JP2004282895A - Direct-current power supply unit provided with charging function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noise due to and the power consumption of a cooling fan for cooling electronic components constituting the main unit of a power supply unit. <P>SOLUTION: A direct-current power supply unit provided with a charging function comprises the cooling fan 101 for cooling the electronic components constituting the main unit 2 of the power supply unit; a control means 60, which controls the actuation and stop of the cooling fan 101; and an output current detecting means 41, which detects the load current passed through a machine tool 4, when the machine tool 4 is used and detects a charging current during charging when the machine tool 4 is not used. When the output current detecting means 41 continuously detects no output current for a predetermined time period, the cooling fan 101 is stopped. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention has a power supply output function of supplying a DC voltage to a cordless power tool (hereinafter simply referred to as a power tool) using a removable battery pack as a power supply via a cable having a removable adapter and charging the battery pack. It relates to a charging device.
[0002]
[Prior art]
Conventionally, power tools have the advantage of being able to work in any place without any restrictions on the operation by the power cable, but when the capacity of the battery pack decreases, the battery pack can be charged or another charged battery can be used. There was a problem that it had to be replaced with a pack. Therefore, use a DC power supply that converts AC to DC when the work place and the AC power supply installation place are close and there is little movement during work. A battery pack and a DC power supply were used together as a power supply for the power tool according to the work situation using a pack.
[0003]
However, there is a problem that efficient work cannot be performed unless a charger and a DC power supply are brought to the work place. To solve these problems, a power output that detects the operation of the power tool, supplies DC power without charging when the cordless tool is operating, and charges the battery pack when the operation of the power tool is stopped A charging device with a function was proposed by Patent Document 1.
[0004]
[Patent Document 1]
JP 2000-184614 A
[Problems to be solved by the invention]
In a DC power supply device with a charge output function as disclosed in Patent Document 1, it is necessary to provide a cooling fan because heat generated by electronic components in the power supply device is large. Regardless of whether the battery pack is charged or whether the power tool is used or not, if the cooling fan is always operated, for example, if the battery pack is not charged or the power tool is not used, the electronic components Does not generate heat, which causes unnecessary noise and power consumption.
[0006]
It is an object of the present invention to obviate the above-mentioned disadvantages of the prior art and reduce noise and power consumption by cooling fans.
[0007]
[Means for Solving the Problems]
The above object is to provide a load current flowing through the power tool when the power tool is used, and to provide an output current detection means for detecting a charging current at the time of charging, and that a predetermined time continuously elapses when the output current detection means does not detect the output current. In some cases, this is achieved by stopping the cooling fan.
[0008]
Further, it is also possible to achieve by providing electronic component temperature detecting means for detecting the temperature of the electronic component, and continuing the operation of the cooling fan when the electronic component temperature detected by the electronic component temperature detecting means is equal to or higher than a predetermined value. It is possible.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing one embodiment of the DC power supply device with a charging function of the present invention.
[0010]
1 is an AC cord set, 2 is a DC power supply main body with a charging function (hereinafter simply referred to as a power supply main body), 3 is an adapter set, an adapter plug connected to the power tool 4 at one end, and connected to the power supply main body 2 at the other end. Output cable. The upper portion of the adapter plug has the same shape as the insertion portion of the battery pack 5, and is detachable from the electric tool 4 like the battery pack 5.
[0011]
FIG. 2 is a block diagram showing one embodiment of a DC power supply device with a charging function. AC cord set 1 is connected to a commercial AC power supply of AC100V. The adapter set 3 is provided with output voltage setting means 3a for outputting a voltage corresponding to each rated voltage to the plurality of power tools 4. The power tool 4 includes a DC motor 4a and a power switch 4b connected in series. When the power switch 4b is turned on, power is supplied from the power supply main body 2 via the adapter set 3. The battery pack 5 that can be mounted on the electric tool 4 includes a rechargeable storage battery 5a and a temperature element 5b (for example, a thermistor or the like) that is mounted near or in contact with the storage battery 5a.
