SU1767567A1 - Control device for electromagnetic apparatus moving system - Google Patents

Abstract

Usage: a device for recording the quality of work of a moving system of electromagnetic mechanisms. SUMMARY OF THE INVENTION: By introducing keys and matching blocks, the stability of the frequency of an oscillating circuit, including the winding of a controlled electromagnetic device, is increased, which makes it possible to reveal latent defects of a moving system such as distortions, and sticking of the corr

Description

The invention relates to devices for detecting the quality of operation of a moving system of various electromagnetic mechanisms, which are valve actuators, dampers, servomechanisms, etc., which are widely used in various industries.

A device for controlling a mobile system of an electromagnetic device is known, comprising a power source, terminals for connecting a controlled device, a diode, a resistor, a program and control unit, a switch, a pulse control unit, a differential amplifier, a fault recorder, an integrating circuit, an additional resistor and a fault recorder recession.

However, the known device does not provide for the detection of latent defects such as mashing or skewing of the moving system, which do not affect the shape of the current rise or fall curve when the electromagnetic device is activated and released.

In addition, the known device does not provide quality control of the mobile system over the entire range of motion of the core and does not allow detecting the core position at which a defect appears in the operation of the mobile system of the electromagnetic device, for example, when the mobile system of the device under test is not fully activated.

This disadvantage of the known control device reduces the accuracy and reliability of the control of the moving system of the electromagnetic apparatus.

The closest, selected as a prototype, is a device for monitoring a moving system of an electromagnetic device, containing a differential amplifier, a first power source, a first switch, the first and second terminals for connecting the winding of the electromagnetic apparatus, the first, second and third resistors, and the output of the first source power through the first switch is connected to the first terminal for connecting the winding of the monitored device, the second terminal for connecting the winding of the monitored device through the first resistor oedinen common bus and via a second rezistor-

cl

with

V4 o VI ate

VI

an inverting input of a differential amplifier, the non-inverting input of which is connected to the first output of the third resistor, the second output of which is connected to the common bus, as well as the second switch, the second power source, the fourth, fifth, and the sixth resistors, pulse driver, element I, input signal converter output converter and matching unit; the input of the specified matching unit is connected to the first terminal for connecting the winding of the apparatus being monitored, and the output via the fourth resistor is connected to the input of the pulse former, the output of which is connected to the first input of the I element, the second input of which is connected to the first input of the device, and the output to the input of the output converter a signal whose setup state is connected to the second input of the device, and the output to the output of the device, the inverting input of the differential amplifier via the fifth resistor and The input signal is connected to the third input of the device, the non-inverting input of the differential amplifier is connected via a sixth resistor to the output of a differential amplifier connected to the control inputs of the first switch and the second switch connected between the input of the matching unit and the output of the second power source,

In such a device, the frequency of self-oscillations of the circuit in which the winding of the monitored device is included depends not only on the change in the inductance of the winding of the device being monitored when it is triggered, but also on the change in the saturation voltage of both the differential amplifier itself and the spread of the power sources of the load on which the specified .amplifier. At the same time, the change in the frequency of the self-oscillation of the circuit due to the indicated destabilizing factors reaches such a magnitude that in the presence of a defect in the moving system of the electromagnetic apparatus (for example, mashing the core), the known device identifies it as a good condition.

This disadvantage of the known control device reduces the accuracy and reliability of the control of the moving system of the electromagnetic apparatus,

The aim of the invention is to increase the accuracy and reliability of the control by increasing the stability of the frequency of self-oscillations of the circuit, which includes the winding of the controlled apparatus, by eliminating the effect of destabilizing

factors on the frequency of self-oscillations of the circuit in the control of the moving system of the electromagnetic apparatus when it is triggered.

