JP2004079215A - Charger for battery forklift - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charger for a battery forklift capable of changing a charging system inexpensively. <P>SOLUTION: A switching regulator 3 is connected to an external ac power supply 1 via a magnet switch 2. The switching regulator 3 is provided with a voltage applying means 7 which detects charging voltage actually that is applied to a battery 5 with the switching regulator 3. Based on the actually applied charging voltage, the voltage applying means 7 calculates charging time that remains until the end of charging in the case of carrying out constant current charge, calculates assumed charging voltage to be applied to the battery 5 at a timing earlier by the time equal to the remaining charging time than the timing of the end of charging in the case of carrying out quasi-constant voltage charge and then outputs it to the charge controller 4. Consequently, the charge controller 4, which is originally used only for quasi-constant voltage charge, can be used for constant current charge. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a charger for charging a battery mounted on a battery forklift.
[0002]
[Prior art]
Conventionally, some battery forklifts are equipped with a charger for charging the battery mounted on the vehicle body with an external power supply, and a quasi-constant-voltage charger or a constant-current charger is used as this charger. Have been.
[0003]
FIG. 6 is a functional block diagram showing an example of a quasi-constant voltage system charger. The quasi-constant voltage system charger includes a magnet switch 102 for turning on / off an external AC power supply 101, a quasi-constant voltage transformer 103, and a rectifier. 104 and a charge controller 105. The charging controller 105 detects the charging voltage applied from the rectifier 104 to the battery 106, and determines the remaining charging time until the end of charging, for example, according to a charging characteristic represented by the relationship between the charging elapsed time and the charging voltage shown in FIG. Calculate. Then, from the start of charging, the magnet switch 102 is turned on to continue charging until the remaining charging time becomes 0, and when the remaining charging time becomes 0, the magnet switch 102 is turned off to terminate charging.
[0004]
According to this quasi-constant voltage system charger, the battery 106 can be charged with the current density kept below a certain value in order to reduce the decrease in battery capacity, but it takes a long time (for example, 8 to 10 hours) to charge the battery 106. Must.
[0005]
On the other hand, FIG. 8 is a functional block diagram showing an example of a constant current type charger. The constant current type charger includes a magnet switch 202 for turning on / off an external AC power supply 201, a magnet switch 202 and a battery 205. And a charging controller 204 connected between them. The charging controller 204 detects a charging voltage applied from the switching regulator 203 to the battery 205, and according to a charging characteristic represented by a relationship between the charging elapsed time and the charging voltage shown in FIG. Calculate time. Then, the magnet switch 202 is turned on to continue charging until the remaining charge time becomes 0 from the start of charging, and when the remaining charge time becomes 0, the magnet switch 202 is turned off to end the charge.
[0006]
According to this constant current type charger, the battery 205 can be charged with a constant current regardless of the progress of charging, so that so-called rapid charging that completes charging in a short time can be performed.
[0007]
[Problems to be solved by the invention]
Since the above-described quasi-constant voltage system charger and the constant current system charger have different configurations, conventionally, a charger of one of the charging systems is selected and mounted on a battery forklift. Therefore, when a quasi-constant voltage system charger is installed, rapid charging like a constant current system cannot be performed, and when a constant current system charger is mounted, charging while suppressing a decrease in battery capacity like a quasi-constant voltage system cannot be performed. Had become.
[0008]
Therefore, for example, if it is attempted to change the quasi-constant voltage system to the constant current system for a battery forklift in which a quasi-constant voltage system charger is already mounted and to enable quick charging, the quasi-low voltage transformer 103 and the rectifier 104 Not only the switching regulator 203 but also the charge controller needs to be replaced from the semi-constant voltage system charge controller 105 to the constant current system charge controller 204 in order to avoid overcharging. There was a problem that the cost for the change was large.
[0009]
SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the prior art and to provide a battery forklift charger that can change the charging method at low cost.
[0010]
[Means for Solving the Problems]
To achieve this object, a magnet switch connected to an external power supply, a switching regulator for adjusting power from the external power supply when the magnet switch is on and supplying the battery to a battery, and turning on / off the magnet switch The switching regulator detects an actual charging voltage applied to the battery by the switching regulator, and terminates charging when performing constant-current charging based on the actual charging voltage. Calculating the remaining charge time until the battery is charged, and calculating the assumed charge voltage applied to the battery at a point in time when the charge is completed by a time equal to the remaining charge time from the end of charging when performing semi-constant voltage charging. Voltage applying means for outputting to the controller is provided, and the charging controller Calculate the remaining charging time until the end of charging when performing quasi-constant voltage charging based on the assumed charging voltage, hold the magnet switch on until the remaining charging time becomes zero, and set the remaining charging time to A technical means is adopted in which the magnet switch is turned off at the time when the value becomes zero.
