Abstract:
The objective of this thesis is to design and analyze performance of novel dual rotor
multiphase brushless DC (BLDC) motors for electric vehicle application. The proposed
motor combines the positive characteristics of multiphase BLDC motor and dual rotor
BLDC motor thus achieving better fault tolerance capability, high power density and less
per phase stator current. Finite element method is used to design three dual rotor BLDC
motors such as 3-phase, 5-phase, and 7-phase. The design parameters and operating
conditions are kept same for fair comparison. The stator current and torque performance
of the proposed motors are obtained using finite element method (FEM) simulation and
compared with traditional 3-phase dual rotor BLDC motor. It is possible to use low power
rating power electronics switches for the proposed motor. Simulation results also validate
low torque ripples and high-power density in the proposed motors. Finally, the fault
analysis of the designed motors shows that the fault tolerance capability increases as the
phase number increases. In the second part of this thesis, a dual-rotor (DR) topology is
introduced into traditional brushless dc motor to achieve high efficiency and improved
output torque. For this purpose, the design parameters of the rotor and stator for the
proposed dual-rotor BLDC motor are optimized. The motor size and permanent magnet
volume for the motor are kept constant. Magnetic equivalent circuit (MEC) method and
genetic algorithm (GA) are selected to perform the required optimization tasks. In addition
to this, a finite element analysis (FEA) tool such as JMAG-Designer is utilized to optimize
the motor design and then validate its results with the magnetic equivalent circuit method
and genetic algorithm. Finally, an optimized design of the stator of the motor is achieved
that results into reduced torque ripples.