[0012]
Reference numeral 10 denotes a switching power supply capable of outputting a predetermined charging current so as to charge various battery packs 5 having different predetermined driving voltages and battery voltages corresponding to the power tool 4 having various driving voltages. , A high-frequency transformer 12, a second rectifying / smoothing circuit 13, a switching element 14, and a switching control circuit 15. The switching control circuit 15 changes the driving pulse width of the switching element 14 to change the output voltage and output of the second rectifying / smoothing circuit 13. Adjust the current.
[0013]
The power output control means 20 controls the drive voltage of the electric tool 4 when the power switch 4b is turned on, and controls the charging current when the battery pack 5 can be charged when the power switch 4b is turned off. And a voltage / current setting circuit 22 for setting the values of the driving voltage and the charging current. When the power tool 4 is being driven, the switching control circuit 15 is fed back based on the signal of the voltage detection circuit 42 to control the switching duty of the switching element 14, and at the same time, the adapter assembly is controlled based on the signal from the output current detection circuit 41. 3 has a function of correcting a voltage drop in the cable. When the battery pack 5 can be charged when the power switch 4b is turned off, the switching control circuit 15 is fed back based on a signal from the output current detection circuit 41 to control the switching duty of the switching element 14, and the battery pack 5 is charged. Is controlled based on the output of the battery state detecting means 50.
[0014]
The power output switching means 30 includes a power output switch circuit 31 for supplying power output to the power tool 4 when the power switch 4b is turned on, and a charge output switch for charging the battery pack 5 when the power tool 4 is not used. It is composed of a circuit 32. The charge output switch circuit 32 includes a relay circuit as proposed in, for example, JP-A-2002-315223.
[0015]
The power output detection means 40 includes an output current detection circuit 41 for detecting a current supplied to the electric power tool 4 when the power switch 4b is turned on or a charging current supplied to the battery pack 5 when the power switch 4b is turned off. A voltage detection circuit 42 for detecting an output voltage of the circuit 13, a trigger detection circuit for detecting that the power switch 4b is turned on, and outputting a charging non-permission signal and a signal for permitting power supply to the electric tool 4 at that moment. 43, an output voltage setting detection circuit 44 for detecting the set voltage of the output voltage setting means 3a of the adapter set 3, and the like.
[0016]
The battery state detecting means 50 includes a battery voltage detecting circuit 51 for detecting the battery voltage of the storage battery 5a, and a battery temperature detecting circuit 52 for detecting the battery temperature according to the characteristics of the temperature element 5b in the battery pack 5.
[0017]
The microcomputer 60 constituting the control means of the present invention sets the drive voltage of the power tool 4 based on the output of the power output detection means 40 and the output of the battery state detection means 50, and sets the battery pack 5 when the power tool 4 is not used. In addition to setting the charging current, it is determined whether or not charging is possible based on whether the power tool 4 is not used, that is, the power switch 4b is turned off and the output of the battery state detecting means 50. When the battery pack 5 is chargeable, a trigger is detected. It has a function of outputting a charge permission signal to the charge output switch circuit 32 via the circuit 43, for example.
[0018]
For example, the display circuit 70 including an LED or the like displays, based on the output of the microcomputer 60, whether the power tool 4 is in use, whether the power tool 4 is usable, or that the battery pack 5 is being charged. Is displayed. The auxiliary power supply circuit 80 supplies a power supply such as the microcomputer 60 and a reference voltage Vcc such as the power supply output control means 20, the power supply output detection means 40, and the battery state detection means 50.
[0019]
The electronic component temperature detecting means 90 includes an electronic component temperature detecting circuit 92 that detects the temperature of the electronic component according to the characteristics of the temperature element 91 that monitors the component temperature in the power supply device main body 2.
