RU222350U1 - MEASURING CONVERTER OF AC TO DC VOLTAGE - Google Patents

Abstract

The utility model relates to electrical measuring technology and can be used to measure alternating voltage in a wide frequency range by converting it to direct voltage. The measuring transducer contains a controlled phase shifter, the input of which is connected to the input of the measuring transducer, a differentiator, a comparator, a single vibrator, two amplitude detectors, a division unit, a scaling unit, an integrator with reset, an adder and a source of a master signal. The output of the comparator is connected to the input of a one-shot device, the output of which is connected to the first input of the integrator with reset, the output of which is connected to the first input of the adder, the output of which is connected to the control input of the controlled phase shifter, the output of which is the output of the measuring transducer, and the output of the master signal source is connected to the second input adder. The input of the measuring transducer is connected to the inputs of the first amplitude detector and differentiator, the output of which is connected to the inputs of the comparator and the second amplitude detector, the output of which is connected to the first input of the division block, the output of which is connected through the scaling block to the second input of the integrator with reset, and the output of the first amplitude detector connected to the second input of the division block. The technical result of the claimed utility model is to increase the speed and accuracy of the converter. 2 ill.

Description

The utility model relates to electrical measuring technology and can be used to measure alternating voltage in a wide frequency range by converting it to direct voltage.

A known measuring converter of alternating voltage to direct voltage [Patent for PM No. 166785 of the Russian Federation, IPC G01R 19/22, publ. 12/10/2016], containing a controlled phase shifter, the first and second quadrators, an adder, a square root extraction unit, a phase detector, a PI controller and a source of a master signal, and the input of the converter is connected to the inputs of the first quadrator and a controlled phase shifter, the output of which is connected to input of the second quadrator, and the outputs of the first and second quadrators are connected, respectively, to the first and second inputs of the adder, the output of which is connected to the output of the converter through the square root extraction block, the input and output of the controlled phase shifter are connected, respectively, to the first and second inputs of the phase detector, the output of which is connected to the first input of the PI controller, the second input of which is connected to the output of the master signal source, and the output of the PI controller is connected to the control input of the controlled phase shifter.

The disadvantage of this converter is the presence of a PI controller, the operation of which is characterized by regulation time due to the presence of an integral component of the PI controller. As a result, the controlled variable reaches the required value after some time, called the settling time, and the converter has low performance. In addition, the presence of a transient process reduces the accuracy of the converter in transient modes.

The closest analogue to the proposed utility model is an AC-to-DC voltage measuring converter [Patent for PM No. 211821 of the Russian Federation, IPC G01R 19/22, publ. 06/23/2022], containing a controlled phase shifter, the input of which is connected to the input of the measuring transducer, an uncontrolled phase shifter, a comparator, a one-shot vibrator, a frequency-voltage converter, an integrator with reset, a source of a master signal and an adder, and the input of the measuring transducer is connected through an uncontrolled phase shifter to the input of the comparator, the output of which is connected to the input of the frequency-voltage converter and the input of the one-shot, the output of which is connected to the input of the integrator with reset, the reset input of which is connected to the output of the frequency-voltage converter, the output of the integrator with reset is connected to the first input of the adder, the output of which is connected to the control input of a controlled phase shifter, the output of which is the output of the measuring transducer, and the output of the source of the master signal is connected to the second input of the adder.

This technical solution was chosen as a prototype.

The disadvantage of this converter is its low performance, especially in the low-frequency region, due to the use of a frequency-voltage converter in the device, the circuit of which uses a low-pass filter at the output. In this case, the time constant of the low-pass filter is chosen to be large enough based on ensuring the specified ripple of the output control voltage at the lowest frequency of the operating range, which determines the low performance and accuracy of the device, especially in transient modes throughout the entire operating frequency range.

The technical result of the claimed utility model is to increase the speed and accuracy of the converter.

