The two-axis (dq0) model represents a salient-pole synchronous machine whose non-uniform air gap makes stator self- and mutual inductances time-varying functions of rotor position; Park's transformation projects the three-phase stator quantities onto direct- and quadrature-axis (and zero-sequence) reference frames rotating with the rotor, rendering these inductances constant and decoupling the analysis into direct-axis and quadrature-axis equivalent circuits. Within this framework, "speed voltage" cross-coupling terms (proportional to rotor speed and to the flux linkage of the orthogonal axis) account for electromechanical energy conversion, while transient and subtransient reactances characterize the machine's reduced effective inductance immediately following a disturbance, due respectively to field-winding and damper-winding flux constraints. This belongs to electrical power system analysis, specifically synchronous machine modeling, and extends round-rotor machine theory to the more general salient-pole case.
The two-axis (dq0) model represents a salient-pole synchronous machine whose non-uniform air gap makes stator self- and mutual inductances time-varying functions of rotor position; Park's transformat…