Voltage Stress Calculation and Measurement for Hairpin Winding of EV Traction Machines Driven by SiC MOSFET

High Frequency Modeling of Electric Machines Using Finite Element Analysis Derived Data

“…Similarly, when the turn-to-turn capacitances are considered, the capacitance between adjacent turns is typically between ~80pF and ~120pF, whereas between non-adjacent turns the values are substantially below 1pF (typically in the fF range and below). This level of difference in capacitance is typical and demonstrated in other studies presented in literature, for example [25]. Given that the omitted capacitances are several orders of magnitude lower than the included values the omission of these capacitors will not impact the results of the model in a significant way.…”

Analysis of Voltage Distribution and Connections within a High-Frequency Hairpin Winding Model

“…In fact, the exact location of each conductor is known, thus more reliable results in terms of voltage stress modeling can be achieved and appropriate countermeasures can be taken, such as the choice of a specific insulation or a proper winding layout. Some studies have been done in order to reach a better understanding of these phenomena in hairpin windings [16]- [19]. The general approach is typically based on the finite element (FE) extraction of the impedances, and on the simulation of the voltage waveforms in the equivalent high frequency (HF) circuit of the winding (or a portion of it).…”

“…The general approach is typically based on the finite element (FE) extraction of the impedances, and on the simulation of the voltage waveforms in the equivalent high frequency (HF) circuit of the winding (or a portion of it). A particular focus has been given to the influence of the voltage input parameters (amplitude, rise time or dv/dt), through some sensitivity analyses [16], [17], and to some possible special connections aimed at reducing the maximum voltage amplitude between adjacent layers [16], [19]. However, more investigations are needed, such as:…”

“…The adopted software is Simcenter ElecNet for the capacitances determination and Simcenter MagNet for resistances and inductances. The evaluation of the parameters, which is briefly recalled below, is carried out as illustrated in [16]- [19]:…”

On the AC Losses in the End Conductors of Hairpin Windings

“…These characteristics allow to increase the electrical load without increasing the machine volume, which usually represents a critical constraint for traction applications. In addition, differently from random windings with round conductors, the position of each conductor within the slots is always known and well defined, thus permitting a better modelling and evaluation of the temperature map [4] and of the insulation stress [5].…”