JP2007210513A - Dc power storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DC power storage device, capable of restricting voltage fall of external wiring, absorbing regenerated power of an electric vehicle, and preventing loss of effect of regeneration of the electric vehicle without causing large-sizing or cost increase of a DC current storage device. <P>SOLUTION: A terminal voltage (stand-by voltage) of an electric double layer capacitor EDLC is set to be close to an upper limit value in a rated voltage range of the external wiring at no-load time and normal load time of an electromotive system. When the external wiring voltage exceeds the upper limit voltage, regenerative power is absorbed by the electric double layer capacitor, while simultaneously, the electric vehicle takes regenerative current restricting action to prevent the terminal voltage of the electric double layer capacitor from exceeding the maximum voltage (prevention of loss of effect of regeneration). When the external wiring voltage becomes lower than a lowest voltage of the rated voltage range, the external wire voltage is prevented from becoming lower than the lower limit of the rated voltage range by use of discharge power from the electric double layer capacitor by pressure dropping action and pressure boosting action of a pressure adjusting chopper (restriction of voltage fall). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a DC power storage device that is connected in parallel to an external line of a DC electric railway and supplies electric power during powering operation of an electric vehicle and absorbs electric power during regenerative operation. The present invention relates to a charge / discharge control method for a power storage medium for regenerative power absorption countermeasures and regenerative invalidation prevention countermeasures for electric vehicles.

  In a DC power system, substations in the secluded line are installed with a relatively long distance. For this reason, in an electric vehicle located at a point remote from the substation, the voltage drop of the outside line increases when a large current flows, such as when starting up, and the voltage at the punter point may become lower than the specified value. is expected. In order to compensate for this voltage drop, a power supply substation (DCVR) is installed or notch suppression is performed on the electric vehicle side.

  Also, in the secluded line area, when the electric vehicle is in a regenerative operation state, there is little opportunity to absorb this regenerative energy as powering power in other electric vehicles, so regenerative invalidation (electric braking is impossible) tends to occur on the electric vehicle side. . Even if the electric vehicle is in a regenerative operation state, even if it is not a quiet area, regenerative invalidation due to a rapid decrease in load occurs when another electric vehicle ends the power running state.

  In this regeneration invalidation, the electric vehicle side stops the regenerative operation and performs braking switching from the electric brake to the mechanical brake, but a braking delay occurs due to the transition time of the switching operation. Due to this braking delay, problems such as failure to stop the electric vehicle at a fixed point and sudden braking of the mechanical brakes, shortening the service life due to increased wear of the wheels and brake shoes remain. The following methods are available as measures for absorbing regenerative power to prevent regeneration and expiration.

(1) Power regeneration method for AC power source by inverter device As shown in FIG. 4A, the inverter device 2 and the inverter transformer 3 that use the DC power regenerated by the electric vehicle 1 as the DC power source on the outside line side. Is converted into AC power with controlled voltage and frequency, and regenerated on the AC power supply side.

  In the case of this method, an AC load that absorbs regenerative power is required, and a transformer, an AC circuit breaker, an inverter device, a DC circuit breaker, and the like are necessary, and the entire device becomes expensive.

(2) Power regeneration method for regenerative resistance device by chopper As shown in FIG. 4B, the DC power regenerated by the electric vehicle 1 is converted to DC power controlled by the chopper device 4, and this is regenerated. The resistance device 5 absorbs the heat.

  In the case of this method, since all of the regenerative power is absorbed by the resistance device, the regenerative power is not effectively used and a large resistance device is required. Further, ventilation equipment and heat radiation equipment for dissipating heat generated in the resistance device are necessary, and if a chopper or the like is included, the equipment becomes relatively expensive.

(3) Power regeneration method using DC power storage device As shown in FIG. 4C, a DC power storage device comprising a step-up / step-down chopper 7 and a DC power storage device 8 is installed on the DC side of the rectifier 6. When the external line voltage exceeds the upper limit of the rated voltage range due to the regenerative operation of the electric vehicle 1, the external line voltage is stepped down by the chopper 7, and the regenerative power is supplied as the charging current of the DC power storage device 8 from the external line through the chopper 7. Absorb (see, for example, Patent Document 1 and Patent Document 2).

