JP3311499B2 - Drive power storage power supply unit - Google Patents

Abstract

PURPOSE:To provide an inexpensive auxiliary storage battery system which can reduce the load on a capacitor and current pump circuit, can be reduced in weight, and has a long service life. CONSTITUTION:A storage battery system is provided with a power source constituted by connecting a main battery 1 which stores electric energy and has a large capacity and auxiliary capacitor 2 having an internal resistance smaller than that of the main battery 1 in parallel with each other, switching means 3 which controls the power supply to a load by switching the feeder line, request generating means which generates a drive request, and control means 5 which detects the voltage of the power source and controls the switching means 3 by generating a pulse signal in accordance with the drive request and drives a drive means 4 in response to the drive request which largely fluctuates in a short time. Even when the energy density of the power unit becomes higher due to the internal resistance of an electric double layer capacitor when the capacitor is used for the power source, a large peak-load current can be supplied from the auxiliary capacitor even when the energy density of the internal resistance is increased by using a capacitor having a small internal resistance as the auxiliary battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving power storage device for driving a driving means in response to a driving request having a large fluctuation in a short time.

[0002]

2. Description of the Related Art There is a motor-equipped bicycle in which an electric motor is mounted on a bicycle as an auxiliary power source and an auxiliary driving force is provided from the electric motor in accordance with the pedaling force. Conventionally, a secondary battery, particularly a lead storage battery, has been often used as a small electric power source such as a motor-equipped bicycle. However, they have a long history but have many problems to use as power sources for practical vehicles. For example, the amount of power stored for weight is small, the charging takes a long time, the cycle life of charging and discharging is limited to about 200 to 500 times, and the amount of stored power and remaining amount are not accurately known. is there. As a result, it has not been possible to replace internal combustion engines and the like that have caused various environmental problems to this day.

The present applicant has already proposed a power storage power supply system in which electricity is stored in an electric double layer capacitor and an electronic circuit is used together with the electric power. According to this system, the electric double layer capacitor is charged and discharged as needed, so it has little effect on the environment, charging is relatively short, and cycle life is 10,000 times or more. Has been realized,
It has advantages that could not be realized with a secondary battery, such as the ability to measure the remaining amount with sufficient accuracy for practical use.

[0004]

However, there are still problems in the power storage power supply system such as further increasing the energy density and reducing the price of the product. For that purpose, it is important to use a device with the smallest possible capacity rationally and to secure a relatively large output capacity and storage capacity without using extra materials, space, and weight.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and in a system in which a capacitor and an electronic circuit are combined for storing electric energy, a load on a capacitor and a current pump circuit used therein is reduced. It is an object of the present invention to provide a low-cost, long-life, low-cost driving power storage power supply device.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention is a driving power storage power supply device for driving a driving means in response to a driving request having a large fluctuation in a short time, and a large capacity for storing electric energy. A power supply in which an electric double-layer capacitor battery of the type described above and an auxiliary electric double-layer capacitor battery having a smaller internal resistance than the large-capacity electric double-layer capacitor battery are connected in parallel, and a power supply line of the power supply is switched to supply power to a load. Switching means for controlling the power supply, a request generation means for generating a drive request, and a voltage of the power supply and a voltage of at least half or less from a voltage at the time of full charge of the electric double layer capacitor battery. Control means for controlling the switching means by generating a pulse signal having a pulse frequency or a pulse width corresponding to the drive request generated by the request generation means; It is characterized in that it comprises.

[0007]

In the power storage device for driving according to the present invention, a large-capacity electric double-layer capacitor battery for storing electric energy and an auxiliary electric double-layer capacitor battery having a smaller internal resistance than the large-capacity electric double-layer capacitor battery are provided. A power supply connected in parallel, switching means for controlling power supply to a load by switching a power supply line of the power supply, request generation means for generating a drive request, and a voltage when the electric double layer capacitor battery is fully charged. Controlling the switching means by generating a pulse signal having a pulse frequency or a pulse width corresponding to the voltage of the power supply and the drive request generated by the request generation means, with a control range of at least half the voltage or less. Control means to use an electric double layer capacitor battery for the power supply, even if the energy density is increased and the internal resistance is increased, By using a small internal resistance in aid, it is possible to supply a large peak load current from the electric double layer capacitor cell of the auxiliary. Therefore,
As a whole, the energy density can be increased, and a large peak load current can be supplied in a wide voltage fluctuation range.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a driving power storage power supply device according to the present invention, and FIG. 2 is a diagram showing an example of a change characteristic of a terminal voltage with respect to an amount of stored energy of an electric double layer capacitor.

