Acoustic noise and vibration of brushless motors for fans
An investigation on vibration and acoustic noise on brushless motors for fan or blower applications is presented, particularly concentrating on the vibration due to electromagnetic origin within the brushless electronically commutated motors. The flux switching motor is introduced as a relatively new class of reluctance machine, which retains the benefits of switched reluctance machines, but with simpler and cheaper power electronic converters. The novel work of this thesis is the introduction of two 8/4 flux switching motors with permanent magnets of internal rotor and external rotor configuration respectively, which are presented as alternatives for the brushless DC motor, and called the permanent magnet flux switching motor. The two new permanent magnet flux switching motors were able to show potential in reducing power consumption, reducing vibration and noise, and reducing the cost of the power electronic drive when compared with an existing commercial 3-phase brushless DC and induction motor. Investigation on the vibration and noise of the flux switching motor was also done by performing experiments, mechanical finite element analysis and algebraic frequency equation analysis. Algebraic frequency equations were implemented into the electromagnetic design environment, stressing the need and potential in having algebraic frequency equations to predict the mechanical resonant frequency of any shape of the electrical machine stator lamination in the electromagnetic design environment.