JPH0732537B2 - Allowable current value control device in electric device control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an allowable current value control device for controlling an allowable current value defined in each of an electric device using a battery as a driving source and a driving device. It is a thing.

(Prior Art) Conventionally, for example, in a traveling DC motor for a battery-powered forklift, a permissible current value is set in advance for a current flowing through the motor in order to ensure safety, and the current flowing through the motor is equal to or more than the permissible current value. When it reaches, the power supply to the DC motor is cut off and the motor is stopped.

Similarly, in other electric devices, the permissible current value is set according to the device in order to ensure safety.

(Problems to be Solved by the Invention) However, the permissible current value does not fluctuate from time to time according to the discharge rate of the battery of the drive source and the load state, but remains at the value initially set.

Therefore, since the permissible current value that does not change from time to time is guaranteed for the electric device, when the battery is supplying a large current to the electric device while the discharge rate of the battery is advanced,
Alternatively, when the electric device is operated in a heavy load state of the battery, there is a problem that the life of the battery is shortened and other electric components are adversely affected.

In order to solve the above problems, the present invention automatically changes the allowable current value of the electric device according to the discharge rate and the load state of the battery, and controls the electric device based on the changing allowable current value, An object of the present invention is to provide a control device for a permissible current value that can extend the life of a battery and improve the reliability of electrical components.

Configuration of the Invention (Means for Solving the Problems) In order to achieve the above object, a first invention is a battery for operating an electric device, a current detector for detecting a current flowing through the electric device, and the current. In the electric equipment control device, which comprises a control means for cutting off the power supply to the electric equipment when the current value of the electric equipment detected by the detector at that time reaches the allowable current value of the electric equipment, discharge of the battery A battery capacity detecting device for detecting the rate, and an allowable current value of the electric device with respect to the discharge rate of the battery at that time detected by the battery capacity detecting device so as to vary the allowable current value relative to the discharge rate of the battery. The gist is an allowable current value control device in an electric device control device provided with a calculation means for calculating.

A second invention is a battery for operating a plurality of electric devices, current detectors for detecting currents flowing in the electric devices, and currents of the electric devices detected by the current detectors. In an electric device control device comprising a control means for shutting off power supply to the electric device when the value reaches an allowable current value of the electric device, a battery capacity detection device for detecting a discharge rate of the battery, and A drive state detector that detects the drive state of an electric device, an indexing unit that determines the load of the battery based on a detection signal from the drive state detector, and an allowable current value of each electric device of the battery at that time. The discharge rate of the battery at that time detected by the battery capacity detecting device and the index so as to vary relative to the discharge rate and the load of the battery. The gist is a permissible current value control device in an electric device control device including a calculation means for calculating the permissible current value of each of the electric devices with respect to the load at that time determined by the means.

(Operation) In the first aspect of the invention, the calculating means calculates the allowable current value of the electric device based on the current discharge rate of the battery detected by the battery capacity detection device, and the allowable current value is relative to the discharge rate of the battery. To make it fluctuate.

Further, in the second invention, the calculation is made based on the discharge rate of the battery at that time detected by the battery capacity detection device and the load of the battery calculated from the drive state of each electric device detected by the drive state detector. The means is to change the allowable current value of each electric device relative to the discharge rate and load of the battery at that time.

(Embodiment) An embodiment of a current value control device embodying the present invention in a battery-operated forklift will be described below with reference to the drawings.

FIG. 1 shows a drive circuit of a battery-operated forklift, in which a traveling motor 1 and a cargo handling motor 2 are connected to a battery 5 made of a lead battery via a traveling contactor 3 and a cargo handling contactor 4, respectively. The traveling and cargo handling motors 1 and 2 are DC series-wound motors, and the traveling motor 1 drives drive wheels (not shown), and the cargo handling motor 2
Drives a hydraulic pump (not shown) in the cargo handling hydraulic circuit.

A forward contactor 6 and a reverse contactor 7 are connected to the field winding 1b of the traveling motor 1, and both contactors 6,
Based on the switching operation of 7, the traveling motor 1 is rotated in the forward and reverse directions, that is, the forklift is moved forward and backward.

A traveling current detector 8 is connected between the armature 1a of the traveling motor 1 and the field winding 1b so as to detect the armature current of the traveling motor 1.

