JPH11185830A - Abnormal battery voltage detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely detect voltage drop of a battery to accurately conduct treatment of the abnormally dropped battery and lengthen the life of the battery by comparing detected voltage with two reference voltage containing at least the limit voltage of the battery to detect the voltage drop of the battery. SOLUTION: When battery voltage drops to reference voltage V1, the output of a comparator 22 is reversed in the state of H, an alarm signal S is given to make a user of a burning equipment recognize the drop of battery voltage. When the battery voltage further drops than the reference voltage V2, the output of a comparator 23 is reversed in the state of H. All signals of three input terminals in an AND circuit 24 are made in the state of H, and the output of the AND circuit 24 is reversed in the state of H. The H signal of the AND circuit 24 becomes a stop signal S2, and the stop signal S2 is outputted to a control circuit. When the stop signal S2 is outputted from the AND circuit 24, the control circuit moves the burning equipment to a post purge operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery abnormality detecting device for detecting an abnormality in a battery voltage for operating various devices, and more particularly, to safely and reliably operate the devices when the battery voltage reaches a limit voltage. The present invention relates to a battery voltage abnormality detection device that can be stopped.

[0002]

2. Description of the Related Art In general, among various devices operated by a battery voltage, for example, in an electric tool without an over-discharge prevention function, a decrease in the voltage of a battery is determined by a user (operator).
Is directly recognized by a decrease in the number of revolutions (torque). Also, in devices such as mobile phones, communication devices, and notebook computers that detect a battery voltage drop and issue an alarm, the user recognizes the battery voltage drop by the alarm.

[0003] In other words, these so-called portable devices are premised on stopping the use of the device by directly recognizing the voltage drop of the battery by the user. , NiCad, Nickel-Metal Hydride batteries are often used, and these batteries have a surface that is more resistant to overdischarge than lead batteries, and there is no practical problem with their use. This is the actual situation.

[0004]

However, when the above-described method of detecting a battery voltage such as a portable device is applied to, for example, a combustion device, there are the following problems.
That is, in a combustion device without an overdischarge prevention function, when an abnormal decrease in the battery voltage occurs, for example, a fan,
In the case where the inherent optimum operating voltages of the pumps and the like are shifted from each other and the fan firstly deteriorates in function (air volume decreases), there is a possibility that safe stop processing of the combustion unit at the time of abnormally low voltage cannot be performed. There is.

[0005] In the case where the entire system of the combustion equipment is directly stopped by the voltage drop, all the equipment is stopped during the combustion, so that the cooling of the combustion part becomes insufficient.
That is, it is difficult to apply the above-described method of detecting a battery voltage abnormality to a combustion device as it is. Furthermore, when the above-described abnormality detection method is applied to, for example, a device that operates with a lead battery, overdischarge of the lead battery cannot be detected, so that the lead battery causes sulfation (sulfurization phenomenon), which significantly shortens the life of the battery. There is a problem of causing damage.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the invention described in claim 1 or 2 is to reliably detect a decrease in battery voltage and accurately perform processing when an abnormality occurs. It is another object of the present invention to provide a battery voltage abnormality detection device that can extend the life of a battery. In addition, the invention described in claim 3 or 4 is applied to claim 1 or 2
It is another object of the present invention to provide a battery voltage abnormality detection device capable of reliably and safely performing a stop operation of a combustion device when a battery voltage is abnormally reduced.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a voltage detecting means connected to a battery via an operation switch to detect a battery voltage, and a voltage detecting means are provided. And a pair of comparators for respectively comparing the voltage detected in step (b) with at least two reference voltages set lower than the battery voltage, and a comparison result signal of the comparator and a predetermined control signal of the device are inputted.
Comparing means having an ND circuit, wherein the comparing means outputs a first abnormal signal based on a comparison result of one of the pair of comparators, and operates based on an output signal of the AND circuit. The second that can shift the equipment in the middle to the stop operation
Is output.

Further, the invention according to claim 2 is characterized in that the first abnormal signal is a battery voltage drop warning signal.

