DACPOL SERVICE is the tester producer mainly for the electrotechnical industry. During the last 10 years it has developed more then 20 unique tester constructions for parameter measurement of the following components:
• Power semiconductors ;
• Power contactors and switches;
• Varistors;
• Fuses.
Producers of components listed above are main recipients of those type of testers. All testers are designed according to the individual customer requirements.
Testers for power semiconductors
In this article we invite you to read the description of the two exemplary testers for diode and thyristor parameters measurement. They were designed due to the inspiration of the semiconductor elements producers. In next editions of Bodo’s Power we will publish more articles about other types of testers.
URRM/UDRM; UTM/UFM; du/dt Tester
During the diodes and thyristors production process some structure and finished element parameters are measured. Industrial testers are used for those parameter measurements. They are equipped with the external presses which provide proper compress force for tested elements.
This tester is designed for the final inspection of the diode and thyristor parameters before packing and sending them to the client.
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| Fig. 1. URRM/UDRM; UTM/UFM; du/dt Tester |
Tester verifies the following parameters:
1. Voltage class – Half wave of the sine voltage: amplitude range 200÷8000V.
2. Forward voltage – Extortion with the sine half wave (amplitude up to 5000 A).
3. Thyristor resistance for the du/dt effect – linear voltage rise (500V/µs ÷ 4000V/µs )
Test current and voltage waveforms are set up within a 1% tolerance. All of the measurements are made by a computer equipped with the measuring boards which cooperate with the non inductive shunts, voltage and current Hall transducers and the high voltage capacitance probe for the du/dt measurement.
Tested element is placed in the external press which is connected to the tester. Tester automatically sets up test conditions based on:
- Parameters received from the master computer of the measurement line
- Bar code read by a reader
- Test parameters manually entered by an operator.
Tester is operated with a touch screen, keyboard, mouse, control buttons and signal lamps. During tests the only thing that an operator needs to do is to exchange tested elements in the press.
Results are automatically assessed by the tester on the basis of criteria recorded in the computer memory. Tests results are displayed on the computer screen in digital form as well as a parameter diagram. Final test results are given by the TEST PASS and TEST FAILURE signal lamps.
Computer software also covers assistance in maintenance (diagnostics and separate control of tester components.)
Tester for the reverse recovery charge (Qrr )measurement
This tester allows for measurement of reverse recovery charge Qrr of both: structures and finished power diodes and thyristors. Tested structure or finished element is placed in the external press which is connected to the tester.
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| Fig.2. Qrr measurement tester |
Tester generates trapezoid-shape current test impulse with the independent regulation of its rise di/dt rate, maximum value and its duration and fall di/dt rate. Reverse recovery charge is calculated by a computer on the basis of the reverse current waveform of the tested element with three methods.
Fig.3. Qrr Measurement methods
Tester allows for a Qrr measurement with a current impulse up to 5000A and 2000 μs duration. Maximum measured value of the reverse current Ir is 1000A and the measurement time is limited to 100 µs.
Tests are performed automatically after entering parameters to the computer. Those parameters can be obtained automatically from the external computer or manually entered by an operator.
Tester operation is controlled by a computer equipped with measuring and control boards. Measuring board registers current and voltage waveforms and the computer makes an assessment based on the criteria specified in the test recipe.
Tests results are displayed on the computer screen in digital form as well as a parameter diagram.
Tests results are displayed on the computer screen in digital form as well as a parameter diagram.
Fig4. Screen display
DACPOL SERVICE long term experience in the industrial tester construction was appreciated by a home and foreign companies.
Constant increase in orders, new application fields and increasing number of permanent clients proves that. This trust obligates to take tasks which are technical challenges.
