Position estimator including saturation and iron losses for encoder fault detection of doubly-fed induction machine

Fault tolerance is gaining interest to increase reliability and availability, for example for distributed energy systems. Doubly fed induction generators need rotor position information for high performance control. As part of a multi-sensor fault tolerant generator system, fault tolerance of the position sensor is presented, using a position estimator. A known position estimator is improved and thoroughly described, including effects of machine saturation and iron losses. The fault detection and isolation is described and the reconfiguration from encoder to sensorless operation is shown. Measurements are provided and show good and fast results. Steady state properties of encoder and sensorless operation are compared.