Vibration Analysis of the Electric Drive System with Inter-turn Short-Circuit and Gear Spalling Faults

Introduction The electric drive system is usually composed of an electric motor and gear transmission system, and widely used for industrial applications. However, the dynamic behaviors of the coupled electromechanical system are still not well understood, especially when there are faults in the system. Purpose The faults such as gear spalling fault of the mechanical system or inter-turn short-circuit fault of electrical device will threaten the operation safety of the electric vehicle. Thus, the faulty dynamic analysis for the electric drive system is crucial for avoiding fatal catastrophes. Method In this paper, the permeance network motor model with inter-turn short-circuit fault and the dynamic planetary gear transmission model considering spalling faults are proposed, respectively. The electromechanical dynamic model integrating two models mentioned above is employed to acquire the fault characteristics. Then, the vibration characteristics of the electric drive system with and without gear fault or inter-turn fault under the effects of time-varying mesh stiffness, slot effect and magnetic saturation are distinguished at different operation conditions. Results The results show that the inter-turn short-circuit fault can trigger conspicuous harmonics within the low frequency domain of the mesh force components, which will predicatively obstruct the detection or diagnosis of the spalling fault. Moreover, the vibration characteristics and vibration mechanism concerning these faults are revealed by the frequency and statistical analysis, which facilitates the condition monitoring for the gear transmission system when the tooth spalling and inter-turn faults are coupled. Conclusion The research results bring theoretical reference for the dynamic analysis and vibration-based condition monitoring of the vehicles' integrated electric drive system.