汽车工程 ›› 2024, Vol. 46 ›› Issue (4): 703-716.doi: 10.19562/j.chinasae.qcgc.2024.04.016

• • 上一篇    

基于EMD-SDP图像特征和改进DenseNet车用PMSM故障诊断

王建平,马建,孟德安(),赵轩,边琦,张凯,刘启全   

  1. 长安大学汽车学院,西安 710064
  • 收稿日期:2023-08-03 修回日期:2023-10-05 出版日期:2024-04-25 发布日期:2024-04-24
  • 通讯作者: 孟德安 E-mail:deanmeng@chd.edu.cn
  • 基金资助:
    国家重点研究发展计划(2020YFB1600604);国家自然科学基金(62103061);陕西省重点研究发展项目(2021LLRH-04-03-02);中央高校基本科研业务费专项资金资助项目(300102223206)

Fault Diagnosis of Automotive PMSMs Based on EMD-SDP Image Features and Improved DenseNet

Jianping Wang,Jian Ma,Dean Meng(),Xuan Zhao,Qi Bian,Kai Zhang,Qiquan Liu   

  1. School of Automobile,Chang'an University,Xi'an  710064
  • Received:2023-08-03 Revised:2023-10-05 Online:2024-04-25 Published:2024-04-24
  • Contact: Dean Meng E-mail:deanmeng@chd.edu.cn

摘要:

永磁同步电机(permanent magnet synchronous motor,PMSM)因转速范围宽、输出转矩大、调速响应快、尺寸小、质量轻等优点被广泛应用于电动汽车驱动系统。受恶劣气候、异常振动和频繁起动-制动工况因素影响,PMSM易发生匝间短路、退磁、轴承磨损等故障。本文针对PMSM相似故障单一维度信号下难区分以及工作条件发生变化时传统诊断方法鲁棒性差的问题,提出了一种基于经验模态分解-对称点模式(empirical mode decomposition-symmetric dot pattern,EMD-SDP)图像特征和改进DenseNet相结合的车用永磁同步电机故障诊断方法。首先,通过实验获取不同状态的电机在多种工况下振动信号,将预处理的振动信号进行EMD处理,求解不同层级本征模态函数(intrinsic mode function,IMF);其次,将原始振动信号转化为SDP图像,对不同层级IMF转化为RGB色彩特征在SDP图像上显示出来;然后,通过融合scSE注意力机制改进DenseNet学习图像数据集构建分类网络模型;最后,按照信号-图像-网络的流程对待测电机状态进行评估与诊断。诊断结果表明:所提出的方法在稳态和变速瞬态工况下均表现良好的性能。在恒速恒载工况下,所提的方法达到最高的故障诊断准确率(99.72%),相比基准的DenseNet的准确率(98.06%)提升了1.66个百分点。改进后的DenseNet模型和DenseNet模型的ROC曲线最接近左上角,AUC均值分别为0.997 4和0.974 5;在加速恒载和减速恒载工况下,改进后的DenseNet模型也达到了最高的诊断准确率,分别为96.88%和97.08%。AUC均值分别为0.987 7和0.986 9。本文所提出的方法的总体性能优于传统方法,能有效地用于速度变化时的故障诊断。

关键词: 永磁同步电机, 故障诊断, 经验模态分解, 对称点模式, scSE, DenseNet

Abstract:

Permanent Magnet Synchronous Motor (PMSM) is widely used in electric vehicle drive systems due to its wide speed range, large output torque, fast speed response, small size and lightweight. PMSMs are susceptible to inter turn short-circuit faults, demagnetization faults, bearing wear faults and other faults due to harsh climate, abnormal vibration and frequent start-brake conditions. In this paper, to address the problems of difficulty in distinguishing PMSM similar faults with single-dimension signals and poor robustness of traditional diagnostic methods when the operating conditions change, a fault diagnosis method is proposed for automotive PMSMs based on the combination of Empirical Mode Decomposition-Symmetric Dot Pattern (EMD-SDP) image features and improved DenseNet convolutional neural network. Firstly, the vibration signals of PMSMs in different states under multiple operating conditions are experimentally obtained, and the pre-processed vibration signals are subjected to EMD to solve the Intrinsic Mode Function (IMF) at different levels. Secondly, the original vibration signals are transformed to the SDP images, and the IMFs at different levels are transformed into RGB color features to be displayed on the SDP images. Then, a classification network model is constructed by improving DenseNet learning image dataset through the fusion of scSE attention mechanism. Finally, the motor state to be measured is evaluated and diagnosed through the signal-image-network process. The diagnostic results show that the proposed method performs well under both steady state and variable speed transient conditions. Under constant speed and load conditions, the proposed method achieves the highest fault diagnosis accuracy (99.72%), which is 1.66% higher than the accuracy of the DenseNet (98.06%). The ROC curves of the improved DenseNet model and the DenseNet model are closest to the upper left corner, with the mean AUC values of 0.997 4 and 0.974 5. Under acceleration and deceleration with constant load conditions, the improved DenseNet model also achieves the highest diagnostic accuracies of 96.88% and 97.08%, with the mean AUC values of 0.987 7 and 0.986 9. The overall performance of the proposed method is better than conventional methods and can be effectively used for fault diagnosis during speed changes.

Key words: permanent magnet synchronous motors, fault diagnosis, empirical mode decomposition, symmetric dot pattern, scSE, DenseNet