Conceptual Diagrams of Extended Building Factor for Analysis and Evaluation of Factors on Core Loss Density Increase in IPMSM

Abstract

This study analyzes and evaluates the stator core loss density of an interior permanent magnet synchronous motor (IPMSM) by proposing and developing conceptual diagrams of an extended building factor while considering the nonlinearity of the magnetic properties of the material. The IPMSM, whose stator and rotor are composed of non-oriented electrical steel, is investigated. First, the motor is driven by a three-phase inverter with the pulse width modulation (PWM) excitation method and then with the threephase sinusoidal excitation technique at a rotational speed of 1500 rpm in each condition. The calculation procedure of the stator core loss of the IPMSM is improved from our previous method. The finite element method (FEM) is used to support the identification and computation of motor iron losses, where the PWM carrier frequency is 10 kHz. In addition, experimental results of the extended building factor diagrams for the ring and IPMSM cores under the sinusoidal and inverter excitations are shown and discussed. The main objectives of this study are to investigate and clarify the reasons for increasing the IPMSM stator core loss density owing to the effects of the core shapes and two excitation methods, as well as to thoroughly identify the dominant impact between the core shape and excitation method on the increase in the iron loss density. Furthermore, based on the extended building factor, particular values of the IPMSM stator and rotor core losses in the experiment can be relatively separated and determined.