[0011]
According to this, since the battery is charged by the switching regulator, it can be rapidly charged by the constant current method, and the actual charging voltage actually applied to the battery by the voltage applying means performs the semi-constant voltage charging. Since the battery is converted into a charging voltage (assumed charging voltage) that is assumed when the charging is performed and is applied to the charging controller, the battery is overcharged even when the charging controller used for the quasi-constant voltage method is used. Will not be.
[0012]
Also, when changing the charging method, the quasi-constant voltage transformer and rectifier may be replaced with a switching regulator, so that, for example, a battery forklift that already has a quasi-constant voltage method charger can be quickly charged. Can be remodeled.
[0013]
In the present invention, for example, the voltage application unit includes a voltage detection unit that detects an actual charging voltage applied to the battery by the switching regulator, and the actual charging voltage detected by the voltage detection unit is a predetermined inversion point. Voltage determining means for determining whether the voltage exceeds the voltage, charging characteristic data when performing constant-current charging represented by the relationship between the charging elapsed time and the charging voltage, and the relationship between the charging elapsed time and the charging voltage. Storage means for storing in advance the charging characteristic data when performing the sub-low voltage charging represented, and constant current charging stored in the storage means when the actual charging voltage exceeds the inversion point voltage. Means for calculating the remaining charge time until the end of charging based on the actual charge voltage in accordance with the charge characteristic data of In the case where the semi-constant-voltage charging is performed in accordance with the charging characteristic data of the semi-constant-voltage charging stored in the storage unit, a time equal to the remaining charging time calculated by the remaining charging time calculating unit from the end of charging. Calculating the assumed charging voltage at the time of going back, and when the actual charging voltage is equal to or less than the inversion point voltage, an assumed charging voltage calculating means for setting the assumed charging voltage to a predetermined value; and Output means for applying the calculated assumed charging voltage to the charging controller may be adopted.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
A battery forklift according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
[0015]
FIG. 1 is a functional block diagram of a battery forklift charger according to one embodiment of the present invention. The charger includes a magnet switch 2 connected to an external AC power supply 1 and a magnet switch 2 connected to the external AC power supply 1. A switching regulator 3 connected to the battery switch 5 for adjusting the power from the external power supply 1 to supply the battery 5 when the magnet switch 2 is on, and a charging controller 4 for controlling on / off of the magnet switch 2. The battery 5 is charged with a constant current charging characteristic as shown in FIG.
[0016]
The switching regulator 3 is composed of a switching regulator body 6 that adjusts the power from the external AC power supply 1 and applies a voltage to the battery 5, and a voltage application unit 7 that applies a predetermined voltage to the charge controller 4. I have. Here, as shown in FIG. 2, the voltage applying means 7 calculates the constant-current charging characteristic data (see FIG. 9) expressed by the relationship between the charging elapsed time and the charging voltage, and the charging elapsed time and the charging voltage. The storage means 71 storing the charging characteristic data of the quasi-low-voltage system (see FIG. 7) expressed by the following relationship: the actual charging voltage V applied between the switching regulator body 6 and the battery 5 (between the terminals of the battery 5 A voltage), and a voltage determination unit 73 that determines whether the actual charging voltage V detected by the voltage detection unit 72 exceeds a predetermined inversion point voltage Vp. Further, when the actual charging voltage V exceeds the inversion point voltage Vp, the voltage applying means 7 determines the remaining charge until the end of charging based on the actual charging voltage V in accordance with the constant current type charging characteristic data stored in the storage means 71. The remaining charge time calculating means 74 for obtaining the time Tr performs the semi-constant voltage charging in accordance with the semi-constant voltage charging characteristic data stored in the storage means 71 when the actual charging voltage V exceeds the inversion point voltage Vp. In this case, the assumed charging voltage V 'at the time when the time equal to the remaining charging time Tr calculated by the remaining charging time calculating means 74 is calculated from the charging end point, and the actual charging voltage V is equal to or less than the inversion point voltage Vp. An assumed charging voltage calculating means 75 for setting the assumed charging voltage V 'to a predetermined value, and an output means 76 for applying the assumed charging voltage V' obtained by the assumed charging voltage calculating means 75 to the charge controller 4. , Comprising a.
