SU765747A1 - Phase angle-to-dc voltage converter - Google Patents

Description

one

The invention relates to electrical measuring converters, in particular, to phase converters of two electrical signals to a voltage.

The invention is intended for automated measurement, control and monitoring systems. In addition, it can be used in the study of systems of automatic control of frequency methods.

It is known that a device consisting of a linear-varying voltage shaping channel, which contains two sources of the reference voltage of different polarity, connected via a switch to the integrator input, in the feedback circuit of which a constant compensator 1 is connected. The output of the first sensor through the amplifier is connected to the trigger input, the output of which is connected to the control input of the key.

The integrator output is connected to the input of the analog storage device, and the output of the second sensor is connected through amplifier1 to the control input of the analog backwash device, the output of which is output

devices. The low accuracy of converting the phase angle to a constant voltage, which decreases with decreasing frequency, is due to the discharge of the capacitor of the analog storage device.

It is also known a device containing input pulse drivers, two integrator amplifiers with bit switches in a feedback circuit, the inputs of which are connected to voltage sources of different polarity, 10 than the output of the first of 1 integrators 1 of the integrators is connected directly, and the second through a key to the input Analog Signal Lock Circuits {2. The output of the first driver, pulses connected to the control inputs

IS keys, which are located in the feedback circuit of the first amplifier-integrator and at the input of the analog signal fixation circuit. The output of the second pulse shaper is connected to the control inputs of the keys, which are located in the communication circuit and at the output of the second device;

The low measurement accuracy (conversion) of this device is due to the presence of an analog signal fixation circuit, due to the fact that the output voltage of the analog signal fixation circuit, proportional to the phase angle, is removed from the capacitor. The voltage on the capacitor does not remain constant during the period, i. this is how capacitor discharges through a parallel-connected resistance, the value of which is not infinite. The capacitor is discharged over a period the greater, the lower the frequency of the signal under study. The ITojTOMy measurement error increases, especially in the infrared:} ki frequencies. The aim of the invention is to improve the accuracy of converting a phase angle to a voltage iffle. This is achieved by the fact that a phase angle to constant voltage converter containing the first and second pulse shapers, three amplifier-integrators, the source of the reference voltage, four switches, two of which are included in the feedback circuits of two amplifier-integrators , and the third is connected to the input of the third amplifier-integrator, two additional analog adders, an inverter, a coincidence element, a zero-organ, a trigger, two keys, three differentiating chains, two circuits, and all three integrator amplifiers are introduced connected to the source of the reference voltage through the third, fourth and fifth keys, the outputs of the first and second integrator amplifiers are connected to the inputs of the first analog adder connected to the input of the inverter, the output of which and the output of the first analog adder are connected via diodes to the input of the zero-organ and to one of the inputs of the second analog adder, the other input of which is connected to the output of the third amplifier-integrator with the sixth key in feedback, the output of the zero-organ is connected to the first input of the trigger, The input of which is connected to the output of the first pulse generator via a differentiating chain, and the output to the control input of a third of its key, the control input of the sixth key connected to the output of the coincidence element, whose inputs are connected to the outputs of the driver of the pulse drivers to the control inputs of the fourth and n addition of keys and through differentiating chains to the control inputs of the first and second keys. In the drawing, the structural diagram of the proposed converter is given. It includes pulse formers 1 and 2, electronic switches 3-8, amplifiersintegrators 9, 10, 11, analog combiners 12, 13, reference voltage source 14, inverter 15, null organ 16, trigger 17, element of coincidence 18 , differentiating chains 19-21, diodes 22-23. The converter works as follows. The inputs of the pulse shaper 1 and 2. periodically varying voltages of the same frequency, but shifted in phase, from which rectangular voltages of one polarity are formed. These pulses are fed to the control inputs of electronic switches 3 and 4, which alternately connect reference voltages of different polarity to the inputs of integrator 9 and 10. Moreover, with the arrival of a pulse, the negative polarity voltage is applied to the input of the amplifier of the integrator 9, and with the arrival of a pulse, the voltage of the positive polarity must arrive at the input of the amplifier integrator 10. When the pulses at the output of the formers 1 and 2 are missing, the voltages applied to the inputs of the integrator amplifiers 9 and 10 are reversed. As a result of integrating the obtained rectangular pulses, the output of the amplifier-integrator 9 forms a voltage of a triangular shape of positive polarity, and the output of the amplifier-integrator 10 is a negative field of pHxx; When a negative polarity voltage is connected to the input of the amplifier-integrator 9, an integration process occurs, with the result that the positive-voltage amplifier's output voltage increases linearly from zero. When the polarity of the input voltage changes, the direction of integration changes and the output voltage decreases linearly to zero. If, for any reason, the output voltage of the amplifier-integrator does not reach the zero level, opening the switch 6 will force the output voltage to zero. This key is opened for a short time by pulses coming from differentiating chain 19, the KOTOpbie is derived from differentiating the leading edges of pulses of pulse generator 1. Since key 6 is conductive for the input voltage of any sign, if there is a signal at the control input of the key, connecting the output voltage of the amplifier of the integrator 9 to a zero level, and therefore its output voltage has a triangular shape of positive polarity. The circuit consisting of keys 4 and 7, pulse generator 2, differentiating chain 20, amplifier-integrator 10, which forms a positive polarity, works in a similar way. Binding to the zero level of the output voltage of the amplifier of the integrator 10 occurs by a pulse coming from the differentiating chain 20, which is obtained from the differentiation of the leading edges of the pulses of the pulse former 2.

