fuzzy logic based efficiency optimization of ipm synchronous motor drive
abstract
interior permanent magnet synchronous motor (ipmsm) is highly appreciated by
researchers in variable speed drive applications due to some of its advantageous features
such as small size, high power density, simple maintenance, high output torque, high
power factor, low noise and robustness as compared to the conventional im and other ac
motors. although these motor drives are well known for their relatively high efficiency,
improvement margins still exist in their operating efficiency. particularly, the reduction
of power loss for ipmsm still remains a challenge for researchers. improvement of motor
drives efficiency is important not only from the viewpoints of energy loss and hence cost
saving, but also from the perspective of environmental pollution. the thesis presents
development of a fuzzy logic based efficiency and speed control system of an ipmsm
drive. in order to maximize the efficiency in steady state operation while meeting the
speed and load torque demands a search based fuzzy efficiency controller is designed to
minimize the drive power losses to achieve higher efficiency by reducing the flux. the
air gap flux level can be reduced by controlling the d-axis armature current as it is
supplied by rotor permanent magnet. in order for the drive to track the reference speed in
transient operation another fuzzy logic based controller is designed to increase the flux
depending on the speed error and its derivative. the torque component of stator current
(q-axis component of stator current) is generated by fuzzy logic based speed controller
for different dynamic operation depending on speed error and its derivative. in this work
a torque compensation algorithm is also introduced to reduce the torque and speed
fluctuations.