Rotorcentric

Rotorcentric, rotor-centric, or rotor-centered is an engineering term used to describe approaches that treat the rotor as the primary reference body in the analysis, control, and monitoring of rotating machinery. In rotor-centric methods, the state of the system is expressed in terms of rotor angle and speed and the relative motion of other components with respect to the rotor, rather than in a fixed or stationary frame (stator- or ground-centric). This perspective is common in both electrical and mechanical domains.

In electrical machines, rotor-centric modeling is exemplified by the use of a rotor reference frame for control and analysis. Transformations such as Park's dq0 conversion map stator quantities into a frame rotating with the rotor, enabling decoupled control of torque and flux. In rotor dynamics, rotor-centric analyses focus on shaft torsion, critical speeds, bearing loads, and rotor-stator interactions, often using sensors or estimators anchored to the rotor itself or to the shaft.

Applications include condition monitoring and fault diagnosis, real-time control of electric machines (for example, field-oriented control in motors), turbine and compressor rotors, flywheels, and other high-speed rotors. Advantages of rotor-centric approaches include simplified equations of motion in the rotating frame and improved insight into rotor-specific phenomena. Limitations involve the need for accurate rotor position or speed information, sensor integration on rotating members, and compatibility with external (stator-originating) disturbances.

See also: rotor dynamics, Park's transformation, rotor reference frame, field-oriented control.