Beckhoff's PC Control Technology Supports Power Semiconductor Evaluation

Beckhoff Automation (headquartered in Verl, Germany) products and technologies are widely used across various industrial sectors worldwide. This article presents a case study of their implementation at the power semiconductor test lab of Infineon Technologies AG in Germany.

In power cycling tests, accurately determining the junction temperature of semiconductors under repeated load is critical for the precision of reliability assessments. An indispensable preliminary step is obtaining the calibration curve for the junction temperature. Infineon Technologies introduced an automated test bench using TwinCAT and EtherCAT measurement terminals from the ELM3xxx series for this process, achieving improved measurement accuracy and a significant increase in overall test lab efficiency.

Automated test bench using TwinCAT and EtherCAT measurement terminals ELM3xxx series. Capable of calculating calibration curves for up to 32 power semiconductors.

Warstein Plant: A Core Hub for Power Semiconductor Manufacturing

Infineon Technologies develops and manufactures power semiconductors with a wide current-carrying capacity, ranging from a few amperes to 3000A, at its Warstein plant in Germany. This production site is a center of technological innovation and a key location for research and development as well as the manufacturing of power module products called Frame Power Modules (FPM). These modules are used in various applications worldwide, including EV inverters, industrial and railway drives, and wind and solar power generation equipment.

Power cycling tests are crucial not only in the development process but also for quality assurance during production. Dr. Martin Rockelrath, head of the test lab, explains: "Test benches for power cycling tests are one of the biggest cost factors for a production site in terms of investment and infrastructure requirements. Therefore, test benches must be utilized as efficiently as possible."

Conducting power cycling tests requires obtaining the junction temperature calibration curve beforehand. Martin Seidelmann, a test engineer at the company, emphasizes the importance of this measurement: "These temperature characteristics form the basis for all subsequent tests performed on the performance evaluation test bench, as they allow for the rapid and accurate calculation of the junction temperature under load."

Inefficiency Caused by Manual, Personnel-Dependent Operations

Traditionally, obtaining the calibration curve involved manually setting the measurement current and gate voltage, and recording the voltage across the module contacts with a calibrated recorder. There were no automatic detection or notification functions in case of anomalies during measurement. The recorders were not networked, so measurement data had to be read out via SD card or USB memory and transferred to another PC for calculating temperature characteristics. Against this backdrop, automation of the test bench began to be considered around 2023.

Fully Automated Test Bench Realized with TwinCAT and EtherCAT Measurement Terminals

The new test bench, employing PC-based control and TwinCAT, can calibrate various types of semiconductor modules such as diodes, IGBTs, and SiC MOSFETs without requiring lengthy setup procedures. Up to 32 modules can be installed and wired in the oven, and a precise current controlled by TCP/IP and TwinCAT is applied. When the specified temperature is reached, the EtherCAT measurement terminal ELM3102-0100 measures and records the module contact voltage with 24-bit resolution and 0.01% accuracy, reliably calculating the calibration curve.

Mr. Seidelmann is impressed with the accuracy of the EtherCAT measurement terminals: "When we calibrated the test bench, the voltage values shown by Beckhoff's ELM terminals matched the calibration standard down to six decimal places."

The measurement current generation is also handled using standard EtherCAT terminals alone. By combining an LED control terminal and an analog input terminal, a measurement current of 10 to 500 mA is controlled with 0.1 mA accuracy, and isolation between channels is achieved in combination with a power supply terminal.

The control system uses the embedded PC "CX5140" and TwinCAT 3, seamlessly integrating with the existing measurement software LabVIEW™ to manage all setpoints and measurement values in real-time.

Mr. Seidelmann describes the results of the test lab automation: "For test preparation, the operator only needs to enter the ID of the module to be measured. TwinCAT handles the rest, such as oven control, measurement current, and gate voltage settings."

Semiconductor modules installed in the oven. The ELM3102-0100 measures voltage under different temperature conditions and measurement currents with 24-bit resolution and 0.01% accuracy.

Effect on the Entire Test Lab: Enabling Two Tests Per Day

This automation has reduced setup time by approximately one hour per test and significantly improved measurement accuracy and reliability. Unattended nighttime operation has also been realized, making it possible to conduct two tests per day. Furthermore, automatic oven door opening via TwinCAT has shortened cooling time, allowing earlier preparation for the next test. This increase in throughput directly contributes to improved Overall Equipment Effectiveness (OEE) and enhances the ability to meet strict deadlines demanded by the development department.

Looking ahead, the team aims to build a system that automatically retrieves calibration curve data from a central database based on the module ID, which Mr. Seidelmann believes "will lead to further improvements in OEE." Based on these results, plans are underway to deploy similar systems at two other sites, one of which is a production facility in Hungary.

Reference URLs:

■ Infineon Technologies Website: www.infineon.com

■ Beckhoff Measurement Technology Application: www.beckhoff.com/measurement

Company Overview of Beckhoff Automation

Beckhoff Automation is a control equipment manufacturer specializing in PC-based control. Its proprietary measurement and control software "TwinCAT" enables industrial PCs running general-purpose operating systems like Windows to be used as real-time controllers (such as NC and PLC). Beckhoff is also the developer of the high-speed, highly synchronized industrial communication standard "EtherCAT." The promoting organization, EtherCAT Technology Group (ETG), is known as the world's largest industrial communication standard promotion group, with over 8,100 member organizations from 76 countries and regions. Industrial controllers equipped with TwinCAT and EtherCAT are adopted in diverse applications worldwide, including industrial robots, automotive, packaging machinery, machine tools, and wind power generation equipment.

https://www.beckhoff.com/en-en/