Study of the effect of load torque on the iron losses of permanent magnet motors by finite element analysis

The output torque of an interior permanent magnet synchronous motor (IPMSM) can be controlled within its allowable range using a pulse-width modulation (PWM) inverter. In this paper, the effect of the load torque on the iron losses of an IPMSM is studied by investigating three driving conditions, namely no-current, no-load and load conditions. The experimental data demonstrates that a torque increase from 0 N·m to 1 N·m causes an iron loss increase of about 20 %. Three-dimensional (3D) finite element analysis (FEA) is performed and demonstrates that the magnet eddy current losses are the most affected by the torque increase.

I. Introduction

With electrical motors being more and more used in home appliances, industrial machining systems and automotive technologies, improving electrical motors efficiency in order to lower the burden on electrical energy production and soften the impact on environment is becoming crucial. The iron losses contribute to the efficiency drop, therefore decreasing them needs an exhaustive analysis. This paper aims at deepening the understanding of the relation between the motor driving conditions and its iron losses.