DE1538379A1 - Drive arrangement, especially for electric vehicles - Google Patents

Description

¹ P 15 38 379.6
R.Nr; 8786
2.12 * 1966 Rb / Sz

Attachment to
Patent application

ROBERT BOSCH GMBH, Stuttgart W, Breitsoheldstrasse Drive arrangement, in particular for electric vehicles

The invention relates to one controlled by a thyristor Drive arrangement, especially for electric vehicles, with an equal * Electric motor, the direction of rotation of which can be switched by at least one contactor is, with the de-energized state of the contactor-a Interruption of the motor circuit.

Today, electric vehicles are mainly used in internal transport used very often and are an important means of rationalization. Because of the high transport performance required, these vehicles and their drives must be very robust and reliable. The nature of the operators must be taken into account ., who often deal very harshly with these vehicles. When maneuvering

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Robert Boson GmbH *. R.No. 8786

• Stuttgart · December 2nd, 1966 Rb / Sζ;

It can change ζ. Β. it can happen that within a very short tent the The direction of travel is changed, whereby the operator may endeavor to set a high speed immediately after switching. As a result, the direct current motor and in particular the thyristor control are heavily loaded, with the on the inductances voltage peaks can destroy the thyristors. The destruction of a thyristor usually leads to this Thyristor is continuously conductive. The DC motor then receives constant current and such a faulty vehicle no longer reacts on the control, but drives inexorably worldly.

It is an object of the invention to avoid the disadvantages indicated.

According to the invention, this is the case with a drive arrangement mentioned at the beginning achieved by the fact that a reversing switch with two different directions of rotation of the DC motor is used to control the contactor corresponding switching positions is provided, with in the supply line of the reversing switch is a normally open contact actuated at the same time as the contactor, and that parallel to this normally open contact an auxiliary contact is arranged, which is only closed, when the current through the thyristor is set to zero on its control unit.

When switching from one direction of travel to the other, this runs through Reversing switch the stop position zero, whereby the current to the switch seat is interrupted and this interrupts the motor circuit. This interruption is only canceled when the Current through the thyristor has been set to zero, because only then the auxiliary contact is closed and the relevant contactor is activated is switched on.

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ORIGINAL-

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Robert Bosch GmbH 'R.Nr. 8786

Stuttgart December 2nd, 1966 Rb / Sζ

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According to a further feature of the invention, the drive arrangement designed so that the normally open contact and auxiliary contact each with their

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a connection jointly via a fuse to one pole of the DC voltage source the drive assembly are connected that ihee other Connections are connected to one another via a diode and that the other connection of the auxiliary contact except with the diode also with is connected to the motor-side connection of the thyristor, so that the The fuse is destroyed and the contactor is switched off if a current flows through the thyristor when the auxiliary contact is closed.

This arrangement, which is advantageously also provided for a drive can be, which is not reversible in its direction of rotation, protects -aufia extraordinarily simple .Weise before that if the thyristor is destroyed the drive can no longer be stopped. The control unit then no longer has any influence on the thyristor, but in the zero position ^ des Control unit, the current through the engine is interrupted and the vehicle comes to a standstill. So if the operator If you set the joystick to zero, this works in the usual way. Man can also provide an emergency stop button that serves as an auxiliary contact is connected in parallel and then also to destruction when actuated the backup leads.

A further development of the invention results from the fact that the contactor switches over a field winding of the direct current motor and that: a first no-load diode is arranged parallel to the armature circuit of the direct current motor. In this way it is prevented that when reversing (changing the direction of rotation) voltages and thus currents arise in the armature circuit, which could lead to the fuse blowing. In a further development of this idea, the drive arrangement is designed in such a way that the armature circuit and field winding are connected in series and that a second no-load diode is connected in parallel with this series circuit. Every time the thyristor is switched off, an inductive counter-voltage is created in the motor circuit, which causes a current to flow through this no-load diode, so that the current in the motor _v

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■ ", ORiGINAL INSPECTED

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Robert Bosch GmbH R.Nr. 8786

Stuttgart. 2.I2.I966 Rb / Sz

is not interrupted abruptly, but depending on the load on the motor falls slowly or quickly. "This also prevents ami Motor voltages that are too high, which can burn out the; mentioned fuse.