A traveling switching transistor (hereinafter referred to as a traveling transistor) 9 is connected in series to the traveling motor 1 and is turned on / off based on a traveling chopper signal SG1 to be described later which is input to a base terminal of the traveling motor 1. The driving motor 1 is drive-controlled. A traveling bypass contactor 10 is connected between the collector and the emitter of the traveling transistor 9.

On the other hand, in the cargo handling motor 2, a cargo handling switching transistor (hereinafter referred to as a cargo handling transistor) 11
Is connected in series to the cargo handling motor 2 and is input to the base terminal of the cargo handling chopper signal SG2 described later.
The motor 2 for loading and unloading is controlled to be driven based on the above. A cargo handling bypass contactor 12 is connected between the collector and the emitter of the cargo handling transistor 11.

As with the traveling motor 1, the cargo handling current detector 13 is connected in series to the armature 2a of the cargo handling motor 2 so as to detect the armature current of the motor 2.

Next, an electric circuit which controls the operation of each contactor and each transistor provided in the drive circuit configured as described above will be described with reference to FIG.

In FIG. 2, the lift lever operation amount detection sensor 21 is composed of a potentiometer, detects the operation amount of the lift lever 22 provided in the driver's seat, and outputs the detection signal to the A / D converter 23.
A digital signal (lift operation amount signal SG3) is output via.

The tilt lever operation amount detection sensor 24 is composed of a potentiometer, detects the operation amount of the tilt lever 25 provided in the driver's seat, and outputs the detection signal via the A / D converter 23 as a digital signal (tilt operation amount signal SG4). Is output. The accelerator pedal operation amount detection sensor 26 is composed of a potentiometer, detects the operation amount of the accelerator pedal 27 provided in the driver's seat, and outputs the detection signal via the A / D converter 23 as a digital signal (accelerator operation amount signal SG5 ) And output.

The traveling current detector 8 charges the capacitor 29 via the resistor 28 with a detection current corresponding to the armature current of the traveling motor 1. Then, the charging voltage having a voltage value corresponding to the armature current is output as a digital signal (running current value signal SG6) via the A / D converter 30. Further, the cargo handling current detector 13 charges the capacitor 32 through the resistor 31 with a detection current corresponding to the armature current of the cargo handling motor 2. Then, the charging voltage of the voltage value corresponding to the armature current is A / D
Digital signal (current value signal SG for cargo handling) via converter 30
Output as 7).

The capacity detector 33 detects the discharge rate of the battery 5 and detects the current discharge rate data signal of the battery 5 (discharge rate signal SG
8) is output to the central processing unit 34 of the next stage via the A / D converter 30.

Central processing unit as control means and calculation means (hereinafter CP
A U) 34 receives the signals SG3 to SG8 and operates according to a control program stored in a program memory 35 including a read-only memory (ROM).

The CPU 34 determines the operation amount of each lever 22, 25 at that time based on the lift and tilt operation amount signals SG3, SG4, and also determines the pedal operation amount at that time based on the accelerator operation amount signal SG5. . This indexing is based on the manipulated variable data for each signal stored in advance in the program memory 35 in addition to the control program.

Then, the CPU 34 issues a cargo handling control signal for driving and controlling the cargo handling motor 2 based on the calculated operation amounts of the levers 22 and 25, and also based on the manipulated variable of the accelerator pedal 27, the traveling motor. Programmable timer (hereinafter referred to as PTM) 36 for running control signals for driving and controlling 1
Output to.

PTM36 is based on the traveling control signal from the CPU34, that is, to output a pulse signal for traveling frequency-modulated according to the operation amount of the accelerator pedal 27, and to the cargo handling control signal. Based on the above, that is, the frequency-modulated pulse signal for cargo handling is output according to the operation amount of the lift lever 22 and the tilt lever 25.

The pulse signal for traveling is output to the transistor 38 via the AND circuit 37, and by turning on / off the transistor 38, the chopper signal SG1 is output to the base terminal of the traveling transistor 9. There is. The pulse signal for cargo handling is output to the transistor 40 via the AND circuit 39, turning on the transistor 40.
When turned off, the chopper signal SG2 is output to the base terminal of the cargo handling transistor 11.