  In this method, when the electric vehicle runs below the lower limit of the rated voltage range of the outside line due to power running operation, the outside line voltage is boosted and controlled by the chopper 7 and the power is supplied from the DC power storage device 8 to the outside line side through the chopper 7. It can also be used for voltage drop countermeasures. Further, it is possible to level the load as seen from the AC power supply side.

  FIG. 5 shows a main circuit configuration of the DC power storage device. The step-up / step-down chopper 7 includes a semiconductor switch SW1 having one end connected to the external line in a direction in which the charging current flowing from the external line can be controlled, a high-voltage side arm including a diode D1 connected in reverse parallel to the semiconductor switch SW1, and the semiconductor switch SW1 and the current The low-voltage side arm composed of the semiconductor switch SW2 connected in series with the other end of the semiconductor switch SW1 and the diode D2 connected in reverse parallel to the semiconductor switch SW2, and one end at the other end of the semiconductor switch SW1. And a reactor L having the other end connected to the electric double layer capacitor EDLC.

  In this configuration, as shown in FIG. 6, when the external line voltage exceeds the upper limit of the rated voltage range in the regenerative operation of the electric vehicle 1, control is performed to step down the external line voltage by the step-up / step-down chopper. That is, the switch SW1 is switched, and the charging current flows from the outside line through SW1 → L to the EDLC during the ON period, and the charging current flows from the reactor L to the EDLC through the EDLC → D2 during the OFF period. The regenerative power is regenerated as EDLC charging power.

  In addition, as shown in FIG. 6, when the outside line voltage falls below the lower limit of the rated voltage range in the power running operation of the electric vehicle 1, the outside line voltage is controlled to be boosted by the step-up / down chopper. That is, the switch SW2 is operated as a chopper, a short-circuit current flows from the EDLC to the EDLC through the L → SW2 during the ON period, and the electromagnetic energy is accumulated in the reactor L, and during the OFF period, the electromagnetic energy is stored in the path from the EDLC to the reactor L → D1. A discharge current is passed through the outside line to suppress the voltage drop across the outside line.

The DC power storage device 8 uses a storage battery in addition to the electric double layer capacitor. When this storage battery is used, it is excellent in long-term energy accumulation and accumulation amount, but it is inferior in quick charge / discharge characteristics, delay in charging such as regenerative power with fast start-up, electric car start / acceleration etc. There is a delay in the discharge following the sudden load change, which may cause a sudden change in external line voltage and regenerative expiration. On the other hand, when an electric double layer capacitor is used, it has excellent rapid charge / discharge performance and can respond to regenerative power absorption from an electric vehicle and sudden load change.
JP 2000-233669 A JP 2001-260718 A

(First issue)
When a DC power storage device composed of an electric double layer capacitor and a step-up / down chopper is used to suppress the voltage drop of the external line, in the configuration of FIG. 5, the terminal voltage (standby voltage) of the electric double layer capacitor is set to the external line voltage. A value lower than the lower limit voltage of the rated voltage range is set to prevent discharge from the electric double layer capacitor to the outside line through the reactor L → diode D1. Also, in order to maximize the amount of electric power that can be supplied from the electric double layer capacitor (accumulated electric energy) when an external voltage drop occurs, the terminal voltage of the electric double layer capacitor is close to the lower limit voltage of the rated voltage range of the external line voltage. Keep it up.

  For example, in the 1500V system, when power is supplied from an electric double layer capacitor at an external voltage of 1200V (lower limit of the rated voltage range of the external voltage), the terminal voltage (standby voltage) of the electric double layer capacitor is set to 1200V or less. The voltage drop of the outside line voltage is suppressed by the boost control by the buck-boost chopper from the double layer capacitor.

