JP5605135B2 - Self-propelled transport system using a capacitor and secondary battery as power source - Google Patents

Description

  The present invention includes a capacitor and a secondary battery in a self-propelled carrier that moves along a predetermined path and conveys a conveyed product, and uses the power charged in the self-propelled carrier to drive the self-propelled carrier. It is about the system.

The automatic transport vehicle is equipped with an electric motor for driving the driving wheel, its drive control device, and an electric double layer capacitor as a driving power source, and the electric double layer capacitor is charged from the charging power source of the charging station installed at an appropriate position in the factory. There is a self-propelled conveyance system using an electric double layer capacitor as a power source that moves an automatic conveyance vehicle by supplying electric power to a drive control device and driving an electric motor (see, for example, FIGS. 1 and 4 of Patent Document 1). In some cases, a lead secondary battery connected in parallel with the electric double layer capacitor is used as an auxiliary energy source for the electric double layer capacitor (see FIG. 2 of Patent Document 1).
In addition, an automatic motor for driving the driving wheel to the automatic guided vehicle, its drive control device, a battery and a capacitor connected in parallel to the battery, from a charging power source (power feeding device) of a charging station installed at an appropriate position in the factory There is a battery that charges a battery and a capacitor, and completes charging at the time of completion of charging of the capacitor excellent in rapid charge / discharge characteristics to release the restraint of the automatic guided vehicle (for example, see Patent Document 2).

JP-A-7-163016 (FIGS. 1-2 and 4) JP 2008-137451 A (FIG. 1)

In a self-propelled transport system using a capacitor as a power source, if the number of self-propelled carriers is larger than the number of charging stations and the line is stopped during a holiday (for example, two days that are weekly holidays), this stop There is a self-propelled carrier that waits at a place other than the charging station during the period. Thus, when the self-propelled carrier waiting in a place other than the charging station is restarted at the end of the holiday, the capacitor has a large amount of spontaneous discharge and the standby power during the stop period causes the remaining voltage of the capacitor to be less than the rated value. The operation may not be resumed due to battery exhaustion.
As measures against such battery exhaustion, it is conceivable to install a large number of charging stations so that the number of charging stations matches the number of self-propelled carriers, or to increase the capacity of the capacitor. However, the cost increases, and the latter measure increases the cost and the volume and weight of the capacitor. Therefore, any of these measures is not suitable for practical use.

As described above, Patent Document 2 discloses a configuration in which a battery and a capacitor are connected in parallel, so that charging of the battery and the capacitor is completed when charging of the capacitor is completed. Charging from the charging power supply (power supply device) only during the stop time of the self-propelled carrier, and charging from the capacitor to the battery when the voltage of the battery drops when the self-propelled carrier moves I have to.
Here, when charging from the capacitor to the battery with the configuration as in Patent Document 2, the upper and lower limit voltages of the charging voltage set in consideration of the effect on the lifetime are restricted, and constant voltage charging is basically used. In the charging of the battery, the voltage of the capacitor decreases as the charging proceeds. Therefore, the amount that can be charged from the capacitor to the battery becomes very small, and the energy of the capacitor cannot be effectively used.

Therefore, in the configuration in which the battery and the capacitor are connected in parallel as in Patent Document 2, the battery is the main power source, and the charging from the charging power source (power supply device) is completed at the time of completion of charging of the capacitor having excellent rapid charge / discharge characteristics. It is necessary to select a battery with a large capacity in consideration of the short charging time for the battery to complete the process, the very small amount that can be charged from the capacitor to the battery as described above, and the prevention of running out of the battery. Therefore, the weight and cost increase.
In addition, since the battery is the main power source, the charge / discharge time of the battery naturally increases, and the battery can be used only for a short time from the charge / discharge cycle life (normally about 500 times at a discharge depth of 50%).
Furthermore, as described above, Patent Document 1 discloses a configuration using a lead secondary battery connected in parallel with an electric double layer capacitor as an auxiliary energy source of the electric double layer capacitor (see FIG. 2 and paragraph [0014]). ), How to charge the electric double layer capacitor and the lead secondary battery and how to use the charged electric power is unclear, and no practical consideration has been made.