The specified technical result is achieved by the fact that in a known measuring converter of alternating voltage to direct voltage, containing a controlled phase shifter, the input of which is connected to the input of the measuring transducer, a comparator, a one-shot, an integrator with reset, a source of a master signal and an adder, and the output of the comparator is connected to the input of the one-shot, the output of which is connected to the first input of the integrator with reset, the output of which is connected to the first input of the adder, the output of which is connected to the control input of the controlled phase shifter, the output of which is the output of the measuring transducer, and the output of the source signal is connected to the second input of the adder, an additional differentiator, amplitude a detector and a division block, wherein the input of the measuring transducer is connected to the input of a differentiator, the output of which is connected to the inputs of the comparator, amplitude detector and the first input of the division block, the output of which is connected to the second input of the integrator with reset, and the output of the amplitude detector is connected to the second input of the division block.

Significant differences of the proposed measuring transducer are the introduction of a differentiator, two amplitude detectors, a division block and a scaling block, as well as the organization of new connections between the elements of the device. The set of elements and connections between them ensures the achievement of a positive effect - increasing the speed and accuracy of the converter.

The essence of the utility model is illustrated by drawings. In fig. 1 shows a functional diagram of the measuring transducer; Fig. 2-time diagrams of voltages _uin , _u1 , _u2 , _u3 , _u8 , _u10 and _uout .

The measuring transducer (Fig. 1) contains a controlled phase shifter 1, a differentiator 2, a comparator 3, a one-shot 4, first and second amplitude detectors 5 and 6, a division unit 7, a scaling unit 8, an integrator with reset 9, an adder 10 and a source of a driving signal 11 .

The measuring transducer works as follows. The input sinusoidal voltage _uin =U _min sinωt with a frequency ω=2πƒ is supplied to the inputs of the controlled phase shifter 1, differentiator 2 and the first amplitude detector 5. At the output of differentiator 2, voltage u ₁ is generated with an amplitude depending on the frequency and amplitude of the input voltage U _{m in} , and shifted in phase relative to _uin by an angle of 90° in the leading direction:

where R _d is the resistance of the differentiator resistor 2;

C _d - resistance of differentiator resistor 2;

R _d C _d - time constant of differentiator 2.

This voltage is supplied to the input of comparator 3 (Fig. 2). Comparator 3 converts this voltage into a rectangular voltage u ₂ (Fig. 2), which is supplied to the input of monostable 4.

Along the edges of the voltage pulses u _2, the one-shot 4 is triggered and at its output narrow pulses u _{3 of} a fixed duration with a frequency ω are formed, which are fed to the first reset input of the integrator with reset 9. At the same time, the second amplitude detector 6 selects from the voltage u ₁ its amplitude value, which supplied to the first input of division block 7:

u ₅ =U _{m in} ωR _d C _d .

In the division block 8, this voltage is divided by the amplitude of the input voltage U _{m inx} , formed at the output of the first amplitude detector 5, and at its output a constant voltage u ₆ is formed, proportional to ωR _d C _d :

u ₆ =ωR _d C _d .

In the scaling block 7, the voltage u ₆ is multiplied by the scale factor K _m = 5 and at the second input of the integrator with reset the voltage u ₇ is obtained:

u ₇ =K _m ωR _d C _d =5ωR _d C _d .

At the output of the integrator with reset 9, a sawtooth voltage u ₈ of negative polarity is formed with a frequency ƒ of the input voltage of the converter, the amplitude of which is determined by the formula:

where U _8m is the amplitude of the output voltage of the integrator with reset 9;

T - period of input voltage _uin ;

ƒ - frequency of input voltage _uin ;

R _and is the resistance of the integrator resistor with reset 9;

C _and is the capacitance of the integrator capacitor with reset 9;

R _and C _and - time constant of the integrator with reset 9.

When choosing the ratio of the parameters of differentiator 2 and integrator with reset 9:

πR _d C _d =R _and C _i ,

the amplitude of the output voltage of the integrator with reset 9 will be U _8m = -10 V and will not depend on the frequency of the input voltage _uin over the entire operating frequency range.

