Design and optimization of a mechanical variable-leakage-flux interior permanent magnet machine with auxiliary rotatable magnetic poles

Abstract

A novel mechanical variable-leakage-flux interior permanent magnet machine (MVLF-IPMM) is proposed for electric vehicles (EVs) in this paper, which employs a mechanical flux-regulating device and auxiliary rotatable magnetic poles. The magnetic poles acting as the flux adjustors can be rotated by the additional device to vary the leakage flux in magnetic circuit and realize the adjustment of the PM flux linkage. Due to the flux-regulating effect, the flux distribution in this machine is complex and changeable. Therefore, the working principle is illustrated in detail. To obtain the perfect coordination between the dominant magnetic poles and auxiliary magnetic poles, a multi-objective optimization method is presented based on the parameter sensitivity analysis combining with the Coefficient of Prognosis (CoP). Then, some design parameters with strong sensitive are selected by the sensitivity analysis and the initial model of the proposed motor is optimized by utilizing the multi-objective genetic algorithm (MOGA). According to the result of the optimization, the machine performances of the initial and the optimal design under the different flux states are compared and analyzed to verify the validity of the new variable-flux motor and the optimization method.

A Novel Variable Flux Spoke Type Permanent Magnet Motor With Swiveling Magnetization for Electric Vehicles

“…However, different approaches should be considered other than weakening the flux by daxis current. In this regard, various types of motors have been proposed [7][8][9][10][11][12]. Fodorean [8] proposed a doubly-excited synchronous motor with field windings in the rotor and the speed range could be improved to 2.8 times the base speed.…”

“…Other than the application of field windings, regulation of air-gap flux density can also be performed by mechanical devices [10,11]. For example, Zhou [10] developed a variable flux motor that mechanically performs field weakening.…”

Analysis of a Novel Mechanically Adjusted Variable Flux Permanent Magnet Homopolar Inductor Machine with Rotating Magnetic Poles for Flywheel Energy Storage System

“…Ideally, the air gap magnetic field could be completely suppressed, whereas, due to the complicated of the rotor and the control method, additional loss will be generated when the segmented rotor rotates relative to each other, which in turn affects its operating efficiency. An adaptive centrifugal device in view of the adjustable air gap magnetic field of PMSM is studied in [16]. Nonetheless, with the continuous change of the motor speed, the PMs are constantly in contact with the stator, which may affect the strength of the PMs.…”

Static Eccentricity Fault Analysis of Surface-Mounted Permanent Magnet Electromotor with Skewed Slots Based on 2D FEA

“…Due to high efficiency, high power density, and good reliability, permanent magnet electromotor is widely used as the core component of the propulsion system in low-power electric vehicles [1][2][3][4]. Assembly technology and machining accuracy in the manufacturing process are imperfect, and the electromotor may have slight air-gap eccentricity before leaving the factory [5].…”