SU1249685A1 - D.c.electric drive - Google Patents

Abstract

- The invention relates to electrical engineering and is used in automatic control systems. The chain of invention is an increase in reliability. In transient conditions, when the load is shed or the control signal is reduced in the contact system, the relative duration of switching on may become zero. Transistors (T) 3 and 4 are closed, the current through diode 11 does not flow, and under the action of EMF, T 10 and 5 open. At the same time, the current in motor 1 varies. In n-direction, T.ei. engine braking is carried out. To limit the base current T 3 and 5, diodes 15 and 16 are entered. Then T 10 in the pauses between pulses is connected to the causd of T 3 and 5 according to the composite transistor scheme, which increases the gain of T 10. This allows you to more effectively slow down the motor at low speeds. x rotation, reduces the amplitude of the current and the power T 10. 1 Il. 9 + (L f2

Description

The invention relates to electrical engineering and can be used in systems for automatic control of direct current electric drives.

The aim of the invention is to increase the reliability of the drive

The drawing is a diagram of a DC drive.

Electric drive contains engine

I, included in the output diagonal of the bridge power amplifier with power transistors 2-5, shunted by reverse diodes 6-9, transistor switch 10, whose basic-emitter junction bridges the diode 11 connected between one (in this case, positive) power supply terminal

and bridge power amplifier. The base of the transistor switch 10 is connected via resistor 12 and diodes 13 and 14 to the leads of motor 1 through diodes 15 and 16, and the collector of transistor switch 10 is connected to the bases of power transistors 3 and 5 connected to another (in this case, negative) power source .

The device works as follows.

In the absence of a control signal in the initial state, the crisis of the mountain 2-5 of the bridge amplifier is closed. Movement-. Tel .1 disconnected from power source

Depending on the polarity of the control voltage, the transistors of one of the diagonals of the bridge amplifier are switched, for example, transistors 3 and 4, and transistors 2 and 3 of the other diagonal are closed. With the arrival of the control pulse, the transistors 3 and 4 open and the load current flows through the circuit: plus power supply, diode

II, transistor 4, measles of motor 1, transistor 3, minus power supply,. The current flowing through the bark of the engine 1 creates torque on the shaft and the engine 1 begins to rotate in a certain direction.

When a current flows through it, a diode 11 creates a voltage drop, which is applied to the base-emitter transition of the tensile switch 10 and keeps it in the closed state. During the pause between the control pulses, transistors 3 and 4 are closed. In this case, until the transistors 3 and 4 of the diagonal amplifier are fully closed

the voltage on the diode 11 closes the transistor switch 10.

After closing the transistors 3 and 4, the current through the diode 11 does not flow

and under the action of self-induced EMF, transistor switch 10 is opened across the circuit: measles motor 1, diode 6 junction emitter-base switch 10, resistor 12, diode 14, measles motor. As a result of opening the transistor switch along the circuit: motor fault 1., diode 6, emitter-collector switch 10, diode 15, base-emitter junction of transistor 3, diode 9 will also flow

5 current, transistor 3 will open and current

in engine 1 will leak into the. Same direction, closed through the power transistor 3 and the shunt diode 9.

0 In transient conditions, for example, at a load shedding or reduction of the control signal in the system –with speed feedback, the relative duration-on can

5 become equal to zero. In this case, the transistors 3 and 4 are closed, the current through the 1-cycle 11 does not flow, and under the action of the emf of rotation, the transistor switch 10 along the circuit opens automatically

0 motor fault 1, diode 8, emitter-base, resistor 12, diode 13, engine measles, therefore, through diode 8, public key 10, diode 16, base-emitter junction of the power transistor 5, diode 7 current will flow from the EMF of rotation and transistor 5 opens. In this case, the current in the motor 1 changes its direction and will flow through the transistor 5 and the diode 7, i.e.

0, the motor 1 is brought into brake mode. When the motor 1 rotates in the opposite direction, when the in-phase transistors 2 and 5 are switched, and 3 and 4 are closed, the processes in the circuit proceed in a similar way. In this case, while current flows through the diode 11, the transistor switch 10 z.kryt. In the pauses between pulses, it opens and turns on the power transistor 5, which together with the diode 7 creates a path for current to flow through the motor 1 under the action of a self-induced EMF, and in deceleration modes the power transistor 3 turns on and forms the main flow circuit of the braking current with diode 9. from EMF of rotation. To limit the base current of the power trans-

five

0

3

tori 3 and 5 in series with the diodes 15 and 16, you can connect resistors or install one common resistor directly into the collector circuit of the transistor switch 10.

Thus, in a direct current drive, the transistor switch in the pauses between the pulses turns out to be connected with each of the power transistors 3 and 5 according to the composite transistor circuit, the gain factor of which is significantly greater than the gain factor of one transistor switch in the known drive and, therefore, in the proposed the electric drive effectively brakes the motor at low speeds of rotation, reduces the amplitude of the current through the transistor capacitance and, accordingly, its installed power that ultimately leads to increased reliability of the drive.

Editor A. Shandor

Compiled by Y. Vorobiev

Technical editor S. Cherni

Order 4338/58 Circulation 631 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st. -, 4

49685.4

Formula of invention

A DC motor containing a motor connected to the diagonal of a bridge power amplifier 5 on power transistors shunted by reverse diodes and a transient power key whose basic-emitter junction is bridged by a diode connected between one output of the power source and the bridge amplifier power 10

The base through a resistor and two other diodes is connected to the output side of the motor winding, and the collector of the transistor switch is connected to power transistors connected to another output of the power supply, characterized in that diodes are additionally inserted into it through which the collector of the transistor switch is connected to the bases of the power transistors of the bridge power amplifier connected to another output of the power source,

Claims (1)

SUMMARY OF THE INVENTION A direct current electric drive comprising a motor included in the diagonal of a bridge power amplifier with power transistors shunted by reverse diodes, and a transistor switch, the base-emitter junction of which is shunted by a diode connected between one output of the source 10 power supply and a bridge power amplifier, the base through a resistor and two other diodes is connected to the terminals of the armature winding of the motor, and the collector of the transistor switch is connected to power, 5 transistors connected to another output of the power source, characterized in that, in order to increase reliability, It additionally introduced diodes through which the 2nd collector of the transistor switch is connected to the bases of power transistors of the bridge power amplifier connected to another output of the power source. ^?