571 Rotating Reference Frame

Although the speed of the dq-winding can be arbitrary as mentioned previously, three of those are the most suitable for machine analysis. These three speeds of dq windings are 0, m, and e. The zero speed is known as the stationary reference frame, where, typically, the stationary d-axis is aligned with the phase a-axis of the stator. The angle of transformation in Equations 5.37, 5.38, and 5.39 is 0 in this case. The d- and q-axes variables oscillate at synchronous frequency in the balanced sinusoidal steady state. When e is chosen as the speed of the reference dq frame, all the associated variables in the stator and in the rotor dq windings appear as DC variables in the balanced sinusoidal steady state. For an arbitrary speed of reference dq windings, the angle of transformation is

0 0

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