  As described above, in the configuration of FIG. 5, the terminal voltage of the electric double layer capacitor is set lower than the lower limit voltage of the rated voltage range of the external line voltage, so that the stored electric energy of the electric double layer capacitor is limited. To increase the amount of stored electric power, it is conceivable to increase the number of electric double layer capacitors in parallel and increase the controllable current capacity of the buck-boost chopper, but this leads to an increase in the size and cost of the DC power storage device. .

(Second problem)
In the case of performing voltage drop suppression and regenerative power absorption using a DC power storage device, in Patent Document 1 and Patent Document 2, when the external line voltage is lowered, the electric double layer capacitor EDLC terminal voltage is boosted and controlled by the buck-boost chopper. The voltage drop is suppressed, and when the external line voltage rises, the external line voltage is stepped down by the step-up / down chopper to absorb the regenerative power. In this case, in order to be able to cope with both voltage drop countermeasures and regenerative power absorption countermeasures, the terminal voltage (standby voltage) of the electric double layer capacitor is used during discharge operation for suppressing voltage drop and for regenerative power absorption. Although the same voltage range is used during charging operation, full voltage charging with a high terminal voltage of the electric double layer capacitor can suppress more voltage drops when voltage drop countermeasures are taken, and the electric double layer capacitor can be suppressed during regenerative power absorption. More regenerative power can be absorbed when the terminal voltage is lower and the charging power is lower. From these, in order to use the amount of discharge power supplied and the amount of charge power to be absorbed in the same voltage range, the amount of power that can simultaneously support both functions of voltage drop countermeasures and regenerative power absorption countermeasures is the amount of power at the time of full charge. And it is less than the amount of power at the time of the minimum charge, and both functions cannot be satisfied simultaneously.

  For this reason, in order to secure the charge / discharge power amount that can cope with both functions of the voltage drop countermeasure and the regenerative power absorption countermeasure, as in the first problem, the number of electric double layer capacitors is increased in parallel. This increases the controllable current capacity of the step-up / down chopper, which increases the size and cost of the DC power storage device.

  In order to increase the amount of charge and discharge power, two DC power storage devices with a low terminal voltage (standby voltage) as a countermeasure for voltage drop and two DC power storage devices with a high terminal voltage as a countermeasure for regenerative power absorption Although it is conceivable to adopt an apparatus configuration, this cannot solve the problems of increasing the size and cost of the equipment.

(Third issue)
In the case of absorbing regenerative power using a DC power storage device, in Patent Document 1 and Patent Document 2, if a power storage medium such as an electric double layer capacitor is fully charged, the regenerative power cannot be absorbed and the electric vehicle is When regenerative operation is performed, regenerative invalidation occurs. For this reason, it becomes necessary to install a resistance device for absorbing regenerative power. In addition, since the electric power storage medium remains fully charged until an electric vehicle that is in power running appears, if the regenerative operation of the electric vehicle continues, regenerative invalidation occurs continuously.

  The purpose of the present invention is to increase the sum of the amount of power supplied to the outside line and the amount of absorbed power and to suppress more voltage drops on the outside line without increasing the size and cost of the DC power storage device. Another object of the present invention is to provide a DC power storage device that can cope with regenerative power absorption of an electric vehicle and can prevent regenerative expiration of the electric vehicle.

In order to solve the above-described problems, the present invention provides a DC power storage device in which a DC / DC converter such as a step-up / step-down chopper is provided between a power storage medium such as an electric double layer capacitor and an external line, and the external line is not loaded Since the outside line voltage rises to the rectifier no-load voltage exceeding the upper limit voltage of the rated voltage range, the conduction between the outside line and the power storage medium is controlled by the conduction control of the DC / DC converter when the upper limit voltage is exceeded. Then, charge the terminal voltage of the power storage medium to the rectifier no-load voltage,
In order to absorb regenerative power, when the external line voltage (the voltage at the terminal connecting the buck-boost chopper and the external line, the same shall apply hereinafter) exceeds the upper limit voltage, the continuity control of the DC / DC converter device controls the connection between the external line and the power storage medium. Is used to absorb the regenerative power from the electric vehicle in regenerative operation as the charging power of the power storage medium, and to increase the pant point voltage of the electric vehicle that performs regenerative operation, use the regenerative current narrowing function of the electric vehicle To prevent the regeneration of electric cars from being revoked,
For voltage drop countermeasures, when the external line voltage falls below the lower limit voltage, the terminal voltage of the power storage medium is stepped down or boosted, and the external line voltage is held at the lower limit voltage by discharging from the power storage medium to the external line. Thus, it is characterized by the following configuration.

