SU1677859A1 - Induction load current bridge switch - Google Patents

Abstract

The invention relates to a pulse technique and can be used for reversing control of polarized electromagnetic relays and DC motors. The purpose of the invention is to increase the efficiency of a bridge current switch in an inductive load by disconnecting the supply voltage at the time of dissipation of energy stored in an inductive load. When an EMF of self-induction occurs and a current appears in the collector circuit of transistor 5, the control signal from the sender 13 opens the switch 12. After the dissipation process ends the energy of the load 14, the signal of the sensor 13 is terminated and the key 12 returns to the initial state. 2 Il. Yo

Description

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The invention relates to a pulse technique and can be used for reversing control of polarized electromagnetic relays and direct current motors.

The purpose of the invention is to increase the efficiency of a bridge current switch in an inductive load by disconnecting the supply voltage by the time of dissipation of the energy stored in the inductive load.

FIG. 1 is a circuit diagram of a bridge current switch in an inductive load; in fig. 2 shows a form of execution of a control key and a current sensor.

The bridge switch of the current in the inductive load contains four power transistor switches 1-4, which are connected by a bridge circuit, the first and second transistors 5, 6 different types of conductivity, four diodes 7-10, which are connected by a bridge circuit, a shunt circuit 11, controlled a key 12 and a current sensor 13, with a load 14 connected to one diagonal of the transistor bridge circuit and a shunt circuit 11 to the other, the first output of which is connected to the first power supply bus 15 and the emitter of the first transistor 5, whose base is connected to the collector second transistor b, the base of which is connected to the second output of the shunt circuit 11, the diode bridge circuit inputs are connected in parallel with the load 14, and the first and second outputs are connected to the emitter of the second transistor b and the first power bus 15, respectively, the collector of the first transistor 5 is connected to the second output of the shunt circuit 11, which is connected via a power circuit of the control key 12 to the second power bus 16, the input of the control key 12 is connected to the output of the current sensor 13. Parallel to the base-emitter junction of the first transistor 5, a resistor 17 is turned on.

The control key 12 can be performed, for example, on a transistor 18, the base of which is connected via a resistor 19 to the first power supply bus 15, and the LED 20.1 of the transistor optocoupler 20 is used as a current sensor 13, the collector-emitter junction of the phototransistor 20.2 of which is connected in parallel with the base transition -emitter transistor 18.

The bridge switch current in inductive load works as follows

When self-induced emf or counter electromotive force occurs and induction current occurs in the collector circuit of transistor 5, the control signal from current sensor 13 opens key 12, after which the energy from

the power source is not consumed, and since the resistance of the current sensor is much less than the active resistance of the load, all stored in the load

14, the energy is dissipated almost at the last and the dissipation time tends to time, due only to the parameters of the load. After the dissipation process is completed, the induction current drops to

zero, the signal of the current transmitter is stopped, the key 12 returns to the initial (closed) state.

FIG. 2 shows an example of the implementation of the current sensor 13 and the key 12. Power

The transistor 18 of the switch 12 is open and saturated with the base current limited by the resistor 19 in the absence of current in the collector circuit of the first transistor 5. When opening the transistor 5 at the moment of occurrence

The EMF of self-induction or counter-electromotive force induced current flowing through the current sensor 13, made in the form of an LED 20.1 transistor optocoupler 20, causes the saturation of the phototransistor 20.2 and thus

locks the transistor 18, i.e. key 12 opens.

The efficiency of the proposed bridge current switch is higher than that of the known ones due to the disconnection of the supply voltage

dissipation time stored in inductive load energy.

Claims (1)

Claims of the invention. A bridge current switch in inductive load, containing four power transistor switches, which are connected in a bridge circuit, the first and second transistors of different conductivity types, four diodes, which are connected a bridge circuit, a shunt circuit, a load diagonal is connected to one diagonal of the transistor bridge circuit, and a shunt circuit is connected to the other, the first terminal of which is connected to the first power rail and the emitter the first transistor, the base of which is connected to the collector of the second transistor, the base of which is connected to the second output of the shunt circuit, the inputs of the diode bridge circuit are connected in parallel with the load, and the first and second outputs are connected respectively to the emitter of the second transistor and the first power bus, characterized in that, in order to increase the efficiency, a control key and a current sensor are introduced, the collector of the first transistor is connected via the current sensor to the second output of the shunt circuit, which is connected to the output of the current sensor via the power supply circuit of the controllable switch, to the second power supply bus. (Reg. 2