SU920585A1 - Power thyristor classification device - Google Patents

Description

The invention relates to devices for measuring and monitoring parameters of power semiconductor devices (PSC) and is intended to define a PSC class.

A device is known that allows to measure the values of Vnp-max and VoJp.-max and determine the class of the device from them. / For this, the smaller of the values of Vnp Tpoh and Voffp -mcir is selected, and multiplied by a factor different from the various types of instruments And.

The disadvantages of this device are both low measurement accuracy and the need for additional processing of the results to determine the class. The latter drastically reduces productivity and can lead to significant subjective errors.

A device for classifying semiconductor valves according to the magnitude of the reverse breakdown voltage is known.

. The disadvantage of this device is the inability to classify. Thyristors in automatic mode. The classification with the manual change of the polarity of switching on the tested device is low proliferative.

It is also known a device for monitoring parameters, a thyristor containing a key, an indicator, a memory unit, a clock generator, a digital voltmeter, a voltage source, a shunt, a current limit unit, a comparison unit, a control unit, voltage limiting keys, a pulse counter, a class indicator , limiting unit of class Sa ..

However, this device, allowing you to control thyristors in automatic mode, is complex in design and has a relatively high power consumption, since measurements are carried out when a packet of high voltage pulses of direct and reverse polarity is applied to a device under test for a large distance, to reduce measurement accuracy.

The purpose of the invention is to improve the measurement accuracy of the monitored parameters of the thyristor.

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This goal is achieved by the fact that a device containing a source of high voltage pulses, a measuring shunt, a current comparison unit, a class voltage measuring unit 30, a memory unit, and terminals. to connect the thyristor under investigation, one of which is connected to the output of a high voltage pulse source, an inverter, an additional memory block, a comparator, a measuring voltage divider, whose input is connected to the output of a high voltage pulse source, and an output to the input the inverter and the input of the memory unit whose output is connected to one of the inputs of the comparator, the second input of which is connected to the output of the inverter and the information input of the additional memory unit whose control input is connected It is connected to the comparator output, and the output is to the first input of a voltage measuring unit of the class, the second input of which is connected to the first output of the current comparison unit, the first input of which is connected to the second terminal for connecting the investigated thyristor and the first output of the measuring shunt, the second output of which is connected A common bus, and the second input of the current comparison unit is connected to the feed terminal: and the current settings, and the second output - to the control input of the high voltage pulse source, as a high voltage pulse source A high voltage bipolar pulse generator was used. Figure 1 shows the functional diagram of the device; Fig. 2 shows time diagrams of the operation of the device for the case of a linearly increasing voltage. The device contains a source of two bipolar pulses of high voltage, a measuring voltage divider on resistors 2 and. 3, measuring shunt 4, inverter 5, memory blocks 6 and 7, comparator 8, current comparison unit 9, class voltage measurement unit 10, terminals 11 and .12 for connecting the test thyristor. The device works as follows. The Start signal source 1 of two polar high voltage pulses produces high voltage pulses one after the other, the first positive, the second negative polarity. The shape of the pulses is not critical, it can be any, bell-shaped, trapezoidal, and up to. As the voltage of the positive polarity on the test device (PI) increases, the current in its circuit increases and at some instant of time becomes equal to the set value. At this point in time, the current comparison unit 9 generates a signal on the second output, stopping the increase in the positive polarity of the voltage source. The voltage on the power supply prior to the moment of operation of the protection is Vnp tnaii. The signal proportional to Vnp is removed from the voltage divider on resistors 2 and 3 and is remembered by the memory block 6. After the protection is triggered by the positive current (leakage current ) source 1 generates a negative polarity pulse. At some point, the protection is triggered by a negative current value (reverse current), thereby determining the voltage values of VoSf max. The limiting of voltage at Vaffp level is the same as described by the signal from block 9 on the second output. A signal proportional to V0Jp t; (negative polarity is removed from the divider on resistors 2-3 and through inverter 5 with a gain equal to one, is fed to the information input of the controlled memory block 7. The block 7 is designed so that it cannot The signal to receive for memory is larger in amplitude than the output signal from block 6. Comparison of these signals is performed by a comparator 8, which produces a signal that closes the input of block 7 if the signal from inverter 5 increases the signal level from block B. Sequentially, block 7 the memory remembers or the value of the voltage VoiJp mcof, if it is not greater than Vnp max in amplitude, or the value of voltage Vnp tal, if Vofp mat exceeds the amplitude of the voltage. The last case is shown in the time diagrams (Fig. 2). Thus, the block 7 remembers the smaller of the two voltage values. This lower value is fed to the input of the voltage measuring unit 10 of the class, which is triggered by the second input at the moment the reverse current protection operates. The accuracy of measuring the parameters of the PSC in the state of low conductivity (including the class) significantly depends on the temperature of the structure of the device under test, since the leakage current, which determines the quality of the device, is a very sensitive parameter. The temperature of the structure, in turn, depends on the power released in the structure, which is in the first dependence on the time of application of the test voltage to the instrument. In contrast to the known one, in which the device under test is subjected to two high-voltage pulse trains, in the proposed device the measurement is performed at a voltage pulse once for each polarity, the measurement time is reduced, and the power is reduced whereby the measurement accuracy is improved.

Claims (3)

1. A device for classifying power thyristors containing a high voltage pulse source, a measuring shunt unit, a current comparison unit, a class voltage measuring unit, a memory unit, and terminals for connecting the investigated thyristor, one of which is connected to the output of the pulse source A high voltage, characterized in that, in order to improve the measurement accuracy, an inverter, an additional memory block, a comparator 20 and a measuring voltage divider, the input of which is connected to the output of the pulse source, are introduced into it. high voltage:, and the output - with the input of the inverter and the input of the memory block, the output 25 of which is connected to one of the inputs of the comparator, the second input of which is connected to the output of the inverter and the information input additional to the memory block, the control input co -, -. This is connected to the comparator output, and the output to the first input of a voltage measuring unit of the class, the second input of which is connected to the first output of the current comparison unit, the first input of which is connected to the second terminal for connecting the test thyristor and the first output of the measuring shunt, the second output of which is connected A common bus and the second input of the current comparison unit are connected to the current setting supply terminal, and the second output is connected to the control input of the high voltage pulse source. 2. The device according to claim 1, of which is l so that the generator of high-voltage bipolar pulses is used as a source of high voltage pulses. Sources of information taken into account in the examination 1. Equipment and control methods for power semiconductor valves. M., Energie, 1971. 2. USSR author's certificate number 241547., cl. H 01 L 21/00, .1968. 3. USSR author's certificate  545938, cl. G 01 R 31/26, 1975 (prototype). Ustonovo ", P i .tnax„ „.f