Balancing reactive current between a DFIG stator and a grid-side inverter

A wind turbine generator arranged to deliver an amount of reactive current to a power grid during an abnormal power grid event, said wind turbine generator comprising:

• a doubly-fed induction generator having a rotor and a stator;
• a power converter coupling the rotor to the power grid, said power converter comprising a grid-side inverter;
• and
• a controller configured to:
• increase, during the abnormal power grid event, a reactive grid-side inverter current output by the grid-side inverter by a first amount by operating a grid breaker connected to the grid-side inverter above the grid breaker's rated current level;
• and
• reduce, during the abnormal power grid event, a stator current from the stator by a second amount based on the first amount.

A wind turbine generator arranged to deliver an amount of reactive current to a power grid during an abnormal power grid event, said wind turbine generator comprising:

• a doubly-fed induction generator having a rotor and a stator;
• a power converter coupling the rotor to the power grid, said power converter comprising a grid-side inverter;
• and
• a controller configured to:
• increase, during the abnormal power grid event, a reactive grid-side inverter current output by the grid-side inverter by a first amount by operating a grid breaker connected to the grid-side inverter above the grid breaker's rated current level;
• reduce, during the abnormal power grid event, a stator current from the stator by a second amount based on the first amount;
• keep the stator current below a predetermined upper stator current limit by keeping a reactive rotor current below a predetermined upper rotor current limit;
• and
• keep the reactive grid-side inverter current above a rated current capacity of the grid breaker in at least part of a predetermined time period.