In order to solve such a problem, the inventors of the present application provide a bidirectional DC-DC converter connected between the electric double layer capacitor and the drive control device, and between the electric double layer capacitor and the drive control device. located on the output side of the bidirectional DC-DC converter, the output side via the switch is connected, a secondary battery charger for charging said secondary battery, wherein both the output voltage of the electric double layer capacitor When the output voltage of the bidirectional DC-DC converter is equal to or higher than the output voltage, the switch is turned off. When the output voltage of the electric double layer capacitor is lower than the output voltage of the bidirectional DC-DC converter, the switch is turned on. When the voltage on the output side of the bidirectional DC-DC converter is equal to or higher than the regeneration start setting voltage, the internal circuit of the bidirectional DC-DC converter is An invention is made about a self-propelled conveyance system including a control circuit that switches to the power side and switches the internal circuit to the power running side when the voltage on the output side of the bidirectional DC-DC converter is equal to or lower than the regeneration completion set voltage. (See Japanese Patent Application No. 2010-174977. Hereinafter, it will be referred to as “prior invention”).

According to the prior invention, the battery life is comparatively long and the increase in weight and cost can be suppressed without causing the battery to run out at the time of resuming operation such as the end of the holiday, and between the electric double layer capacitor and the drive control device. Since the bidirectional DC-DC converter is connected to the battery, the regenerative energy, which was conventionally converted into heat energy by the regenerative resistor unit and stored, is stored in the electric double layer capacitor via the bidirectional DC-DC converter. Can be reused to eliminate waste of energy.
However, although regenerative energy can be stored, the stopping position of the self-propelled carrier may vary, for example, by about 200 to 300 mm, so there is room for improvement from the viewpoint of improving the stopping accuracy of the self-propelled carrier. It was.

  Accordingly, in view of the above-described situation, the present invention intends to solve a capacitor and a secondary battery that can store and reuse regenerative energy and reduce variations in stopping accuracy of a self-propelled carrier. The point is to provide a self-propelled transport system powered by the power.

  The inventor of the present application conducted experiments and studies on the case where the stopping accuracy of the self-propelled carrier varies, and the state of the switch when storing regenerative energy generated when the motor decelerates to a stop, that is, the switch is off. Thus, it is found that there is a large variation in stopping accuracy between when the capacitor is operated as a power source and when the switch is on and the secondary battery is operated as a power source. It came to be completed.

In order to solve the above problems, a self-propelled conveyance system using a capacitor and a secondary battery as a power source according to the present invention is provided with a motor and its drive in a self-propelled carrier that moves along a predetermined path and conveys a conveyed item. A control device, a capacitor and a secondary battery as a power source for driving the motor, and a power receiver connected to the capacitor, and a power feeder and a charge electrically connected to the power receiver in a charging station installed at a predetermined position Power supply for the capacitor and the secondary battery is supplied to the drive control device to drive the motor, and the self-propelled carrier is moved by using the capacitor and the secondary battery as a power source. A self-propelled transport system comprising a bidirectional DC-DC converter connected between the capacitor and the drive control device, the capacitor and the drive Located between the control device, on the output side of the bidirectional DC-DC converter, the output side via the switch is connected, a secondary battery charger for charging the secondary battery, the output voltage of the capacitor is the The switch is turned off when the output voltage of the bidirectional DC-DC converter is equal to or higher than a predetermined threshold value, and the switch is turned off when the output voltage of the capacitor is lower than the output voltage of the bidirectional DC-DC converter or the predetermined threshold value. And switching the internal circuit of the bidirectional DC-DC converter to the regeneration side when the voltage on the output side of the bidirectional DC-DC converter is equal to or higher than the regeneration start set voltage, and the bidirectional DC-DC converter A control circuit for switching the internal circuit to the power running side when the voltage on the output side is equal to or lower than the regeneration completion set voltage, the switch and the secondary Connected between the pond, from said secondary battery side flowing current to the drive control apparatus, and a rectifying means passes no current is in the opposite direction, by said rectifying means, said switch is turned off Occurs when the motor decelerates to a stop when the motor is driven using the capacitor as a power source or when the motor is driven using the secondary battery as a power source when the switch is on. The regenerative energy to be stored is stored only in the capacitor .

According to such a configuration, when the voltage on the output side of the bidirectional DC-DC converter is equal to or higher than the regeneration start setting voltage, the internal circuit of the bidirectional DC-DC converter is switched to the regeneration side, and the bidirectional DC-DC converter When the output side voltage is below the regeneration completion set voltage, the internal circuit is switched to the power running side, so power is supplied from the electric double layer capacitor to the drive control device via the bidirectional DC-DC converter during power running operation. When regenerative electric power is generated, such as when the motor decelerates to a stop, the regenerative energy can be stored in the electric double layer capacitor via the bidirectional DC-DC converter and reused.
In addition, since a rectifier is connected between the switch and the secondary battery to pass current from the secondary battery side to the drive control device and not to flow in the opposite direction, the switch is turned on. Even so, regenerative energy is not stored in the secondary battery.
That is, it occurs when the motor decelerates to a stop both when the switch is off and the motor is driven with the capacitor as the power source, and when the switch is on and the motor is driven with the secondary battery as the power source. Since the regenerative energy to be stored is stored only in the capacitor, the stopping accuracy of the self-propelled carrier does not vary when the capacitor is used as the power source or when the secondary battery is used as the power source.