Further details and advantageous developments of the invention;

result from what is described below and in the drawing illustrated embodiment. ;

It show ^:!

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Fig. 1 shows the circuit of a drive arrangement according to the invention, and

FIG. 2 shows diagrams for explaining the mode of operation of the arrangement up to 4 according to FIG. 1.

The drive arrangement shown in Fig. 1 contains a direct current motor 10 with a field winding 11 which is connected in series during operation, depending on the desired direction of rotation with the help of two; . Sehaltschützeη 12, Ij5 the direction of current flow through the field winding 11 can be adjusted. For this purpose, the contactor 12 has two contacts 14, 15 and the contactor XJ> two contacts 16, 17, which are interrupted in the de-energized state - as shown. One pole of the contacts 14 and 16 is connected to one another and to one terminal of the field winding 11. Likewise, one pole of the contacts 15 and 17 is connected to one another and to the other terminal of the field winding 11. :

The other poles of contacts 15 and 16 are with each other and with one Connection 18 of the motor ID connected. Likewise the other poles are the Contacts 14 and 17 are connected to one another and to a connection point 20. · '·

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BATH ORIGINAL

Robert Bosch GmbH R.Nr, 8786

■ Stuttgart 2.I2.I966 Rb / Sz

The second connection 22 of the motor 10 is via a series resistor 1 and a line 24, hereinafter referred to as the negative line, to the Negative pole of a DC voltage source, not shown, connected, e.g. a vehicle battery, the voltage of which depends on the size of the vehicle and the required power is approximately in the range between 20 V and 100 V. The battery voltage is only determined by the switching voltage the thyristors limited. Its positive pole is connected to a line 25, which is referred to below as the positive line.

With the negative line 24 are the anodes of a first diode 26 and a second diode 27 connected. The cathode of the diode 26 is connected to the terminal 18, the cathode of the diode 27 is connected to the junction point 20.

To control the current through the field winding 11 and the motor 10 A power supply & yj? ig-§Q £ 28, the anode of which has a fuse 29 is connected to the positive line 25 and its cathode via the one winding half of a trans " formator 32 is connected to the connection point 20. Parallel to the thyristor 28 is the series connection of a resistor 33 and a condenser 34, which serves to improve the commutation.

The thyristor 28 has a thyratron-like characteristic; H. he can once it is conductive, it can only be blocked by the fact that its Cathode becomes briefly more positive than its anode. To achieve this, a capacitor 35 of e.g. B. 500 / UF provided, one of which Electrode with the anode of the thyristor 28 and its other electrode is connected to the anode of a thyristor 36 and der.Kathode a diode 37, 'the anode of which is connected to the other half of the winding of the transformer 32. The cathodes of thyristors 28 and 36 are connected with each other. The series shell is parallel to the thyristor 36 . tung.-a resistor 38 and a capacitor 39

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ORIGfNAL INSPECTED

Robert Bosch GmbH R.Nr. 8786

Stuttgart December 2nd, 1966 Rb / Sζ

Between the connection point 20 and the positive line 25 is also a contact 42 of a bridging protection 4j5 is arranged.

To control the two thyristors 28 and J> 6 , two pulse generators 44 and 45 * are used, which are connected in such a way that one pulse generator is blocked when the other pulse generator is working. These pulse generators can contain, for example, a unijunction transistor or a blocking oscillator. They are controlled by a control part 46, at the input of which a control device 47 is connected, which is operated by an operator, e.g. B. the driver of an electric cart, 'is served. When this control device 47 is in its zero position, it closes an auxiliary contact 48, as is the case with the operative connection A-A in Pig. I is indicated

The control section 46 also controls the bypass contactor 415, one terminal of which is connected to the positive line 25 and the other terminal of which is connected to the control section 46. In addition, the control part 46 is connected to the two terminals of the series resistor 23; the voltage drop across this resistor, which is a direct measure of the current i _M through the motor 10, is used to limit the current i ^.