The output voltage u ₈ of the integrator with reset 9 is summed in the adder 10 with the bias voltage u ₉ =U _cm =5 V from the source of the master signal 11, as a result of which an alternating sawtooth falling voltage u ₁₀ with an amplitude of 5 V is formed at the output of the adder 10. to the control input of controlled phase shifter 1.

The device uses a controlled phase shifter 1, which allows you to linearly change the phase ϕ of the input signal from -180° to +180° when the control voltage changes from -5 V to +5 V (Fig. 2). This sawtooth control voltage u ₁₀ , acting on the controlled phase shifter 1, changes the phase ϕ of its input signal from -180° to +180° with the frequency ƒ of the input voltage u _input (Fig. 2).

As a result, taking into account that the input voltage _uin lags behind the output voltage _u8 of the integrator with reset 9 at an angle of 90°, at the output of the controlled phase shifter 1 and at the output of the measuring transducer, the output voltage _uout is formed:

u _out =U _{m in} sin(ωt+ϕ)=U _{m in} sin{ωt+[180° - (ωt+90°)]}=U _{m in} sin(90°)=U _{m in} (+1)=U _{m in} .

From the resulting expression and timing diagrams (Fig. 2) it is clear that the frequency of the output voltage u _{out of} the converter is zero, that is, the conversion of alternating voltage to direct voltage takes place. In this case, the value of the DC output voltage _{uout of} the converter is equal to the amplitude of the input voltage _uin and is proportional to its effective value:

Thus, the use of a differentiator, two amplitude detectors, a division unit and a scaling unit in the measuring transducer makes it possible to achieve the required technical result - increasing the speed and accuracy of the transducer.

In the practical implementation of the proposed measuring transducer, the controlled phase shifter 1 can be made according to the scheme (Patent for PM No. 206198 of the Russian Federation, G01R 19/22. Controlled phase shifter, published 08/30/2021). Differentiation 2 can be performed using known circuits using an operational amplifier (OP-amp) with a timing RC circuit. Comparator 3 can be implemented on the K554CA3 chip. One-shot 4 can be made on the K561AG1 chip. Amplitude detectors 5 and 6 can be made according to one of the well-known schemes (A. J. Peyton, V. Volsh. Analog electronics on operational amplifiers. - M.: BINOM, 1994, p. 292, Fig. 11.17; p. 304, Fig. 11.29). Division block 7 can be implemented on an op-amp by connecting the voltage multiplier on the K525PS3 microcircuit to its negative feedback circuit. Scaler 8 is a non-inverting op-amp amplifier. An integrator with reset 9 can be implemented on an op-amp according to the scheme (V.G. Gusev, Yu.M. Gusev. Electronics and microprocessor technology. - M.: Higher school, 2005. - p. 459, Fig. 6.18, c) . Adder 10 is a non-inverting op-amp adder. The source of the driving signal 11 is a conventional stable voltage source.

Claims (1)

An AC-to-DC voltage measuring transducer containing a controlled phase shifter, the input of which is connected to the input of the measuring transducer, a comparator, a one-shot integrator, an integrator with reset, a source of a master signal and an adder, wherein the output of the comparator is connected to the input of a one-shot device, the output of which is connected to the first input of the integrator with reset. , the output of which is connected to the first input of the adder, the output of which is connected to the control input of the controlled phase shifter, the output of which is the output of the measuring transducer, and the output of the source signal is connected to the second input of the adder, characterized in that a differentiator, first and second amplitude detectors, a division block and a scaling block, wherein the input of the measuring transducer is connected to the inputs of the first amplitude detector and differentiator, the output of which is connected to the inputs of the comparator and the second amplitude detector, the output of which is connected to the first input of the division block, the output of which is connected to the second input through the scaling block integrator with reset, and the output of the first amplitude detector is connected to the second input of the division block.