit of 1200 V or more (time t6: curve D in FIG. 3), the controller 10 charges the electric double layer capacitor EDLC under the step-down control of the step-down chopper 7 ( The step-down control is stopped in the state of charge of waveform D 'of FIG. 3 to 1600V.

If the voltage drop of the external line continues and the terminal voltage decreases to the lowest voltage (500 V) by the discharge of the electric double layer capacitor EDLC (time t7), the controller 10 stops the control of the step-up chopper 7. When the driving operation of the electric vehicle ends (time t8) and the external line voltage returns to 1200 V or more (time t9: curve E in FIG. 3), the system charges the electric double layer capacitor EDLC (curve in FIG. 3). As shown in E ′).

Thus, the terminal voltage of the electric double layer capacitor EDLC is controlled in the range of 500 V to 1600 V.

That is, at the time of the voltage drop suppression means, such a system enables the electric double layer capacitor EDLC to be charged or discharged over a wide voltage range (500 V to 1600 V), compared to the conventional apparatus, and the capacity of the electric double layer capacitor EDLC. Even if it remains in the same state as this prior art system (without increasing the number of parallel elements), the amount of power that can be supplied for suppressing the voltage drop can be greatly increased.

In the illustrated embodiment, the DC / DC converter is composed of a step-up chopper and a discharge control switch. However, as long as it allows charging and discharging between a power storage medium such as an electric double layer capacitor EDLC and an external line, an equivalent working effect can be achieved by using a charging and discharging circuit having a different configuration from the illustrated embodiment. Can be.

The system according to the illustrated embodiment is provided for performing charge / discharge control such that, in the no-load state and the normal load state of the external line, the terminal voltage of the electric double layer capacitor is near the upper limit voltage of the rated voltage range of the external line. However, the system may be provided to control the terminal voltage of the electric double layer capacitor between the lower limit voltage and the upper limit voltage of the rated voltage range of the external line.

For example, the terminal voltage of the electric double layer capacitor is set to a middle value between the lower limit voltage and the upper limit voltage. From this state, the system operates to satisfy both functions of the voltage drop suppressing means and the regenerative power absorbing means. In addition, if the terminal voltage of the electric double layer capacitor is higher than the no-load voltage of the rectifier, the system allows the terminal voltage of the electric double layer capacitor to naturally decrease while maintaining the voltage balance of the entire external line, even if there is no retrograde driving vehicle. In addition, in a series of power regenerative operations in one or more vehicles, if the terminal voltage of the electric double layer capacitor is continuously increased, the system uses the current squeegeeing control of the electric vehicle to suppress the regenerative failure.

In the embodiment shown, the power storage medium comprises an electric double layer capacitor. Even using hybrid capacitors, large capacity capacitors, and / or accumulators as power storage media, equivalent effects and operation can be achieved. Moreover, although the example which controlled the semiconductor switch to arbitrary voltage was shown, providing a dead band to this arbitrary voltage can prevent chattering of a semiconductor switch.

The system according to the present invention can absorb regenerative power when the external line voltage exceeds the upper limit voltage of the rated voltage range, and suppress the voltage drop when the external line voltage becomes below the lower limit voltage of the rated voltage range.

In addition, the power storage device not only enables the charging and discharging of the electric double layer capacitors over a wider voltage range than the conventional device, but also regenerates the energy storage of the electric double layer capacitor equivalent to or more than the energy storage amount in the fully charged state of the conventional device. Absorption of power is possible. Thus, the system can satisfy both functions of the voltage drop suppressing means and the regenerative power absorbing means. When the terminal voltage of the electric double layer capacitor is above the no-load voltage of the rectifier, the system naturally reduces the terminal voltage of the electric double layer capacitor, along with the voltage balance of the entire external line system, even without a backing vehicle. If the terminal voltage of the electric double layer capacitor continues to rise by the continuous regenerative operation operation, the system can prevent the regenerative failure due to the use of the current squeegeeing control of the electric vehicle.

In addition, the amount of power that can be supplied can be significantly increased for suppressing the voltage drop without causing the system to be enlarged and the cost increased.

Claims (12)