The previously described part of the circuit of FIG. 1 operates as follows: If a certain value has been set on the control unit 47, the thyristor 28 is periodically switched on by the pulse generator 44 and switched off again by the thyristor J56 controlled by the pulse generator 45. Depending on the setting of the control device 47, one of the curve forms shown in FIGS. 2 to 4 is obtained for the motor current i ". In Fig. 2, the thyristor 28 is only turned on for a short time T1 and turned off for a subsequent long time. During the time T, the current i _M increases exponentially; During the pause that follows, it continues to flow through the diodes 26, 27 and in the process drops again exponentially. Overall, the result is a low mean value of the current over time. In FIG. 3, on the other hand, the switch-on _{duration T 2 is} longer and correspondingly also

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Robert Bosch GmbH R.Nr. 8786

Stuttgart 2.I2.I966 Rb / Sz

'the mean current greater. And in Fig. 4, the Einochaltzeit T, much longer, so that the mean current becomes even greater.

Finally, if the thyristor 28 is continuously switched on, so the maximum current flows, the control part 46 becomes the bypass contactor 43 connected in parallel to the thyristor 28, so that the entire motor current i .. flows through contact 42.

The thyristors 28 and 36 work as follows: When they are blocked, The capacitor 35 is charged approximately to the voltage between the lines 25 and 24. Now comes an ignition pulse to the control electrode of the thyristor 28, this becomes conductive. The top half of the transformer 32 * which in this case acts like an inductance now together with the capacitor 35 and the thyristor 28 a series resonant circuit j becomes through the first oscillation in this resonant circuit the capacitor 35 is reloaded to about twice the voltage, namely is now the electrode of the capacitor 35 * with the cathode of the Diode 37 is connected to about the level of the voltage between lines 25 and 24 more positive than the other electrode, like the one in FIG Fig. 1 is indicated by the characters + and -. Since the diode 37 If further oscillations are blocked, this state of charge is retained.

The transformer 32 achieves that the charge reversal on Capacitor 35 increases with increasing motor current.

If the thyristor 28 is now to be blocked again, the thyristor will be 36 ignited by the pulse generator 45. This discharges the Capacitor 35 through thyristors 36 and 28. By the countercurrent in the thyristor 28 this is blocked. The remaining charge on the capacitor 35 flows via the transformer 32 to the motor 10 * Ist der If the capacitor 35 is discharged, the thyristor 36 also blocks again.

If the thyristor 28 is switched on again, the repeats itself described process.

009813/0467

Robert Bosch GmbH R.Nr. 8786

Stuttgart 2.12.1966 Rb / Sz

If the thyristor 28 is destroyed by an overvoltage or some other occurrence, a current flows continuously through it, and the speed of the motor 11 can no longer be influenced on the control unit 47 ^! - will. The same applies to the case where the contact 42 is welded j or the lock-up relay it can not \ open more for other reasons. This condition is very dangerous in a vehicle. The device described below is used to avoid it '..

To control the contactors 12, 13, a reversing switch 49 is provided, which is shown in FIG. 1 in its zero position. It consists of two changeover switches 52, 53, each of which, in addition to the zero position, has a forward position ν and a reverse position r. In addition, | A normally open contact 54 is provided, which is actuated by a relay 55. One pole of the normally open contact 54 is, as well as the one pole of the auxiliary contact 48, connected to the negative line ¹ via a fuse 56. The other pole of the normally open contact 54 is connected to the switching arms of the two changeover switches 52 and 55 and to the anode of a diode 57, the cathode of which is connected to the other pole of the contact 48 and to the connection point 20. :

The contactors 12 and 13 and the relay 55 are each connected to the; a connection of their magnetic windings to the positive line 25 connected i closed. The other connection of the safety protection 13 is connected to the fixed contact v, the other connection of the contactor 12 with the j fixed contact r of the switch 53 connected. The other port 1 of relay 55 is connected to the fixed contacts ν and r of switch 52 tied together. j

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If the reversing switch 49 is brought into the switch position ν during operation and if the control unit is in its contact 48 closed * » sen held zero position, a current flows from the positive line 25 j via the relay IJ, the switch 53, the diode 57, the contact 48! V and the fuse 56 to the negative line 24, so that the contactor 1J5 attracts and.the motor 10 rotates in the forward direction. Simultaneously

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ORIGINAL INSPECTED

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Robert Bosch GMBH . R.No. 8786

: Stuttgart 2.12.19-66 Rb / Sz

• A current also flows from the positive line via the relay 55 and this closes its contact 54, which bridges contact 48. The offer remains switched on when the contact 48 is opened.

