JPH10150705A - Running speed controller and its method for battery car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a shortage in maximum speed at the start of operation for a battery forklift. SOLUTION: A running motor 11 is driven under chopper control in a normal running while a switching transistor 25 is turned on and off by a running motor control unit 27. While an accelerator pedal is fully pushed, a bypass contractor 29 and a switch 5 are turned on. At this point, an output voltage V3 from an error amplifying circuit 7 is made larger and an equivalent resistance value is made smaller during a relation of V1 <V2 , where V1 is a voltage that corresponds to a vehicle speed fed from a speedometer 9 and V2 is voltage corresponding to the maximum speed, so a current in a field winding 1 is reduced to increase the vehicle speed. When V1 >V2 , the output voltage V3 is made smaller, and the equivalent resistance value is made large, so the current in field winding 1 is increased to reduce the vehicle speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a running speed control apparatus and method for a battery car for controlling high-speed running of a battery car at the time of starting by using a DC series running motor.

[0002]

[0005] A battery car, for example, a battery forklift, has a problem that the original traveling performance (maximum speed) cannot be obtained unless the vehicle is driven for about 30 minutes from the start of the day. An object of the present invention is to eliminate the shortage of the maximum speed at the start of work to solve the above-mentioned problem.

[0003]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention firstly provides a DC series-wound traveling motor which is driven to rotate by a DC power supply of a battery, and a driving motor for the traveling motor. A motor control unit that controls the vehicle speed by chopper-controlling the supplied current; and a bypass contactor that is connected in parallel to the motor control unit and that is turned on when a state in which the accelerator operation unit of the vehicle is operated to the maximum for a predetermined time continues. A variable resistance portion connected in parallel to the field winding of the traveling motor to generate an equivalent resistance corresponding to the supplied control voltage and perform field-weakening control on the field winding; and a predetermined vehicle. The maximum traveling speed of the vehicle is compared with the current traveling speed.When the current traveling speed is lower than the maximum traveling speed of the vehicle, the control voltage is increased, while the current traveling speed exceeds the maximum traveling speed of the vehicle. A control voltage generator for reducing the control voltage; and a control voltage generator interposed between the control voltage generator and the variable resistor. The control voltage generator is turned on when the bypass contactor is turned on. And a switch unit for conducting the resistance unit.

According to the running speed control device for a battery car having such a configuration, when the control voltage generator determines that the current running speed is lower than the maximum running speed of the vehicle, the generated control voltage is reduced. As the resistance increases, the resistance value of the variable resistance section decreases.At this time, when the accelerator operation section is operated to the maximum and the bypass contactor is turned on, and the switch section is turned on, the current flowing through the field winding decreases. As a result, the number of revolutions of the traveling motor increases. vice versa,
If it is determined that the current traveling speed is higher than the maximum traveling speed of the vehicle, on the contrary, the generated control voltage decreases, the resistance value of the variable resistor increases, and the current flows through the field winding. The current increases and the number of revolutions of the traveling motor decreases.

Second, the variable resistance section includes a transistor having a gate for receiving a control voltage input, and having a resistance value decreasing as the control voltage increases.

According to the above configuration, when the control voltage input to the gate is large, the equivalent resistance of the transistor becomes small, and when the control voltage is small, the equivalent resistance of the transistor becomes large. .

Third, the control voltage generator includes an amplifier circuit for amplifying and outputting a difference between voltage values corresponding to the maximum traveling speed and the current traveling speed, respectively.

According to the above configuration, the difference between the voltage values corresponding to the maximum traveling speed and the current traveling speed is amplified by the amplifier circuit and output, and the output value is introduced to the variable resistor.

Fourthly, the chopper control is performed on a DC series-wound traveling motor that is rotated by a DC power supply of a battery, and when the accelerator operation unit is operated to its maximum and the bypass contactor is turned on, In a running speed control method for a battery vehicle, wherein a current flowing through a field winding of the running motor is suppressed to perform speed control in a high speed range, an accelerator operation unit is operated to a maximum and the bypass contactor is turned on. In the state where, based on the difference between the predetermined maximum traveling speed of the vehicle and the current traveling speed of the vehicle, the resistance value of the variable resistor connected in parallel to the field winding of the traveling motor is calculated. This is a method of controlling the running speed of a battery vehicle that changes the field winding to perform field weakening control on the field winding.