5To achieve the goal in

a known device comprising five resistors, a differential amplifier, two switches, two power sources, terminals for connecting an electromagnetic device, a matching unit, a pulse driver, an And element, an output signal converter and an input signal converter, whose input is connected to the first input terminal of the device , the output converter input through the first resistor is connected to the first output of the second resistor and to the inverting input of the differential amplifier, non-inverting input to expensively through

0, the third resistor is connected to the common bus of the device, the output of the differential amplifier is connected to the control inputs of the first and second keys, the first output of the first key is connected to the common bus of the device through the first power source, the first output of the second key is connected to the common power supply bus and the second terminal of the first switch is connected to the second terminal of the second switch, the input of the first matching unit and the first terminal for connecting the winding of the electromagnetic device, while the second terminal for connecting The winding of the electromagnetic apparatus is connected to the second

5 by the output of the second resistor and through the fourth resistor to the common bus of the device; the output of the specified matching block through the fifth resistor is connected to the input of the pulse generator, the output of which is connected to the first input of the element I, the second input of which is connected to the second input terminal of the device, and the output element And is connected to the input of the input converter, the installation input of which is connected to the third input terminal of the device, and the output of the output converter is connected to the output output of the device, entered t the retired and fourth 1 keys, the second and third matching units, and the control outputs of these keys are connected to the output of the differential amplifier, the output of the first power source is connected to the input of the second matching unit, the output of which is connected to the first output of the third key, the output of the second power source connected to the input of the third matching unit, the output of which is connected to the first output of the fourth key, the second output of which is connected to the second output of the third key and the non-inverting differential input preamplifier.

FIG. 1 shows a functional diagram of the device; FIG. 2, 3, and A are timing diagrams, and FIG. 5 shows an algorithm for controlling and analyzing the operation of the device.

The device contains the first input pin 1 of the device connected to the input of the converter 2 of the input signal, made, for example, on a digital-to-analog converter, the output of which through the first resistor 3 is connected to the first output of the second resistor 4 and to the inverting input (U-input) of the differential amplifier 5, the non-inverting input (H-input) of which is connected via the third 6 resistor to the common bus of the device, and the output of the differential 5 amplifier is connected to the control inputs of the first 7 and second 8 keys. The first output of the first key 7 is connected via a first power supply 9 with a voltage + E to a common bus, which through a second power supply 10 with a voltage of -E is connected to the first output of the second switch 8, the second output of which is connected to the second output of the first switch and The first terminal for connecting the winding 11 of the electromagnetic device, the second terminal for connecting the winding 11 of the electromagnetic device is connected to the second terminal of the second resistor and through the fourth resistor 12 to the common bus of the device. The first matching unit 13 is connected to the first output to connect the winding of the electromagnetic device, and the output through the fifth resistor 14 to the input of the driver 15 pulses, made, for example, on a comparator, the output of which is connected to the first input of the element 16 AND, the second input of which is connected to the second input terminal 17 of the device, and the output of the element I is connected to the input of the converter 18 of the output signal, the installation input, to the zero state of which is connected to the third input terminal 19 of the device, and the output to the output terminal 20 devices. The third 21 and fourth 22 keys, the second 23 and third 24 matching blocks, the inputs of these matching blocks are respectively connected to the outputs of the first 9 and second 10 power sources, and the outputs of the second and third matching blocks, respectively, through the third and fourth keys are connected to the H-input of the differential the amplifier, the control inputs of the third and fourth keys are combined and connected to the output of the differential amplifier.

The winding 11 of the electromagnetic apparatus has a complex resistance, which consists of an inductance coil 25 and a resistor 26.

5 The first matching block 13 consists of

of resistors 27 and 28.

The output converter 18 is made, for example, on a pulse counter 29 and a register 30,

0 The second and third matching blocks 23 and 24 consist of resistors 31, 32 and 33, 34, respectively, with the same division factors. At the same time, the resistance of the resistor 31 is equal to the resistance of the resistor 35, and the resistance of the resistor 32 is equal to the resistance of the resistor 34. The operation mode of the keys 7 and 21, as well as 8 and 22 is chosen so that the keys 7 and 21 are closed with a positive voltage on them the inputs, and the keys 8 and 22 are closed with a negative voltage on their control inputs.

The mode of operation of the differential amplifier 5 is selected so that it has a hysteresis characteristic due to the positive feedback, which is formed when the switch 21 is closed and the source 9 is connected through the block 23 to the H input of the amplifier 5, or similarly when the switch 22 is closed and connecting source 10 in the same way through block 24.

