This paper proposes a novel control scheme for doubly-fed induction generator（DFIG） wind turbines with dual-PI rotor current regulator. The dual-PI regulator consists of two PI regulators for the positive- and negative-sequence components of rotor current in the positive- and negative-synchronous reference frames respectively， and regulates both the positive- and negative-sequence components of rotor current precisely. Under the asymmetrical grid voltage conditions caused by faults， stator's active and reactive power models as well as the electromagnetic torque model are drawn， and four alternative control targets for the DFIG wind turbines are presented. Based on the four targets， reference values of the positive- and negative-sequence components of rotor current are calculated. Experiments are carried out on a 10 kW DFIG test rig by using the proposed dual-PI current control scheme. It proves the proposed method significantly improves the DFIG wind turbine's fault ride through capability under asymmetrical system conditions.