With this configuration, when the voltage of the battery decreases, the voltage is detected by the voltage detecting means, and the first comparator which is set lower than the battery voltage by one of the pair of comparators. If the detected voltage is lower than the first reference voltage as compared with the reference voltage, the comparator outputs a first abnormal signal of a low battery warning signal. When the detection voltage further decreases and falls below a second reference voltage lower than the first reference voltage, a predetermined signal is input from both of the pair of comparators to the AND circuit, and the AND circuit operates when the device is in a predetermined operation. Only in the case of (2), the second abnormality signal is output to shift the device to the stop operation.

That is, the battery voltage drop is detected stepwise by a pair of comparing means, and at the first stage when one of the comparators detects the voltage drop, a first abnormal signal such as a battery voltage drop warning signal is output. Is output to make the user recognize, and at the second stage in which the voltage drop is detected by both comparators, the operation is shifted to a stop operation of stopping the operating device. As a result, a drop in the battery voltage is reliably detected, and an abnormal signal corresponding to the degree of the drop in the voltage is output so that the user can accurately recognize the battery. In addition, the processing at the time of abnormality can be accurately performed, the damage to the battery is reduced, and the life of the battery can be extended.

In the invention according to claim 3, the comparing means compares a comparison result of the pair of comparators with a signal during operation of the fan and the pump of the combustion device, and operates the fan and the pump of the combustion device. A second abnormality signal is output when both the pair of comparators detect a decrease in the battery voltage in a state where the battery voltage is low.

[0012] With this configuration, when the battery voltage falls below the second reference voltage in a state where the fan and the pump of the combustion device are operating and the combustion section is burning, the comparing means sets the second abnormal condition. A signal is output to shift the combustion equipment to the post-purge operation, and after the elapse of the post-purge time, the fan, pump, and the like of the combustion equipment are completely stopped. Thus, when the battery voltage is abnormally reduced, the fan or the like can be stopped after the post-purge operation is ensured, and the safe stop operation of the combustion equipment can be performed.

According to a fourth aspect of the present invention, there is provided a power supply unit capable of continuing supply of battery power to a control circuit for controlling a device for a predetermined time when the second abnormality signal is output from the comparison unit. It is characterized by being provided. With this configuration, when the battery voltage falls below the second reference voltage and the second abnormality signal is output from the comparison unit, the power supply unit supplies power to the main part of the control circuit that controls the combustion equipment. Is supplied to keep the control circuit operable. Thus, when the battery voltage drops, power supply to loads other than the control circuit is cut off, but the main part of the control circuit is in an operable state, and a stop operation such as a post-purge operation is more reliably and reliably performed. It can be done safely.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIGS. 1 to 4 show an embodiment in which the battery voltage abnormality detecting device according to the present invention is used in a combustion device such as an infrared heater that generates fuel by burning fuel by a burner, for example, and
1 is a circuit diagram thereof, FIG. 2 is a circuit diagram of a main part thereof, and FIGS. 3 and 4 are timing charts showing the operation.

In FIG. 1, a battery voltage abnormality detecting device 1 has a control circuit 2 as control means provided inside a combustion device, and the control circuit 2 includes a voltage detection circuit 3 as voltage detection means. And a power supply circuit 4 and a self-holding circuit 5 as power supply means. The control circuit 2 includes, for example, a CPU 6 and a comparison circuit 7 as a comparison unit.

The power supply circuit 4 connected to the terminal 2a of the control circuit 2 has a three-terminal regulator 8, and an input terminal of the three-terminal regulator 8 has a diode 9 for preventing backflow.
Is connected, and the plus side of the electrolytic capacitor 10 whose minus side is grounded is connected. Electrolytic capacitor 10 connected to the input terminal of three-terminal regulator 8
As a result, the power cutoff to the control circuit 2 is delayed as described later.

The diode 9 of the power supply circuit 4 is connected to an operation switch 12 also serving as a power switch via a diode 11 for preventing backflow. The operation switch 12 is connected via a fuse 13 to a battery such as a lead battery. 14 plus terminals. The diode 9 is connected to the self-holding circuit 5.

