Influence of rectifier characteristic harmonics on loss and temperature field of high‐speed permanent magnet generator

Abstract

Due to the high-frequency output of the high-speed permanent magnet generator (HSPMG), a rectifier is needed in the application process. However, the different characteristic harmonics generate by the rectifier will seriously affect the electromagnetic and temperature fields of the generator. Taking a 117 kW, 60 000 rpm HSPMG as example, the influence of different harmonic current content and frequency on the generator loss and temperature field are studied. The influences of different harmonic current content and frequency on the rotor eddy current loss and its distribution variation are analyzed. Furthermore, based on the rotor eddy current loss analysis, a 3D temperature and fluid coupling model is established. The temperature distribution of HSPMG under different harmonic content and frequency are studied by using hydrodynamics and heat transfer theory, especially for the permanent magnet (PM) temperature field. The influence laws of different harmonic content and frequency on the loss are obtained, and the sensitive factor of PM temperature rise is found. The study provides optimization suggestions for reducing eddy current loss and preventing PM thermal demagnetization caused by harmonics.