According to the above control method, the resistance value of the variable resistor connected in parallel to the field winding of the traveling motor is changed based on the comparison between the maximum traveling speed of the vehicle and the current traveling speed. Field-weakening control is performed on the field winding, whereby the shortage of the maximum speed at the start of work is eliminated, and the original running performance can be obtained.

[0011]

According to the first invention or the fourth invention,
Based on the comparison between the maximum traveling speed of the vehicle and the current traveling speed, the resistance value of the variable resistor connected in parallel to the field winding of the traveling motor is changed to perform field weakening control on the field winding. As a result, the shortage of the maximum speed at the start of work can be resolved, and the original running performance can be obtained.

According to the second aspect, the resistance value of the transistor connected in parallel to the field winding of the traveling motor is changed based on the comparison between the maximum traveling speed of the vehicle and the current traveling speed. Since the field-weakening control is performed on the magnetic winding, the shortage of the maximum speed at the start of work can be eliminated, and the original running performance can be obtained.

According to the third aspect, the difference between the voltage values corresponding to the maximum traveling speed of the vehicle and the current traveling speed is amplified by the amplifier circuit and output, and the output value is introduced to the variable resistance section. Then, the resistance value was changed, and thereby the field winding was controlled to be weakened.
The shortage of the maximum speed at the start of work can be eliminated, and the original running performance can be obtained.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing a schematic configuration of a running speed control device for a battery car according to an embodiment of the present invention. The battery vehicle here is a battery-powered forklift. The traveling motor, which is a DC series motor, is chopper-controlled by an on / off signal applied to the base of the switching transistor. Both ends of the field winding 1 in such a traveling motor are provided with a transistor (MO) as a variable resistor.
The drain D and the source S of the SFET 3 are connected. An error amplifier 7 as a control voltage generator is connected to the gate G of the transistor 3 via a switch 5 serving as a switch.

The switch 5 is turned on when the bypass contactor enabling the high-speed running at the maximum rotation speed of the running motor is turned on instead of the chopper control (when the fully open state of the accelerator of the battery car continues for a predetermined time). Then, it is turned on. The error amplifying circuit 7 receives a signal of a display speed of the speedometer 9 in the battery car, that is, a signal of a voltage V ₁ according to a current traveling speed and a signal of a voltage V ₂ according to a predetermined maximum speed in the battery car. It is to amplify the voltage value of the difference between respective signal values (V ₂ -V _1), and outputs a voltage signal V ₃ of appropriate size.

When the above-described voltage signal V ₃ is input to the gate G of the transistor 3, the transistor 3 has an equivalent resistance value corresponding to the gate voltage, the current flowing through the field winding 1 decreases, and the motor speed decreases. As the vehicle speed increases, the vehicle speed is improved due to the weak field control. V ₁
When the voltage of the difference between V ₂ becomes small as V ₃ becomes small,
Accordingly, the resistance value of the transistor 3 increases, and the current flowing through the field winding 1 increases, thereby suppressing an excessive increase in vehicle speed. In this way, until V ₁ is coincident to the V _2, rises to the current vehicle speed is equal to the maximum speed in other words.

Conventionally, assuming that the maximum speed of a battery car is 15 k / m, as shown in FIG. 2, unless the warm-up operation is performed for about 30 minutes at the start of operation, the rolling resistance of the tire and the frictional force of the lubricating oil are reduced. Due to the influence, traveling at the maximum speed could not be performed stably. However, by performing the traveling speed control described above, it is possible to quickly reach the maximum speed from the start.
As a result, the shortage of the maximum speed at the start of operation when using the battery car can be eliminated, and the original running performance can be obtained. In addition, the shortage of the maximum speed due to the difference in tire type (difference in tire effective radius), difference in mast type (due to difference in weight due to difference in tire effective radius), and variation in the characteristics of the traveling motor can be solved.

FIG. 3 is a circuit diagram which embodies the running speed control device described above. The traveling motor 11 includes an armature winding 13 and the field winding 1, and is supplied with power from a battery 15. A flywheel diode 17 connected in parallel between the traveling motor 11 and the battery 15;
19 suppresses noise generated from the traveling motor 11. A forward contactor 21 and a reverse contactor 23 are connected to both ends of the field winding 1, and by switching these, forward and backward operations of the battery vehicle are performed.