The self-holding circuit 5 includes a self-holding relay 15 having contacts 15a and 15b, which are normally open contacts, and a transistor 16 connected to the self-holding relay 15. The base of the transistor 16 is a control circuit. 2 terminal 2b. The transistor 16 has an emitter grounded and a collector connected to a self-holding relay 15 (coil) in series. Therefore,
When the transistor 16 is turned on with the operation switch 12 turned on, the battery power is supplied from the battery 14 to the self-holding relay 15, and the contacts 15a and 15b are closed.

The contact 15a of the self-holding relay 15
Is connected in parallel with the operation switch 12, one end is connected to the battery 14 via the fuse 13, and the other end is connected to a power supply line 17 for supplying battery power to a fan and an ignition transformer (not shown) of the combustion equipment. It is connected. Further, a contact 15b of the self-holding relay 15 is connected to the diode 11 side of the operation switch 12, and is connected in series to a power supply line 18 for supplying battery power to a pump (not shown) of the combustion equipment.

The voltage detection circuit 3 is formed by a resistor 20 and a resistor 21 connected in series, and a connection point a between the resistors 20 and 21 is connected to a comparison circuit in the control circuit 2 via a terminal 2c of the control circuit 2. 7 is connected. One end of the resistor 20 is connected to the terminal of the operation switch 12 on the diode 11 side, and one end of the resistor 21 is grounded.

As shown in FIG. 2, the comparison circuit 7 to which the voltage detection circuit 3 is connected includes a pair of comparators 22,
23, and an AND circuit 24. Comparator 2
Reference numerals 2 and 23 have one input terminal connected to the connection point a of the voltage detection circuit 3 via the terminal 2c, and the other input terminals connected to DC power supplies 25 and 26 of reference voltages V1 and V2. Have been. The reference voltage V1 of the DC power supplies 25 and 26,
V2 is a set voltage for detection, and V0>V1> V2
(Where V0 is the voltage of the battery 14 during operation and V2 is the limit voltage of the battery 14), and the reference voltages V1 and V2 and the detection voltage Vi at the point a detected by the voltage detection circuit 3 are The signals are compared by the comparators 22 and 23, respectively.

The comparator 22 is turned on when V1> V0, and outputs a battery voltage drop warning signal S1 ("H" signal, hereinafter referred to as a warning signal S1) as a first abnormal signal. In addition to the output to the processing circuit, the output is output to the first input terminal of the AND circuit 24. Further, the comparator 23 is turned on when V2> V0 and “H”
The signal is output to a second input terminal of the AND circuit 24. A
A third input terminal of the ND circuit 24 receives an operation signal S3 of the fan and the pump of the combustion equipment.

The operation signal S3 input to the third input terminal is an "H" signal when the fan or the like is operating, and an "L" signal when the fan is not operating. Therefore, when all of the three input terminals are at “H”, the AND circuit 24 outputs an “H” signal from its output terminal, so that the outputs of the comparators 22 and 23 are both “H”. And when the operation signal S3 is "H",
A stop signal S2 is output as a second abnormal signal. The comparators 22 and 23 and the AND circuit 24 make the battery 1
4 will be detected in two stages as described below.

Next, the battery voltage abnormality detecting device 1
Will be described with reference to the timing charts of FIGS. First, the basic operation of each circuit of the battery voltage abnormality detection device 1 will be described with reference to FIG.
As shown in FIG. 3A, at time t0, the operation switch 12
Is turned on, battery power is supplied from the battery 14 to the three-terminal regulator 8 of the power supply circuit 4 via the diodes 11 and 9, the three-terminal regulator 8 is operated, and a predetermined DC power is supplied to the control circuit 2. Is done.

At the same time when the operation switch 12 is turned on,
The battery voltage is supplied to the voltage detection circuit 3 and the resistance 2
The detection voltage Vi divided at 0 and 21 is input to the comparison circuit 7 via the terminal 2c. The detection voltage Vi is applied to the comparison circuit 7.
Is input, the control circuit 2 recognizes the ON state of the operation switch 12.

