Design Optimization of Multi-Layer Permanent Magnet Synchronous Machines for Electric Vehicle Applications

Abstract

This paper presents a comparison between two design methodologies applied to permanent magnet synchronous machines for hybrid and electric vehicles (HEVs and EVs). Both methodologies are based on 2D finite element models and coupled to a genetic algorithm to optimize complex non-linear geometries such as multi-layer permanent magnet machines. To reduce the computation duration to evaluate Induced Voltage and Iron Losses for a given electrical machine configuration, a new methodology based on geometrical symmetries and magnetic symmetries are used and is detailed. Two electromagnetic models have been developed and used in the design stage. The first model was the stepped rotor position finite element analysis called abc model which considered the spatial harmonics without any approximation of the waveform of flux linkage inside the stator, and the second model was based on a fixed rotor position called dq model, with the approximation that the waveform of flux linkage inside the stator was sinuous. These two methodologies are applied to the design of a synchronous machine for HEVs and EVs applications. Design results and performances are analyzed, and the advantages and drawbacks of each methodology are presented. It was found that the dq model is at least 5 times faster than the abc model with high precision for both the torque and induce voltage evaluation in most cases. However, it is not the case for the iron losses computation. The iron loss model based on dq model is less accurate than the abc model with a relative deviation from the abc model greater than 70% at high control angle. The choice of the electromagnetic model during the optimization process will therefore influence the geometry and the performances of the obtained electrical machine after the optimization.

Optimal Design of High-Speed Electric Machines for Electric Vehicles: A Case Study of 100 kW V-Shaped Interior PMSM

“…This machine is used in most electric and hybrid vehicles due to its high power density. The stator and rotor of the machine are geometrically modeled in [24]. The geometric parameters of a one-layer V-shaped IPMSM are listed in Table 2.…”

“…The latter can be reduced further by using mechanical and electrical symmetries of the machine, which makes it possible to launch the simulations on only one pole of the machine and 1⁄6 of the electrical period. Electromagnetic quantities are reconstructed based on these symmetries, as detailed in [24]. The machine has three phases and is supplied with sinusoidal current using an ABC model.…”

“…The former allows defining ampere-turns based on the required fill factor and slot area. Hence, the number of winding turns is not previously known but is determined downstream of the simulations according to the evaluated induced voltage and maximum DC voltage [24].…”

“…In this work, more than 9,000,000 machines were evaluated during the optimization process. To evaluate the machine's performances, we will use the design methodology of the V-shaped IPMSM described in [24]. However, since high-frequency losses in windings are not considered, an adapted optimization methodology, including hybrid models of AC losses in windings, is defined.…”

Sliding Mode Control of an Electric Vehicle Driven by a New Powertrain Technology Based on a Dual-Star Induction Machine

“…This machine comprises a stator equipped with two identical three-phase windings and a squirrel-cage rotor. It is a dual-star induction machine known for its reliability, robustness, high efficiency, and excellent performance compared to single-star machines [12][13][14]. This innovative approach opens up new perspectives in the field of electric vehicle propulsion, offering a promising alternative to meet the increasing demands for performance and energy efficiency.…”