Design of high-speed permanent magnet motor considering rotor radial force and motor losses
Journal
Energies
Journal Volume
13
Journal Issue
22
Date Issued
2020
Author(s)
Abstract
Different from the design of conventional permanent magnet (PM) motors, high-speed motors are primarily limited by rotor unbalanced radial forces, rotor power losses, and rotor mechanical strength. This paper aimed to propose a suitable PM motor with consideration of these design issues. First, the rotor radial force is minimized based on the selection of stator tooth numbers and windings. By designing a stator with even slots, the rotor radial force can be canceled, leading to better rotor strength at high speed. Second, rotor power losses proportional to rotor frequency are increased as motor speed increases. A two-dimensional sensitivity analysis is used to improve these losses. In addition, the rotor sleeve loss can be minimized to less than 8.3% of the total losses using slotless windings. Third, the trapezoidal drive can cause more than a 33% magnet loss due to additional armature flux harmonics. This drive reflected loss is also mitigated with slotless windings. In this paper, six PM motors with different tooth numbers, stator cores, and winding layouts are compared. All the design methods are verified based on nonlinear finite element analysis (FEA). ? 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Subjects
Design; Electric motors; Rotors (windings); Sensitivity analysis; Stators; Winding; Flux harmonics; High speed motors; Nonlinear finite element analyses (FEA); Permanent magnet motor; Radial forces; Rotor frequency; Unbalanced radial forces; Winding layout; Permanent magnets
Type
journal article