Field orientation control of a permanent magnet motor

A control system for a permanent magnet motor having a stationary assembly, a plurality of winding stages associated with the stationary assembly and adapted to be energized in at least one preselected sequence and a permanent magnet rotor arranged in selective magnetic coupling relation with the winding stages for rotation in response to energization of the winding stages in the preselected sequence, the control system comprising monitoring means connected for sampling voltage and current supplied to the winding stages and producing signals representative thereof, three-phase to two-phase converter means for converting the voltage and current signals to corresponding two-phase rotating vector components, power inverter control means for selectively energizing the winding stages in a sinusoidal fashion to effect the rotation of the permanent magnet rotor, vector rotator means responsive to DC signals representative of quadrature and direct axis current command signals and to the two-phase rotating vector components for producing two-phase .alpha. and .beta. control signals from the DC signals, said two-phase control signals varying in synchronism with the two-phase vector components, and function generating means responsive to a torque command signal for producing the direct and quadrature axis DC current command signals, the synchronously-varying two-phase control signals being applied to said power inverter control means for effecting the energization of the winding stages.