A method for operating an asynchronous doubly-fed wind turbine generator connected to a power grid in a grid-forming mode to emulate a virtual synchronous machine, the doubly-fed wind turbine generator comprising a line-side converter coupled to a rotor-side converter via a direct current link, the method comprising: receiving, via a controller (26, 120, 156) at least one reference command from an external controller; controlling rotor flux of the doubly-fed wind turbine generator using the at least one reference command; and providing power droop control for the doubly-fed wind turbine generator through at least one of rotor-side reference frame rotation and d-axis flux control; and wherein the at least one reference command comprises a power reference command and the power reference command comprising one of an active power reference command (P ref) or a reactive power reference command (Q ref); characterized by a voltage reference command (V ref) from an external controller and in that controlling the rotor flux of the doubly-fed wind turbine generator using the at least one reference command further comprises: receiving the voltage reference command (V ref) from the external controller; receiving a stator voltage (V STATOR) from a stator of the doubly-fed wind turbine generator; determining a flux command (ψ m,cmd; ψ dq,cmd) using the voltage reference command (V ref) and the stator voltage (V STATOR); and determining a rotor current command (l rdq,cmd) based on the flux command (Ψ m,cmd; ψ dq,cmd); and wherein determining the rotor current command (l rdq,cmd) based on the flux command further comprises: determining an air gap flux feedback signal (ψ dq,fbk) using at least one of stator current (I S), the stator voltage (V S), rotor current (I R), or rotor voltage (V R); and determining the rotor current command (I rdq,cmd) based on the flux command (ψ m,cmd; ψ dq,cmd) and the air gap flux feedback signal(ψ dq,fbk). receiving, via a controller (26, 120, 156) at least one reference command from an external controller; controlling rotor flux of the doubly-fed wind turbine generator using the at least one reference command; and providing power droop control for the doubly-fed wind turbine generator through at least one of rotor-side reference frame rotation and d-axis flux control; and wherein the at least one reference command comprises a power reference command and the power reference command comprising one of an active power reference command (P ref) or a reactive power reference command (Q ref); characterized by a voltage reference command (V ref) from an external controller and in that controlling the rotor flux of the doubly-fed wind turbine generator using the at least one reference command further comprises: receiving the voltage reference command (V ref) from the external controller; receiving a stator voltage (V STATOR) from a stator of the doubly-fed wind turbine generator; determining a flux command (ψ m,cmd; ψ dq,cmd) using the voltage reference command (V ref) and the stator voltage (V STATOR); and determining a rotor current command (l rdq,cmd) based on the flux command (Ψ m,cmd; ψ dq,cmd); receiving the voltage reference command (V ref) from the external controller; receiving a stator voltage (V STATOR) from a stator of the doubly-fed wind turbine generator; determining a flux command (ψ m,cmd; ψ dq,cmd) using the voltage reference command (V ref) and the stator voltage (V STATOR); and determining a rotor current command (l rdq,cmd) based on the flux command (Ψ m,cmd; ψ dq,cmd); and wherein determining the rotor current command (l rdq,cmd) based on the flux command further comprises: determining an air gap flux feedback signal (ψ dq,fbk) using at least one of stator current (I S), the stator voltage (V S), rotor current (I R), or rotor voltage (V R); and determining the rotor current command (I rdq,cmd) based on the flux command (ψ m,cmd; ψ dq,cmd) and the air gap flux feedback signal(ψ dq,fbk). determining an air gap flux feedback signal (ψ dq,fbk) using at least one of stator current (I S), the stator voltage (V S), rotor current (I R), or rotor voltage (V R); and determining the rotor current command (I rdq,cmd) based on the flux command (ψ m,cmd; ψ dq,cmd) and the air gap flux feedback signal(ψ dq,fbk).