Durability testing on power electronics for the renewable industry

Solar cells as well as wind turbines have to work in a reliable and safe way during their lifetime in all climates worldwide. This is why OWI-Lab has performed extended climatic tests on power electronics (inverters) for the solar power market.

Sirris has one of the largest climatic test chambers in Europe. The test lab is used for research, test and validation projects of different electro-mechanical systems that need to work in harsh and extreme climatic environments. The facility was opened in 2012 and in the beginning of its operations it was mainly used by its OWI-Lab department to functionally test large multi-MW components for wind turbines (e.g. gearboxes, transformers, power converters, hydraulic components, etc…). Also off-highway, mining, agricultural and defence companies benefit from the state-of-the-art climatic test lab. 

Last year the facility was used to test power electronics (inverters) for the solar power market, as also this renewable energy power source needs to work in a reliable and safe way during its lifetime in all climates worldwide.   

Large climatic test chamber & thermal images during functional power converter

In the past, a focus competence in the laboratory has been cold start-up performance and cold climate compliance testing. As tropical and desert (i.e. dry-heat) situations also pose engineering challenges to certain equipment (mainly power electronics and cooling systems), the lab is looking into a broader scope of climatic tests than the extreme cold and icing environments. In order to meet compliance with such test requirements, a special coating was installed inside the climate chamber and additional features to cope with a humidity test range from 8% to 95% have been implemented. Also a 950 W/m² solar heat array was purchased.      

Due to the size of the test chamber, its range of test temperatures and cycle programming ability, the new humidity test capabilities and the ability to provide high power for functional testing of multi-MW power converters, the test laboratory is ideal for testing multi-MW power electronics for the renewable energy business like wind power, solar energy plans and wave & tidal applications.    

Reliable power electronics in deserts and arctic 

Renewable energy sources such as wind power and solar energy are taking a larger part of the energy mix. More and more such energy sources are installed in remote locations in which they need to operate in harsh climatic conditions. Renewable energy sources are installed worldwide, which means they need to be able to cope with the desert heat of the Middle-East, as well as with the arctic cold in the Northern part of America for example. All involved electro-mechanical machinery needs to be designed for these environments, as some of these locations are much harder to reach for operations and maintenance purpose than what we are used to in a moderate climate. Inverter and power converter manufacturers therefore put their prototypes first to the test in the laboratory in order to ensure safe and reliable operations in all climatic conditions. 

Typical examples of renewable energy sources in harsh climatic environments: desert heat, extreme cold and high humid environment for solar, wind and tidal power applications

Extended testing possibilities in varying extreme climates 

'By placing one power inverter in the climatic test chamber and another one outside we were able to construct a closed loop ‘back-to-back’ test set-up of 1 MW, which we can extend up to more than 6 MW if needed. This way we could test the specimen on full power and only supply the losses in the circuit' Pieter Jan Jordaens, business developer for the climatic test facility, says. 'Our test team analysed the standards and needed equipment to dimension the electric power needed, as well as the humidifier and drying unit for this full scope environmental test campaign.' 

Bastiaan Reymer, test engineer on the test campaign: 'The tests on the system were performed continuously 24/7 for several days. By controlling the climate chamber with programmable software the temperature and humidity can be varied with great precision, to create extreme environment cycles compliant with the IEC standards.” The climatic test laboratory team performed all climatic environment tests according:  

IEC-60068-2-1 Environmental Test - Cold

IEC-60068-2-2 Environmental Test - Dry Heat

IEC-60068-2-14 Environmental Test - Change of Temperature

IEC-60068-2-30 Environmental Test - Damp heat Cyclic (humidity testing)

Power inverter test campaign in climate chamber – back-to-back configuration