Posted on 29 June 2019

Industrial Testers

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Testers for power semiconductors

Two exemplary testers for diode and thyristor parameters measurement are described. The testers have been designed due to the inspiration from the semiconductor elements producers.

By Adam Sitnik, Dacpol


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.

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).

URRM/UDRM; UTM/UFM; du/dt Tester

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).

Qrr measurement tester

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.

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.

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.

Computer software allows realization of the test cycle, detects and localizes failures, allows for separate control of every component and validates tester operation after the maintenance.

Qrr Measurement methods

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

Screen display

Producers of components listed above are main recipients of those type of testers. All testers are designed according to the individual customer requirements.



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