The resistor 12 in the device performs the function of a feedback sensor, the output of which through the resistor 4 is connected to the I-input.

5 house amplifier 5.

The quality control of the operation of the moving system of an electromagnetic device is based on the well-known position that the inductance of the electromagnetic winding

0 of the apparatus, all other things being the same, is determined by the magnetic resistance of the gap in the magnetic circuit of the electromagnet of the apparatus being monitored. If there is no current in the winding of the monitored apparatus, the measles of its moving system is kept in a neutral position, and the inductance of the winding by the electromagne apparatus is minimal in this case. When the electromagnet core moves, the gap in the electromagnet magnetic circuit decreases, and the coil inductance increases the maximum angle of the gap in the magnetic core of the electromagnet coil is completely closed, and the inductance of the winding of the device being monitored becomes maximum.

Considering the above circumstances, the winding 10 of the device under test is included in the self-oscillating circuit (Fig. 1),

whose self-oscillation frequency is chosen different from the mechanical resonant frequency of the controlled electromagnetic apparatus, and the device operating range is chosen significantly less than the saturation current to avoid changing the self-oscillation frequency of the circuit due to the exponential load current applied to the nonlinear zone (the initial linear portion of the exponential is selected).

The device (see Fig. 1) works as follows.

Before the start of operation of the circuit, a short pulse is supplied to the input 19 of the device, under the action of which the output signal converter 18, consisting of counter 29 and register 30, is set to the zero state.

After switching on the power supply of the device and in the absence of a signal from converter 2 at the output of amplifier 5, if there is no input signal from the output of block 2, a positive voltage U + y or a negative voltage 1 G is jumped (the sign of the voltage is determined by the sign of the zero level of the amplifier ). In this case, either switch 21 shuts off respectively and connects the output of unit 23 to the H input of amplifier 5, or switches 22 closes and connects the output of block 24 to the H input of amplifier 5, whereupon the voltage at either the H input of amplifier 5 is set or

+ E

Raz-re r32 + re

R32-R6 R32 + Re

(one)

+ R31

or

R34-R6 R34 + Re

R34-R6 RSI + Re

(2)

+ R33

where Re, RSI, R32, Rss, R34 are the resistors of the positive feedback amplifier 5;

+ E and -E are voltages of power supply sources 9 and 10, respectively.

Let, for example, the voltage U + y be established at the output of the amplifier 5. Under the action of this voltage, the keys 8 and 22 are closed, and the keys 7 and 21 are opened by connecting the winding 11 to the power supply 9 and, accordingly, the output of the unit 23 to the H input of the amplifier 5. As a result, the voltage U + at the H input of the amplifier 5, and in the winding 11, the current begins to increase, and

the voltage drop across the resistor 12, pr - is proportional to the output current, through the resistor 4 is fed to the U-input of the amplifier 5 (Ur, Fig. 2, a). At the moment of time

35, the voltage Ur reaches the voltage level and + (Fig. 2, a), as a result of which switching of the amplifier 5 takes place (the moment of time is the point 35, Fig. 2, b). When changing the voltage sign at the output of the amplifier

0 5 and setting U y, keys 7 and 21 are closed, and keys 8 and 22 are opened, connecting winding 11 to source 10 and output of block 24 to the H input of amplifier 5. As a result, U5 is set at the H input of amplifier 5, and in the winding 11, the current begins to decrease (Fig. 2, c). At time 36, the voltage Ur and at the U input of amplifier 5 reaches the voltage level O (FIG. 2, a), as a result of which the amplifier 5 switches again (time point 36, FIG. 2 b). Further, the processes are repeated periodically, as a result of which, at the output of the amplifier 5, pulses with a duty cycle of 0.5 are formed (Fig. 2, b). Often, the generated pulses, other things being the same, are determined by the inductance of the winding 11. This is the load of the self-oscillating circuit.

If a constant voltage is applied from the output of the converter 2, then a voltage is created on the resistor 12 with such a sign as to compensate for the input signal at the U input of the amplifier 5. In this case, the duty cycle of the pulses at the output of the amplifier

5 5 will be different from 0.5, and the rate of change of current in the load with increasing and decreasing turns out to be different. This difference is, the greater, the greater the input voltage (Fig. 4, g, e).

