Abstract:
In an yet another effort to produce better PM-less, rotor-winding-less,
brushless electric motor drives, this thesis reports on design, optimization,
numerical analysis and control of a multiphase, high saliency rotor, dual-flattop
alternative current control BLDC reluctance machine drives. The aim is to
produce high torque density, low loss / torque in a PM-less, rotor winding-less
machine by full usage of machine windings and core and of inverter kVA.
A new derivation of the principle of operation, essential rotary and
linear machine topologies and a 2D FEM analysis for torque density and torque
pulsations on the designed prototypes are made available and show promising
results. Advanced iron loss computation by FEA indicates moderate core loss,
although high air-gap magnetic flux density and current harmonics occurs as a
natural behavior of a BLDC machine. Experimental flux-decay and run-out
tests results are presented, which, together with standstill torque
measurements, validate the FE design.
An optimal design code for an automotive application was developed
based on particle swarm optimization and magnetic equivalent circuit for
performance evaluation.
Electrical and mechanical parameter identification is followed by BLDCMRM
mathematical model and control strategy development. Running
experiments (motoring and generating) with speed reversal and field
weakening modes (thus 4-quadrant operation) is also shown on two different
test-rigs, one for the 5 phase BLDC-MRM (supplied by a full bridge inverter)
and one for the 6 phase BLDC-MRM (working with a reduced number of
switches).
