EOL Test System for inverters of air conditioning compressors

Electric vehicles not only place new demands on battery and drive technology, but also on the comfort features such as interior air conditioning. So far, conventional vehicles have used the engine waste heat for the vehicle heater and have installed an air conditioning compressor directly at the powertrain to cool the vehicle. In electric and hybrid vehicles, these devices need a separate power supply. Therefore, an inverter is necessary, so that air conditioning compressors can still provide a pleasant indoor climate. This inverter converts the provided DC voltage of 380-490 V to a 3-phase AC voltage.


This inline EOL Tester has been developed to ensure that only functioning inverters get into circulation. An integrated transport system carries the DUTs to their test position and contacts them fully automatically. The communication interfaces of the inverter via LIN and CAN are now checked. This is followed by a complete check of all quality-relevant parameters of the output stages in partial-load operation. These parameters include for example:

  • Current consumption
  • Switching times of the output drivers
  • Output current in normal operation as well as in case of an error
  • Correct writing of customer data

A smooth integration of the EOL test system into the customer's production line was ensured by the integrated transport system. Additionally, the testing of two different inverter models is guaranteed without much modification effort.

Equipment components:

  • DC and high voltage power supplies
  • PXI measuring system
  • Current clamps
  • PLC control unit
  • 4 channel mixed-domain oscilloscope
  • Touch screen monitor for easy, fast operation
  • etc.

Special Feature:

In cooperation with our customer NI® software products such as the test management software TestStand were used for this test system.