System and method for stabilizing sub-synchronous interaction of a wind turbine generator

A method for improving sub-synchronous interaction (SSI) damping of a doubly-fed generator of a wind turbine connected to a power grid, the method comprising:

• altering, with a symmetric control component, a transfer function of a d-q control loop within a controller of the generator;
• generating at least one d-q reference signal for the generator based on the altered transfer function so as to achieve symmetric control of the wind turbine generator;
• generating a control signal for the wind turbine generator based, at least in part, on the d-q reference signal;
• and,
• operating the wind turbine generator based on the control signal.

A system for operating a doubly-fed generator connected to a power grid using direct-quadrature (d-q) control technology, the system comprising:

• one or more sensors configured to measure an alternating-current (a-c) quantity of the power grid;
• a controller communicatively coupled to a processor, the processor comprising a d-q control loop having at least one symmetric control component, the d-q control loop being configured to perform one or more operations, the one or more operations comprising:
• converting the a-c quantity to a d-q quantity;
• providing the d-q quantity to a d-q control loop within the controller;
• altering, with a symmetric control component, a transfer function of the d-q control loop;
• generating at least one d-q reference signal for the wind turbine generator based on the altered transfer function so as to achieve symmetric control of the wind turbine generator;
• generating a voltage-current signal for the wind turbine generator based, at least in part, on the at least one d-q reference signal;
• and,
• operating the wind turbine generator based on the voltage-current signal so as to stabilize sub-synchronous interaction of the wind turbine generator.