Due to possible overheat, abrasion or mechanical vibrations, demagnetization fault is inevitable in permanent magnet synchronous motors (PMSMs), which could greatly decrease the motor’s efficiency and hence an electrified vehicle’s performance. This paper, from an energy efficiency point of view, proposes to analyze the tolerance ability of different electrified vehicles on motor demagnetization faults, via PMSM flux density degradation modeling, efficiency estimation and dynamic programming (DP) based powertrain energy management. The relationship between different demagnetization levels and resultant motor efficiencies is obtained, and analyzed according to the motor operation area. Demagnetized PMSM is adopted in a pure electric vehicle (PEV), a hybrid electric vehicle (HEV) and a plug-in hybrid electric vehicle (PHEV) for energy efficiency analysis. Tolerance analysis indicates that the powertrain efficiency decrease caused by motor demagnetization is more severe under urban driving conditions, especially with PEV and PHEV configurations compared with HEV. A demagnetization threshold investigation is also given in this paper.

由于可能的过热，磨损或机械振动，永磁同步电动机（PMSM）不可避免会出现退磁故障，这可能会大大降低电动机的效率，从而降低电动车辆的性能。本文从能源效率的角度，提出了通过基于PMSM磁通密度退化模型，效率估算和基于动态规划（DP）的动力总成能量管理来分析不同电动车辆对电动机退磁故障的耐受能力。获得了不同的退磁水平与最终电机效率之间的关系，并根据电机工作区域进行了分析。纯电动汽车（PEV）采用了去磁的PMSM，混合动力汽车（HEV）和插电式混合动力汽车（PHEV）进行能效分析。公差分析表明，在城市驾驶条件下，由电动机退磁导致的动力总成效率下降更为严重，特别是与HEV相比，在PEV和PHEV配置下。本文还给出了退磁阈值研究。