Further, the CPU 34 determines the armature current (average value) of the traveling and cargo handling motors 1 and 2 at that time based on the traveling current value signal and the cargo handling current value signal SG6, SG7, respectively. This indexing is based on the data of each armature current for each signal SG6, SG7 stored in advance in the program memory 35.

Further, the CPU 34 receives the discharge rate signal SG8 and calculates the allowable current value Imd of the traveling motor 1 and the allowable current value Imp of the cargo handling motor 2 based on the current discharge rate of the battery 5. There is. Then, in this embodiment, the CPU3
4 is a battery 5 as shown by the solid line in FIGS. 3 and 4.
The allowable current values Imd, Imp are decreased as the discharge rate advances after the discharge rate advances and reaches a predetermined discharge rate.

Further, the CPU 34 determines the states of the traveling motor 1 and the cargo handling motor 2 based on the calculated armature currents (average values) of the traveling and cargo handling motors 1 and 2 at that time, that is, whether the forklift is only traveling. It is designed to judge whether only the cargo handling work is performed, or whether the traveling and the cargo handling work are simultaneously performed. When the traveling and the cargo handling work are performed at the same time, the CPU 34 considers the discharge rate of the battery 5 and the heavy load of the battery 5 (in this embodiment, the traveling and the cargo handling are performed at the same time). Then, the allowable current values Imd and Imp of the motors 1 and 2 are calculated.

In this embodiment, the allowable current values Imd and Imp with respect to the discharge rate when traveling and cargo handling work are performed at the same time.
As shown by the broken lines in Figs. 3 and 4, CP
U34 calculates each allowable current value Imd, Imp. That is, the permissible current value Imd of the traveling motor 1 is generally smaller than the permissible current value Imd when traveling only as shown by the solid line in FIG. 3, and the permissible current value Imp of the loading motor 2 causes the battery 5 to discharge a predetermined amount. After reaching the rate, it is set to be smaller than the allowable current value Imp indicated by the solid line in FIG.

When each allowable current value Imd, Imp at that time is calculated, the CPU 34 uses the D / A converter to convert the reference signal based on each allowable current value Imd, Imp.
Output to 41. The D / A converter 41 converts the reference signal based on the permissible current value Imd into an analog signal (voltage) and outputs it as a traveling reference voltage to the positive side input terminal of the comparator 42, and at the same time, outputs the reference signal based on the permissible current value Imp. It is converted into an analog signal and output as the cargo handling reference voltage to the plus side input terminal of the comparator 43. The traveling reference voltage set based on the allowable current value Imd is the allowable current of the armature current of the traveling motor 1. When it reaches the value Imd, it coincides with the detection signal (detection voltage) output to the minus side input terminal of the comparator 42 based on the detection result of the traveling current detector 8.
Then, when the armature current of the traveling motor 1 flows by the allowable current value Imd or more at that time and the detected voltage becomes larger than the traveling reference voltage, the output of the comparator 42 is inverted from the positive potential (H level) to the zero potential (L level). The L level signal is sent to the AND circuit 37 via the one-shot circuit 44.
Output to.

Therefore, when the armature current of the traveling motor 1 flows more than the permissible current value Imd at that time, the AND circuit 37 causes the PTM36
The frequency-modulated pulse signal for traveling, which is output from, is blocked, and as a result, the traveling transistor 9 is turned off, and the power supply to the traveling motor 1 is cut off.

Similarly, the armature current of the cargo handling motor 2 is the allowable current value of the cargo handling reference voltage set based on the allowable current value Imp.
When it becomes Imp, it coincides with the detection voltage output to the minus side input terminal of the comparator 43 based on the detection result of the cargo handling current detector 13. Then, when the armature current of the cargo handling motor 2 exceeds the allowable current value Imp at that time and the detected voltage becomes higher than the cargo handling reference voltage, the output of the comparator 43 is inverted from the H level to the L level, and the L level signal. Is output to the AND circuit 39 via the one-shot circuit 45.

Therefore, when the armature current of the cargo handling motor 2 flows more than the permissible current value Imp at that time, the AND circuit 39 causes the PTM36 to operate.
The frequency-modulated pulse signal for cargo handling outputted from is blocked, and as a result, the cargo handling transistor 11 is turned off and the power supply to the cargo handling motor 2 is cut off.