  As described above, according to the self-propelled transport system using the capacitor and the secondary battery as the power source according to the present invention, the battery life is relatively long without causing the battery to run out at the time of resuming operation such as after holidays, and the weight and cost are relatively long. Since the increase can be suppressed and a bidirectional DC-DC converter is connected between the capacitor and the drive control device, the regenerative energy conventionally converted to heat energy by the regenerative resistor unit and discarded. It can be stored and reused in the capacitor via the bi-directional DC-DC converter, eliminating the waste of energy, and when the switch is off and the motor is driven with the capacitor as the power source and when the switch is on and secondary In any case where the motor is driven by a battery, the regenerative energy generated when the motor decelerates to a stop is To power storage relied exhibits the remarkable effect of never stopping accuracy of the self-propelled carrier varies if you are power or if the secondary battery has a capacitor and the power supply.

It is a schematic plan view which shows an example of the whole structure of the self-propelled conveyance system which used the capacitor and secondary battery which concern on embodiment of this invention as a power supply. It is a block diagram which shows the state which is charging with respect to the automatic conveyance vehicle stopped in the charging station. It is the block diagram which showed the bidirectional | two-way DC-DC converter in FIG. 2, a drive control apparatus, etc. in detail. (A) shows the flow of energy when the output voltage Vi of the capacitor is equal to or higher than the output voltage Vo of the bidirectional DC-DC converter, and (b) shows the flow of energy when the output voltage Vi is less than the output voltage Vo. FIG. It is a block diagram which shows the flow of energy in case the voltage of the output side of a bidirectional | two-way DC-DC converter is more than the regeneration start setting voltage Vs, (a) is a switch-off state, (b) is a switch on. Shows the state.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments shown in the accompanying drawings, and includes all the embodiments that satisfy the requirements described in the claims. It is a waste.

  The self-propelled conveyance system using the capacitor and the secondary battery according to the embodiment of the present invention shown in FIG. 1 as a power source, for example, along the predetermined path R in the factory formed by a magnetic guide tape, A self-propelled carrier for detecting a position and carrying a transported object, an unmanned automatic transport vehicle 1, 1,..., A charging terminal 6A that is a power feeder provided in the middle of a predetermined route R, and charging The charging station 2A, 2B composed of the power source 3 and the like, and the loading table lifter or the unloading table lifter (not shown) for loading and unloading the transported objects installed at the positions of the charging stations 2A, 2B, and the operation of each device It is configured by a control device 4 or the like that controls the charging power source 3 that is a constant current power source, and more automatically than the number of charging stations 2A and 2B (two locations) on the predetermined route R. Okukuruma 1, 1, has a ....

As described above, there are loading table lifters or lowering table lifters at the charging stations 2A and 2B. When the automatic transport vehicle 1 comes to these positions, the automatic transport vehicle 1 stops and is positioned for loading. The loading / unloading work of the conveyed product is performed by the table lifter or the lifting table lifter, and the capacitor 7 on the automatic conveyance vehicle 1 is used by the charging power source 3 by using the stop time of the automatic conveyance vehicle 1 corresponding to this work time. Charging to (see FIG. 2) is performed.
Here, the capacitor 7 is excellent in rapid charge / discharge characteristics. The capacitor 7 includes an electric double layer capacitor and a lithium ion capacitor, and also includes a secondary battery having characteristics capable of rapid charge / discharge. .

