SU761948A1 - Apparatus for searching current leakage locations in series-parallel connections of semiconductor phototransducers - Google Patents

Description

The invention relates to electrical engineering, can be used to create devices for monitoring photoelectric converters and their connections.

A device for searching for leakage currents is known, which contains a modulated light source, a magnetometer sensor, a phase detector and a display unit {1].

A disadvantage of this device is that it is impossible to locate leaks in a non-contact tone method.

The closest to the technical entity is a device containing a modulated light source consisting of a series-connected master oscillator, a frequency divider unit of a logic unit, a control unit, an LED modulator, the output of which is connected to the input of the test object, the output of which is connected to the magnetometer input a sensor in series with which an AC amplifier is connected, an amplitude-phase detector, one of whose 25 inputs is connected to the corresponding output of the unit the logic elements of the modulated light source, and the output through a low-pass filter. with the input of the information processing and display unit {2]. thirty

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The disadvantages of this device are low accuracy and limited functionality, which do not allow detecting various kinds of damage.

The aim of the invention is to improve the accuracy and expansion of functionality.

This goal is achieved by the fact that the known device of current leakage places in series-parallel connections of semiconductor photoconverters containing a modulated light source, consisting of series-connected master oscillator, frequency divider, ¹⁵ logic unit, control unit, LED modulator, whose output is connected the input of the test object, the output of which is connected to the input of a magnetometer sensor, in series with which an AC amplifier is connected, amplitude The bottom-phase detector, one of the inputs of which is connected to the corresponding output of the block of logic elements of the modulated light source, and the output is provided with an additional amplitude-phase detector, a summing amplifier and an additional filter low frequencies, and magnetometry.ri761948

The coaxial sensor is equipped with an additional winding, the pins of which are connected through an additional low-pass filter connected in series and a summing amplifier with an output of an additional amplitude-phase detector, whose inputs are connected respectively to an output of an AC amplifier and with a corresponding output of a logic element block of a modulated light source.

In addition, the LED modulator is made on anti-parallel-connected LEDs, and the control unit is made on the basis of a bipolar current source with an antisymmetric waveform.

The drawing shows a structural electrical circuit of the device.

The diagram shows a modulated light source that includes a master oscillator 1, a frequency divider 2 and a block of logic elements 3, a control unit 4, an LED modulator 5, a control object 6, a magnetometric sensor 7, an AC amplifier 8, an amplitude phase detector 9, an additional amll FOB, AZ detector 10, low pass filter 11, information processing and indication unit 12, summing amplifier 13 and additional low pass filter 14.

The device works as follows.

The master oscillator 1 generates a reference frequency, four times the frequency of the main harmonic, to which the resonant circuit of the magnetometer sensor 7 is tuned. Frequency divider 2, consisting, for example, of three triggers, generates frequencies 2 / o, / o and / o, entering the input

block of logic elements 3, generating control signals. The control unit 4, made on the basis of a bipolar current generator, generates an antisymmetric signal, which arrives at the LED modulator 5 and generates a stimulating light signal at the input of the object to be monitored 6 with a frequency twice the current frequency. In the presence of a leakage current in the object, a current and an electromagnetic field occur in it, which is received by the magnetometer sensor 7, which is structurally connected to the LED modulator 5.

Moreover, since the sensor is tuned to the main harmonic / o, the electromagnetic field of the modulator supply current does not affect the sensor, since the supply current field does not contain a harmonic, which is the second harmonic in the Fourier spectrum of this signal. This leads to a sharp increase in noise immunity of the system and to simplify the design due to the reduced requirements for shielding both the sensor and the lead wires.

The signal from the output of the sensor 7 through the AC amplifier 8 is fed to the inputs of the amplitude-phase detectors 9 and 10. The other inputs of these detectors are fed reference signals from the output of the block of logic elements 3.

The reference signal supplied to the amplitude-phase detector 9 must be in phase with the sensor signal or shifted with respect to it by l if the current in the line of the object has changed its direction with respect to the leak. The output of the amplitude-phase detector, thus, an signal appears, the polarity of which determines the direction of the leakage current, and the magnitude - the amplitude of the leakage current. This signal, passing through the low-pass filter. / /, Enters the information processing and indication unit 12, where relevant information on the magnitude and direction of the signal is recorded, for example, on switch instruments and light indicators.

