Abstract:
The present thesis investigates an interior permanent magnet synchronous
motor with 8 rotor poles and nonuniform (6+6) stator slots and concentrated
windings fed with trapezoidal currents.
The electromagnetic design of the proposed solution was done algorithmically and
it was validated using Finite Element Method (FEM). FEM-analysis offers direct
results for torque, back-EMF and inductances. Whenever possible, FEM-calculated
characteristics are compared with experimentally obtained ones, in order to
validate the FEM-computations for this type of machine. The BLDC model
developed in this thesis takes into account the phase commutation phenomenon,
the real waveforms of back-EMF and inductances, based on FEM calculations.
For the sensorless control of brushless DC PM motor drive, this thesis introduces and
investigates a FEM assisted position and speed observer, based on the line-to-line
PM flux linkage estimation. Even if the proposed observer relies on the fundamental
model of the machine, a safe starting strategy under heavy load torque, called I-f
control, is used, with seamless transition to the proposed sensorless control.
