Design and optimisation of energy‐efficient PM‐assisted synchronous reluctance machines for electric vehicles

Abstract

The design and optimisation of a permanent magnet‐assisted synchronous reluctance (PMaSynR) traction machine is described to improve its energy efficiency over a selection of driving cycles, when installed on a four‐wheel‐drive electrically powered vehicle for urban use, with two on‐board powertrains. The driving cycle‐based optimisation is defined with the objective of minimising motor energy loss under strict size constraints, while maintaining the peak torque and restricting the torque ripple. The key design parameters that exert the most significant influence on the selected performance indicators are identified through a parametric sensitivity analysis. The optimisation brings a motor design that is characterised by an energy loss reduction of 8.2% over the WLTP Class 2 driving cycle and 11.7% over the NEDC and Artemis Urban driving cycles, at the price of a 4.7% peak torque reduction with respect to the baseline machine. Additional analysis, implemented outside the optimisation framework, revealed that different coil turn adjustments would reduce the energy loss along the considered driving cycles. However, under realistic size constraints, the optimal design solutions are the same.

In-Depth Exploration of Design and Analysis for PM-Assisted Synchronous Reluctance Machines: Implications for Light Electric Vehicles

“…Their design enables compact and lightweight construction, which proves advantageous in EVs, where reducing weight is pivotal for maximizing efficiency and range. With a higher power density, they can deliver substantial power outputs relative to their size and weight, thereby improving acceleration and the overall EV performance [29,30].…”

Circular Economy Aspects of Permanent Magnet Synchronous Reluctance Machine Design for Electric Vehicle Applications: A Review

“…Although for a drivetrain solution with ferrite magnets, STPMSM might be beneficial because more magnets can be fitted into the rotor [127], low-power ferrite magnets are also widely used in PMASynRMs due to their cost-effectiveness and eco-friendliness [50,96]. The potential for mini and small-category EV applications of this motor type has been proven by the SYRNEMO project [128] and by designing and optimising a PMaSynRM for an EV implemented within the TELL project [129,130].…”

“…PMASynRMs using ferrite magnets generally have lower torque density than REE-based IPMSMs for similar EV applications [128,157]. Because of that, the previous [128, [159][160][161] and recent [129,[162][163][164][165] research investigated ferrite magnet-based PMASynRMs in a power range of 25 kW to 69 kW and a torque range of 83 Nm to 182 Nm at a speed range of 0 rpm to 14,000 rpm. The research mostly refers to the TELL project's EV [130] and the FreedomCAR and Vehicle Technologies (FCVT) requirements specified by the U.S. Department of Energy [166], which covers mini (A) segment electric vehicles with 2WD and one electric machine drivetrain and might be appropriate for small (B) segment electric vehicles with 4WD and two electric machine drivetrains [167].…”

“…Low-power ferrite magnets are widely used in PMASynRMs due to their cost-effectiveness and eco-friendliness, as presented beforehand. The potential for electric vehicle applications of this motor type has been extensively explored in the literature [124,[127][128][129].…”

A Two-Stage Bayesian optimisation for Automatic Tuning of an Unscented Kalman Filter for Vehicle Sideslip Angle Estimation

“…The electric motors have faster dynamics than a conventional powertrain, and the first-order transfer function is tuned by measurements on a powertrain rig by the electric motor manufacturer. The electric motor has a time constant of ∼6 ms, and the initial inverter reaction and torque ripple can be neglected [23]- [25].…”