(1) A DC power storage device in which a DC / DC converter is provided between a power storage medium and an outside line of a DC electric railway,
The DC / DC converter is
When the outside line voltage exceeds the upper limit voltage of the rated voltage range of the outside line, the power storage medium is charged / discharged by conducting between the outside line and the power storage medium, and when the outside line voltage falls below the upper limit voltage, Regenerative power control means for cutting off between the external line and the power storage medium;
When the external line voltage is lower than the lower limit voltage of the rated voltage range of the external line and the terminal voltage of the power storage medium is higher than the external line voltage, the power storage medium is discharged from the power storage medium to the outside line while stepping down the terminal voltage. When the external line voltage is lower than the lower limit voltage and the terminal voltage of the power storage medium is lower than the external line voltage, a voltage drop that discharges from the power storage medium to the external line side while boosting the terminal voltage of the power storage medium Suppression means;
It is provided with.

  (2) The regenerative power absorbing means has a function of narrowing the regenerative current of the electric vehicle when the external voltage exceeds the upper limit voltage due to absorption of the regenerative power from the electric vehicle and the external line voltage increases due to conduction between the power storage medium and the external line. The terminal voltage of the power storage medium is suppressed to be equal to or lower than the maximum voltage of the terminal voltage by cooperating with the regenerative current narrowing-down operation.

  (3) The DC / DC converter is characterized in that when an external line is not loaded, the external line and the power storage medium are electrically connected, and the terminal voltage of the power storage medium is charged to the no-load voltage of the rectifier. To do.

  (4) The DC / DC converter reduces the external line voltage when the external line is equal to or higher than the lower limit voltage and the terminal voltage of the power storage medium is equal to or lower than the upper limit voltage of the external line. The power storage medium is charged from the outside line side, and when the terminal voltage is higher than the outside line voltage, the power storage medium is charged from the outside line side while boosting the outside line voltage.

  (5) The DC / DC converter includes a discharge control switch that controls or cuts off a discharge current from the power storage medium to the outside line when the terminal voltage of the power storage medium is higher than the outside line voltage. Features.

(6) The main circuit of the DC / DC converter is as follows:
The semiconductor switch SW1 having one end connected to the external line in a direction in which the charging current flowing from the external line can be controlled, and the high-voltage side arm composed of the diode D1 connected in reverse parallel to the semiconductor switch SW1, and the semiconductor switch SW1 have the same direction in which the current can be controlled. And a low-voltage side arm comprising a semiconductor switch SW2 connected in series with the other end of the semiconductor switch SW1, a diode D2 connected in reverse parallel to the semiconductor switch SW2, and a reactor L having one end connected to the other end of the semiconductor switch SW1. A buck-boost chopper,
Discharge control comprising a semiconductor switch SW3 connected between the other end of the reactor L and the power storage medium and capable of controlling a discharge current from the power storage medium, and a diode D3 connected in reverse parallel to the semiconductor switch SW3 A switch,
It is provided with.

  As described above, according to the present invention, regenerative power is absorbed when the outside line voltage exceeds the upper limit voltage of the rated voltage range, and voltage drop is suppressed when the outside line voltage falls below the lower limit voltage of the rated voltage range. Can do.

  In addition, compared to conventional devices, electric double layer capacitors can be charged and discharged over a wide voltage range, so regenerative power can be absorbed while the amount of power stored in the electric double layer capacitor is equal to or greater than the full charge of conventional devices. Therefore, if both the functions of voltage drop countermeasures and regenerative power absorption countermeasures are satisfied and the terminal voltage of the electric double layer capacitor exceeds the no-load voltage of the rectifier, even if there is no power running vehicle, The electric double layer capacitor terminal voltage naturally drops while maintaining the overall voltage balance, and even if the electric vehicle performing regenerative operation continues to rise, the electric double layer capacitor terminal voltage continues to be controlled. Due to this, regenerative revocation does not occur.