Thus, each sign of the input signal corresponds to a certain duty cycle of the pulses at the output of amplifier 5 (Fig. 4, g), and the constant component of the load current linearly depends on the level

5 input signal. At the same time, the frequency of the pulse-width signal, as well as at the zero input signal, is determined, other things being the same, by the inductance 25 of the load

0 Due to the presence of negative current feedback, a resistive-inductive load acting as an inertial link, and a hysteresis loop in the differential amplifier 5 performing the function

5 of the comparator, the device for monitoring the moving system of the electromagnetic apparatus enters the self-oscillation mode. As mentioned above, the operating range of the device currents is chosen to be significantly less than the load saturation currents, and the frequency of self-oscillations of the circuit is different from the resonant frequency of the device being monitored.

Considering the above, we will calculate the frequency of self-oscillations of the circuit and determine the effect of destabilizing factors.

FIG. Figure 3 shows the nature of the voltages in the device, taking into account the load saturation current at zero input command from the digital to analog converter 2. The current in the inductive load increases exponentially with a constant time determined by the parameters of the load and resistor 12.

Neither 1K (Fig. 3) can be considered as linear. The time IK corresponds to one quarter of the period of the frequency (Tk) of the oscillations of the circuit.

5From the similarity of OAC and OBD triangles

(Fig. 3) follows:

ten

tkUPUe

tt-5-. whence tk tt yours;

I out inasinas

the frequency of self-oscillations of the circuit is equal to

one

one

Uh

Tk 4tk 4-Ue-TE

(6)

Yours

L.25

R26 + R12

where are yours - time constant load, which determines the resonant frequency of the electromagnetic apparatus;

  load inductance;

R26 is the resistance of the load;

Ri2 is the resistance of the feedback sensor.

The saturation current to which the current through the load tends depends on the voltages E of the power supply sources 9 and 10 and the total load resistance, and the saturation voltage (UHac) is

and

U

usE-R12

R26 + R12

The current in the load does not have time to increase to its saturation due to the presence of a negative feedback circuit through resistor 4, as a result of which the voltage at the point e only reaches the voltage Ue, which is equal to

R3 + R4 Rs

where Ue is the switching voltage of the amplifier 5, recalculated to the device point e (Fig. 1);

Ur is the switching voltage of amplifier 5 at point g of the device (Fig. 1), which is (U);

RS is the resistance at the U-input of amplifier 5;

R4 is the resistance of the negative feedback resistor.

Due to the fact that the threshold value (Ue) of the amplifier is always chosen to be significantly less than the saturation voltage (Unac), then the initial portion of the eccentric current rise to time

20

Substituting the values of the formulas 3, 4, 5 into the formula 6,

E-Ri2-R3 (R26 + Ri2)

K (R26 + R12) -4-U2- (R3 + R4) TL25

E-Ri2-R3

4-U2- (R3 + R4) -L25

(7)

25

thirty

Since switching of amplifier 5 occurs at the moments of time when the voltage Ur is reached by the voltages U + or U, which determine the hysteresis threshold of the amplifier 5 (Un / ic), then formula (7) can be written as

fKE-FVR12

4-lW- (R3 + R4) -L25

(eight)

five

0

five

0

five

It can be seen from formula (8) that the frequency of self-oscillations depends not only on the inductance of the winding of the electromagnetic apparatus (I-25), but also on the voltage of the power source E, the value of the hysteresis threshold (Urnc), the values of resistors RS, R4, Ri2.

