Study of PMSM drives are a topic of interest of current
researchers. The inherent advantages of these machines
include high power density, low inertia, and high speed
capabilities. However, the control performance of the PMSM
is greatly affected by the uncertainties of the plant which are
usually mismatched motor parameters, external load
disturbances, unmodelled and non-linear dynamics [1]. Hence,
different control schemes are adopted for speed controlling
purposes. A permanent magnet synchronous motor (PMSM)
has permanent magnets to produce the air gap magnetic field.
PM machines are generally classified as [2]: (1) the popularly
used surface permanent magnet (SPM) machines in which
magnets are mounted on the rotor surface and (2) the buried
or interior permanent magnet (IPM) machines in which
magnets are mounted inside the rotor. SPM motors have qaxis
inductance equal to the d-axis inductance (Lq=Ld).
Torque angle control under constant torque operation (within
base speed) and flux control as an additional component for
higher speeds is proposed in this paper.