[0017]
FIG. 3 is a flow chart of a control program of the voltage applying means 7. In the voltage applying means 7, first, the voltage detecting means 72 detects the actual charging voltage V (S1), and the actual charging voltage V is used as the voltage determining means. If it is determined at 73 that the voltage is equal to or lower than the inversion point voltage Vp (No in S2), the assumed charging voltage V ′ is set to a constant value, for example, the inversion point voltage Vp by the assumed charging voltage calculating means 75 (S3), and the assumed charging is performed. The voltage V 'is applied from the output means 76 to the charge controller 4 (S4).
[0018]
On the other hand, if the voltage determination means 73 determines that the actual charging voltage V exceeds the inversion point voltage Vp (Yes in S2), the remaining charge time calculation means 74 stores the constant current charging characteristic data stored in the storage means 71. Thus, the remaining charging time Tr from the time of detection of the charging voltage to the end of charging is obtained based on the actual charging voltage V (S5). The storage means 71 stores constant-current charging characteristic data shown in FIG. 9, and the remaining charge time calculation means 74 stores the charge elapsed time at the time of detection of the charge voltage corresponding to the actual charge voltage V from the storage means 71. At the same time as reading t, the charging elapsed time T at the end of charging is read. Then, the remaining charge time Tr is obtained by performing a calculation by subtracting the charge elapsed time t at the time of detecting the charge voltage from the charge elapsed time T at the time of completion of the charge.
[0019]
Further, in the assumed charging voltage calculating means 75, the remaining charging time calculating means 74 calculates the charge time from the end of charging when performing the semi-constant voltage charging in accordance with the semi-constant voltage charging characteristic data stored in the storage means 71. An expected charging voltage V 'at a point in time that is equal to the remaining charging time Tr is calculated (S6). The storage unit 71 stores the charging characteristic data of the quasi-constant voltage method shown in FIG. 7. The assumed charging voltage calculation unit 75 reads the elapsed charging time T ′ at the end of charging from the storage unit 71, The remaining charge time Tr obtained by the remaining charge time calculation means 74 is subtracted from the charge elapsed time T 'at the end of charging to calculate the charge elapsed time t'. Then, by reading the charging voltage V 'corresponding to the elapsed charging time t' from the storage means 71, the assumed charging voltage V 'is obtained. The assumed charging voltage V 'obtained by the assumed charging voltage calculating means 75 in this way is applied from the output means 76 to the charging controller 4 (S4).
[0020]
FIG. 4 is a functional block diagram of the charge controller 4. The charge controller 4 stores semi-constant-voltage charge characteristic data represented by the relationship between charge elapsed time and charge voltage shown in FIG. Storage means 41, a voltage detection means 42 for detecting the voltage V 'applied from the voltage application means 7, and the remaining voltage based on the voltage V' detected by the voltage detection means 42 according to the charging characteristic data of the storage means 41. The remaining charge time calculating means 43 for obtaining the charge time Tr ', the remaining charge time determining means 44 for determining whether the remaining charge time Tr' is greater than 0, and the determination result of the remaining charge time determining means 44 A switch driving unit 45 for turning on / off the magnet switch 2.
[0021]
FIG. 5 is a flow chart of a control program of the charge controller 4. In the charge controller 4, first, the voltage V 'applied from the voltage application means 7 is detected by the voltage detection means 42 (S11), and the remaining charge is performed. According to the charging characteristic data of the quasi-constant voltage method stored in the storage means 41 by the time calculation means 43, the remaining charge time Tr 'until the end of charging is obtained based on this voltage V' (S12). The storage characteristic data of the quasi-constant voltage method shown in FIG. 7 is stored in the storage means 41, and the remaining charge time calculation means 43 reads the charge elapsed time t 'corresponding to the voltage V' from the storage means 41, The elapsed charging time T 'at the end of charging is read. Then, a remaining charge time Tr 'is obtained by performing a calculation by subtracting the charge elapsed time t' from the charge elapsed time T 'at the end of charging. Note that the remaining charge time Tr 'has a value equal to the remaining charge time Tr obtained by the remaining charge time calculation means 74 of the voltage applying means 7.