The working memory 46 is a readable and rewritable memory (RAM), and temporarily stores the calculation result when the CPU 34 performs the calculation process at any given time.

Next, the operation of the allowable current value control device configured as described above will be described.

When the forklift is traveling without performing cargo handling work, the CPU 34 outputs a traveling control signal based on the operation amount of the accelerator pedal 27 to the PTM 36. The PTM36 outputs a traveling pulse signal whose frequency is modulated based on the traveling control signal and outputs a chopper signal SG1 to the traveling transistor 9 to drive the traveling motor 1 at a speed corresponding to the operation amount of the accelerator pedal 27. Control.

In addition, since the lift lever 22 or the tilt lever 25 of the loading motor 2 is not operated, the loading transistor 11
, The chopper signal SG2 is not output, the same cargo handling transistor 11 is turned off, and the cargo handling motor 2 is stopped.

On the other hand, the CPU 34 executes the calculation processing operation of the permissible current values Imd, Imp of the traveling and cargo handling motors 1 and 2 at that time based on the discharge rate signal SG8 from the capacity detection device 33. Based on the traveling current value signal SG6, the CPU 34 determines that only traveling is being performed at this time, and calculates the allowable current value Imd of the traveling motor 1 based on the discharge rate of the battery 5 at that time.

Then, the CPU 34 outputs the reference voltage based on the calculated allowable current value Imd to the comparator 42 via the D / A converter 41.

On the contrary, when the forklift is carrying out the cargo handling work with the forklift stopped, the CPU 34 calculates the allowable current value Imp of the cargo handling motor 2 based on the discharge rate of the battery 5 at that time, as in the above. Allowed current value Imp
Based on the reference voltage via the D / A converter 41
Output to 3.

On the other hand, when traveling and cargo handling work are being performed at the same time, CP
The U34 outputs a traveling control signal based on the operation amount of the accelerator pedal 27 to the PTM36, and also outputs a cargo handling control signal based on the operation amount of the levers 22 and 25 to the PTM36.

The PTM36 outputs a traveling pulse signal whose frequency is modulated based on the traveling control signal and outputs a chopper signal SG1 to the traveling transistor 9 to drive the traveling motor 1 at a speed corresponding to the operation amount of the accelerator pedal 27. Control. At the same time, the PTM36 outputs a cargo handling pulse signal whose frequency is modulated based on the cargo handling control signal and outputs the cargo handling transistor.
The chopper signal SG2 is output to 11 to drive and control the cargo handling motor 2 at a speed corresponding to the operation amount of each lever 22, 25.

On the other hand, the CPU 34, based on the discharge rate signal SG8 from the capacity detection device 33, similarly to the above, the traveling and loading motors 1,
The calculation processing operation of the allowable current values Imd and Imp of 2 is executed. CPU3
4 judges based on the traveling and cargo handling current value signals SG6 and SG7 that the traveling and the cargo handling work are being carried out at the same time, and the discharge rate of the battery 5 at that time and the running and the cargo handling work are carried out at the same time. The allowable current values Imd and Imp of the traveling motors and the cargo handling motors 1 and 2 are calculated based on the existence of the motor.

Then, the CPU 34 supplies a reference voltage based on each of the calculated allowable current values Imd, Imp to each comparator 42, via the D / A converter 41.
Output to 43.

As described above, in the present embodiment, the allowable current values Imd, Imp of the traveling motor 1 and the cargo handling motor 2 are lowered as shown by the solid lines in FIGS. 3 and 4 as the discharge rate of the battery 5 increases. Therefore, the maximum power consumption of the battery 5 in the state where the discharge rate of the battery 5 is advanced can be suppressed to a low level, and the life of the battery 5 can be extended.

Further, in the present embodiment, when the cargo handling work and the traveling are simultaneously performed, that is, when the battery 5 is in the heavy load state, the traveling motor 1 depends on the heavy load state and the discharge rate of the battery 5 at that time. Since the allowable current values Imd and Imp of the cargo handling motor 2 are varied as shown by the broken lines in FIGS. 3 and 4, the life of the battery 5 can be further extended and the reliability of electrical components can be improved. Can be improved.