In FIG. 1, 1 and 2 are electric double layer capacitor batteries, 3 is a switching regulator, 4 is an electric motor, 5 is a control signal generator, C1 and C2 are capacitors,
R1 and R2 indicate internal resistance. The electric double-layer capacitor battery 1 has a relatively high internal resistance R1 with a large capacitance of the capacitor C1 having an increased energy density, and the electric double-layer capacitor battery 2 has a capacitor C2 of about several percent of the capacitor C1. The internal resistance R2 is also small. The switching regulator 3 controls a current of the electric motor 4 as a load by switching a power supply line by pulse width modulation control or pulse frequency control, and a control signal generating unit 5 generates a control signal. is there. As the control value, for example, a drive request value is detected by a torque sensor, and the control signal generator 5 determines a pulse width and a pulse frequency according to the voltage of the electric double layer capacitor batteries 1 and 2 and the control value, and performs switching. The switching time and the switching frequency of the regulator 3 are controlled.

In the electric double layer capacitor battery, as shown in FIG. 2, when the battery voltage when the stored energy is 100% is 100% (point A), the stored energy is 2%.
At 5%, the battery voltage drops to 50% (point B) when fully charged. Generally, the range of voltage fluctuation allowed for a DC power supply is 5%, 10%, and 20%, depending on the application.
It is rare that high efficiency operation can be expected with a voltage drop of 50% or more. Therefore, if this electric double layer capacitor battery is used as it is in place of the conventional battery, the voltage drop is so severe that it cannot be used as it is. Therefore, in the present invention, the control signal generator 5 detects the voltage of the electric double layer capacitor batteries 1 and 2, adjusts the pulse width and pulse frequency according to the power supply voltage, and controls the output voltage and current. , The energy stored in the electric double layer capacitor battery 1 becomes 25%, and stable control can be performed even if the voltage drops to 50% (point B) at the time of full charge.

That is, the control signal generator 5 detects the voltage of the electric double layer capacitor batteries 1 and 2, and if the voltage of the electric double layer capacitor batteries 1 and 2 decreases, the pulse width and The pulse frequency is increased, and the pulse width and the pulse frequency are increased as the control value increases. When the drive request τ is supplemented by a certain value Δ or more, a control signal is generated based on the value exceeding the certain value (τ−Δ). 0 <α <1) or a function f (τ−Δ), and a coefficient α or a function f
(Τ) may be used as a control value.

In a device using a lead battery as a power source for a motor-equipped bicycle, if the lead battery has a rated current of, for example, 25 A, the current continues to flow even if it exceeds that, and the peak current value becomes 50.
It reaches A. On the other hand, if the rated current is set to 25 A and the current limiting circuit is operated accurately with that value, power assist which cannot be practically used alone by itself will result.

On the other hand, in the present invention, the rated output is 25 A
By making the capacity of the switching regulator 3 capable of supplying a current of up to about 45 A in units of several seconds in a transitional manner, power assist stronger than that of a lead battery can be obtained. In this case, the electric double layer capacitor battery is
When the energy density is increased, the internal resistance becomes relatively high. Therefore, when such a peak load current is increased in the electric double layer capacitor battery, the ohmic loss due to the internal resistance increases. Therefore, in order to reduce the ohmic loss, an auxiliary electric double-layer capacitor battery 2 having a small internal resistance and a capacity of about several percent is provided in parallel with the main electric double-layer capacitor battery 1. Most of the head load current is supplied by the auxiliary electric double layer capacitor battery 2, and the ohmic loss in the electric double layer capacitor battery 1 can be greatly reduced. Therefore, it is possible to provide an efficient power supply that can increase the energy density and cope with the peak load current.

FIG. 3 is a view showing another embodiment of the power storage device for power assist according to the present invention.
Denotes a current pump, 8 denotes an output converter, and 9 denotes an electric double layer capacitor battery.

In FIG. 3, a torque sensor 6 is attached to, for example, a pedal of a motor-equipped bicycle to detect a stepping torque. The current pump 7 is provided with a voltage limiter for limiting the output voltage within a certain value, and supplies a constant current by switching control. For example, a switching type constant current type DC / DC converter has a wide change range of the input voltage ( (For example, 100% to 25%). The output converter 8 is controlled by a signal of the control signal generation unit 5 in accordance with a torque request detected by the torque sensor 6 and performs switching control of the load current. For example, a switching type constant voltage output DC / DC converter And operates with high efficiency over a wide range of change in input voltage (for example, 100% to 25%), and usually has an input terminal for external control. The electric double layer capacitor battery 9 bears a peak load current and has a smaller voltage fluctuation and a larger current than the electric double layer capacitor battery 2, so that the withstand voltage is low but the capacity is large. On the other hand, the electric double layer capacitor battery 2 has a relatively small capacity and a high withstand voltage. By providing the electric double layer capacitor battery 9, the electric double layer capacitor battery 2 may be omitted.

