JPS62217807A - Damping and controlling device in electromobile - Google Patents

Abstract

PURPOSE:To reduce the electrostatic capacity of an absorber-condenser by using a DC motor of a hydraulic drive system for power consumption when something is wrong with the regenerative damping system. CONSTITUTION:In an ordinary regenerative damping the power generated to an armature 4 of a DC motor is returned to a battery 1 through diodes 5 and 7 by the ON/OFF operation of a thyrister chopper 6. In case the cable to connect the terminal of the battery 1 to the braking unit in regenerative damping is burnt out, the power generated to the DC motor for traveling is charged to an absorber-condenser 8. When the charging voltage of the absorber-condenser 8 gets to the set voltage, a thyrister chopper 19 of a hydraulic control system is actuated by the output signal from an overvoltage detector 9.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a brake control system for electric vehicles such as lift forklifts and battery towing tractors.

(Prior Art) Control technology for DC motors using thyristor choppers has been widely put into practical use in the field of electric vehicles, and regenerative braking is usually used for braking. FIGS. 3 and 4 each illustrate a control technology for a driving DC motor that is applied to an industrial vehicle such as a lift forklift or a battery towing tractor. 1 in the figure is a battery,
2 is a connector, 3 is a field winding of a DC motor for vehicle running, 4 is an armature of the DC motor, 5 and 7 are diodes, and 61 is an i-silisk chopper. During normal regenerative braking, the thyristor chopper 6 is turned on and off.
! The electric power generated in the armature 4 of the DC motor by IJJ is returned to the battery 1 through the diode 5.7. However, during this regenerative braking, the cable or connector 2 that connects the terminal of the battery 1 and the terminal on the control equipment side is damaged due to vibration, fatigue, or connector emergency #O12.
If the wire is disconnected due to incorrect operation of the device, it will not be able to absorb the generated power, and as a result, a burnout accident will occur in the electrical equipment.

Therefore, conventionally, in order to prevent such accidents from occurring,
When an abnormality occurs due to the disconnection, the following method is taken. That is, in the example shown in FIG. 3, the power generated in the armature 4 is charged to the absorber capacitor 18, and in the example shown in FIG. is charged in the absorber capacitor 8, and when the voltage of the absorber capacitor 8 exceeds the set value, this is detected by the overvoltage detector 9, and the thyristor 10 is ignited to transmit the generated power to the resistor 11. is designed to be consumed.

To drive the DC motor for normal running, operate the running/braking switching control section 12 to the running side, turn off the current to the contactor coil 13, turn on the contactor 13a, and turn on the thyristor. Turn on chopper 6, 0
The cutting speed is controlled by the conductivity of the thyristor chopper 6.

In addition, the direction of rotation of the DC motor at this time, that is, the forward and backward movement of the vehicle, is determined by the direction switch 14 for switching between forward and backward movement.
By switching a or 14b, the contactor coil 15a or 15b connected in series thereto is excited,
It is controlled by switching the connection of the field winding 3 to the power supply side terminal of the contactor 16a or 16b.

(Problem to be Solved by the Invention) However, in the conventional braking control device described above, in the case of the former charging method using the absorber capacitor 8, a large capacitor with sufficient capacitance to respond to the charging of the generated power is used. This requires an absorber capacitor 8 and a thyristor chopper 6 with high withstand voltage.In addition, in the case of the latter method using the resistor 11, even if the absorber capacitor 8 can be made smaller, on the other hand, the resistor Vessel 1
1, a large one was required. In other words, in the conventional system, an absorber capacitor 8 or a resistor 11 and a thyristor chopper 6 or a thyristor 1 prepared for consumption of generated power during braking are used.
However, there were problems such as high cost and a large installation space.

By the way, industrial vehicles such as forklifts are equipped with a hydraulic pump as an essential component for cargo handling work. Towing tractors are also equipped with a hydraulic pump for power steering.

Therefore, in the present invention, when a trouble such as a disconnection occurs in the regenerative braking control system during regenerative braking, the DC motor installed separately for driving the hydraulic pump is used as a regenerative electric power consumer for the driving DC motor. By using this, the above-mentioned conventional problems are solved.

(Means for Solving the Problems) The technical means for solving the above problems is to develop an electric vehicle equipped with a direct current electric motor for vehicle running and a direct current electric motor II for driving a hydraulic pump. In the CF, there is an absorber capacitor that charges the electric saw generated during regenerative braking of the running motor, and a charging voltage of the absorber capacitor is detected and the charging voltage is set to a predetermined voltage. An overvoltage detector that outputs 4r:@ when the voltage is reached, and a switching element that is made conductive by the output signal of this overvoltage detector are provided, and this switching element is connected in series to the DC Ti motor for driving the hydraulic pump. That's what I did.

