Dynamic modeling and harmonic analysis of surface-mounted three-phase AC permanent magnet synchronous motor

Abstract

CNC machine tools have high requirements for precision and smoothness of motion. As the power source, the performance of the servo motor has a significant impact on the movement of the machine tool. Harmonic is a common phenomenon in motors, which brings adverse effects on the performance of the motor, even the whole machine and the machined parts. Therefore, it’s of great significance to study the source, characteristics, and influencing factors of the harmonics. In this paper, the time domain modeling, simulation, and analysis are carried out for the harmonic phenomenon of the surface-mounted 3-phase AC permanent magnet synchronous motor (PMSM). Firstly, a dynamic model of the servo motor integrated with its control and driving system is established under ideal conditions, and the simulation of the motor running state is realized in the time domain. On this basis, the modeling and simulation are carried out for the inverter dead-zone, cogging torque, rotor mixed-eccentricity, and 3-phase asymmetry, respectively, and the frequency components of the harmonics caused by these factors are obtained. Finally, the influence of load and motor rotational velocity on 3-phase current and torque harmonics is analyzed, and the interactions between the inverter and the motor are investigated. The results show that the inverter and the motor are coupled to each other as an integrated system, and they have impacts on each other. The established model is verified by experiments.