As shown in FIG. 2, an automatic guided vehicle 1 that is a self-propelled carrier has, on its base, driving wheels 15 and 15, driven wheels 16 and 16, a motor 14 that drives the driving wheels 15 and 15, and a driving control device thereof. 13, a capacitor 7 that is a main power source as a power source for driving the motor 14, a power receiving terminal 6 B that is a power receiver connected to the charging terminal 6 A connected to the capacitor 7, and the capacitor 7 and the drive control device 13 , A bidirectional DC-DC converter 8 that converts a DC output voltage (for example, 54 V or less) of the capacitor 7 into another constant DC voltage (for example, 24 V) according to a load, the capacitor 7, and the drive control device 13. is between, on the output side of the bidirectional DC-DC converter 8, for example, the output side via the switch 11 is a thyristor are connected, the lead-acid battery 10 is an auxiliary power supply When the voltage Vi of the lead storage battery charger 9 and the voltage detector 12A to be charged is equal to or higher than the output voltage Vo (for example, 24V) of the bidirectional DC-DC converter 8, the switch 11 is turned off (the switch 11 is turned off), and the voltage When Vi is less than the voltage Vo, a control circuit 12 for turning on the switch 11 (turning on the switch 11) is provided.

  The control circuit compares the voltage Vi of the voltage detector 12A, which is the output voltage of the capacitor 7 (the input voltage of the bidirectional DC-DC converter 8), with the output voltage Vo (for example, 24V) of the bidirectional DC-DC converter 8. In addition to the configuration in which the switch 11 is controlled to be switched by 12, the voltage Vi is compared to a predetermined threshold (for example, 23V) different from the output voltage Vo of the bidirectional DC-DC converter 8, and the voltage Vi is equal to or higher than the predetermined threshold. Alternatively, the switch 11 may be turned off, and the switch 11 may be turned on when the voltage Vi is less than a predetermined threshold.

The charging terminal 6A, which is a power feeding body connected to the charging power source 3 shown in FIG. 2, can be contact-coupled with the power receiving terminal 6B, which is a power receiving body on the side of the automatic transport vehicle 1, and release this coupling. Therefore, the cylinder 5 controlled by the control device 4 can move in the direction approaching and away from the power receiving terminal 6B. Note that the power feeding body and the power receiving body may be a pair of electrically connected connectors or the like, or transmit power from the power feeding body (power feeding side coil) to the power receiving body (power receiving side coil) by electromagnetic induction. The capacitor 7 may be charged by non-contact power feeding.
In the state in which the automatic transport vehicle 1 stops at the charging station 2A or 2B shown in FIG. 1 and the charging terminal 6A is in contact with the power receiving terminal 6B as shown in FIG. Is calculated, and this command value is supplied to the charging power source 3, and the charging current is supplied from the charging power source 3 to the capacitor 7 via the charging terminal 6A and the power receiving terminal 6B.

After the charging of the capacitor 7 is completed, after the contact coupling between the charging terminal 6A and the power receiving terminal 6B is released by the cylinder 5 controlled by the control device 4, the discharging power from the capacitor 7 is bi-directional DC. The drive wheels 15 and 15 are driven by the drive torque of the motor 14 that is supplied to the drive control device 13 through the DC converter 8 and is drive-controlled by the drive control device 13, and therefore moves along the predetermined route R.
In this way, the discharge power from the capacitor 7 is supplied to the drive control device 13 via the bidirectional DC-DC converter 8 (see the thick arrow A in FIG. 4A), but the surplus power at that time is lead. A lead-acid battery is supplied to the storage battery charger 9 (see the thick arrow B in FIG. 4A), and a constant voltage (for example, 27.3 V to 29.1 V) is supplied to the lead-acid battery 10 by the lead-acid battery charger 9. 10 (for example, nominal voltage 24V) is charged.

The lead storage battery 10 in the above description may be another secondary battery such as a nickel metal hydride battery or a lithium ion battery.
In the case of the lead storage battery 10, for example, a charging time of about several hours is required. Therefore, the capacity of the capacitor 7 is set so that the lead storage battery 10 can be fully charged by surplus power in a predetermined number of cycle discharges of the capacitor 7. Is selected.

  Moreover, although the charging voltage (for example, 27.3V-29.1V) of the lead storage battery 10 exceeds the allowable range (for example, 24V ± 10%) of the power supply voltage of the drive control device 13, when the lead storage battery 10 is charged, that is, automatically. Since the switch 11 is turned off by the control circuit 12 during normal operation of the transport vehicle 1 (for example, operation during weekday line operation), the lead storage battery charger 9 and the lead storage battery 10 are not connected to the drive control device 13. Therefore, a voltage exceeding the allowable range of the power supply voltage is not applied to the drive control device 13, and the lead storage battery 10 is not discharged to drive the motor 14.

