System and method for coordinated control of reactive power from a generator and a reactive power compensation device in a wind turbine system

A wind turbine system configured to supply real and reactive power to a grid, comprising:

• a wind turbine with a rotor, hub, and a plurality of blades coupled to the hub;
• a doubly fed induction generator (DFIG) system coupled to the rotor, the DFIG system further comprising a power converter with a line side converter (LSC) and a rotor side converter (RSC), wherein the DFIG system is configured to generate a generator stator-side reactive power (Qs) and a generator line-side reactive power (Ql);
• a dedicated reactive power compensation device operationally configured with the DFIG system to generate a reactive power (Qmvb);
• a control system configured to:
• receive a reactive power command (Qcmd) made on the wind turbine system;
• determine a maximum reactive power capacity for each of (Qs), (Ql), and (Qmvb) at an operating state of the wind turbine system and a grid state;
• and
• coordinate supply of reactive power between (Qs), (Ql), and (Qmvb) at the operating state of the wind turbine system and the grid state to meet (Qcmd) by prioritizing (Qmvb) as a first source of reactive power, and one or both of (Qs) and (Ql) as a second source of reactive power.