A collector of a switching transistor 25 is connected to the field winding 1 of the traveling motor 11, and an on / off signal is supplied to a base of the switching transistor 25 from a traveling motor control unit 27 constituted by a microcomputer. The input is input, and chopper control is performed on the traveling motor 11. The switching transistor 25 and the traveling motor control unit 27 constitute a motor control unit that controls the vehicle speed.

The bypass contactor 29 connected in parallel with the switching transistor 25 is turned on after a full-open state of an accelerator pedal as an accelerator operation portion of the vehicle continues for a predetermined time, and at this time the high-speed operation is performed at the maximum rotation speed of the traveling motor 11. Running is possible, and conversely, it is turned off when the accelerator pedal is returned. The traveling motor control unit 27 turns ON / OFF the forward contactor 21, the reverse contactor 23, the bypass contactor 29, and the switch 5 interposed between the transistor 3 and the error amplifier circuit 7.
Turned off.

The speedometer 9 comprises a vehicle speed display control unit 31, a vehicle speed display unit 33, and a D / A conversion unit 35, each of which is a microcomputer, and which outputs a pulse signal corresponding to the vehicle speed of a vehicle speed sensor 37 attached to a differential portion. The input is received by the vehicle speed display control unit 31. The vehicle speed display control unit 31 controls the vehicle speed display unit 33 to digitally display the vehicle speed, and controls the D / A conversion unit 35 to convert a digital signal corresponding to the vehicle speed into an analog signal (V ₁ ). / A converter 35 outputs a voltage signal V corresponding to the vehicle speed.
₁ is output to the error amplifier circuit 7.

On the other hand, the voltage signal V ₂ corresponding to the maximum speed to be compared with the voltage signal V ₁ is determined by the resistor 39 and the Zener diode 41, and the error amplifier circuit 7 operates as described in FIG. , V ₁ and V ₂ are amplified to determine a voltage V ₃ applied to the gate G of the transistor 3.

The error amplifier circuit 7 is composed of two circuits, a differential amplifier circuit 43 and an integration circuit 45. Differential amplifier circuit 43
Are resistors 47, 49, 51, 53 and an operational amplifier 55.
The integrating circuit 45 includes a resistor 57 and a capacitor 5
9, an operational amplifier 61 and a variable resistor 63.
Variable resistor 63 is to adjust the level of the output voltage V ₃ from the integrator 45 in accordance with such a characteristic of the traction motor 11, which is set in advance to the resistance value.

Next, the operation of the traveling speed control device will be described. Maximum voltage V ₁ and the voltage V ₂ is input to the differential amplifier circuit 43 of the error amplifier circuit 7, as shown in FIG. 4, a voltage corresponding to the vehicle speed, particularly V ₂ is that defined in the catalog of the vehicle A predetermined voltage value corresponding to the speed (for example, 15 k / m) is set.

The differential amplifier 43 amplifies the difference voltage between V ₁ and V ₂ and outputs a voltage V _1a . The output relationship between the voltage V _1a and voltages V ₁ was, as shown in FIG. 5, it has a direct proportion.

The integrating circuit 45 charges and discharges the capacitor 59 according to the voltage _V1a output from the differential amplifier circuit 43. The output voltage of the integration circuit 45 is level adjusted by the variable resistor 63 defines the voltage V ₃ applied to the gate G of the transistor 3. That is, the following sequence is obtained.

If the current running speed has not reached the maximum speed and V ₁ <V ₂ (V _1a <V ₂ ), the integration circuit 4
5 (a) shows the current flow in the capacitor 59 of FIG.
It becomes arrow A direction shown by the output voltage V ₃ at this time is increased. When the output voltage V ₃ increases, as shown in FIG. 6 (b), smaller equivalent resistance R of the transistor 3, the current flowing through the the accompanying field winding 1 which vehicle speed is increased is reduced.

Conversely, in a state where V ₁ > V ₂ (V _1a > V ₂ ) where the current traveling speed exceeds the maximum speed, the current flow in the capacitor 59 is shown in FIG. becomes the direction of arrow B, the output voltage V ₃ at this time is reduced. When the output voltage V ₃ becomes smaller, as shown in FIG. 7 (b),
The equivalent resistance value R of the transistor 3 increases, and accordingly, the current flowing through the field winding 1 increases, and the vehicle speed decreases.

