Germany funds research into reliability of PV inverters and energy storage systems

Whether it is inverter products or energy storage systems, their innovation cycles have caught up with the renewal of electronic products. Therefore, when a lot of empirical experience is needed to improve products, it is often found that the original models are no longer produced, and the experience of old products can only be used on new models or new products.

To this end, as part of Germany's "Energy Transition Innovation" program, the Federal Ministry of Economics has invested heavily and commissioned the Fraunhofer Institute for Microstructure of Materials and Systems IMWS to develop an evaluation method that can effectively predict the reliability and service life of photovoltaic inverters and storage systems.

The new research project aims to close the gap between empirical evidence and knowledge about the performance of materials and components in photovoltaic systems. The researchers want to analyze field data of inverter failures and analyze possible aging mechanisms at the component level, while also evaluating and optimizing test and measurement procedures for accelerated aging.

Based on these data, scientists hope to develop a method for predicting the service life of inverters and storage systems, which will help system manufacturers and operators further reduce the cost of photovoltaic technology and enable system operators to more reliably ensure the service life of equipment.

In order to successfully complete the project, Fraunhofer IMWS established a research alliance including PV inverter manufacturer SMA Solar Technology AG and electronic capacitor company MerzSchaltger?teGmbH, as well as the Institute of Mechanical Components of the University of Stuttgart. Although Chinese inverter companies are active in the European market, TestPV has not yet learned whether there are any Chinese inverter and energy storage companies involved.

"In photovoltaic applications, inverters convert the DC voltage of solar modules into AC voltage and then feed it into the grid," says Bianca Böttge, a researcher who coordinates the project at Fraunhofer IMWS. "They also play a key role in the provision of reactive or controlled power and in energy management, for example in combination with battery storage systems."

The researchers believe that the interaction of voltage, temperature and humidity accelerates aging and failure processes, and the inverter should be extremely resistant to environmental factors to ensure continuous operation for more than 20 years. In order to ensure the necessary performance, Fraunhofer IMWS said that power electronic components are currently being tested extensively and in some cases are manufactured in a way that exceeds requirements.

In China, third-party research institutions such as CQC, CTC, and CGC have begun outdoor empirical testing of inverters and energy storage systems.

Figure: Outdoor demonstration base under typical climate