  In addition, the amount of power that can be supplied for suppressing voltage drop can be significantly increased without increasing the size and cost of the DC power storage device.

  FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention. The main circuit configuration different from FIG. 5 is connected between the other end of a reactor L and the power storage medium, and the power storage medium Is provided with a discharge control switch 9 comprising a semiconductor switch SW3 in a direction capable of controlling the discharge current and a diode D3 connected in antiparallel with the semiconductor switch SW3.

  The control device 10 is provided with a switching and conduction / cutoff control function of the discharge control switch 9 in addition to the step-up / step-down control function of the step-up / step-down chopper 7, and the following control is performed based on various voltage condition settings and voltage detection signal monitoring. Means are provided.

  In the description and drawings of the present embodiment, the DC side of the rectifier of the feeder substation, the feeder output side of the power storage device, the feeder, the overhead wire, and the trolley wire will be collectively referred to as an external line.

  (A) Use an electric double layer capacitor whose maximum charging voltage is higher than the maximum voltage expected to be generated on the external line due to regenerative power from the electric vehicle, and when the external line is not loaded, the upper limit of the rated voltage range of the external line The rectifier is charged to a no-load voltage exceeding.

  (B) Regenerative power absorption countermeasures and regenerative invalidation prevention countermeasures are implemented by turning on the switches SW1 and SW3 in order to conduct between the external line and the electric double layer capacitor when the external line voltage exceeds the upper limit voltage of the rated voltage range. (Conduction) control and regenerative power is absorbed as charging power to the electric double layer capacitor, and this power absorption prevents regenerative invalidation of the electric vehicle due to a sudden rise in external line voltage and charging to the electric double layer capacitor The regenerative power absorbed by the electric double layer capacitor can be effectively used by discharging from the electric double layer capacitor to the electric vehicle that performs power running.

  When the external line voltage continues to rise due to this power absorption and further increases, the terminal voltage and the external line of the electric double layer capacitor are cooperated with the regenerative current narrowing operation by the regenerative current narrowing function of the electric vehicle. The voltage is coordinated so as not to exceed the maximum voltage, and even in this state, regenerative current narrowing control of the electric vehicle prevents regenerative invalidation.

  (C) As a countermeasure for voltage drop, when the external line voltage is lower than the lower limit voltage of the rated voltage range and the terminal voltage of the electric double layer capacitor is higher than the external line voltage, the semiconductor switch SW3 of the discharge control switch 9 is switched. The terminal voltage of the electric double layer capacitor is stepped down to discharge from the electric double layer capacitor to the outside line side, and this discharge keeps the outside line voltage at or above the lower limit voltage of the rated voltage range. Further, when the terminal voltage of the electric double layer capacitor becomes lower than the external voltage due to this discharge, the semiconductor switch SW3 is turned on (conduction) and the semiconductor switch SW2 of the step-up / down chopper 7 is switched to the switching operation. The terminal voltage of the multi-layer capacitor is boosted to continue the discharge, and the outside line voltage is maintained at or above the lower limit voltage of the rated voltage range.

  In addition, the narrowing down of the regenerative current by the electric vehicle is equipped with an existing electric vehicle, and the punter point voltage of the electric vehicle is monitored. When this voltage exceeds a specified value, the regenerative current is reduced from 100% accordingly. By narrowing down to 0%, it is possible to prevent an excessive increase in the punter point voltage. Generally, in a DC1500V electric vehicle, as shown in FIG. 2, when the punter voltage is DC1600V or less, the aperture ratio is 1.0 (diaphragm amount 0%), and when DC1800V or more, the aperture ratio is 0 (diaphragm amount 100%). In the range from 1600V to 1800V, the aperture ratio is linearly reduced to 0 in proportion to the voltage to suppress the regenerative current. Excess braking energy due to the narrowing of the regenerative current is absorbed by the mechanical brake.

