SU789936A1 - Apparatus for measuring magnetic induction flux increments - Google Patents

Description

The invention relates to a technique for measuring flux of magnetic induction and can be used, in particular, in measuring parameters and characteristics of magnetic cores in magnetic digital and analog storage devices. Magnetic induction flux meters for cores are known by the pulsed sensing method, which contain an oscillating current program generator, a gating circuit, and an integrator or low pass filter connected to a DC amplifier l. The disadvantage of such meters is low sensitivity and low speed. The closest proposed meter contains a generator of a reversible toxis program, a gating circuit including a key management unit and two keys, one of which is normally open and connected to the output winding of the core under study, and the second is normally closed, a low-pass filter and a DC amplifier 2. However, with a decrease in the BLOWNESS of the input pulses, the sensitivity of the known meter decreases; Since the low-pass filter has a frequency-dependent transmission characteristic, the required accuracy of the measurement result can be ensured only with a certain and sufficiently large number of input pulses. This will result in a decrease in speed. The purpose of the invention is to increase the sensitivity and speed. This goal is achieved in that a device for measuring the increment of the flux of magnetic induction, comprising a generator of a reversal current program and a gating unit connected to its output, including a control unit with two keys, one of which is normally open and connected to the output winding of the core, and the second is normally closed, the integrator is introduced.

Double the voltage, two anapowy memory elements and an adder, and the output of the gating is connected via an integrator with one input of the adder and through the same integrator, an analogue memory element and a voltage doubler - with another input of the adder, whose output is The input is connected to the input of the second analog memory element, and the output of the latter is connected to the output of the entire device, and the control inputs of both memory elements are connected to the corresponding output 1 of the key management unit.

FIG. 1 is a functional diagram of the proposed magnetic induction flux increment meter; in fig. 2 is the normalized spectral noise density of its measuring part.

The meter contains generator 1 of the magnetising current (GTPT) program, test core 2, block 3 of managing keys and analog memory elements (CU), strobe keys 4 and 5, integrator 6, analog memory elements (AED) 7 and 8, doubler 9 voltage (UN), the adder 10 and the meter AND voltage (I). The gating unit includes block 3 of control by keys 4 and 5 and analogue memory elements 7 and 8, synchronized from generator 1 of the reversing current program, and two keys 4 and 5, one of which (4) is normally open and serves to gage the signal coming from the output winding of the core under study to the integrator input, the other (5) is normally closed and serves to close the integrator input to the zero bus.

The device works as follows.

In the measurement mode, the generator 1 generates a program of pulses continuously arriving at the core 2, from the other generator arm, the operation of the key control unit 3 and the analog memory elements is synchronized. The current pulses passing through the excitation winding of the core 2 cause its magnetization reversal. At the same time, voltage pulses are induced on the output winding, the vol-second areas of which are proportional to the intensity of the magnetic induction flux. Magnetic induction flux increment measurement is performed by the reaction of the core to current pulses of one arbitrary polarity. The selection of the required reversal magnetization pulses arriving at the input of the integrator 6 is performed by keys 4 and 5 controlled by potentials MMI from the key management unit. The measurement process in the device is carried out over a period of time T. Moreover, the magnetization reversal pulses of the core arrive at the input of the integrator 6 only during half of this time, i.e. T / 2. The voltage at the integrator output at this time can be written as T | 2

 and, --1 UcC.iHu, (t) dt -Tu wdt Ti., a) dt.

choo

where (/(-.(-t) is the voltage of the sieve being measured

. nal UujCt) - voltage and noise voltage.

An analog memory element 7 connected to the output of the integrator 6, by a signal from control unit 3, stores this voltage. During the next time, i.e., from T / 2 to T, the currents that intermagnetize the core do not arrive, and the voltage at the output of the integrator b at time T can be written as

Tid-b) () ...

about oh | a

This voltage is fed to the subtracting input of the adder 10. The summing input of the adder 1O through the doubler 9 receives the voltage from the output of the analogue memory element 7. Thus, the voltage at the output of the adder at time T is equal to

t | at / at

and 2 -: 2 and, - 0, -.) dt - Ju, Wdt-Iu {t) di

ooT | 1

and the signal from control unit 3 is stored by the second analogue memory element 8, then arriving at the output of the entire device. Thus, at the output there is a component due to noise and the drift U,

T | 2t

S (((1O T | 2

It is obvious that the value of V depends on the frequency and phase of the harmonic components Oc, (t)

To determine the normalized spectral noise density of the proposed device, we will assume that

ui U SiMfmt if), then

and

and ,, - (u; Ttif) -2co5 (u; -i «f) - -cos4

Considering -P a random variable uniformly distributed from O to 2 //, ((and) -) 4cosu; t-4co5UJ The obtained normalized spectral noise density for a randomly distributed quantity from O to 2 Ti is shown in FIG. 2. A similar characteristic for the low-pass filter used in the known device has a transmission coefficient in the low-frequency region of 1, and then more or less quickly, depending on the order of the filter, drops to the bottom. From a comparison of these characteristics, it is clear that the noise level at the output of the device is much lower, i.e., the sensitivity is higher. It is also known that providing high accuracy when using a first-order low-pass filter requires several hundred reversal pulses, i.e. a long measurement time. A decrease in the measurement time in a known device is achieved by increasing the order of the low-pass filter, i.e., by significantly increasing the complexity of the device. In the proposed device, in principle, a single pulse is sufficient, but to obtain the required output voltage, the measurement is carried out within several units of tens of magnetization reversals. The use of an integrator, a voltage doubler, analog memory elements and an adder allows reducing the inventive formula. A device for measuring the increment of a flux of magnetic induction containing a generator of the reversal current program and a gating unit connected to its output, including a control unit with two keys, one of which are normally open and connected to the output winding of the core, and the second is normally closed, characterized in that, in order to increase sensitivity and speed, in it is entered by an integrator, a voltage doubler, two analog memory elements and an adder, and the output of the gating unit is connected via an integrator with one input of the adder and through the same integrator, an analog memory element and a voltage doubler with another input of the adder, whose output is connected with the input of the second analog memory element, and the output of the latter with the output of the entire device, and the control inputs of both memory elements are connected to the corresponding Im M outputs of the key management unit. Sources of information taken into account when exaertig 1. Pirogov AI, Shamaev Yu. M. Magnetic Core for devices of automation and computing. M., 1973, p. 175-176. 2. USSR author's certificate K 222470, cl. And OZ K 13/20, 1968, LN4% V% of Figure 2 fr Yi12 2tf 41GyT

Claims (1)

Claim A device for measuring the increment of the magnetic induction flux, comprising a magnetizing current program generator and a gating unit connected to its output, including a control unit with two keys, one of which is normally open and connected to the output winding of the core, and the second is normally closed, characterized in that, with a circuit for increasing sensitivity and speed, an integrator, a voltage doubler, two analog memory elements and an adder are introduced into it, and the output of the gating unit is connected through an integrator with one input of the adder and through the same integrator, an analog memory element and a voltage doubler, with another input of the adder, the output of which is connected to the input of the second analog memory element, and the output of the latter is connected to the output of the entire device, and the control inputs of both memory elements are connected to corresponding outputs of the key management unit.