The error is completely eliminated due to the intrinsic resistance R26 of the winding 11 of the electromagnetic apparatus

Due to the fact that the magnitude of the hysteresis voltage (Drue) also depends on the supply voltage E, the dependence of the self-oscillation frequency (fK) on the voltage E of the power supply sources 9 and 10 is completely excluded. To confirm this, we will calculate the voltage value 1Lis

The value of voltage 1) His, taking into account the equality of the resistances of the resistors of blocks 23 and 24 and formulas (1) and (2) is calculated by the formula

E. R32-R6

II - R32 + R6, Q1

Ui-isR-- (Y)

R32-R6 R32 + Re

+ R31

Substituting and the formula (8) the value of the formula (9), we get

E-FVR12firR32-R6 R32 + Re

+ Rsi

4-ЕFte-Re R32 + Re

(R3 + R4) -L25

R3 Ri2R32 Re R32 + Re

+ R31

4 L25- (R3-fR,)

From consideration of formula (10), it can be seen that the frequency of self-oscillations (fK) of the circuit does not depend on the voltage of the power supply sources 9 and 10 and the saturation value of the amplifier 5, i.e. These destabilizing factors are excluded and do not affect the frequency (fK) of self-oscillations of the circuit. In this case, the current in the winding 11 of the electromagnetic apparatus changes with the frequency of self-oscillations of the circuit (time interval to the point P, fig. 4, h). A change in the current in the winding 11 of the electromagnetic apparatus creates a magnetic field, under the action of which the measles of the moving system of the electromagnetic apparatus are excited with a frequency of self-oscillation of the circuit. The self-oscillation voltage pulses applied to the load 11 through the block 13 and the resistor 14 are fed to the input of the driver 15 (performed, for example, on the comparator), from the output of which these pulses go to the first input of the element 16I, which is closed until the signal arrives at the beginning accounts for the device input 17; The signal for the start of the account for the device input 17 may be formed from a computer (for example, a computer type-1300). Upon the arrival of the counting signal at the device input 17, element 16I opens, and pulses from the output of the driver 15 pulses through the element 16I arrive at the input of the driver 18 of the output signal and, therefore, at the input of counter 29, which during the time At (also determined by the computer) counts the incoming pulses of self-oscillation frequency of the contour converted into a code. Upon the arrival of a signal from the computer to stop the counting at the device input 17, element 16I is closed, and the pulse counting is stopped. The frequency of self-oscillations of the circuit recorded in the counter 29 pulses in the form of a code is fed to the input of the register 30, from the output of which the code of the frequency with the period Ti (Fig. 4, g) goes to the output of the imaging unit 18, and therefore, to the output 20 of the device COMPUTER,

which captures and stores information sent to the AI cell. At the end of the recording of the frequency code, the computer issues a zeroing signal to the input 19 of the device, under the action of which the counter 29 and the register 30 of the former 18 are set to zero. At the next clock cycle the computer issues a code-voltage command from the cell Bi to the input 1 of the device, which the

0 is fed to the input of a digital-to-analog converter 2, from the output of which a signal in the form of a constant voltage (time t, fig 4, e) through a resistor 3 is fed to the U input of the amplifier 5. As described above, the current in the winding 11 begins to grow, and the bark of the moving system of the electromagnet begins to move in the direction of reducing the gap in the magnetic circuit, and the inductance of the coil of the electromagnetic apparatus increases, therefore, the frequency of self-oscillations of the circuit, the period of which becomes T2, decreases (Fig. 4, g) Essa (the time delay is set from the computer) from the moment of time t2,

5, as described above, the computer stores information on frequency with a period of T2 and also at time t4 with a period of T3. At the end of the issuance cyclogram sequence of stresses

0 The amplifier 5 being fed to the U-input is used to process information in a computer by analyzing the deviation frequency of the circuit's self-oscillations. With the normal operation of the mobile system

5 of the apparatus being monitored, the condition is satisfied (Fig. 4, g)

By the magnitude of the self-oscillation frequency deviation, by the fixed points of movement of the core, the position and work

0 moving system of the electromagnetic apparatus. The control and analysis algorithm can be constructed as shown in FIG. five,

In the case of jamming of the core of the mobile system of the monitored apparatus, the frequency deviation of the self-oscillations is absent from the moment the movement of the core of the moving system ceases (Fig. 4, and K), and in the case of mashing, the frequency deviation of the self-oscillation contour does not correspond to the fixed system electromagnetic apparatus in the process of its control.

