Analysis of IGBT Power Cycling Capabilities Used in Doubly Fed Induction Generator Wind Power System

The doubly fed induction generator (DFIG) is one of the most popular topologies applied in wind power systems. Its main advantage is to adjust the speed of a large system with much lower power converters. This is because its rotor-side converter (RSC) operates under slip frequency and it needs only to support slip power to the overall system. However, this slip frequency is much lower than the grid frequency, and insulated-gate bipolar transistors (IGBTs) in the RSC are susceptible to power cycling failures. This paper provides a method to analyze the power cycle capability of a DFIG power converter under wind power applications. Different current control methods, including minimal stator losses, minimal rotor losses, and minimal overall losses, are analyzed and compared. It is verified that the sizes of the IGBT must be selected appropriately to avoid earlier power cycling failures. Designing a wind power converter into the targeted system is critical for cost reduction without sacrificing the reliability of the whole system.