[0020]
The cooling fan control unit 100 includes a cooling fan control circuit 102 that operates and stops the cooling fan 101 according to a signal from the microcomputer 60.
[0021]
Next, the operation of the power supply device main body 2 of the present invention will be described with reference to the block diagram of FIG. 2 and the flowchart of FIG. When the AC cord set 1 is connected to a commercial AC power supply of 100 VAC, the auxiliary power supply circuit 80 is activated and supplies the reference voltage Vcc to the microcomputer 60, the power supply output control means 20, and the like. Then, the microcomputer 60 resets a charging completion flag, a charging flag, a battery pack flag indicating that the battery pack 5 has been inserted into the battery pack insertion slot of the power supply main body 2, and an output current zero counter in the RAM serving as storage means. At the same time, a signal for turning off the charge output switch circuit 32 of the power supply output switching means 30 is output to perform an initial set (step 301). Subsequently, the microcomputer 60 outputs a signal for activating the switching power supply 10 to the switching control circuit 15 of the switching power supply 10 (step 302). When the power switch 4b of the power tool 4 is turned on, the trigger of the power output detection means 40 is activated. The detection circuit 43 turns on the power output switch circuit 31 in the power output switching means 30 and supplies a predetermined drive voltage corresponding to the rated voltage of the power tool 4.
[0022]
Next, the electronic component temperature based on the temperature data input to the microcomputer 60 from the electronic component temperature detection circuit 92 that detects the electronic component temperature in accordance with the characteristics of the temperature element 91 that monitors the electronic components in the power supply main body 2 is: It is determined whether the temperature is lower than a predetermined temperature (step 303). If it is not less than the predetermined value, the cooling fan 101 is operated (step 304), and the process jumps to step 307. If it is equal to or less than the predetermined value, it is determined whether or not the state of zero output current has passed a predetermined time S (step 305). If the predetermined time S has not elapsed, the process jumps to step 307. If the predetermined time S has elapsed, the cooling fan 101 is stopped (step 306).
[0023]
Next, the microcomputer 60 determines whether or not the battery pack 5 is inserted into the power supply main body 2 based on the outputs of the battery voltage detection circuit 51 and the battery temperature detection circuit 52 of the battery state detection means 50 (Step 307). When it is determined that the battery pack 5 is inserted, the battery pack flag is set (step 308). When the battery pack 5 is not inserted, the charge completion flag, the charging flag, the battery pack flag, and the output current zero in the RAM are set. The counter is reset (step 309). Subsequently, to determine whether the power switch 4b has been turned off, it is determined whether or not the output current is zero based on the output of the output current detection circuit 41 (step 310).
[0024]
If the output current is zero, it is determined whether or not the battery pack 5 is inserted into the power supply main body 2 (step 311). If the battery pack 5 is not inserted into the power supply main body 2, the cooling fan 101 is turned off. It is determined whether the operation is in progress (step 338). If it is determined in step 338 that the cooling fan 101 is not operating, the process returns to step 303 again.
[0025]
If it is determined in step 338 that the cooling fan 101 is operating, it is determined whether the output current zero counter has started (step 339). If the output current zero counter has not started in step 339, the process returns to step 303 again. In step 339, if the zero output current counter has started, the zero output current counter is started (step 340), and the process returns to step 303 again.
[0026]
If the battery pack 5 is inserted in step 311, it is determined whether or not the battery pack 5 has been charged (step 312). If the battery pack 5 has been charged, the processing from step 338 to step 340 is performed, and step 303 is performed. Return to If the battery pack 5 is not in the charging completed state in step 312, it is determined whether or not the battery pack 5 is being charged (step 313). Whether the battery pack 5 is present or not is determined based on the output of the battery temperature detection circuit 52 (step 314). When the battery pack 5 is at a high temperature, the processing from step 338 to step 340 is performed, and the process returns to step 303. If the temperature of the battery pack 5 is not high in step 314, it is continuously monitored whether or not the power switch 4b is turned on based on the output of the trigger detection circuit 43 (step 315), and the power switch 4b is turned on in step 315. If not, first, the microcomputer 60 outputs a signal to operate the cooling fan 101 from the microcomputer 60 to operate the cooling fan 101 via the cooling control circuit 102 (step 316). A signal is output to the current setting circuit 22 (step 317), and then a charge permission signal is output to the trigger detection circuit 43 and the charge output switch circuit 32 (step 318). At the same time as turning off the charging output switch circuit 32 to start charging, and It sets a flag (step 319), returns to step 303.
