This Paper deals with the steady state model of DFIG in synchronously rotating (d-q) reference frame. The important mathematical formulas have been derived, which includes electromagnetic torque, active and reactive power of stator as well as rotor. The performance analysis of torque and different power over slip is investigated in MATLAB environment. It has been found that the DFIG operating characteristics are depended on both stator and rotor d-q components of voltages. The stator voltage and frequency at gride are required to be maintained constant, therefore the rotor voltage excitation plays important role to get desired slip or torque. In this paper mathematical coding of different characteristics of DFIG is developed in MATLAB. The effect of rotor voltage excitation (d-q) on the DFIG performance is simulated and analysed extensively to identified the stable operating zine.