From the outputs of the integrator amplifiers 9 and 10, the triangular-shaped voltages are fed to the inputs of the analog adder 12, the output of which, after summing, produces a trapezoidal voltage. The amplitude of this voltage is proportional to the magnitude of the phase angle.

The voltage from the output of the analog adder 12 is fed to the anode of the diode 23 and to the input of the inverter 15, the output of which is connected to the anode of the diode 22. With the help of these diodes, the positive part of the trapezoidal voltage half-cycle is cut off and the input voltage of the analog adder 13 receives positive half-periods of voltage trapezoidal shape. The same voltage is applied to the input of the null organ 16, the output of which produces short pulses at times when the voltage at the input of the null organ is zero.

At the output of the differentiating chain 21, pulses are received from the differentiation of the leading and trailing edges of the pulses of the pulse former 1. The pulses coming from the zero-output output and the differentiating chain 21 alternately switch the trigger 17, at the output of which voltage pulses are received, including a switch 5. In as a result, a negative polarity voltage is applied to the input of the amplifier-integrator 11 and a positive part of the triangular voltage is formed. The voltage will increase until the pulse arrives from the nullorgan, which switches the trigger, as a result of which a positive polarity is applied to the input of the amplifier-integrator. Then a falling part of the voltage of a triangular shape is formed. The formation will continue until the arrival of the pulse from the coincidence element 18 to the control input of the key 8. The key is turned on, the voltage at the output of the amplifier of the integrator 11 becomes zero and will remain so until the pulse at the output of the coincidence circuit. At the output of the coincidence circuit 18 there will be an impulse of voltages, when at its both inputs there are sigals corresponding log.1, or log.O. Otherwise, the output voltage is zero. ,

At the output of the amplifier-integrator 11, triangular pulses are formed. The amplitude of these pulses is proportional to the phase angle. When designing integrator amplifiers, the following condition must be fulfilled: the steepness of the pulses of a triangular shape of the amplifier integrator 11 must be twice as large as the slope of the integrator amplifiers 9 and 10. As a result of the summation of the voltage and pulses in the analog adder 13. a signal is formed in the form of this voltage. The magnitude of this voltage is proportional to the phase angle. This is evident from the voltage chart, which is considered for phase angles of 45 ° and 135 °.

The proposed converter provides high-precision conversion of the phase angle to analog voltage in a practically unlimited frequency range compared to converters using memory devices.

The use of the invention in automated control measurement and control systems will provide better and more reliable testing of power system elements.

Claims (2)

Invention Formula Phase-to-voltage phase converter containing the first and second pulse formers, three integrator amplifiers, the reference voltage source, four keys, two of which are included in the feedback circuits of two integrator amplifiers, and the third is connected to the input of the third amplifier -integrator, characterized in that, in order to improve the accuracy of the conversion, two additional adders, an inverter, a coincidence element, a zero-body, a trigger, two keys, three differentiating chains, two diodes, are introduced ohm, the inputs of all three amplifiers-1 integrators are connected to the reference voltage source via the third and fourth and fifth switches, the outputs of the first and second integrator amplifiers are connected to the inputs of the first analog adder connected to the input of the inverter, the output of which the output of the first analog adder is connected via diodes to the input of the zero-organ and to one of the inputs of the second analog adder, the other input of which is connected to the output of the third amplifier-integrator with a switching key in feedback, output zero The rgan is connected to the first trigger input, the second input of which is connected to the output of the first pulse shaper via a differentiating chain, and the output to the third input of the third key, and the gravity input of the sixth key is connected to the output of the coincidence element, the inputs of which are connected to the outputs of the pulse shaper to control inputs of the fourth and fifth keys. 7 P, - -765747. eight and through differentiating chains - to admin-1. Copyright svkdete / thsness USSR № 264804, Leading inputs of the first and second keys.kl. G 01 R 25/04, 1965. Information sources, 2. USSR author's certificate No. 569965, taken into account during examination. G 01 R 25 / OOi 1976.