Fault tolerance for wind turbine power converter

Power converter is one of the key assemblies in modern wind turbines. In modern wind turbines with variable speed generator configurations, i.e. Doubly Fed Induction Generator or Synchronous Generator, back to back power converters are introduced to control the speed and torque of generator, the active and reactive power fed into the Grid. The power converter in variable speed wind turbines is an essential assembly which is sensitive to failures. The power converter malfunction will cease the operation of wind turbine and generate disturbance to the Grid. Recently, it has been widely accepted in wind industry the power converter should be robust, and have good capability of fault tolerance. Meanwhile, the fault-tolerant methods need to be cost-effective and easy to implement. Fault tolerance control in power converter usually contains the following steps, i.e., fault detection and diagnosis, fault isolation, reconfiguration. The sensor for fault tolerance also needs to be taken into account. There are several types of faults in power converter, e.g., open-switch of IGBT, short-switch of IGBT, DC-link fault. This paper gives an overview of different fault-tolerant methods for power converter of wind turbines, by analysing these methods in detail. We finally conclude some interesting areas for future research.