  Hereinafter, a specific example in the case of applying the control operation for the voltage drop countermeasure, the regenerative power absorption countermeasure, and the regeneration invalidation prevention countermeasure to the 1500 V system will be described in detail.

(1) Operating condition of feeder system The rated voltage range of the outside line is DC 1600V (upper limit) to 1200V (lower limit), and the no-load voltage of the rectifier 6 is DC 1620V. The charging maximum voltage of the electric double layer capacitor EDLC is set to DC 1800V.

(2) At no load The control device 10 controls the semiconductor switch SW1 of the step-up / step-down chopper 7 to be on (conductive) when the external voltage is 1600 V or more, and when the electric double layer capacitor EDLC is less than 1600 V, the rectifier of the feeder substation The electric double layer capacitor EDLC is charged from 6, and the charging voltage is charged to 1620 V, which is the no-load voltage of the rectifier 6.

(3) During normal load The control device 10 supplies power from the electric double layer capacitor EDLC in parallel with the power supply from the rectifier 6 when the electric vehicle is powered and the external line voltage drops below 1620 V of the rectifier no-load voltage. Since the external line voltage and the terminal voltage of the electric double layer capacitor EDLC are in an equilibrium state, the discharge control switch 9 is turned on (conductive). However, the discharge control switch 9 is turned off when the outside line voltage falls below 1600V (but 1200V or more), and power running power is supplied only from the rectifier 6 within the rated voltage range of the outside line.

(4) Regenerative power absorption countermeasure and regenerative invalidation prevention countermeasure As shown in FIG. 3, when the external line voltage rises due to the regenerative power from the electric vehicle and the external line voltage exceeds 1600 V, which is the upper limit of the rated voltage range (time t <b> 1), the control device 10 performs the on (conduction) control of the semiconductor switch SW <b> 1 of the buck-boost chopper 7 and the on control of the semiconductor switch SW <b> 3. At this time, since the terminal voltage of the electric double layer capacitor EDLC is also 1600 V, a charging current is caused to flow from the outside line side to the electric double layer capacitor EDLC by ON control of the semiconductor switch SW1, and regenerative power is absorbed by the charging.

  At this time, the terminal voltage of the electric double layer capacitor EDLC rises due to the regenerative power of the electric car, and the punter point voltage of the electric car also rises. Also decreases. In addition, when the regenerative operation of the electric vehicle ends (when the increase in the external line voltage ends and the voltage decreases toward the rectifier no-load voltage 1620V, the waveform A in FIG. 3), the semiconductor switch SW3 is now turned on. Therefore, the external line tries to maintain a voltage balance with the external line voltage in the surrounding section, so that the terminal voltage of the electric double layer capacitor EDLC naturally decreases, and then settles to 1620 V of the rectifier no-load voltage if there is no load. If there is an electric vehicle that is in power running when the upper limit voltage is exceeded, electric power is supplied from the electric double layer capacitor EDLC to the electric vehicle up to the rectifier no-load voltage. The double layer capacitor EDLC supplies electric power to the electric vehicle in parallel, and the outside line voltage is settled below the upper limit voltage by the electric vehicle that is powered running (waveform B in FIG. 3).

  Also, when the terminal voltage of the electric double layer capacitor becomes lower than the rated voltage upper limit (1600V) of the external line, the discharge from the electric double layer capacitor EDLC is stopped by the off (cutoff) control of the semiconductor switch SW3. Only power is supplied 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 of 1800V (time t2), the regenerative current from the electric vehicle becomes zero by the current narrowing operation, and the outside line voltage is also the rated voltage Although it exceeds the upper limit (1600V) and temporarily becomes 1800V, since the regenerative current is zero, there is no further increase in voltage and regenerative invalidation is prevented.

  Therefore, in the regenerative power absorption measure and regenerative invalidation preventive measure, the outside line voltage may temporarily exceed the rated voltage upper limit (1600V), but eventually settles below the rectifier no-load voltage or the rated voltage upper limit, and the electric double layer The terminal voltage of the capacitor EDLC is controlled in the range of 1600V to 1800V.

