Patent ID: 8698461
Filing Date: 2014-04-15
Classification: H02J,H02P,Y02E

Abstract:
1. A method to control power output of a doubly-fed induction machine to a grid including the steps: measuring grid voltage and grid current in a three phase coordinate system, transforming grid voltage and grid current into a stator frame coordinate system, decomposing the grid voltage and grid current in the stator frame coordinate system in a positive sequence system and in a negative sequence system, calculating active and reactive power in the positive and negative sequence system, and controlling active and reactive power in the positive and negative sequence system, wherein, active and reactive power in the positive and negative sequence system are used as independent state variables in a state controller, whereas the state controller generates manipulated values in the positive and negative sequence system separately which are subjected as manipulated state vectors to a state feedback in the stator frame coordinate system without further control loops before the manipulated vector resulting from state feedback is used to set rotor voltage.