[0027]
If the output current is not zero in step 310, a signal for operating the cooling fan 101 is output from the microcomputer 60, the cooling fan 101 is operated via the cooling control circuit 102 (step 320), and the output current zero counter is cleared. (Step 321) Subsequently, it is monitored whether or not the power switch 4b is turned on based on the output of the trigger detection circuit 43 (Step 322). If the power switch 4b is turned on in step 322, it is determined whether or not there is a charging flag (step 323). If there is a charging flag, the process jumps to step 315. If there is no charging flag, the process returns to step 311.
[0028]
If the power switch 4b is not turned on in step 322, a full charge determination is made by detecting the battery voltage of the battery pack 5 (step 324). The full charge determination is performed by inputting the battery voltage to the microcomputer 60 via the battery voltage detection circuit 51. As is well known, a peak charge detection, -ΔV detection, and the like are known as full charge determinations by battery voltage detection.
[0029]
If the battery pack 5 is fully charged, the charging flag is reset (step 335), the charging completion flag is set (step 336), the charge output switch circuit 32 is turned off (step 337), and the process returns to step 303 again. .
[0030]
If the battery pack 5 is not fully charged in step 324, it is determined whether or not the battery pack 5 is at a high temperature that should not be charged based on the output of the battery temperature detection circuit 52 (step 325). At the time, the processes after step 335 are performed again as described above. When the battery pack 5 is not at a high temperature, a battery temperature gradient having a predetermined sampling width is continuously calculated based on the output of the battery temperature detection circuit 52 from the characteristics of the temperature element 5b incorporated in the battery pack 5, and the temperature gradient is determined to be a predetermined value. If the value is equal to or larger than the value K, a full charge determination is performed by a well-known dT / dt detection for determining a full charge (step 326). If the temperature gradient of the battery pack 5 is equal to or smaller than the predetermined value K in step 326, the process returns to step 303. If a temperature gradient equal to or higher than the predetermined value K is detected, the battery pack 5 is determined to be fully charged, and the process from step 335 is performed again as described above.
[0031]
In step 313, when the battery pack 5 is being charged, that is, in this case, when the power switch 4b is turned on once during charging and then the power switch 4b is turned off, it is determined whether or not the output current zero counter has started. It is determined (step 327). If the output current zero counter has started, the process jumps to step 331. In step 327, if the output current zero counter has not started, the output current zero counter is started (step 328), and then the state of zero output current continues, that is, the continuous unused time of the power tool 4 for a predetermined time. It is determined whether or not T (S> T) has elapsed, that is, whether or not the power switch 4b is continuously turned off (step 329). When a predetermined time has elapsed, charging of the battery pack 5 is restarted. Therefore, the process skips to step 315. The predetermined time is desirably set in consideration of, for example, a sampling time of a battery voltage and a battery temperature for full charge determination or an actual use form of the power tool 4, and is, for example, one minute.
