Discrete-time linear parameter varying control of doubly-fed induction generators

This paper is concerned with the design of discrete-time current controller for Doubly-Fed Induction Generators (DFIGs). First, a self-scheduled Linear Parameter Varying (LPV) current controller is designed in continuous-time domain. This design is based on viewing the mechanical angular speed as an uncertain yet online measurable parameter and on subsuming the problem into the framework of the LPV controller synthesis. The design objectives are to guarantee decoupling of electrical torque and reactive power, and to achieve high robust dynamic performance for all admissible trajectories of the rotor speed in the operating range. Then, the existing continuous-time controller is replaced with an equivalent discrete-time controller that guarantees the stability of the resulting digital control system for a consistent sampling frequency. Performance and robustness of the controlled system are demonstrated via some experimental results.