Strategy for enhancing reliability and lifetime of DC-AC inverters used for wind turbines. (June 2018)

• Record Type: Journal Article
• Authors: Batunlu, C.; Albarbar, A.
• Is Part Of: Microelectronics and reliability. Volume 85(2018)
• Page Start: 25
• Page End: 37
• Publication Date: 2018-06
• Subjects: Reliability -- Lifetime -- Power electronics -- Wind turbines -- DC-AC inverters; Electronic apparatus and appliances -- Reliability -- Periodicals; Miniature electronic equipment -- Periodicals; Appareils électroniques -- Fiabilité -- Périodiques; Équipement électronique miniaturisé -- Périodiques; Electronic apparatus and appliances -- Reliability; Miniature electronic equipment; Periodicals; 621.3815
• DOI: 10.1016/j.microrel.2018.04.006
• Languages: English
• ISSNs: 0026-2714

Abstract

Abstract: Lifetime of wind turbine inverters is below expectations therefore, novel design and drive strategies are timely required to achieve optimum life span. In this work, a novel driving strategy to mitigate stresses on inverters is proposed. First, an electro thermal analysis was carried out using finite element modelling methods. Subsequently, the outcomes of the models were validated using DC/AC IGBT based power inverter module interfaced to 1.1 kW electrical outputs of a horizontal wind turbine operated under different wind speeds. Real time data was collected using both dSPACE system and high speed thermal imaging camera. The proposed driving method is based on adjusting the switching frequency according to wind speed. Edge detection scheme was embedded in Simulink to determine temperature fluctuations caused by variations in wind speed profile. Effects of these fluctuations are mitigated by regulating the switching frequency and power losses based on a look up table and interpolation method. The proposed strategy of operation reduces cyclic temperature depended lifetime span (total lifetime consumption) to 1.45 × 10 −5 cycles compared to 1.88 × 10 −5 when operated under conventional fixed frequency. Wire-bond thermal stress was also reduced from 54.5 MPa, for the fixed switching frequency, to 45.5 MPa. This represents about 21% reduction in total lifetime consumption of inverter's wire-bond which, brings huge benefits to wind energy industry. Highlights: Adaptive operating strategy for mitigating inverters thermal stress was developed. Real-time monitoring system was designed and implemented. Realistic model was derived for predicting power loss in wind turbine inverters. Theoretical findings were validated using data from an operational wind turbine. Cost effective operation strategy to extend lifetime (~21%) of wind turbine inverters.