SU771577A1 - Device for measuring maximum permissible growth rate of thyristor direct voltage - Google Patents

Description

(54) DEVICE FOR MEASURING MAXI 1 ALSO

ACCEPTABLE DIRECTIONAL DIRECTIONAL SPEED

12 The invention relates to the electrical industry and can be used to measure the parameters and classification of power thyristors in their manufacture and use. Devices are known for measuring the maximum allowable velocity. direct thyristors. One of the known devices includes a drive, a source of charge current, a forward voltage rise driver, a voltage amplitude limiter, a driver control circuit, and an indicator, in which an oscilloscope is used. The device has a low measurement accuracy, since it provides a manual adjustment of the voltage rise rate and a visual indication of the moment of switching of the thyristor l. Another known device also contains a accumulator, a voltage amplitude limiter, a forward voltage rise shaper of a shaper control circuit, a current sensor, a recording time of the thyristor VOLTAGE at some given slew rate of the direct voltage. The disadvantage of this device is the limited measurement range 2. The closest technical solution to the invention is a device 3, which contains a current generator connected through a drive to a front-edge former, a voltage limiter and a test cathode of the device, the first of which is connected to the circuit of the anode. a current sensor connected to the control unit, a generator, the input of which is connected to the control unit, and the output is connected to a pulse counter and through a pulse shaper to one and current generator inputs to the second input of which is connected transformation code Tel-voltage, connected through a decoder with the momentum meter, owls, connected to the indicator. To improve the measurement accuracy, automatic recording of the time of switching on the thyristor and digital indications, the value of the maximum permissible rate of increase of direct voltage, is introduced.

The drawbacks of the known device are a narrow range of values of permissible direct voltage rise rates, limited by possible changes in the current generator current, as well as high power consumption since the current generator exceeding the current generator after switching on the thyristor under test is turned on } which is significant, especially for powerful thyristors, and increases with increasing temperature at which the tests are conducted.

The purpose of the invention is to reduce power consumption and extend the limits of measurement.

The goal is achieved by additionally introducing a second current sensor and an OR circuit into the device, the decoder output being connected to the auxiliary front-edge driver input, and a second current sensor connected in series with the voltage limiter, the output of which is connected through the OR circuit to the second input of the converter - voltage and to the second input of CXeNUJ OR

The output of the first current sensor is connected.

The drawing shows a functional diagram of the proposed device.

The device contains a drive 1, a current generator 2, a pulse shaper 3, a master oscillator 4, a front edge shaper 5, a voltage limiter b connected to the device under test 7, a sensor then. 8, converter 9, code-voltage, decoder 10, pulse counter 11, terminal unit 12, current sensor 13, indicator 14, circuit OR 15

In the initial state, the decoder 10 sets in the converter 9 the code voltage and the front-edge former 5 code corresponding to the minimum value of the voltage rise rate of the direct voltage (dU / dt). The Start signal from the output of the control unit 12 includes a master oscillator 4, which, with its leading edge, triggers the pulse shaper 3. The shaper triggers a current generator 2, which generates a current pulse with the amplitude necessary to form the specified increase rate dU / dt. If the used device 7 does not switch from a predetermined dU / dt value, then at the moment the voltage suppressor trips b, the current sensor 8 outputs a signal to the converter 9, a code voltage to reduce the current amplitude to the minimum possible value. If the device under test 7 does not switch and during the time of action of the pulse tip, the pulse counter switches over by the falling edge of the master oscillator 4. 11. The counter will change the output code of the decoder 10 and, accordingly, the output output of the HCl.

code-voltage and thus suitable. It drives the device to form a larger dU / dt value. The next impulse of the master oscillator 4 cycle repeats. If the test thyristor 7 switches from dU / dt, then the output of the current sensor 13 will receive a signal to the control unit 12 and through the OR 15 circuit to the converter 9, code-voltage, which again reduces the current generator current amplitude 2 to the lowest possible, the control unit 12 will turn off the master oscillator 4 and give an end of measurement signal. This completes the dU / dt determination process, and the indicator 14 will indicate the dU / dt value preceding the one from which the device under test has switched.

Due to the fact that after switching on the thyristor under test at a given rate of increase in direct voltage, it is not necessary to maintain the thyristor on state and the output current of the current generator is reduced to the minimum possible value, in this device, compared to the known, significantly less power is used from the current generator, and this makes it possible to expand the range of variation of its current and thereby expand the range of measurement of the maximum allowable rate of increase in direct voltage.

Claims (3)

Invention Formula A device for measuring the maximum permissible rate of rise of the direct voltage of the thyristors, comprising a current generator connected through a drive to a front-edge driver, a voltage limiter and the cathode of the test device, the anode of which is connected to the first current sensor connected to the control unit , the input of which is connected to the control unit, and the output with the pulse counter and through the pulse shaper is connected to one of the inputs of the current generator, to the second input of which the transducer is connected A code-voltage generator connected via a decoder to a pulse counter to which an indicator is connected, characterized in that, in order to reduce power consumption and extend the measuring range, a second current sensor and OR circuit are additionally introduced into the device, and the decoder output connected to the auxiliary input of the front-edge driver, in series with the limiter for 5p, a second current sensor is connected, the output of which is connected through the OR circuit to the second input of the code-voltage converter and to the second input of the circuit OR the output of the first current sensor is switched off. Sources of information, which are taken into account in the examination. 1. Bardin V. M, et al. Equipment and methods for controlling the parameters of power semiconductor gates. M., Energie, 1971, p. 123-126. 2. Gorokhov V. A., Shchedrin M. Yu. Physical principles of the use of thyristors in pulsed circuits. M., Soviet Radio, 1972, p. 163-165. 3. USSR author's certificate  429384, cl. G 01 R 31/26, 1974 (prototype).