When power is supplied from the power supply circuit 4 and the control circuit 2 recognizes the ON state of the operation switch 12 based on the detected voltage Vi from the voltage detection circuit 3, the control circuit 2 outputs a control signal to each load of the combustion equipment. To start driving. First, the operation of the combustion equipment is started, as shown in FIG.
When the operation switch 12 is turned on at time t0, battery power is supplied to the fan via the operation switch 12, the diode 11, and the power supply line 17, and the fan rotates.

After a lapse of a time t1 at which the fan reaches a predetermined number of revolutions, the control circuit 2 returns to its terminal 2b.
Outputs a "close signal" to the self-holding circuit 5. In response to the "close signal" from the control circuit 2, a voltage is supplied to the base of the transistor 16 of the self-holding circuit 5, and the transistor 16 is turned on. When the self-holding relay 15 is turned on, FIG.
The contacts 15a and 15b are turned on and closed as shown in FIG.
The battery power is supplied to the power supply line 17 via the contact 15a regardless of whether the operation switch 12 is turned on or off, that is, the function of the operation switch 12 is invalidated.

By supplying the battery power to the power supply line 17, the ignition transformer is turned on to operate as shown in FIG. 3D, and the battery power is supplied to the pump via the power supply line 18 by turning on the contact 15b. The pump is supplied, and the pump is turned on to operate as shown in FIG. By operating the ignition transformer and the pump, a burner (not shown) burns. After the ignition transformer operates for a predetermined time t2, the ignition transformer is turned off and stopped by the control signal of the control circuit 2.

When the operation of the combustion equipment is stopped, the operation switch 12 is turned off, so that the battery voltage is not supplied to the resistors 20 and 21 of the voltage detection circuit 3, and the detection voltage Vi of the voltage detection circuit 3 is reduced. When the control circuit 2 recognizes this, and the operation switch 12 is turned off, the supply of battery power to the pump by the power supply line 18 is cut off and the pump is stopped. At this time, although the supply of the battery power to the fan via the operation switch 12 is cut off, the battery power is supplied by the contact 15a of the self-holding relay 15 which is kept on, and the operation of the fan is continued. You. After the operation switch 12 is turned off, the rotation of the fan cools the combustion equipment main body and performs a post-purge operation.

After the control circuit 2 recognizes that the operation switch 12 has been turned off by the detection voltage Vi (= 0 V) of the voltage detection circuit 3, the control circuit 2 activates, for example, a built-in timer to set a predetermined time t3 (post-purge time). ), An "open signal" is output from the terminal 2b to the self-holding circuit 5. Due to this “open signal”, the transistor 16 of the self-holding circuit 5
Is turned off, the power supply to the self-holding relay 15 is cut off, and the self-holding relay 15 is turned off. When the self-holding relay 15 is turned off, the contacts 15a and 15b are opened and supply of battery power to the fan is stopped. The fans
After the supply of the battery power is stopped, the motor is completely stopped after rotating for a predetermined time due to its inertia.

On the other hand, CP, which is the heart of the control circuit 2,
Even when the operation switch 12 is turned off, the battery power is supplied to the power supply circuit 4 via the contact 15a while the contact 15a of the self-holding relay 15 is on even when the operation switch 12 is turned off. The CPU 6 is supplied with DC power from the power supply circuit 4 and maintains an operable state.

When the self-holding relay 15 is turned off and the contact 15a is opened, the supply of the battery power to the power supply circuit 4 is cut off. However, power supply circuit 4
Is stored, and the electric power of the electrolytic capacitor 10 causes the power supply circuit 4 to operate for a predetermined time. Therefore, the power supplied from the power supply circuit 4 to the CPU 6 of the control circuit 2 is not stopped at the same time as the self-holding relay 15 is turned off, but is stopped after a predetermined time, so that the control circuit 2 No unstable period.

