SU1386928A1 - Rectifier drive current sensing device - Google Patents

Description

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The invention relates to electrical washer technology and can be used for electric drives for various purposes.

The purpose of the invention is to increase the speed and accuracy by expanding the pass band 1 (and reducing the level of interference).

The drawing shows the principle scheme of the proposed current sensor valve actuator.

I The sensor contains shunt 1, the leads of which are connected to the first and second inputs of the push-pull modulator 2 and its first and second control inputs, respectively. The push-pull modulator 2 consists of the first 3 and second 4 transistors, the bases of which are connected to the third and fourth | control inputs of the push-pull modulator 2, respectively, and the first 5 and second 6 windings of the separation transformer 7, the beginnings of which connected to the emitters of the first 3 and second 4 transistors, respectively, and the ends of these windings of the isolation transformer 7 are connected to the collectors of the second 4 and first 3 transistors and the second and first inputs of the push-pull modulator 2. The push-pull demodulator 8 consists of three There are 9 and fourth 10 transistors, the emitters of which are connected to the ends of the third 11 and fourth 12 windings of the isolation transformer 7, respectively, its second and nerve control inputs. The bases of the third 9 and fourth 10 transistors are connected to the third and fourth control inputs of the push-pull demodulator 8, respectively. The first and second outputs of the push-pull demodulator 8 are connected to the first and second inputs of the differential amplifier 13, respectively. The first, second, third, and fourth control inputs of the push-pull modulator 2 are connected to the first, second, third, and fourth outputs of the source 14 of the switching signals, respectively, the fifth, the second, the seventh, and the eighth outputs of which are connected to the first, second, third, and the fourth control inputs of the push-pull demodulator 8, respectively. The first 3, the second 4, the third 9 and the fourth 10 transistors are of the same conductivity type.

The current sensor valve actuator works as follows.

The voltage taken from shunt 1 and proportional to the current of the monitored circuit is modulated by a push-pull modulator 2, the transistors 3 and 4 of which are alternately opened and different polarity pulses appear on the windings 5 and 6 of the isolation transformer 7. The amplitude of the pulses corresponds to the instantaneous value of the voltage on the shunt 1, and the frequency of the pulses corresponds to the frequency of the source 14 of switching signals. Since only one transistor is used in each arm of the modulator, the resistance value of the transistor in the open state has a minimum value, and therefore, based on the allowable value of the static modulus of the modulator, inductance of windings 5 and b of the isolation transformer 7 and associated with them the parasitic inductances of stray and capacitance have the lowest possible values. As a result, the upper limit of the sensor bandwidth, limited mainly by the parameters of the transformer 7, has the highest value. The effect of the residual voltage of the transistors is compensated directly on the primary windings of the transformer 7 without transforming the voltages to the demodulator 8. The pulsed disturbances caused by the reloading of the parasitic capacitances of the secondary windings of the transformer of the source of the 14 switching signals also have a minimum value, since its first and the second outputs are connected to the shunt. The distributed capacitance of the power circuit in which the shunt is installed with respect to the common point of the sensor has a much greater value than the parasitic capacitance between the primary and secondary windings of the transformer of the source 14 of switching signals.

The push-pull demodulator 8 operates similarly to modulator 2 and the compensation of the effect of residual voltages of transistors 9 and 10 occurs on the secondary windings 11 and 12 of transformer 7, but the polarity of the connection of these windings to transistors 9 and 10 is reversed compared to modulator 2 In this case, there is some compensation for the constant winding of the transformer core 7.

Taking into account that with full symmetry of the demodulator circuit 8, the interference pulses from the recharge of the parasitic capacitances of the secondary windings of the transformer of the switching source source 14 are of the same magnitude and change synchronously with respect to the common sensor point at both outputs of the demodulator 8, at the output of the amplifier 13, made according to the differential input circuit, the said disturbance will have a significantly smaller value than in the case of another embodiment of the amplifier 13.

Claims (1)

Invention Formula The current sensor valve actuator containing a shunt, to the first and second terminals of which are connected the first and second inputs of the push-pull modulator and its first and second control inputs, respectively, and the push-pull modulator consists of the first and second transistors of the same type of conductivity, the bases of which are connected to the third and fourth control inputs of a push-pull modulator, respectively, and the first and second windings of an isolation transformer, a push-pull demodulator consisting of the third and fourth transistors of the same type of conductivity with push-pull transistors, modulator and the third and the fourth winding of the isolation transformer, the first output of the push-pull demodulator connected to its first control input and the first input of the amplifier, and the second output to of the contact demodulator connected to its second control input, the third and fourth control inputs of the push-pull demodulator connected to the bases of the third and fourth transistors, respectively, the source of the switching signals, the first, second, third and fourth outputs of which are connected to the first, second, third and the fourth control inputs of the push-pull modulator, respectively, and the fifth, sixth, and seventh 0 five 0 The eighth outputs of the switching signal source are connected to the first, second, third and fourth control inputs of a push-pull demodulator, respectively, characterized in that, in order to increase speed and accuracy, the emitters of the first and second transistors of the push-pull modulator are connected to the beginnings of the first-to-second; i the second windings of the dividing Tpaiicdior: mator, respectively, and their ends of the COP are repaired with collectors of the second and first transistors and the second and first inputs, and 5 h of the clock modulator, respectively, the emitter of the third and fourth transistors of the two-stroke demodulator separators 101 transformer, respectively, and their beginning connected to the collectors of the fourth and third transistors and the second and first outputs of the push-pull demodulator, respectively, the amplifier is made differential cial and its second input connected to a second push-pull output of the demodulator, and an output - with output current sensor.