  As described above, since the number of automatic transport vehicles 1, 1,... Is larger than the number of charging stations 2A, 2B (two places), the line is stopped during a holiday (for example, two days that are weekly holidays). Since there are automatic transport vehicles 1, 1,... Waiting in a place other than the charging stations 2A, 2B during this stop period, the automatic transport vehicles 1, 1,. When the operation is resumed at the end of the holiday, the voltage Vi of the voltage detector 12A, which is the output voltage of the capacitor 7 (the input voltage of the bidirectional DC-DC converter 8), is the output voltage Vo (for example, 24V) of the bidirectional DC-DC converter 8. The power supply from the bidirectional DC-DC converter 8 to the drive control device 13 may be interrupted.

In this case, since the voltage Vi of the voltage detector 12A is less than the output voltage Vo of the bidirectional DC-DC converter 8, the switch 11 is turned on by the control circuit 12 as described above, and the discharge power from the lead storage battery 10 is driven. It is supplied to the control device 13 (see the thick line arrow C in FIG. 4B).
In addition, the lead storage battery 10 supplies standby power until the holiday ends after the voltage Vi of the voltage detection unit 12A becomes less than the output voltage Vo of the bidirectional DC-DC converter 8 during the stop period. A power supply with sufficient capacity is selected for the power required to travel to the charging station.
In addition, since the lead-acid battery charger 9 resumes operation when charging of the capacitor 7 is resumed at the end of the holiday, the output side of the bidirectional DC-DC converter 8 and the output side of the lead-acid battery charger 9 are connected in parallel. The switch 11 is turned off by the control circuit 12 so as not to become.

According to the configuration described above, during normal operation of the automatic guided vehicle 1, the discharge power from the capacitor 7 that is the main power source is supplied to the drive control device 13 via the bidirectional DC-DC converter 8. While the motor 14 is driven, surplus power of the discharge power from the capacitor 7 is supplied to the lead storage battery charger 9, and a constant voltage is supplied to the lead storage battery 10 by the lead storage battery charger 9 to charge the lead storage battery 10. Therefore, the energy of the capacitor 7 can be used effectively.
Further, as described above, when the voltage Vi of the voltage detection unit 12A is less than the output voltage Vo of the bidirectional DC-DC converter 8, the control circuit 12 turns on the switch 11, and the lead storage battery 10 serving as the auxiliary power supply Since the discharge power is supplied to the drive control device 13, the battery does not run out when the line changes from the non-operating state to the operating state, for example, after the holiday.

Furthermore, since the lead storage battery 10 is not a main power supply but an auxiliary power supply, the lead storage battery 10 has a short charge / discharge cycle life because the number of times of charge / discharge of the lead storage battery 10 is reduced with respect to the configuration using the lead storage battery 10 as the main power supply. It is possible to use it for a long time despite the configuration using
Furthermore, since the lead storage battery 10 is not a main power supply, it is only necessary to have a capacity capable of moving the automatic transport vehicle 1 to the charging station 2A or 2B at the end of the holiday, so that an increase in weight and cost can be suppressed. .
In addition, the cost can be reduced and the capacity of the capacitor 7 can be increased as compared with a configuration in which many charging stations are installed so that the number of charging stations matches the number of automatic transport vehicles 1, 1,. Compared to the above, the cost and the volume and weight of the capacitor 7 can be reduced.

  In the above, in the automatic transport vehicles 1, 1,... Waiting in a place other than the charging stations 2A, 2B, the voltage Vi of the voltage detection unit 12A becomes less than the output voltage Vo of the bidirectional DC-DC converter 8, and the bidirectional DC -Although the case where the power supply from the DC converter 8 to the drive control device 13 is interrupted at the time of resuming the operation after the holiday has been described, even if it is not at the time of resuming the operation after the holiday, for example, in the predetermined route R Similarly, when the storage unit waits for a long time at a position where there is no charger, when the power supply from the bidirectional DC-DC converter 8 to the drive control device 13 is cut off, the control circuit 12 switches the switch 11. Since the discharge power from the lead storage battery 10 is supplied to the drive control device 13 because the battery is inserted, it is possible to avoid running out of the battery.

Next, a configuration example for using regenerative energy and its operation will be described.
As shown in FIGS. 2 and 3, a bidirectional DC-DC converter 8 is connected between the capacitor 7 and the drive control device 13, and the output side of the bidirectional DC-DC converter 8 is detected by the voltage detection unit 12 </ b> B. The voltage on the drive control device 13 side can be detected.
Therefore, according to the voltage detected by the voltage detection unit 12B, the control circuit 12 causes the bidirectional DC-DC converter 8 when the voltage of the voltage detection unit 12B is equal to or higher than a predetermined regeneration start setting voltage Vs (for example, 28V). Is switched to the regenerative side (see regenerative converter 8B in FIG. 3), and when the voltage of the voltage detector 12B is equal to or lower than a predetermined regeneration completion set voltage Ve (for example, 24V), the internal circuit is switched to the power running side ( (See the powering converter 8A in FIG. 3).