On the other hand, in the state of V ₁ = V ₂ (V _1a = V ₂ ) where the current traveling speed is equal to the maximum speed, no current flows through the capacitor 59 and the output voltage V ₃ becomes constant. Since the equivalent resistance value R of the transistor 3 is also constant, the current flowing through the field winding 1 does not change, and the vehicle speed is constant.

When the power loss of the transistor 3 exceeds the rating or when a smaller equivalent resistance value is required, the problem can be solved by connecting a plurality of MOS FETs in parallel. For example, if N pieces are connected in parallel, the allowable power loss becomes N times and the equivalent resistance becomes 1 / N.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a schematic configuration of a running speed control device for a battery vehicle according to an embodiment of the present invention.

FIG. 2 is a correlation diagram between the maximum speed and the warm-up operation time when the accelerator is fully opened immediately after starting in a conventional battery car.

FIG. 3 is a circuit diagram that embodies the traveling speed control device of FIG. 1;

FIG. 4 is a correlation diagram between a voltage value input to the error amplifier circuit of FIGS. 1 and 3 and a vehicle speed;

FIG. 5 is a correlation diagram between an input value and an output value in the differential amplifier circuit of FIG. 3;

6A and 6B are explanatory diagrams of the operation of the integration circuit of FIG. 3 when the vehicle speed has not reached the maximum speed, wherein FIG.
(B) shows the correlation between the output voltage value and the resistance of the transistor.

7A and 7B are explanatory diagrams of the operation of the integration circuit of FIG. 3 when the vehicle speed exceeds the maximum speed, wherein FIG. 7A shows a current flow;
(B) shows the correlation between the output voltage value and the resistance of the transistor.

[Description of Signs] 1 Field winding 3 Transistor (variable resistance section) 5 Switch (switch section) 7 Error amplifier circuit (control voltage generation section) 11 Running motor 15 Battery 25 Switching transistor (motor control section) 27 Running motor Control unit (motor control unit) 29 Bypass contactor 43 Differential amplifier circuit (amplifier circuit)

Claims (4)

[Claims] 1. A DC series-wound traveling motor rotatably driven by a DC power supply of a battery, a motor control unit that controls a vehicle speed by chopper-controlling a current supplied to the traveling motor, and a motor control unit. A bypass contactor that is connected in parallel to the vehicle and that is turned on when a state in which the accelerator operation section of the vehicle is operated to the maximum for a predetermined period of time; and a control voltage that is connected in parallel to the field winding of the traveling motor and is supplied. A variable resistance unit that generates an equivalent resistance corresponding to the above and performs field weakening control on the field winding, and compares a predetermined maximum traveling speed of the vehicle with the current traveling speed, and determines that the current traveling speed is A control voltage generator for increasing the control voltage when the current traveling speed is lower than the maximum traveling speed of the vehicle, and decreasing the control voltage when the current traveling speed exceeds the maximum traveling speed of the vehicle; A switch unit that is interposed between the pressure generation unit and the variable resistance unit, and that is turned on when the bypass contactor is turned on to conduct the control voltage generation unit and the variable resistance unit. Running speed control device for a battery car. 2. The battery vehicle according to claim 1, wherein the variable resistance section includes a gate that receives a control voltage input, and includes a transistor whose resistance value decreases as the control voltage increases. Travel speed control device. 3. The control voltage generator according to claim 1, further comprising an amplifier circuit for amplifying and outputting a difference between voltage values corresponding to the maximum traveling speed and the current traveling speed, respectively. A running speed control device for a battery car. 4. A chopper control for a DC series-wound traveling motor rotatably driven by a DC power supply of a battery, and said traveling is performed when an accelerator operation section is operated to a maximum and a bypass contactor is turned on. In a running speed control method for a battery car, a current flowing through a field winding of a motor is controlled to perform speed control in a high-speed range.
In a state where the accelerator operation unit is operated to the maximum and the bypass contactor is turned on, the field of the traveling motor is determined based on a difference between a predetermined maximum traveling speed of the vehicle and a current traveling speed of the vehicle. A running speed control method for a battery vehicle, comprising: changing a resistance value of a variable resistor connected in parallel to a winding to perform field weakening control on the field winding.