If the direction of rotation of the motor 10 is to be reversed, the Reversing switch 49 from its position ν through the zero position to the Position r brought for reverse travel. When passing through the zero position, the current through the relay 55 is interrupted, so that the Normally open contact 54 is opened again. This will make the switch 12 initially de-energized as long as the control unit 47 is not yet in its Zero position is returned. Only when this zero position is reached and the auxiliary contact 48 is closed, the sound insulation 12 is a " switched and · the motor 10 runs in reverse.

The arrangement described thus achieves in a very simple manner that the motor 10 can only be reversed when no current is flowing through the thyristor 28.

If the thyristor 28 is defective, so that it conducts continuously, or can the contact 42 no longer open, so that, - the motor 10 to the control unit 47 no longer obeys, it is sufficient if the operator the control unit 47 returns to its zero position. It then flows a current from the connection point 20 via the auxiliary contact 48 and the fuse 56 to the negative line 24. This current destroys instantly- * borrowed the fuse 56, so that the contactor 12 (or -Γ5) de-energized and interrupts the motor circuit. The engine 10 then comes quickly to a standstill.

The diode 57 prevents in a simple manner that in operation ■ from the connection point 20 via the normally open contact 54 to a current Negative line 24 flows and the fuse 56 is destroyed in the process.

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ORIGINAL INSPECTED

Robert Bosch GmbH R.Nr. 8786

Stuttgart 2.I2.I966 Rb / Sz

The safety circuit described is extremely simple in structure and offers very good protection against accidents caused by defects in the thyristor 28 or errors at the contact 42. In addition, it allows a Reversing only when the thyristor 28 is blocked.

The diodes 26 and 27 prevent that even after the disconnection

th of the thyristor 28 one of the inductance of the motor armature 10 or the field winding 11 caused current to flow through the fuse 56 and can destroy them. Safe functioning is guaranteed by these diodes.

OQ9813 / 0487

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original inspected

Claims (5)

Robert Bosch GmbH R.Nr. 8786 Stuttgart 2.12.1966 Rb / Sz claims 1. Drive arrangement controlled by a thyristor, especially for Electric vehicles, with a direct current motor, whose direction of rotation is switchable by at least one contactor, whereby the de-energized state of the switching protection is an interruption of the motor current - corresponds to a circle, characterized in that a reversing switch (49) with two switching positions (v, r) corresponding to the different directions of rotation of the direct current motor (10) is provided to control the stop contactor (12 / 1J>) Each reversing switch has a normally open contact (54) actuated at the same time as the contactor (12, 13), and that an auxiliary contact (48) is arranged parallel to this normally open contact (54) which is only closed when the current flows through the Thyristor (28) ! whose control unit (47) is set to zero. 2. LAntriebsanDDnung according to claim 1, characterized in that iNo.contact (54) and Kilfcontact (48) each with their 'a connection jointly via a fuse (56) to one pole are connected to the DC voltage source of the drive arrangement, i that their other connections are connected to one another via a diode (57) • are bound and that the other connection of the auxiliary contact (48) except ! with the diode (57) also with the motor-side connection (20) of the . Thyristor (28) is connected, so that the fuse (56) destroyed - · 1 U'nrlqnan (ArLTaM aIs.Z } \ i. \ 5a5 3 * of the amendment law of 4. 9.1 - 2 - COPY
ORIGINALINSPECTED Robert Bosch GmbH 'R.Nr. 8786 ■ Stuttgart 2.I2.I966 Rb / Sz. and so that the contactor (12, IJ) is switched off if at ge, - ' closed auxiliary contact (48) a current through the thyristor (28).! flows. 'j 3. Drive arrangement according to claim 2, characterized in that parallel to the thyristor (28), a switch (42) for bridging the 'thyristor (28) is arranged, and that the other terminal of the
Auxiliary contact (48) not only with the diode (57) but also with the motor! side connection (20) of this switch (42) is connected. j 4. Drive arrangement according to at least one of claims 1 to 5, there-. characterized in that the contactor (12, 13) switches a field winding (11) of the direct current motor (10) and that a first no-load diode (26) is arranged parallel to the armature circuit (10) of the direct current ₍ motor. \ 5. Drive arrangement according to claim 4, characterized in that the armature circuit (lo) and field winding (11) are connected in series and that ^l a second idling diode (27) in parallel with this series circuit
is switched. 5. xT, ^ 00981 3/0 ^ 67 COPY
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