Holistic modeling of high frequency behavior of inverter-fed machine winding, considering mutual couplings in time domain

Prediction of the voltage distribution within the winding due to pulse-width modulated voltage impinging at the machine terminals is prevalent in literature. For this purpose, the state-of-art work employs a high-frequency model of the stator winding, but fails to represent the mutual inductive and resistive couplings between the turns and the coil. Herein, this paper proposes a multi-conductor transmission line model for representing the high-frequency behavior of the stator winding. A distinctive feature of the proposed model is that it incorporates the mutual inductive and resistive coupling between the turns and the coils using a current-dependent voltage source with due account of frequency dependent parameters in the form of a ladder network. It enables the modeling of the mutual coupling of both single and multi-layer winding in the time domain without the explicit use of modal transformation, convolution integral or inverse Fourier transform. The close agreement between the simulation and the experimental results validates the proposed model of an automotive-grade 60 kW permanent magnet synchronous machine adapted in the Toyota Prius vehicle. In addition, a more intuitive analytical model is proposed to explain the voltage distribution and to characterize the peak voltage stress within the winding. The analytical model can be used to predict voltage stress as an alternative to the high-frequency model.