Next, the operation will be described. A constant current is constantly supplied from the electric double layer capacitor battery 1 through the current pump 7. However, when there is no drive request, the voltage of the electric double layer capacitor battery 9 increases to reach a predetermined limit voltage. Then, the voltage limiter function of the current pump 7 operates. When there is a drive request, a control signal is generated by the control signal generator 5 in accordance with the detection value of the torque sensor 6, the switching of the output converter 8 is controlled, and a current corresponding to the drive request is supplied to the electric motor 4. . At this time, power is supplied from the electric double layer capacitor battery 1 through the current pump 7 for a steady portion of the drive request, but is temporarily supplied to the electric double layer capacitor battery for a temporarily larger drive request. 9 is supplied. In this way, even if the current capacity of the electric double layer capacitor battery 1 is reduced, it is possible to cope with a large current for a short time by increasing the current capacity of the electric double layer capacitor battery 9. In this way, the electric double layer capacitor battery 1 has a terminal voltage that varies according to the amount of stored energy, as shown in FIG.
The voltage on the input side of is stabilized.

For example, in the case of a motor-equipped bicycle, a beard-like drive request appears intermittently each time the pedal is depressed, so that a large current supply is required intermittently. Also, the presence of the electric double layer capacitor battery 9 can supply a necessary current. That is, when the peak load current is supplied via the current pump 7, it is necessary to at least make the current capacity of the current pump 7 short enough to withstand it. By providing 9 on the output side, the peak load current of electric double layer capacitor battery 1 and current pump 7 can be reduced. Also,
The electric double layer capacitor battery 9 has a lower applied voltage, so that the withstand voltage may be lower than that of the case of FIG. 1 in which the electric double layer capacitor battery 2 is inserted. Electric capacity is required.

FIG. 4 is a diagram showing an example of a basic configuration of a current pump used in the present invention.
12 is a current sensor for detecting an output current, 13 is a voltage sensor for detecting an output voltage, 14 is current setting means for setting a constant current, 15 is voltage setting means for setting a limited voltage, 16
Indicates control means.

The current pump is provided with a voltage limiter for limiting the output voltage to within a certain value as described above, and supplies a constant current by switching control. An example of the basic configuration is shown in FIG. 4. In FIG. 4, the control means 16 compares the output voltage detected by the voltage sensor 13 with the limit voltage set by the voltage setting means 15, and sets the output current detected by the current sensor 12 to the set current set by the current setting means 14. The switching means 11 is controlled so that the output current becomes a constant current within the limit voltage.

Note that the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in the above embodiment, the load current is controlled in accordance with the control value while detecting the battery voltage. However, a configuration may be employed in which the load current is further detected and the feedback control is performed. Although the application example of the motor-equipped bicycle has been described, the invention can be similarly applied to a hybrid drive device in which an engine and an electric motor are combined and in which a predetermined driving force is secured by the engine and the electric motor is used for auxiliary driving. In this case, instead of detecting the depression torque of the pedal, for example, the depression amount of the accelerator pedal is detected, and is distributed to the driving force of the engine and the driving force of the electric motor according to the depression amount. Of course, if it is configured to ensure the driving force of the electric motor according to the amount of depression, it goes without saying that the present invention can be applied to an electric vehicle as it is.

[0021]

As is apparent from the above description, according to the present invention, a large-capacity main storage battery and an auxiliary storage battery having a small internal resistance are connected in parallel, and the control means detects the voltage of the power supply and drives the power supply. The pulse signal is generated as required and the switching means is controlled to switch the power supply line to control the power supply to the load.If an electric double layer capacitor battery is used as the power supply, the energy density is increased and the internal resistance is reduced. Even if the power becomes high, a large peak load current can be supplied from the auxiliary storage battery by using an auxiliary storage battery having a small internal resistance. Therefore, the energy density can be increased as a whole, and a large peak load current can be supplied, so that a relatively small capacity device can be used rationally and a relatively large output capacity and a large amount of stored power can be secured.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a driving power storage power supply device according to the present invention.

FIG. 2 is a diagram illustrating an example of a change characteristic of a terminal voltage with respect to a stored energy amount of an electric double layer capacitor.

FIG. 3 is a view showing another embodiment of the power storage device for power assist according to the present invention.

FIG. 4 is a diagram showing an example of a basic configuration of a current pump used in the present invention.

[Explanation of symbols]

1, 2 ... electric double layer capacitor battery, 3 ... switching regulator, 4 ... electric motor, 5 ... control signal generator, C
1, C2: capacitor, R1, R2: internal resistance

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-50-158012 (JP, A) JP-A-53-69315 (JP, A) JP-A-6-86407 (JP, A) JP-A-6-86407 217456 (JP, A) JP-A-8-9511 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60L 11/18 B60L 3/00 H01G 9/155 H02J 9/06 505

Claims (1)

(57) [Claims] 1. A large-capacity electric double-layer capacitor battery for storing electric energy, comprising: a large-capacity electric double-layer capacitor battery for driving a driving means in response to a drive request having a large fluctuation in a short time. A power supply connected in parallel with an auxiliary electric double layer capacitor battery having an internal resistance smaller than that of the electric double layer capacitor battery, switching means for switching a power supply line of the power supply to control power supply to a load, and The request generating means to be generated and the voltage when the electric double layer capacitor battery is fully charged.
The control range is up to at least half the voltage,
The voltage of the power supply and the drive demand generated by the demand generation means.
And a control means for controlling the switching means by generating a pulse signal having a pulse frequency or a pulse width according to the request .