High‐speed solid rotor induction motor design with improved efficiency and decreased harmonic effect

Abstract

Depending on its mechanical and thermal advantages, solid rotor induction motors (SRIMs) are widely used in demanding high-speed applications. Since eddy currents are set free in SRIMs, great part of rotor losses is caused by space harmonics created in the air-gap. Rotor losses are increased tremendously in high-speed applications with the remarkable increase in driving frequency. Here, an innovative design representing a novel stator and rotor combination that is not achieved in previous studies is proposed by structural changes to stator to eliminate major effective space harmonics. An unconventional stator slotting pattern and winding distribution is calculated by nature-inspired numerical optimisation techniques while keeping the fundamental winding factor relatively high. An example design where novel concepts are implemented is presented and a comparison is given in terms of important operational quantities with that of a standard SRIM.

A Comprehensive Disturbing Effect Analysis of Multi-Sectional Rotor Slot Geometry for Induction Machines in Electrical Vehicles

“…Content may change prior to final publication. rotates in the same direction with the fundamental, while those of order of (6k − 1) rotates in reverse direction [30].…”

Shielded axially slitted solid rotor design for high‐speed solid rotor induction motors

“…When designing a solid rotor, its geometrical properties play a prominent role in its overall torque production and efficiency. One of the main reasons as to why a solid rotor structure falls behind a CRIM in terms of lower‐output power, lower‐power factor and lower efficiency is its higher rotor impedance, higher reluctance of solid steel than that of a laminated steel, higher eddy currents and greater adverse effects of harmonics [5–21].…”

“…Since CRIM and smooth SRIM were shown to be the worst for high-speed operations [18], only performance results of AS-SRIM, CC-SRIM and SAS-SRIM with end-rings are compared. lower efficiency is its higher rotor impedance, higher reluctance of solid steel than that of a laminated steel, higher eddy currents and greater adverse effects of harmonics [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”

“…The unsatisfactory performance of the smooth SRIM pushed researchers to develop novel additional design solutions such as placing end-rings, opening slits and coating rotors [12][13][14][15][16][17]. Copper end-rings are added to rotor ends in order to improve the electromagnetic performance of the rotor.…”

“…Further performance improvements by authors are also available by changing both the stator core and slot geometry in order to optimise air‐gap mmf harmonics [16].…”