[0022]
Then, the remaining charge time determination means 44 determines whether or not the remaining charge time Tr 'is greater than 0 (S13). If the remaining charge time Tr' is greater than 0 (Yes in S13), the switch driving means 45 turns on the magnet. The switch 2 is turned on (S14), and if it is 0 or less (No in S13), the switch driving unit 45 turns off the magnet switch 2 (S15).
[0023]
Thus, the battery 5 can be rapidly charged by the constant current method using the switching regulator 3 while using the charge controller 4 which is originally used only for the quasi-constant voltage method charging. There is no danger.
[0024]
In addition, quick charging is possible by a very simple modification of replacing the quasi-constant voltage transformer and rectifier of the conventional quasi-constant voltage system charger already mounted on the battery forklift with the switching regulator 3 having the built-in voltage applying means 7. Since there is no need to replace the charge controller, it can be modified at low cost.
[0025]
【The invention's effect】
As described above, according to the present invention, the quasi-constant voltage transformer and the rectifier can be changed from the quasi-constant voltage system to the constant current system by a simple modification of replacing the quasi-constant voltage transformer and the rectifier with a switching regulator having a voltage application unit. Can be obtained. In addition, since there is no need to change the charging controller when changing the charging method, the charging can be performed at low cost.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing a charger of the present invention.
FIG. 2 is a functional block diagram showing a switching regulator included in the charger of the present invention in detail.
FIG. 3 is a flowchart of a control program for a switching regulator.
FIG. 4 is a functional block diagram showing in detail a charge controller provided in the charger of the present invention.
FIG. 5 is a flowchart of a control program of a charge controller.
FIG. 6 is a functional block diagram showing an example of a conventional semi-constant voltage system charger.
FIG. 7 is a charging characteristic diagram of a semi-constant voltage system.
FIG. 8 is a functional block diagram showing an example of a conventional constant current type charger.
FIG. 9 is a charging characteristic diagram of a constant current method.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 external AC power supply 2 magnet switch 3 switching regulator 4 charge controller 5 battery 7 voltage application means 71 storage means 72 voltage detection means 73 voltage determination means 74 remaining charge time calculation means 75 assumed charge voltage calculation means 76 output means

Claims (2)

A magnet switch connected to an external power supply, a switching regulator for adjusting power from the external power supply to supply the battery to the battery when the magnet switch is on, and a charging controller for controlling on / off of the magnet switch. With
The switching regulator detects the actual charging voltage applied to the battery by the switching regulator, determines the remaining charging time until the end of charging when performing the constant current charging based on the actual charging voltage, In the case of performing the voltage-based charging, a voltage application unit is provided that obtains an assumed charging voltage to be applied to the battery at a point in time that is equal to the remaining charging time from a charging end point and applies the charging voltage to the charging controller.
The charging controller obtains a remaining charging time until the end of charging when performing semi-constant voltage charging based on the assumed charging voltage from the voltage applying unit, and determines the magnet switch until the remaining charging time becomes zero. , And when the remaining charge time becomes zero, the magnet switch is turned off. The voltage applying means,
Voltage detection means for detecting the actual charging voltage applied to the battery by the switching regulator,
Voltage determining means for determining whether the actual charging voltage detected by the voltage detecting means exceeds a predetermined inversion point voltage,
Charging characteristic data when performing constant-current charging represented by the relationship between charging elapsed time and charging voltage, and charging characteristics when performing sub-low-voltage charging represented by the relationship between charging elapsed time and charging voltage Storage means for storing data in advance;
When the actual charging voltage is higher than the inversion point voltage, a remaining charging time calculation for obtaining a remaining charging time until the end of charging based on the actual charging voltage in accordance with the charging characteristic data of the constant current charging stored in the storage means. Means,
When the actual charging voltage is higher than the inversion point voltage, the remaining charge from the end of charging when performing the semi-constant voltage charging in accordance with the charging characteristic data of the semi-constant voltage charging stored in the storage means. An assumed charging voltage at a point in time when the time equal to the remaining charging time obtained by the time calculating means is calculated, and when the actual charging voltage is equal to or less than the inversion point voltage, the assumed charging voltage is set to the predetermined charging voltage. Voltage calculation means,
2. The battery forklift charger according to claim 1, further comprising output means for applying the assumed charge voltage obtained by the assumed charge voltage calculation means to the charge controller.

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