JPH08265915A - Traveling motor controller for battery forklift - Google Patents

Abstract

PURPOSE: To reduce battery consumption without causing the problem of insufficient climbing power or maximum speed by determining a current being fed to a traveling motor based on a current command value determined from the r.p.m. of motor and an extracted function, and an input power to battery and then feeding the traveling motor with the current thus determined. CONSTITUTION: A function extracting means 13 extracts a function of r.p.m. of motor/current command value and a current value operating means 14 determines a current command value from the r.p.m. of motor detected by a rotation sensor 6 and an extracted function and delivers the current command value to a power conversion circuit 8. A current being fed to a traveling motor 4 is then determined based on the current command value and a power being inputted from a battery 1 and the current thus determined is fed to the traveling motor 4. Since the function of r.p.m. of motor/current command value includes a current command data satisfying the climbing power in low speed region and a current command value data satisfying the maximum speed in high speed region, battery consumption can be reduced while eliminating the problem of insufficient climbing power or maximum speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a traveling motor for traveling a battery forklift truck via a transmission device and tires.

[0002]

9 and 10 show a conventional example of a traveling motor control device for a battery forklift. Conventionally,
As means for adjusting the traveling performance (traveling feeling) of the battery forklift, one that increases or decreases the motor current limit value in the low speed range (see FIG. 9) and one that changes the rising slope of the motor current value in the low speed range ( (See FIG. 9),
Another method is to make the voltage applied to the motor in the medium speed range and the high speed range constant by controlling the duty ratio of the PWM voltage with the battery voltage being 100% (see FIG. 10).

[0003]

In the conventional traveling motor control device for a battery forklift shown in FIGS. 9 and 10, when attempting to reduce the battery consumption, which is an important factor of the battery forklift, the current in the low speed range is reduced. If it is decreased, there will be a problem that the climbing power will be insufficient (Fig. 9).
However, if the fixed duty applied to the motor in the medium speed range and the high speed range is reduced, there occurs a problem that the maximum speed cannot be obtained (see FIG. 10).

The present invention is proposed in view of the above-mentioned problems, and its object is to reduce the battery consumption without causing the problem of insufficient climbing power and the problem of not reaching the maximum speed. It is an object of the present invention to provide a traveling motor control device for a battery forklift truck, which can reduce the number of battery packs.

[0005]

In order to achieve the above object, the present invention provides an accelerator and an output from the accelerator in a control device for a travel motor that drives a battery forklift through a transmission device and a tire. The accelerator opening determination signal for determining which of the preset accelerator classifications the accelerator opening signal is included in, and the motor rotation speed / current command value function group for each accelerator classification prepared in advance Motor speed / corresponding to the judgment result
Function extracting means for extracting a current command value function, and current value calculating means for obtaining a current command value to be output to the power conversion circuit based on the extracted motor rotation speed / current command value function and the motor rotation speed from the rotation sensor And a power conversion circuit that adjusts the motor voltage to be output so that the calculated current command value and the motor current to be output to the travel motor become the same when power is input from the battery.

[0006]

The traveling motor control device for a battery forklift according to the present invention is configured as described above, and the accelerator classification determining means inputs the accelerator opening from the accelerator, and the accelerator opening is included in any of the accelerator classifications. Then, the function extraction means extracts the motor rotation speed / current command value function corresponding to this judgment result, and the current value calculation means obtains the current command value from the motor rotation speed of the rotation sensor and the extracted function. This current command value is output to the power conversion circuit. This electric power conversion circuit obtains a current to be supplied to the traveling motor based on the output current command value and the electric power input from the battery, and outputs this current to the traveling motor. Then, in the motor speed / current command value function, the current command value data that satisfies the climbing force in the low speed range, the current command value data that satisfies the maximum speed in the high speed range, and the current command value data that reduces the battery consumption in the medium speed range Therefore, the battery consumption can be reduced without causing the problem of insufficient climbing power and the problem of not reaching the maximum speed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a travel motor control device for a battery forklift according to the present invention will be described with reference to FIGS. 1 is a block diagram of the traveling motor control device, FIG. 2 is a system diagram of the traveling motor control device, FIG. 3 is a flowchart showing the contents of the processing program of the CPU of FIG. 2, FIG. 4 is a system diagram of the battery forklift, and FIG. FIG. 6 is an explanatory diagram showing accelerator classification data, FIG. 6 is an explanatory diagram showing motor rotation speed / current command value function group (accelerator classification) data, and FIG. 7 is motor rotation speed / current command value function group (accelerator classification) data. FIG. 8 is an explanatory diagram showing the characteristics of the motor rotation speed / current command value function.

In FIG. 4, 1 is a battery, 2 is an accelerator, 3 is a traveling motor control device, which is the most characteristic feature of the present invention, 4 is a traveling motor, 5 is a transmission device, 6 is a rotation sensor for detecting the number of revolutions of the motor, 7 Are forklift tires. Next, the traveling motor control device 3 will be specifically described with reference to FIG. 1
Reference numeral 0 is a ROM for storing a processing program, 11 is a RAM for storing accelerator classification data and motor rotation speed / current command value function group (accelerator classification) data, and 9 is an accelerator classification determining means 12-current of FIG. 1 according to the processing program. A CPU that executes the value calculation means 14 is a power conversion circuit that outputs a motor current to the traveling motor 4 based on the current command value from the CPU 9 and the power from the battery 1.