Technical effect of use

5 of the proposed technical solution is expressed in increasing the accuracy and reliability of the control. This is expressed in that the proposed device, in comparison with the prototype, allows not only to register the fact of the presence of a defect in

operation of the mobile system, affecting the mobile system by creating a magnetic field by a self-oscillating circuit, which allows controlling the quality of the mobile system throughout the entire range of motion of the core of the mobile system of the electromagnetic apparatus, but also provides increased stability of the self-oscillation frequency of the circuit by eliminating the influence of destabilizing factors on the frequency of self-oscillations of the circuit when controlling the moving system of the electromagnetic apparatus by eliminating the effect on the indicated hour From the variations in the voltage of the power sources of the load, as well as in the workloads of the saturation voltage of the amplifier 5. Typically, the voltage spreads of a powerful power source operating on a pulsed (switched) load are ± 10%, and the voltage variations of the saturation voltage of the amplifier 5 operating in comparator mode, it is in the order of ± 15%. At the same time, the accuracy of the ratio of resistors (see Formula 10) can be easily achieved by at least 1%, which makes it possible to increase the stability of the frequency of self-oscillations by a factor of 10 or more.

The above mentioned situation allows for latent inspection of latent defects such as perrhos, rubbing the core or incomplete operation of the moving system of the monitored device, as well as using the proposed device to control a wider class of electromagnetic devices, such as changing the value of the winding inductance in the event of a failure of the moving system controlled apparatus occurs by a small amount.

In addition, the proposed device can be used as a device for controlling an electromagnetic device with simultaneous control of the quality of operation of its moving system, since the frequency of self-oscillations of the circuit is chosen different from the natural resonant frequency of the electromagnetic apparatus and does not affect the operation of the device when used as a control device for the electromagnetic apparatus.

Claims (1)

Claims of Invention A device for monitoring a moving system of an electromagnetic device, comprising five resistors, a differential amplifier, two switches, two power sources, leads for connecting the winding of the electromagnetic device, the first matching unit, a pulse shaper. I element, output signal converter and input signal converter, the input of which is connected to the first input terminal of the device, output through the first resistor is connected to the first output of the second resistor and to the inverting input of the differential amplifier, the non-inverting input of which through the third resistor is connected to the device common bus, output the differential amplifier is connected to the control inputs of the first and second keys, the first output of the first key through the first power source and the first output of the second key the second power supply source is connected to the common bus of the device, and the second output of the first switch is connected to the second output of the second switch, the input of the first matching unit and the first output for connecting the winding of the electromagnetic device, while the second terminal for connecting the winding of the electromagnetic device is connected to the second output of the second the resistor and through the fourth resistor to the common bus of the device; the output of the first matching unit is connected through the fifth resistor to the input of the pulse former, the output of which is connected to vym input AND gate, a second input coupled to a second input terminal of the device, and the output of AND - with the input of the output converter, the setup input of which is connected to the third input terminal of the device, and the output to the output terminal of the device, which is characterized in that increase the accuracy and reliability of the control, the third and fourth keys are entered into it, the second and third matching blocks, and the control outputs of the keys are connected to the output of the differential amplifier, the output of the first power source is connected to the input of the second matching block, the output of which is connected to the first output of the third key The output of the second power supply is connected to the input. The third matching unit, the output of which is connected to the first output of the fourth key, the second output of which is connected to the second output of the third key and to the non-inverting differential input booster. z 7 and: i TO z Those Ujf g h sch ft P RT h LQSLQLl WITH; Lg with U i -fi / e j-Ј) $ I 7 S3 / - 3 / - - 3--, -t $ Ј A -, J-c -JV СЧГЮ hC &: / ifj. / - - / u Sff-rffii / SS ZchEs  f f tj / i, i . .....one J.:,;. i.-: -f3I L i: x ± Ј: ЈJ I L .g oV - r -. ° -, L.J, - L v / 5d f os / j UL1 ..- ..: Gg L.L (. IO f Ј- l: L .lz . I .. ) t Cf-. 7, .- - I A 7 fZ v / Я- Г5.Л; KTCToi c. bЈL one L. About -JJ3, -.    - U $ -,-, $, - frejc r eОЈь рОе ( Phie S