Compared with vector controls

a direct power control (DPC) is simpler in structure and better in dynamic performances when applied to the doubly fed induction generator (DFIG). Three DPC strategies with constant switching frequencies are presented by using the space vector modulation (SVM) technique. These strategies aim to control the rotor flux (RFDPC)

rotor current (RCDPC) and electromagnetic torque (EMTDPC) of a DFIG respectively

based on the relationships between DFIG statevariables and control variables. Their satisfactory steadystate and dynamic performances suits for different control objectives. Simulation results demonstrate that the DPC strategies can control the active and reactive power separately in the steadystates. RFDPC effectively reduces oscillation time during voltage fluctuation periods; RCDPC is capable of depressing the magnitudes of oscillating rotor currents; and EMTDPC has the capability of eliminating electromagnetic torque vibration and consequently diminishing stresses on the turbine shaft.