(5) Voltage drop countermeasures As shown in FIG. 3, when the electric vehicle is in power running and the outside line voltage falls below the lower limit (1200V) of the rated voltage range (time t3), the control device 10 switches the semiconductor switch SW3. By controlling, the terminal voltage of the electric double layer capacitor EDLC is stepped down to start discharging from the electric double layer capacitor EDLC through the reactor L and the diode D1, and the voltage drop is reduced in cooperation with the power supply from the rectifier 6 side. Suppress. When the voltage drop suppresses the outside line voltage to return to the lower limit of 1200 V or more (time t4: waveform C in FIG. 3), the control device 10 controls the semiconductor switch SW3 to be off to stop the discharge from the electric double layer capacitor EDLC. Then, the step-up / step-down chopper is switched to boost control to charge the electric double layer capacitor EDLC (waveform C ′ in FIG. 3), and the control is stopped by charging up to 1600V.

  Further, when the external line voltage does not return to the lower limit voltage of 1200 V or higher and the voltage drop is continuously suppressed, and the terminal voltage of the electric double layer capacitor EDLC becomes lower than the external line voltage (time t5), the control device 10 switches the semiconductor switch SW3. For the on (conduction) control, the semiconductor switch SW2 of the step-up / step-down chopper 7 is switched to a switching operation, the discharge is continued by boosting the terminal voltage, and the external line voltage is cooperated with the power supply from the rectifier 6 side. The voltage drop is suppressed. With this discharge, the terminal voltage of the electric double layer capacitor EDLC is lowered to the lower limit voltage (1200 V) or less. When the external voltage returns to the lower limit of 1200 V or more due to this voltage drop suppression (time t6: waveform D in FIG. 3), the control device 10 charges the electric double layer capacitor EDLC by the step-down control of the step-up / down chopper 7 (FIG. No. 3 waveform D ′) The step-down control is stopped by charging up to 1600V.

  When the voltage drop of the outer line continues and the terminal voltage reaches the minimum voltage of 500 V due to the discharge of the electric double layer capacitor EDLC (time t7), the control device 10 stops the control of the step-up / step-down chopper. When the power running of the electric vehicle ends (time t8) and the outside line voltage returns to 1200 V or more (time t9: waveform E in FIG. 3), the electric double layer capacitor EDLC is charged (waveform E ′ in FIG. 3).

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

  That is, the electric double layer capacitor EDLC can be charged / discharged in a wider voltage range (500V to 1600V) than the conventional device when voltage drop countermeasures are taken, and the electric double layer capacitor EDLC has the same capacity (the number of parallel devices) as that of the conventional device. Even without increasing the power), the amount of power that can be supplied to suppress the voltage drop can be greatly increased.

  In the embodiment, the case where the DC / DC converter is configured by the step-up / step-down chopper and the discharge control switch has been described. However, the charging / discharging of the electric power between the electric double layer capacitor EDLC and the external line is enabled. An equivalent effect can be obtained by using a DC / DC converter having a charge / discharge circuit configuration.

  In the embodiment, the case where the charge / discharge control is performed so that the terminal voltage of the electric double layer capacitor is close to the upper limit voltage of the rated voltage range of the external line at the time of no load and normal load of the external line is shown. The terminal voltage of the multilayer capacitor may be charged and discharged within the range of 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 an intermediate value between the lower limit voltage and the upper limit voltage, and from this state, both the voltage drop countermeasure and the regenerative power absorption countermeasure are satisfied, and the terminal voltage of the electric double layer capacitor is a rectifier. Even if there is no power running vehicle, the terminal voltage of the electric double layer capacitor is reduced naturally while balancing the voltage of the entire outside line, and the regenerative electric vehicle continues to be an electric double layer. When the capacitor continues to rise, regenerative invalidation is prevented by current throttle control of the electric vehicle.