The controlled object 6 can be in different operating conditions - it can be a separate group or a set of groups, fortified, for example, on a metal frame. In the last case, a parametric effect of the object on the sensor was revealed, leading to the adjustment of the sensor circuit relative to the frequency of the master oscillator /. This detuning dramatically changes the amplitude at the output of the phase detector 9 due to a significant phase shift. For example, if the quality factor of the circuit is 100, the detuning of the circuit relative to the reference frequency by 1% leads to a phase shift of more than 60 ° and a decrease in amplitude of about 50%. Taking into account the possibility of an additional phase shift and signal path, an error is possible even in determining the direction of the current flowing through the FEN line.

To eliminate this error, the device provides for the phase adjustment of the oscillating circuit of each sensor to the same resonant frequency, equal to the frequency of the master oscillator. Obviously, with this change and the frequency of the master oscillator will not affect the measurement result. Auto-tuning of the circuit is carried out using a phase detector 10, a summing inertial amplifier 13 and an additional winding of the magnetometer sensor 7. The phase detector 10 is supplied with a reference signal from the output of logic device 3, shifting π

relative to the input signal.

When adjusting the contour, the average value of the signal taken from the phase detector is zero, and the properties of the contour are defined as

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are divided by the amount of current flowing through the magnetizing winding of the sensor from the amplifier 13 through the filter 14. In turn, this current is set in advance and can be controlled within certain limits. When the detuning of the circuit, there is a change in the phase shift between the signal and the support, which causes the output of the phase detector signal, the average value of which depends on the magnitude of the phase shift, and the sign is determined by the direction of the phase shift. The specified value is added to the amplifier with a predetermined. In this case, oscillations of the output signal of the amplitude-phase detector are smoothed by filter 14. Negative feedback through the magnetizing winding of the sensor acts on the system in such a way as to reduce the change in the phase difference. Since the frequency is a derivative of the phase, the self-tuning system presented is astatic in frequency.

The magnetometer sensor is made in the form of a ferrite torus with a gap of 0.2 mm, having two windings, one of which is a magnetizing, the other is a signal one, which together with a capacitor forms an oscillating circuit - a sensitive element of the sensor. The circuit is tuned to a frequency of about 100 kHz.

A device can have one or several sensors. In the first case, the sensor can move along the illuminated ruler; the leakage point is found by changing the direction of the current flowing through the sensor during its movement. With several sensors, they are fixed motionless along the illuminator parallel to the ruler. The leakage location is determined in the relevant area between the sensors according to the status of signal lamps, which may indicate, for example, both the fact of a leakage and the direction of the leakage current along the ruler. A more precise position of the leak is found by moving the entire sensitive head (p. Sensors, illuminator and indicators) to the left - to the right no more than half the area between the sensors, and.

The device can also be used to search for detachments of photovoltaic cells from the group and 'contact breaks between parallel photovoltaic cells in the rulers. To do this, it is sufficient to introduce a damper that blocks the luminous flux of the modulator 5 to all photoconverters, except for one. In this case, if the FEP with peeling is illuminated, there is no signal from the sensors; if there is a break in the ruler, then there are no signals from the sensors located on the outer side of the half-line, starting from the place of the break and passing through the illuminated solar cell. Tu

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the same function can be performed by the device variant, which is equipped not with a diaphragm, but with a second measuring system (head) in which two magnetometric sensors are installed on both sides of the LEDs that illuminate only one element of a series of solar cells. The effect of this device is quite similar to the action of the system with the diaphragm, but in this case there is the possibility of enhanced local light exposure.

Claims (2)

Claim 1. Device for locating current leaks in series-parallel connections of semiconductor photovoltaic cells containing a modulated light source consisting of a series-connected master oscillator, frequency divider, logic unit, elements, control unit, LED modulator, the output of which is connected to the input of the test object, output which is connected to the input of a magnetometer sensor, in series with which are connected an AC amplifier, an amplitude phase detector, one of the Dov which is connected to the corresponding output of the block of logic elements of the modulated light source, and the output through a low-pass filter with the input of the information processing and display unit, characterized in that, in order to improve accuracy and enhance functionality, it is equipped with an additional amplitude-phase detector, a summing amplifier and an additional low-pass filter, and the magnetometer sensor is equipped with an additional winding, the conclusions of which are connected through serially connected additional tively low pass filter and a summing amplifier with output additional amplitude phase detector having inputs connected respectively to the output of the AC amplifier and the corresponding output logic block elements of the modulated source Szeto. ! 2. The device according to p. ^ Characterized in that the LED modulator is made on anti-parallel-connected LEDs, and the control unit is made on the basis of a bipolar current source with an antisymmetric waveform.