In the above embodiment, when the traveling and the cargo handling work are performed at the same time so that the cargo handling work is prioritized and the work efficiency is improved, the allowable current value Imp of the cargo handling motor 2 becomes higher than the discharge rate of the battery 5. When it is not set, the value is set to be the same as that for the cargo handling work only.
The permissible current value Imd may be reduced as a whole.

Further, in the above embodiment, the traveling motor 1 and the cargo handling motor 2 of the forklift are explained, but this may be applied to other electric devices.

Further, although the allowable current value with respect to the discharge rate is shown in FIGS. 3 and 4 in the above-mentioned embodiment, this may be implemented by appropriately changing it.

EFFECTS OF THE INVENTION As described in detail above, according to the present invention, it is possible to prolong the life of a battery and to improve the reliability of electrical components.

[Brief description of drawings]

FIG. 1 is a drive circuit diagram of a forklift, FIG. 2 is an electric block circuit diagram of an allowable current value control device, FIG. 3 is a diagram for explaining an allowable current value of a traveling motor with respect to a discharge rate of a battery, and FIG. The figure is a diagram for explaining the allowable current value of the cargo handling motor with respect to the discharge rate of the battery. In the figure, 1 is a traveling motor, 2 is a cargo handling motor, 5 is a battery, 8 is a traveling current detector, 9 is a traveling transistor, 11 is a cargo handling transistor, 13 is a cargo handling current detector,
21 is a lift lever operation amount detection sensor, 22 is a lift lever, 24 is a tilt lever operation amount detection sensor, 25 is a tilt lever, 26 is an accelerator pedal operation amount detection sensor, 27 is an accelerator pedal, 33 is a capacity detection device, 34 is A CPU, 35 are program memories, and 42, 43 are comparators.

Front page continuation (72) Inventor Mineo Ozeki 54 Kawata, Asai, Ichinomiya-shi Akita (72) Inventor Tetsuji Suzuki 5 Wakatake Dormitory, Oshibana 5, Nishibiwajima-cho, Nishikasugai-gun, Aichi (56) Reference JP-A-52-4026 (JP) , A) Japanese Unexamined Patent Publication No. 47-30060 (JP, A) Actually opened 58-196541 (JP, U) Actually opened 57-47822 (JP, U)

Claims (5)

[Claims] 1. A battery that operates an electric device, a current detector that detects a current flowing through the electric device, and a current value of the electric device detected by the current detector at that time is an allowable current value of the electric device. In the electric equipment control device, which comprises a control means for shutting off the power supply to the electric equipment when the electric current reaches the battery capacity, a battery capacity detection device for detecting the discharge rate of the battery, and a discharge rate of the battery at that time for the allowable current value. A permissible current value controller for calculating the permissible current value of the electric device with respect to the discharge rate of the battery at that time detected by the battery capacity detection device, . 2. The electric device control apparatus according to claim 1, wherein the calculating means calculates the permissible current value so that the permissible current value is relatively lowered as the discharge rate of the battery increases. Allowable current value control device. 3. A battery for operating a plurality of electric devices, each current detector for detecting a current flowing in each of the electric devices, and a current value of the electric device detected by each of the current detectors at that time. An electric device control device comprising: a control unit that cuts off power supply to the electric device when the allowable current value of the electric device is reached; a battery capacity detection device that detects a discharge rate of the battery; Drive state detector for detecting the drive state of, the indexing means for determining the load of the battery based on the detection signal from the drive state detector, the allowable current value of each of the electrical equipment discharge rate of the battery at that time And the battery discharge rate at that time detected by the battery capacity detection device and the index so as to vary relative to the load of the battery. And a calculating means for calculating the allowable current value of each of the electric devices with respect to the load at that time calculated by the means. 4. A drive state detector is provided for each electric device to detect the drive state of each electric device, and the indexing means determines whether or not each electric device is driven by each drive state detector. The calculation means calculates an allowable current value of each of the electric devices with respect to the discharge rate of the battery detected by the capacity detection device and the presence or absence of driving of each of the electric devices calculated by the indexing device. A permissible current value control device in the electric device control device described in the paragraph. 5. The permissible current value control device in an electric device control device according to claim 4, wherein the drive state detection device is a current detector that detects a current flowing in each of the electric devices.