Next, the operation of the voltage detection circuit 3 and the comparison circuit 7 of the battery voltage abnormality detection device 1 will be described with reference to FIG. The voltage of the battery 14 is, for example, as shown in FIG.
As shown in (a), although the voltage gradually decreases from the specified voltage V, the voltage range from the specified voltage V to the minimum allowable voltage V0 is a normally usable voltage range. At least within this range, the combustion equipment operates normally. Then, the fan and the pump of the combustion equipment are also operated, and the third input terminal of the AND circuit 24 is
The operation signal S3 of the "H" signal shown in FIG. 4D is input.

When the battery voltage drops to the reference voltage V1 in this state, the output of the comparator 22 is inverted to "H" as shown in FIG.
An alarm signal S1 shown in (f) is issued to make the user of the combustion equipment recognize that the battery voltage has dropped. When the alarm signal S1 is issued, the user takes measures such as charging the battery 14 or replacing the battery 14 with a new one.

However, if this measure is not performed, the battery voltage further drops and falls below the reference voltage V2, and the output of the comparator 23 is inverted to "H" as shown in FIG. Become. As a result, the signals at the three input terminals of the AND circuit 24 all become “H”, and the output of the AND circuit 24 is inverted to “H” as shown in FIG. The “H” signal of this AND circuit is output to the control circuit 2 as the stop signal S2 shown in FIG.

When the stop signal S2 is output from the AND circuit 24, the control circuit 2 determines that the battery voltage is at the limit voltage (discharge end voltage) and shifts the combustion equipment to the post-purge operation. This post-purge operation is performed in the same manner as when the operation switch 12 is turned off. After the post-purge time t3 has elapsed, the supply of battery power to the load of a combustion device such as a pump or a fan is stopped. Disconnect battery 14 from the load.

After the battery 14 is disconnected from the load, only the operating power (bias and idle current) of the control circuit 2 is supplied to the control circuit 2 to continuously transmit the alarm signal S1. Therefore, when the battery voltage is the reference voltage V
2 (limit voltage), the load is forcibly disconnected from the battery 14 after the post-purge operation, and only the operating power of the control circuit 2 is supplied. Therefore, the dotted line b in FIG.
Is reduced as shown by the solid line c, and a decrease in the capacity of the battery 14 can be suppressed.

As described above, in the battery voltage abnormality detection device 1 of the above embodiment, the detection voltage Vi detected by the voltage detection circuit 3 and the two reference voltages V1, V2
Are compared by comparators 22 and 23, respectively, and the detection voltage Vi is detected.
Is lower than the reference voltage V1, an alarm signal S1 is issued. Therefore, the alarm signal S1 allows the user to recognize the decrease in the battery voltage, thereby coping with the stop of the combustion equipment due to the abnormal decrease in the battery voltage. be able to

When the detected voltage Vi falls below the limit voltage (reference voltage V2) of the battery 14, the stop signal S2
To force the combustion equipment to postpurge operation, even if the battery voltage drops abnormally during operation of the combustion equipment and the operating voltage of the fan or pump deviates from the setting, The post-purge operation can be reliably performed by the control circuit 2, so that the fan does not stop immediately when the voltage drops, and the stop operation when the abnormal voltage of the combustion equipment drops can be performed safely and reliably.

Further, by setting the reference voltage V2 to the limit voltage, when the limit voltage is detected, the operation of the combustion equipment is stopped and at the same time the post-purge operation is performed with certainty. There is no longer a stop at a high temperature, and the handling of the combustion equipment after the stop can be easily performed.

Further, since overdischarge of the battery 14 composed of a lead battery can be prevented, the occurrence of sulfation of the battery 14 can be suppressed, the life of the battery 14 can be extended, and the running cost of the combustion equipment can be reduced. It becomes possible.

Furthermore, since the battery 14 is automatically disconnected from each load after the post-purge operation by simply turning off the operation switch 12, no manual operation is required, and the combustion equipment is stored for a long time in summer. In some cases,
It is not necessary to remove the battery 14 from the device body one by one, and no special manual operation is required, so that the usability of the combustion device can be improved.

