Finite-element analysis of an electromechanical field of a BLDC motor considering speed control and mechanical flexibility

This research presents a finite-element analysis of the electromechanical field of a BLDC motor considering speed control and mechanical flexibility. The magnetic field is analyzed by the nonlinear time-stepping finite-element method considering the switching action of the pulse width modulation (PWM) inverter. Magnetic force and torque are calculated by the Maxwell stress tensor. Mechanical motion of a rotor is determined by a time-stepping finite-element method considering the flexibility of shaft, rotor, and bearing. Both magnetic and mechanical finite-element equations are combined in the closed loop to control the speed using PWM. Simulation results are verified by the experiments, and they are in good agreement with the experimental results