  Moreover, although the case where an electric double layer capacitor was used as an electric power storage medium was shown in embodiment, even if it uses a hybrid capacitor, a large capacity capacitor, and a storage battery, an equivalent effect can be obtained. Furthermore, although the example which controls a semiconductor switch by arbitrary voltages was shown, it cannot be overemphasized that chattering of a semiconductor switch can be prevented by providing a dead zone in this arbitrary voltage.

The circuit block diagram of the direct-current power storage device which shows embodiment of this invention. The figure which shows the example of the regeneration electric current narrowing characteristic of an electric vehicle. The operation | movement waveform diagram of the regeneration invalidation prevention of an electric vehicle and voltage drop suppression in embodiment. The figure which shows the conventional electric power regeneration system. The main circuit block diagram of the conventional DC power storage device. Operation waveform diagram of regeneration invalidation prevention and voltage drop suppression of electric vehicle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric vehicle 6 Rectifier 7 Buck-boost chopper 8 Electric double layer capacitor 9 Discharge control switch SW1-SW3 Semiconductor switch D1-D3 Diode L Reactor

Claims (6)

A DC power storage device provided with a DC / DC converter between the power storage medium and the outside line of the DC electric railway,
The DC / DC converter is
When the outside line voltage exceeds the upper limit voltage of the rated voltage range of the outside line, the power storage medium is charged / discharged by conducting between the outside line and the power storage medium, and when the outside line voltage falls below the upper limit voltage, Regenerative power control means for cutting off between the external line and the power storage medium;
When the external line voltage is lower than the lower limit voltage of the rated voltage range of the external line and the terminal voltage of the power storage medium is higher than the external line voltage, the power storage medium is discharged from the power storage medium to the outside line while stepping down the terminal voltage. When the external line voltage is lower than the lower limit voltage and the terminal voltage of the power storage medium is lower than the external line voltage, a voltage drop that discharges from the power storage medium to the external line side while boosting the terminal voltage of the power storage medium Suppression means;
A direct-current power storage device comprising:   The regenerative power absorbing means exceeds the upper limit voltage due to absorption of regenerative power from the electric vehicle, and when the external line voltage rises due to conduction between the power storage medium and the external line, the regenerative current by the regenerative current narrowing function of the electric vehicle The DC power storage device according to claim 1, wherein the terminal voltage of the power storage medium is suppressed to be equal to or lower than a maximum voltage of the terminal voltage in cooperation with the narrowing-down operation.   The DC / DC converter is configured to conduct between the external line and the power storage medium when no external line is loaded, and charge the terminal voltage of the power storage medium to the no-load voltage of the rectifier. The direct-current power storage device according to 1 or 2.   In the DC / DC converter, when the external line is equal to or higher than the lower limit voltage and the terminal voltage of the power storage medium is equal to or lower than the upper limit voltage of the external line, when the terminal voltage is lower than the external line voltage, The power storage medium is charged from the outside line, and when the terminal voltage is higher than the outside line voltage, the power storage medium is charged from the outside line side while boosting the outside line voltage. The direct-current power storage device described.   The DC / DC converter includes a discharge control switch that controls or cuts off a discharge current from the power storage medium to the outside line when a terminal voltage of the power storage medium is higher than an outside line voltage. The direct-current power storage device according to claim 1. The main circuit of the DC / DC converter is
The semiconductor switch SW1 having one end connected to the external line in a direction in which the charging current flowing from the external line can be controlled, and the high-voltage side arm composed of the diode D1 connected in reverse parallel to the semiconductor switch SW1, and the semiconductor switch SW1 have the same direction in which the current can be controlled. And a low-voltage side arm comprising a semiconductor switch SW2 connected in series with the other end of the semiconductor switch SW1, a diode D2 connected in reverse parallel to the semiconductor switch SW2, and a reactor L having one end connected to the other end of the semiconductor switch SW1. A buck-boost chopper,
Discharge control comprising a semiconductor switch SW3 connected between the other end of the reactor L and the power storage medium and capable of controlling a discharge current from the power storage medium, and a diode D3 connected in reverse parallel to the semiconductor switch SW3 A switch,
The DC power storage device according to claim 1, further comprising:

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