With such a configuration and operation, during powering operation, power is supplied from the capacitor 7 to the drive control device 13 via the powering converter 8A of the bidirectional DC-DC converter 8, and regenerative power is generated when the motor 14 decelerates to a stop. If this occurs, the regenerative energy can be stored in the capacitor 7 via the regenerative converter 8B of the bidirectional DC-DC converter 8 and reused (see the thick arrow D in FIG. 5).
Moreover, when using regenerative energy in this way, as shown in FIG.2 and FIG.3, between the switch 11 and the lead storage battery 10, an electric current is sent from the lead storage battery 10 side to the drive control apparatus 13 side, Since the diode 17 that is a rectifying means that does not flow current in the opposite direction is provided,
Even if the switch 11 is on as shown in FIG. 5B, regenerative energy is not stored in the lead storage battery 10.
That is, in either case where the switch 11 is off and the motor 14 is driven with the capacitor 7 as a power source, and when the switch 11 is on and the motor 14 is driven with the lead storage battery 10 as a power source, FIG. As shown in a) and (b), since the regenerative energy generated when the motor 14 decelerates and stops is stored only in the capacitor 7, it is automatically detected when the capacitor 7 is used as a power source or when the lead storage battery 10 is used as a power source. The stopping accuracy of the transport vehicle 1 does not vary.

  In the above description, the case where the self-propelled carrier of the self-propelled conveyance system is the automatic conveyance vehicle 1 that moves along the guide tape is shown. However, the self-propelled carrier is an overhead type that moves along the guide rail. Or it may be of the floor type.

R Predetermined path Vi Capacitor output voltage Vo Bidirectional DC-DC converter output voltage Vs Regeneration start set voltage Ve Regeneration complete set voltage 1 Automated guided vehicle (self-propelled carrier)
2A, 2B Charging station 3 Charging power supply 4 Control device 5 Cylinder 6A Charging terminal (feeding body)
6B Power receiving terminal (power receiving body)
7 Capacitor 8 Bidirectional DC-DC converter 8A Powering converter 8B Regenerative converter 9 Lead-acid battery charger (secondary battery charger)
10 Lead acid battery (secondary battery)
11 switch 12 control circuit 12A, 12B voltage detector 13 drive control device 14 motor 15 drive wheel 16 driven wheel 17 diode (rectifying means)

Claims (1)

A self-propelled carrier that moves along a predetermined path and carries a transported object includes a motor, a drive control device thereof, a capacitor and a secondary battery as a power source for driving the motor, and a power receiver connected to the capacitor. A charging station installed at a predetermined position, provided with a power feeding body electrically connected to the power receiving body and a charging power source, and supplying electric power charged in the capacitor and the secondary battery to the drive control device, and the motor A self-propelled transport system that uses a capacitor and a secondary battery as a power source to move the self-propelled carrier by driving
A bidirectional DC-DC converter connected between the capacitor and the drive control device;
A secondary battery charger for charging the secondary battery, which is located between the capacitor and the drive control device, and whose output side is connected to the output side of the bidirectional DC-DC converter via a switch ;
When the output voltage of the capacitor is equal to or higher than the output voltage of the bidirectional DC-DC converter or a predetermined threshold value, the switch is turned off, and the output voltage of the capacitor is less than the output voltage of the bidirectional DC-DC converter or the predetermined threshold value. And when the voltage on the output side of the bidirectional DC-DC converter is equal to or higher than the regeneration start set voltage, the internal circuit of the bidirectional DC-DC converter is switched to the regeneration side, A control circuit that switches the internal circuit to the power running side when the voltage on the output side of the bidirectional DC-DC converter is equal to or lower than the regeneration completion set voltage;
Rectifying means connected between the switch and the secondary battery, for causing a current to flow from the secondary battery side to the drive control device side, and not flowing a current in the opposite direction;
Equipped with a,
In either case where the switch is off and the motor is driven with the capacitor as a power source and the switch is on and the motor is driven with the secondary battery as a power source by the rectifying means. A self-propelled conveyance system using a capacitor and a secondary battery as a power source , wherein regenerative energy generated when the motor decelerates and stops is stored only in the capacitor.

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