GE and Fraunhofer Join Forces to Predict Lifetime of Power Electronics in Photovoltaic Plants

June 10, 2012 by Jeff Shepard

Solar power will play a key role in tomorrow’s energy mix in Germany. In order for the sector to grow and to ensure a good return on investment, the reliability of photovoltaic (PV) power plants is critical. Further development of PV power electronics will help improve overall plant reliability.

Constant load fluctuations burden the power electronics of solar inverters in PV plants. This increases the risk of sudden plant failure. Up to now it was almost impossible to safely predict the service life of expensive power semiconductors. GE announced that together with Fraunhofer Institute for Reliability and Microintegration IZM, a method to forecast the remaining life time of power electronics is being developed. The first prototype of this measurement system will be presented in Berlin in September 2012.

The achievements so far of the still ongoing joint CoMoLeFo project (Condition Monitoring für Leistungselektronik in der Fotovoltaik or Condition Monitoring for Power Electronics in Photovoltaics) are identification and detection of relevant aging mechanisms of Insulated Gate Bipolar Transistor (IGBT) power modules. IGBTs are switch elements designed for high-power levels and constitute the central component of modern inverters. Mathematical algorithms and measuring data are now able to make precise assessments concerning the condition of semiconductors during operation. This enables a forecast of the remaining life time of an IGBT and therefore conditions based maintenance. Reliability is improved and hence, the operating time can be increased significantly while expenses caused by unscheduled downtimes and consequences thereof are reduced.

"The results we have seen so far during the project enhance our knowledge of failure mechanisms and are particularly valuable both when it comes to refining simulation models and to designing new power electronics systems," notes Dr. Ing. Andreas Middendorf, head of the CoMoLeFo project at Fraunhofer Institute for Reliability and Microintegration IZM.

CoMoLeFo is based on two complementary processes: One process indirectly determines the chip temperature by measuring relevant electrical parameters of the IGBT during operation. In order to evaluate the resulting load exposure to the system, the temperature data is applied to a physics of failure model. The other process monitors the parameter shift due to aging. In this way, the remaining life time of the IGBTs can be determined by a software based remote diagnostic system. The information can be forwarded to the customer and the service company.

"CoMoLeFo will enable condition monitoring of the system. This will be accompanied by improved availability of our inverters. We will be able to offer our customers more targeted service thanks to the forecasts. This will help saving time and reducing costs for our customers," notes Dr. Georg Möhlenkamp, senior leader, product management for GE Energy’s Power Conversion business.

In addition to GE Energy and Fraunhofer Institute for Reliability and Microintegration IZM, the other companies involved in the project sponsored by TSB Berlin with RDF funds include imc MeΒsysteme GmbH and Elbau Elektronik Bauelemente GmbH.

More news and information regarding the latest developments in Smart Grid electronics can be found at Darnell’s SmartGridElectronics.Net.