Comparative analytical and experimental study of fabricated identical surface and interior permanent magnet BLDC motor prototypes

Abstract

This paper presents a novel and exhaustive investigation involving in-depth analysis, performance evaluation and comparative study of two 0.75 hp, 4-pole, 1500 rpm laboratory prototypes of Brushless DC (BLDC) motors of identical nominal ratings with surface and interior permanent magnet rotor structures having the same stator and winding (integral slot distributed winding). Both the motors were designed and developed in the lab. The major electrical variables (such as rated power, speed, voltage, current, number of poles, etc.) and the stator (such as core material, stator lamination, stack length, winding pattern and wire gauge) of the fabricated prototypes have also been kept identical to pin-point the direct influence of the two different rotor configurations (viz., surface vs interior permanent magnet) on the parameters, performance and operation of these BLDC motors. Additionally, to ensure unbiased basis for appropriate comparison, the overall volumes of magnets/pole in both the motors have also been kept similar. A detailed comparison of different quantities like air-gap flux density distribution, THD in induced voltage, torque ripple, losses and efficiency, torque-speed characteristics with field-weakening capability, steady state parameters at different operating conditions, etc. has been conducted for the said motors and the salient points duly highlighted. The vulnerability of the permanent magnets to demagnetisation based on armature reaction, particularly during a sudden fault, has also been investigated in both the cases. The theoretically determined parameters and analytically evaluated performance figures have been verified through standard FEM packages, and later validated experimentally on the fabricated prototypes. Very good mutual agreement has been observed between predicted and experimental values.

A 2D and 3D Analysis on Electromagnetic Parameters of Spoke-shape Interior Permanent Magnet Synchronous Motor Using FEM

“…Based on the performance in wider speed applications, the IPM machine is preferable as compared to SPM. IPM also has more efficiency, but equivalent magnetic circuit analysis can be complicated [6]. To make it easier for understanding, an IPM motor with a spoke shape designed rotor is considered in this study.…”

Evaluation of brushless DC motor structure design for the electric impact using 3-D finite element analysis

“…Hence, this optimized design is used to enhance the potential of overload while handling this design efficiently and get large torque during short time. Hence, this produces the BLDC motor design in regular manner and also reduces design time [5]. In the account of design consideration, the initial design parameters are magnet assembly gap, rotor saturation, Assumed flux leakage coefficient, rotor saturation, and permanent magnet [6].…”