SU782111A1 - Dc motor control device - Google Patents

Description

(54) DEVICE FOR ELECTRIC MOTOR CONTROL

one

The invention relates to electrical engineering and can be used in an automated electric drive, in particular, in pulse-width and frequency-pulse converters, designed to control DC motors.

A device for controlling a direct current electric motor is known, comprising a transistor bridge, in the diagonal of which a direct current electric motor ij is connected.

The closest to the invention in its technical essence is a device for controlling an electric motor of direct current, containing two restrictive throttles and a transistor bridge, in the diagonal of which is included an electric motor 2 J.

A disadvantage of the known devices is the impossibility of obtaining a continuous current in the core circuit in the reverse mode during the operation of the current protection, and therefore an increase in the deceleration time during the reverse, as well as the complexity of the control circuit.

The purpose of the invention is to simplify the device and increase speed when reversing. DIRECT CURRENT

This goal is achieved by inserting two anti-parallel transistors, the emitters of which are connected to the throttle, and the base of each transistor is connected to the electric motor and to the collector of another transistor.

FIG. 1 is a schematic diagram of the device; in FIG. 2 10 timing charts of currents and voltages.

Electric motor 1 is included in the diagonal of the bridge formed by transistors 2, 3, 4, 5. In the collector circuit of transistors 3 and 4 of the lower shoulders of the bridge, chokes 6 and 7 are connected. Electric motor 1 is enclosed by two switched on anti-parallel transistors 8 and 9. Emitters , transistors 8, 9 are connected to drossel m 6 and 7, and the base of each transistor is connected to the electric motor 1 n to the collector of the other transistor. To another

25, the diagonal of the transistor bridge is connected to a power source, with the plus power source being connected through a resistor 10 to the emitters of transistors 3 and 4, controlling the transistors of an axis 30 using two pulse-width modulators (PWM) 11, 12 and current protection unit 13.

The device works as follows.

When the signal U is applied to the input of the control circuit, at the output of one of the PWM, for example, 12 pulses of output are produced. 2, time to). These pulses open transistors 2, 4. In the core of electric motor 1 current flows through the circuit: plus power supply — measuring resistance 10 — open transistor 4 — choke 7 — measles of electric motor 1 — open transistor 2 — minus the power supply. From time t and until time tj, the emf of self-induction of the throttles 7 creates a current that is behind ("walks along the circuit; the base-emitter of transistor 9" -emitter of transistor 9 — choke 7 — measles of electric motor 1. From the moment of time t, the circuit operation is repeated. To reverse the current in the bark of electric motor 1, the input signal Ug of another polarity must be supplied. time tj opens transistors 3, 5. In the core of electric motor 1, a current Tj-T flows due to the power source and the presence of a counter-EMF of the motor .1 along the circuit: open transistor 3 - minus power supply.,

When the current cor reaches the magnitude of the current protection actuation, the time instant t trips the current protection device 13 and closes the transistors 3 and 5. The self-induced EMF Drossel 6 generates a current that closes in the circuit: base-emitter of transistor 8; the latter opens f and the EMF of self-induction of the core creates a current Z., which closes along the circuit: the electric motor 1, the collector-emitter of the open transistor 8, the choke b, the electric motor 1. Measures 1. From time t (the circuit repeats.

Thus, the device allows to obtain a continuous limited current in the reverse mode, increase the speed and simplify the control circuit 5.

Claims (2)

1.Patent of France No. 2210333, cl. H 02 R 7/00, published in 1974. 2.Pokratyev LD and others. Pulsed and relay servo drives of direct current with semiconductor amplifiers. M., Energie, 1969, p. 40