(Function) During regenerative braking, if the above-mentioned trouble occurs in the brake control system and the regenerative braking function is disabled, the direct current T
The power generated in the i-motor is charged to an absorber capacitor, and when the voltage of this absorber capacitor reaches a set value, it is determined that there is an abnormality, and the power is consumed by feeding it to a DC motor for driving a hydraulic pump.

(Example) Hereinafter, an example of the present invention will be specifically described based on the drawings. First, the embodiment shown in FIG. 1 will be explained. In the figure,
The dashed line frame Δ indicates the lif+ control system of the driving DC electric machine a, and since this control system is composed of the same members as the conventional one described above, the same -? It will be replaced with the explanation by attaching the letter V. On the other hand, the chain line frame B shows the control system of the DC motor for the hydraulic pump drive V installed for cargo handling.
7 is the field winding of the DC electric motor (1), and 18 is the armature of the DC motor. The DC motor is driven by the ON/OFF operation of a thyristor chopper 19 as a switching element connected in series to the drive circuit. This Nyristor chopper 19 is operated not only by an operation from the driver's seat but also by an output signal from an overvoltage detector 9 in the travel control system.

That is, during regenerative braking, as soon as the charging voltage of the absorber capacitor reaches a predetermined voltage, one of the 11 resistor jumpers is activated by a force signal from the overvoltage detector 9 that detects this. It is configured so that it can be obtained.

This embodiment is configured as described above, and therefore,
During normal regenerative braking, thyristor chopper 6 is turned on,
The power generated in the armature 4 of the t-current motor by the 0FFvJ operation is returned to the battery 1 through the diodes 5 and 7. However, during regeneration III llJ, if a new cable is connected between the terminal of the battery 1 and the terminal of the control 11m device, the electric power generated in the DC motor for driving is charged to the absorber capacitor 8. be done.

When the charging voltage of the absorber capacitor 8 reaches the set voltage, the output signal q from the overvoltage detector 9 that detects this causes the thyristor chopper 19 of the hydraulic control system to be activated.
is activated. Even if it is during regenerative braking, if an abnormality occurs in the regenerative braking system, DC power will be generated when the vehicle starts moving! The regenerated electric power of the v1 machine can be consumed in the form of driving a self-flow electric motor driven by a hydraulic pump.

In addition, generally the cylinder's J: Eel cargo handling attachment]
The hydraulic actuator for operation is under the control of the control valve operated via the operating device located on the driver's seat side.
Unless this control valve is opened or closed, the hydraulic actuator will not be operated, and even if the hydraulic pump is rotated by the drive of the DC electric machine, no substantial problem will occur. Furthermore, even if the eight direct current hydraulic drive systems are already in operation during braking, the regenerated power has already started to be consumed, so there is no problem. The same applies to the power steering hydraulic pump of the towing tractor.

Next, the embodiment shown in FIG. 2 will be described.

In this embodiment, a transistor chopper 6' is used in place of the thyristor chopper 6 as a switching element in the travel control system, and a series circuit including a resistor 20 and an absorber capacitor 8 is connected in parallel to the transistor chopper 6'. The other circuit configurations are the same as those in the previous embodiment. A transistor chopper is different from the above-mentioned embodiment in that normally a series circuit of a large resistor and a content transistor must be connected in parallel with the chopper to protect the transistor, and there is no need to add a special capacitor. However, the same applies to other work/11 effects.

(Effects of the Invention) As detailed above, the present invention provides
Since the hydraulically driven direct current electric fIJ machine, which is naturally provided in Ukuri vehicles, is used as the electric power d1 cost, the capacitance M of the absorber capacitor can be reduced, the withstand voltage of the switching element can be lowered, and it is possible to reduce the voltage resistance of the switching element. This eliminates the need to specially provide a power absorption load circuit using a thyrisk and a resistor, and for this reason,
This provides an effect of reducing cost 1- and solves the problem of installation space.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the brake control device of the present invention;
FIG. 2 is a circuit diagram showing another embodiment of the brake control device 211 of the present invention, and FIGS. 3 and 4 are circuit diagrams 'r'' illustrating conventional brake control devices, respectively. 1...Battery 3... Field winding 4... Armature 5... Diode 6... Nyristor chopper 8... Absorber/denser 9... Overvoltage detector 17... Field winding 18.・Armature

Claims (1)

[Claims] In an electric vehicle equipped with a DC motor for driving the vehicle and a DC motor for driving a hydraulic pump, an absorber capacitor for charging electric power generated during regenerative braking of the DC motor for driving, and a charging voltage of the absorber capacitor. An overvoltage detector that detects the charging voltage and outputs a signal when the charging voltage reaches a preset predetermined voltage, and a switching element that is made conductive by the output signal of this overvoltage detector, and this switching element A braking control device for an electric vehicle connected in series to the DC motor for driving the hydraulic pump.