[0032]
In step 329, if the state of zero output current has not continued for a predetermined period of time, a charge disapproval signal is continuously output to the trigger detection circuit 43 and the charge output switch circuit 32 (step 331). It is determined whether or not the battery pack 5 is inserted into the power supply main body 2 (step 332). If the battery pack 5 is not inserted into the power supply main body 2, the process jumps to step 338. When the battery pack 5 is inserted, the power switch 4b is turned on once during charging, and the battery pack 5 should not be charged at a high temperature in order to continuously determine full charge even in a state where charging is not performed. Whether the battery pack 5 is present is determined based on the output of the battery temperature detection circuit 52 (step 333). When the temperature of the battery pack 5 is high, the processes after step 335 are performed again as described above. When the battery pack 5 is not at a high temperature, a battery temperature gradient having a predetermined sampling width is continuously calculated based on the output of the battery temperature detection circuit 52 from the characteristics of the temperature element 5b incorporated in the battery pack 5, and the temperature gradient is determined to be a predetermined value. If the value is equal to or larger than the value K1 (K1 ≦ K), a full charge determination is performed by detecting dT / dt for determining a full charge (step 334). If the temperature gradient of the battery pack 5 is equal to or less than the predetermined value K1 in step 334, the process returns to step 303. If a temperature gradient equal to or higher than the predetermined value K1 is detected, the battery pack 5 is determined to be fully charged, and the processes from step 335 are performed again as described above.
[0033]
Here, the determination thresholds K and K1 for dT / dt detection are different between during charging and when charging is stopped. However, the present invention is not limited to this, and may be set to the same value. The most important thing is that the calculation of the temperature gradient in the dT / dt detection is performed continuously irrespective of whether the battery pack 5 is being charged or not, so that the power tool can be operated immediately before the battery pack 5 is fully charged. Even if it operates, the full charge determination is performed by detecting the battery temperature regardless of the presence or absence of the charging current, so that the full charge detection can be reliably performed.
[0034]
This is because even if the supply of charging current to the battery pack 5 is stopped immediately before full charge, the battery pack 5 generates oxygen gas just before full charge like a nickel-cadmium battery or a nickel-metal hydride battery, and generates heat due to the absorption reaction. This is because in such a battery, even after the charging is stopped, the temperature rises to a considerable extent. Therefore, it is effective to determine whether the battery is fully charged by detecting the temperature continuously.
[0035]
【The invention's effect】
As described above, according to the present invention, the cooling fan is stopped by stopping the cooling fan after a predetermined time has elapsed after use of the power tool or when the temperature of the electronic components in the power supply body has reached a predetermined value or less. Noise and power consumption can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a DC power supply device with a charging function of the present invention.
FIG. 2 is a block diagram showing an embodiment of the DC power supply device of the present invention.
FIG. 3 is a flowchart for explaining the operation of the DC power supply device of the present invention.
[Explanation of symbols]
2 is a power supply main body, 3 is an adapter set, 4 is a power tool, 5 is a battery pack, 10 is a switching power supply, 20 is a power output control means, 30 is a power output switching means, 40 is a power output detection means, and 43 is a trigger. A detection circuit, 50 is a battery state detection circuit, 52 is a battery temperature detection means, 60 is a microcomputer, and 90 is a cooling fan control means.

Claims (2)

A DC power supply device with a charging function for supplying a DC voltage via a cable provided with a detachable adapter to a cordless tool powered by a detachable battery pack and charging the battery pack when the cordless tool is not used,
A cooling fan for cooling the electronic components constituting the DC power supply, control means for controlling the operation and stop of the cooling fan, and an output current for detecting a load current flowing through the tool when using the tool and detecting a charging current when charging A DC power supply device with a charging function, comprising: a detection unit, wherein the cooling fan is stopped when a predetermined period of time has continuously elapsed during which the output current detection unit does not detect the output current. A DC power supply device with a charging function for supplying a DC voltage via a cable provided with a detachable adapter to a cordless tool powered by a detachable battery pack and charging the battery pack when the cordless tool is not used,
A cooling fan that cools electronic components constituting the DC power supply device; an electronic component temperature detecting unit that detects a temperature of the electronic component; and a control unit that controls operation and stop of the cooling fan. A DC power supply with a charging function, wherein the cooling fan is continuously operated when the temperature of the electronic component detected by the detecting means is equal to or higher than a predetermined value.

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