SU1046721A1 - Material magnetic property determination device - Google Patents

Abstract

A DEVICE FOR DETERMINING MAGNETIC PROPERTIES OF MATERIALS, containing an integrator, a limiter and an amplifier, that is, in order to improve the accuracy of measuring magnetic losses, a sequentially connected step voltage generator, a comparator and a pulse shaper were introduced into it, two sampling and storage units, a pulse counter, a voltage converter — the number of pulses and a logic unit, the input of the integrator being connected to the source of the first signal, and the output — to the second input of the comparator; The pulse unit is connected to the control input of the first sampling and storage unit, the output of which is connected to the control input of the limiter, the inputs of the limiter, and the first sampling and storage unit are connected to the second signal source, the output of the limiter is connected to the series-connected amplifier, the second sampling unit and storage, the control input is connected to the output of the pulse former, a voltage converter — the number of pulses, and a pulse counter, VCF of the comparator and converter (/) voltage is the number of pulses connected. yen with the inputs of a logical block, the output of which is connected to the input of a step voltage generator.

Description

The invention relates to a measurement technique and is intended to determine the magnetic properties of materials: magnetic losses and magnetic field strength associated with the hysteresis loop width. The determination of the magnetic losses of materials is associated with the measurement of active power in the load by a low power factor (cos -). It is known a device for measuring active power in a load with a low cos содержащ, containing a total integrator (or a differentiator / and a power meter I J. However, the measurement accuracy of this device for nonlinear load is insufficient. A device for determining magnetic losses, containing a differentiator, a limiter and the amplifier of one of the signals, as well as the integrator of the second signal GZ J. However, the accuracy of measuring a known device is insufficient. The purpose of the invention is to improve the accuracy of measuring magnetic losses. Targeted target is achieved by the fact that a sequentially connected step voltage generator, a comparator and a pulse shaper, two sampling and storage units, a pulse counter, and a voltage converter are introduced into a device for determining the magnetic properties of materials containing an integrator, a limiter and an amplifier. the number of pulses and the logic block, the integrator input being connected to the first signal source, and the output to the second comparator input, the output of the pulse former connected to the control input of the first block Sample and storage, the output of which is connected to the control input of the limiter, the inputs of the limiter, and also the first block of the sample and storage is connected to the source of the second signal, the output of the limiter is connected to the serially connected 1st amplifier, second unit of the sample and storage, control the input of which is connected to the output of the pulse driver, the voltage converter - the number of pulses and the pulse counter, the outputs of the comparator and the voltage converter, the number of pulses connected to the inputs of the logic unit, the output coupled to an input voltage step generator. FIG. 1 shows a functional diagram of the device; in fig. device operation diagram A voltage g proportional to the rate of change of magnetic induction from the measuring winding of the sample is fed to the integrator 1, whose bypass, as well as the output of the step voltage generator 2 is connected to the inputs of the comparator 3, the output of the comparator 3 is connected to the input of the pulse forming device -4 pulses, the output which is connected to the control input of the first block 5 of the sample and storage. The measuring input of the block 5 receives a signal and, pro-proportional intensity of the magnetic field H (t). The output voltage of the unit 5 is fed to the control input of the limiter 6, the measuring input of which is connected to the signal source and ,. The output of the limiter 6 is connected to the input of the amplifier 7, connected in series with the second voltage sampling and storage unit 8, the control input of which is connected to the output of the driver 4. The output of the device 8 is connected to a voltage connected to the number of pulses and a counter. 10 pulses. The outputs of the comparator 3 and the converter 9 are connected to the inputs of the logic unit 11, the output of which is connected to the control input of the generator .e 2. - The device works as follows. For example, and. (fig. 2 cl) generator 2 is compared by comparator 3 with a signal UQ proportional to induction B (t) (fig. 25). The output pulse of comparator 3 has a rectangular shape, with differences at times ty f corresponding to the equality U :: Ug. Shaper 4 produces two short pulses during each period, the leading fronts of which are formed at times t and 12, respectively. The first impulse allows to form in the unit 5 an indirect voltage proportional to H (), the second one - H (t2) (Fig. 2b |, These voltages go to the limiter. 6, the output voltage of which (Fig. 2g) contains a significant constant. The latter is reduced (or eliminated) by amplifier 7, which allows to obtain an output signal from isp (Fig. 2E), with the difference UPJ, (t) - u (, -j. proportional to h K (t) - H (t2) is the width of the hysteresis loop corresponding to the induction B, K B, and, where K. is the coefficient of proportionality. The value is converted to constant The second generation is stored by the second sampling and storage unit 8, and then into the number of pulses by the converter 9. The resulting number of pulses is summed in the counter 10. After the counting of the pulses is finished, the output voltage of the generator 2 is changed by the value of and, -, and the signal conversion is repeated to as long as the voltage and (fig. 2l) is not less than the minimum voltage Uft. Then the number of pulses recorded by the counter 10 is proportional to the magnetic loss m. The increase in the measurement accuracy of the magnetic losses is due to the fact that Signals are eliminated by differentiation, which is accompanied by significant phase errors, which is characteristic. Ternost for testing magnetic materials in strong fields. In FIG. Figure 2e shows the dependence of the strength of the magnetic field H on the magnetic induction of B dl. the two halves of the ascending and descending branches of the hysteresis loop, as well as h h (B). The largest loop width, hysteresis, is no more than 23 times the value of h 2H (0), while H (B, P can be hundreds of times more than H (0). This is the reason for the poor accuracy of known means measurements of magnetic losses, since the measured value is a very small part of the input signal. In the proposed device, the measurement result is obtained by processing the signal Uj obtained by the constraint H {t), and the value U (., (t) and (tJ is close to the greatest change in this tension.

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Claims (1)

DEVICE FOR DETERMINING MAGNETIC PROPERTIES OF MATERIALS, containing an integrator, limiter and amplifier, which is ensured by the fact that, in order to increase the accuracy of measuring magnetic losses, a step-voltage generator, a comparator and a pulse shaper are connected in series , two sampling and storage units, a pulse counter, a voltage converter — the number of pulses and a logic unit, the integrator input being connected to the first signal source, and the output to the second comparator input, the former output pulses are connected to the control input of the first block of sampling and storage, the output of which is connected to the control input of the limiter, the inputs of the limiter, as well as the first block of sampling and storage are connected to the source of the second signal, the output of the limiter is connected to a series-connected amplifier, the second block of sampling and storage, controlling the input of which is connected to the output of the pulse shaper, the voltage converter is the number of pulses and a pulse counter, and the comparator and converter steps I voltage is the number mpulsov soedi-. K yens with inputs of a logical unit whose I output is connected to the input | (step voltage generator. · 11046721