A high torque low-speed multi-phase brushless machine a perspective application for electric vehicles

Abstract

Abstract-This paper presents the design, analysis, simulation, and modeling of a high-torque low-speed multiphase permanentmagnet brushless machine. The machine fits an in-wheel motor arrangement to be used for electric vehicle applications. This paper presents issues regarding the high-level modeling comprised of a transient model in conjunction with their corresponding experimental evaluation. Analysis was made to combine the modeling efforts with the expected behavior concerned with mutual inductance and armature reaction effects, so as to have realistic simulation results verified by the experimental setup. Comprehensive experimental results corroborate the work.

Design and evaluation of a polyphase brushless DC-machine direct drive system

“…A radial flux based motor was designed to be applied as inwheel high-torque low-speed motors direct drive system [6]. The machine is composed of a rotor with 275 mm of external diameter.…”

“…The machine is composed of a rotor with 275 mm of external diameter. There are magnets bonded on the internal surface making up the twelve pole [6] [7], where five phases were accommodated within 60 slots (12 coils for each phase) in a double-layer lap winding construction. With a built-in shaft optical sensor, the motor phase windings are excited sequentially, the optical position system addresses a look-up table, a phase is turned-on at the same time that one coil leaves the polar section.…”

“…A mechanism of switching all the equations, saving initial conditions for next circuit and retrieving the currents from all those difference equations was implemented in Simulink/Matlab. Even though such model has been used in the literature [8] [9] [10] [11] other issues were found also important for accurate machine mathematical model: the mutual inductance between phases and the armature reaction due the inherent current distortion that actually occurs in brushless dc-machines [6] [7]. The mutual inductance can be considered by observing how the air-gap flux is composed by all five contributions and building up the inductance matrix (experimental parameter identification of self and mutual inductance were performed to obtain them).…”