Influence of design parameters on flux‐weakening performance of interior permanent magnet machines with novel semi‐overlapping windings

Abstract

This study performs a design and parametric study of interior permanent‐magnet (IPM) machines equipped with novel semi‐overlapping windings (NSWs). The influence of the key design parameters including; number of turns per phase, stack length, distance and angle between V‐shaped magnets, rotor yoke thickness, magnetic bridge width and thickness and number of magnet segments on the flux‐weakening (FW) performance characteristics are evaluated in detail. The influence of material of segmentation (material of bridge namely, air or iron) is also considered. A combination of analytical calculation‐based program and a time‐stepping 2D finite‐element analysis based program are employed to evaluate the FW characteristics. The accuracy of the FW calculations, particularly the performance at high‐speed regions, is verified over changes in torque components; namely reluctance and permanent magnet (PM), inductance components, PM flux coefficient and inverse saliency ratio due to the change in considered design parameter. The electromagnetic torque, torque ripple, output power and FW capability are investigated by parametric analyses. Moreover, the power losses and efficiency maps together FW curves are calculated for the optimal NSW IPM machine. The experimental measurements, taken from manufactured prototype, verify that the performed analyses and methods described in this study are accurate and reliable.

Improving the Flux-Weakening Capability of Interior Permanent Magnet Machines by Number of Turns Changing Methodology

“…For the FW calculations, the dq equivalent circuit of the IPM machine is employed. More details about the FW algorithm employed in this study can be found in [41].…”

Torque Capability Comparison of Induction and Interior Permanent Magnet Machines for Traction Applications

“…When phase current has a phase advance angle in comparison to the q-axis, the d-axis current 𝑖 𝑑 acts as a weakening current. Thus, the motors are controlled by maximum torque-per-ampere (MTPA) mode below corner speed and flux-weakening control mode above the corner speed [30] 𝑉 𝑑 2 + 𝑉 𝑞 2 ≤ 𝑢 𝑚𝑎𝑥 2…”

Manufacturable Edgewise Winding Solutions Considering Parallel Slot and Parallel Tooth Stator Structures

“…The simulation is repeated at 3x rated speed to observe impacts when moving into field-weakening (FW) operation. The stranded design needs the largest amount of FW as it has higher air gap flux density, which requires more negative daxis current to counteract [26]. When increasing the speed, the efficiency trend changes, as edgewise PS is most efficient.…”