An electrolytic capacitor 10 for delay is connected to the input side of a three-terminal regulator 8 for supplying power to the control circuit 2.
After the self-holding relay 15 is turned off and the contact 15a is opened, the three-terminal regulator 8 can be operated for a predetermined period of time to supply power to the CPU 6 of the control circuit 2; Can eliminate the excessively unstable period of the control circuit 2 and perform a stable and safe operation of stopping the combustion equipment.

The circuit configuration of the voltage detection circuit 3, the power supply circuit 4, and the self-holding circuit 5 in the above embodiment is merely an example, and it can be variously modified without departing from the gist of the present invention. Not even. Further, in the above-described embodiments, a combustion device has been described as an example of a device. However, the present invention is not limited to this, and is applicable to any device that is operated by a battery, and in particular, is repeatedly operated and stopped. Can be.

[0045]

As described in detail above, claim 1 or 2
According to the invention described above, since the decrease in the battery voltage is detected by comparing the detected voltage with at least two reference voltages including the limit voltage of the battery, the voltage drop is reliably detected, and the abnormal signal corresponding to the degree of the voltage decrease is detected. Can be issued, and the user of the device can accurately recognize the voltage drop, and for example, the device can be safely and reliably operated at the time of abnormal voltage drop, for example, the device can be reliably stopped. Damage to the battery is reduced, and its life can be extended.

According to the third aspect of the present invention, even if the battery voltage of the operating combustion equipment is abnormally lowered, the fan and the like can be stopped after the post-purge operation has been reliably performed. Thus, the safe stop operation of the combustion equipment can be performed.

According to the fourth aspect of the present invention, when the battery voltage of the combustion equipment becomes low, power supply to loads other than the control circuit is cut off, but the main part of the control circuit remains for a predetermined time. Since the operable state can be attained, there is an effect that a stop operation such as post-purge can be performed more reliably and safely.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a battery voltage abnormality detection device according to the present invention.

FIG. 2 is a circuit diagram of a main part of the same.

FIG. 3 is a timing chart showing the same operation.

FIG. 4 is another timing chart showing the same operation.

[Explanation of symbols]

 1 ... Battery voltage abnormality detection device 2 ... Control circuit 3 ... Voltage detection circuit 4 ... Power supply circuit 5 Self-holding circuit 6 CPU 7 Comparison circuit 8 Three terminals Regulator 10 ... Electrolytic capacitor 12 ... Operation switch 14 ... Battery 15 ... Self-holding relay 15a, 15b ... · Contact 16 ······· Transistor 17, 18 ····· Power supply line 22, 23 ····· Comparator 24 ·········· AND circuit S1 ··· Low battery alarm signal S2 ····· Stop signal S3 ······ Operation signal V0 ········ Battery voltage V1, V2 ····· reference voltage in the rolling

Claims (4)

[Claims] 1. A voltage detecting means connected to a battery via an operation switch to detect a battery voltage, and a voltage detected by the voltage detecting means is compared with at least two reference voltages set lower than the battery voltage. And a comparison means having an AND circuit to which a comparison result signal of the comparator and a predetermined control signal of the device are inputted, wherein the comparison means compares one of the pair of comparators. And outputting a first abnormal signal based on a comparison result of the devices and outputting a second abnormal signal capable of shifting an operating device to a stop operation based on an output signal of the AND circuit. Voltage abnormality detection device. 2. The battery voltage abnormality detection device according to claim 1, wherein the first abnormality signal is a battery voltage drop warning signal. 3. The comparison means compares the comparison result of the pair of comparators with a signal of the combustion equipment fan and the pump during operation, and in a state where the combustion equipment fan and the pump are operating,
3. The battery voltage abnormality detection device according to claim 1, wherein the second abnormality signal is output when both of the pair of comparators detect a decrease in battery voltage. 4. A power supply means which is capable of continuing to supply battery power to a control circuit for controlling a device for a predetermined time when a second abnormal signal is output from said comparison means. The battery voltage abnormality detection device according to any one of claims 1 to 3, wherein