A study on a start-up method during a blackout of a doubly-fed induction generator applied to gas engine cogeneration system

A doubly-fed induction generator (DFIG), which is one of the variable speed generator, applied to a gas engine cogeneration system has been investigated. To operate during a blackout as an emergency power supply is one of important roles for the gas engine cogeneration system. However, the DFIG requires the initial excitation for startup during a blackout because DFIG has no excitation source. In this paper, the excitation method to generate a rated voltage at the primary side during a blackout, which is called "blackout start" has been proposed. In addition, a stand-alone operation following the blackout start has been investigated using both computer simulation and experiments with a gas engine simulator. Moreover, the proposed blackout start and stand-alone operation method has been verified through experiments using a real gas engine.