A direct current power storage device comprising a direct current / direct current converter connected between a power storage medium and an external line of a direct current electric railway. The DC / DC converter, When the external line voltage exceeds the upper limit voltage of the rated voltage range of the external line, a conductive connection is formed between the external line and the power storage medium to charge or discharge the power storage medium, and the external line voltage Regenerative power control means for interrupting a discharge path from the electric power storage medium to the external line when the voltage falls below an upper limit voltage; And If the external line voltage is less than the lower limit voltage of the rated voltage range of the external line, and the terminal voltage of the power storage medium exceeds the external line voltage, the power storage while stepping down the terminal voltage of the power storage medium. When the medium is discharged in the direction of the external line, the external line voltage is less than the lower limit voltage, and the terminal voltage of the power storage medium is less than the external line voltage, while boosting the terminal voltage of the power storage medium. Voltage drop suppressing means for discharging the power storage medium in the external line direction; DC power storage device comprising a. The method of claim 1, When the upper limit voltage is exceeded by absorption of regenerative power from an electric vehicle, and the external line voltage rises due to the conduction of the electric power storage medium and the external line, the regenerative power control means squeezes a regenerative current of the electric vehicle. And the terminal voltage of the electric power storage medium is suppressed to a maximum voltage of the terminal voltage or less along with a regenerative current squeegeeing operation of the function. The method according to claim 1 or 2, The DC / DC converter, The non-loading of the external line, connecting the external line and the power storage medium, and charging the power storage medium until the terminal voltage of the power storage medium reaches the no-load voltage of the rectifier; DC power storage device. The method according to claim 1 or 2, The DC / DC converter, If the external line is equal to or greater than the lower limit voltage of the rated voltage range and the terminal voltage of the power storage medium is less than or equal to the upper limit voltage of the rated voltage range, the external line if the terminal voltage is less than the external line voltage. Means for charging the power storage medium from the external line while stepping down a voltage, and charging the power storage medium from the external line while boosting the external line voltage if the terminal voltage exceeds the external line voltage. The DC power storage device, characterized in that. The method according to claim 1 or 2, The direct current / direct current converter includes a discharge control switch that controls or blocks a current discharge from the power storage medium to the external line when the terminal voltage of the power storage medium exceeds the external line voltage. The DC power storage device. The method according to claim 1 or 2, The DC / DC converter includes a main circuit, The main circuit, A semiconductor switch SW1 provided in a direction of controlling a charging current flowing from the external line, the semiconductor switch SW1 including a first end and a second end connected to the external line, and a diode D1 in anti-parallel connection with the semiconductor switch SW1. High voltage side arm, A low voltage side arm provided in the direction of the semiconductor switch SW1 and including a semiconductor switch SW2 connected in series with the second end of the semiconductor switch SW1, and a diode D2 in anti-parallel connection with the semiconductor switch SW2; A booster chopper including a reactor including a first end and a second end connected to the second end of the semiconductor switch SW1; And A semiconductor switch SW3 provided between the second end of the reactor L and the power storage medium, and configured to control a discharge current from the power storage medium, and A discharge control switch including a diode D3 in anti-parallel with the semiconductor switch SW3; The DC power storage device comprising a. The method of claim 3, wherein The DC / DC converter, If the external line is equal to or greater than the lower limit voltage of the rated voltage range and the terminal voltage of the power storage medium is less than or equal to the upper limit voltage of the rated voltage range, the external line if the terminal voltage is less than the external line voltage. Means for charging the power storage medium from the external line while stepping down a voltage, and charging the power storage medium from the external line while boosting the external line voltage if the terminal voltage exceeds the external line voltage. The DC power storage device, characterized in that. The method of claim 3, wherein The direct current / direct current converter includes a discharge control switch that controls or blocks a current discharge from the power storage medium to the external line when the terminal voltage of the power storage medium exceeds the external line voltage. The DC power storage device. The method of claim 4, wherein The direct current / direct current converter includes a discharge control switch that controls or blocks a current discharge from the power storage medium to the external line when the terminal voltage of the power storage medium exceeds the external line voltage. The DC power storage device. The method of claim 3, wherein The DC / DC converter includes a main circuit, The main circuit, A semiconductor switch SW1 provided in a direction of controlling a charging current flowing from the external line, the semiconductor switch SW1 including a first end and a second end connected to the external line, and a diode D1 in anti-parallel connection with the semiconductor switch SW1. High voltage side arm, A low voltage side arm provided in the direction of the semiconductor switch SW1 and including a semiconductor switch SW2 connected in series with the second end of the semiconductor switch SW1, and a diode D2 in anti-parallel connection with the semiconductor switch SW2; A booster chopper including a reactor including a first end and a second end connected to the second end of the semiconductor switch SW1; And A semiconductor switch SW3 provided between the second end of the reactor L and the power storage medium, and configured to control a discharge current from the power storage medium, and A discharge control switch including a diode D3 in anti-parallel with the semiconductor switch SW3; The DC power storage device comprising a. The method of claim 4, wherein The DC / DC converter includes a main circuit, The main circuit, A semiconductor switch SW1 provided in a direction of controlling a charging current flowing from the external line, the semiconductor switch SW1 including a first end and a second end connected to the external line, and a diode D1 in anti-parallel connection with the semiconductor switch SW1. High voltage side arm, A low voltage side arm provided in the direction of the semiconductor switch SW1 and including a semiconductor switch SW2 connected in series with the second end of the semiconductor switch SW1, and a diode D2 in anti-parallel connection with the semiconductor switch SW2; A booster chopper including a reactor including a first end and a second end connected to the second end of the semiconductor switch SW1; And A semiconductor switch SW3 provided between the second end of the reactor L and the power storage medium, and configured to control a discharge current from the power storage medium, and A discharge control switch including a diode D3 in anti-parallel with the semiconductor switch SW3; The DC power storage device comprising a. The method of claim 5, The DC / DC converter includes a main circuit, The main circuit, A semiconductor switch SW1 provided in a direction of controlling a charging current flowing from the external line, the semiconductor switch SW1 including a first end and a second end connected to the external line, and a diode D1 in anti-parallel connection with the semiconductor switch SW1. High voltage side arm, A low voltage side arm provided in the direction of the semiconductor switch SW1 and including a semiconductor switch SW2 connected in series with the second end of the semiconductor switch SW1, and a diode D2 in anti-parallel connection with the semiconductor switch SW2; A booster chopper including a reactor including a first end and a second end connected to the second end of the semiconductor switch SW1; And A semiconductor switch SW3 provided between the second end of the reactor L and the power storage medium, and configured to control a discharge current from the power storage medium, and A discharge control switch including a diode D3 in anti-parallel with the semiconductor switch SW3; The DC power storage device comprising a.

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