Next, the operation of the CPU 9 will be described in detail with reference to FIGS. First, the CPU 9 inputs the accelerator opening degree from the accelerator 2 (S1), and then inputs the accelerator classification data from the RAM 11 (S2). Here, the accelerator classification data is obtained by classifying the signal from the accelerator 2 according to the accelerator opening degree, and an example of the same accelerator classification data is shown in FIG. 7 (accelerator classification data is three according to the accelerator opening degree). Data shall be classified as above).

Next, the CPU 9 judges which of the sections in FIG. 5 the accelerator opening input in S1 is included in (S3), and then the motor speed / current command value function group (accelerator section) data from the RAM 11. Is input (S4). Here, the motor rotation speed / current command value function group (accelerator classification) data refers to the traveling motor characteristics associated with the accelerator classification (see FIG. 6), and these functions have an accelerator classification of 0. When the current command value is 0, the output characteristic is fixed. When the accelerator classification is 0, the minimum output characteristic that drives the vehicle is the minimum classification. When the accelerator classification is the maximum classification, the climbing force and the vehicle It is set to have maximum speed and output characteristics that reduce battery consumption.

Regarding the accelerator section between the minimum section and the maximum section, as in the example of the eight sections shown in FIG. 7, it is set between the minimum section and the maximum section so that battery consumption and vehicle driving feeling are improved. ing. Further, referring to FIG. 8, details of the above function will be described for the function F (7) when the accelerator section is maximum.

The maximum current limiting straight line 15 is set so as to satisfy the climbing force. The motor characteristic curve 16 is a curve when the maximum voltage (battery voltage) is output to the traveling motor 4. The battery consumption improvement curve 17 satisfies the maximum speed by making the current command value at the maximum speed the same as the motor characteristic curve 16, and also satisfies the climbing force by intersecting the maximum current limiting straight line 15.

The function F (7) is the maximum current limiting straight line 1
5 and a battery consumption improvement curve 17. Next, the CPU 9 extracts the corresponding motor rotation speed / current command value function from the function group based on the determination result of S3. That is, if the determination result of S3 is 7, the function F (7) of FIG. 6 is extracted (S5).

On the other hand, the CPU 9 inputs the motor rotation speed from the rotation sensor 6 (S6), and calculates a current command value to be given to the power conversion circuit 8 from this rotation speed and the function extracted in S5 (S7). Is output to the power conversion circuit 8 (S
8). The power conversion circuit 8 obtains a current to be passed through the traveling motor 4 from the output current command value and the electric power input from the battery 1, and this current is output to the traveling motor 4.

[0015]

As described above, the traveling motor control device for the battery forklift according to the present invention has the accelerator classification determining means 1 as described above.
2 inputs the accelerator opening from the accelerator 2 to determine where the accelerator opening is included in the accelerator classification, and the function extracting means 13 determines a motor rotation speed / current command value function corresponding to this determination result. Extraction and current value calculation means 14
Calculates a current command value from the motor rotation speed of the rotation sensor 6 and the extracted function, and outputs this current command value to the power conversion circuit 8. The power conversion circuit 8 obtains a current to be passed through the traveling motor 4 based on the output current command value and the electric power input from the battery 1, and this current is output to the traveling motor 4. Then, in the motor speed / current command value function, the current command value data that satisfies the climbing force in the low speed range, the current command value data that satisfies the maximum speed in the high speed range, and the current command value data that reduces the battery consumption in the medium speed range Therefore, there is an effect that the battery consumption amount can be reduced without causing the problem that the climbing power is insufficient and the problem that the maximum speed cannot be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of a travel motor control device for a battery forklift according to the present invention.

FIG. 2 is a system diagram of the traveling motor control device.

3 is a flowchart showing the contents of a processing program of the CPU of FIG.

FIG. 4 is a system diagram of a battery forklift.

FIG. 5 is an explanatory diagram showing accelerator classification data.

FIG. 6 is an explanatory diagram showing motor rotation speed / current command value function group (accelerator classification) data.

FIG. 7 is an explanatory diagram showing motor rotation speed / current command value function group (accelerator classification) data.

FIG. 8 is an explanatory diagram showing characteristics of a motor rotation speed / current command value function.

FIG. 9 is an operation explanatory view of a conventional travel motor control device for a battery forklift.

FIG. 10 is an operation explanatory view of the traveling motor control device.

[Explanation of symbols]

 1 Battery 2 Accelerator 4 Traveling Motor 6 Rotation Sensor 8 Power Converter Circuit 11 RAM 12 Accelerator Classification Determining Means 13 Function Extracting Means 14 Current Value Computing Means

Claims (1)

[Claims] 1. A controller for a travel motor that drives a battery forklift via a transmission device and tires, which is included in any one of an accelerator and an accelerator section in which an accelerator opening signal output from the accelerator is preset. And a function for extracting a motor rotation speed / current command value function corresponding to the judgment result from a group of prepared motor rotation speed / current command value functions for each accelerator classification. Extraction means, current value calculation means for obtaining the current command value to be output to the power conversion circuit based on the extracted motor rotation speed / current command value function and the motor rotation speed from the rotation sensor, and the power input from the battery. Power conversion circuit for adjusting the output motor voltage so that the calculated current command value and the motor current output to the traveling motor become the same. A traveling motor control device for a battery forklift, characterized by comprising: