A Novel Multi-Criteria Local Latin Hypercube Refinement System for Commutation Angle Improvement in IPMSMs

The commutation angle, γ, of an interior permanent magnet synchronous motor's (IPMSM) vector diagram, plays an important role in compensating the back electromotive force (back-EMF); both under phase current variations and an extended speed range, is required by the application. This commutation angle is defined as the angle between the fundamental of the motor phase current and the fundamental of the back-EMF. It can be utilised to provide a compensating effect in IPMSMs. This is due to the reluctance torque component being dependent on the commutation angle of the phase current even before entering the extended speed range. A real-time maximum torque per current and voltage strategy is demonstrated to find the trajectory and optimum commutation angles, γ, where the level of accuracy depends on the application and available computational speed. A magnet volume reduction using a novel multi-criteria local Latin hypercube refinement (MLHR) sampling system is also presented to improve the optimisation process. The proposed new technique minimises the magnet mass to motor torque density whilst maintaining a similar phase current level. A mapping of γ allows the determination of the optimum angles, as shown in this paper. The 3rd generation Toyota Prius IPMSM is considered as the reference motor, where the rotor configuration is altered to allow for an individual assessment.</p

Commutation Angle Maps Evaluation for Magnet Arrangements of Interior Permanent Magnet Synchronous Machines in Electric Vehicles

© 2021 IEEE. This is the accepted manuscript version of a conference paper which has been published in final form at 10.1109/SEST50973.2021.9543397The commutation angle, γ , of an interior permanent magnet synchronous motor's (IPMSM) vector diagram, plays an important role in compensating the back electromotive force; both under load phase current variations and/or when an extended speed range, being near the constant power range, is required by the application. This commutation angle is defined as the angle between the fundamental of the phase current and the fundamental of the back-emf. It can be utilized to provide a compensating effect in IPMSMs. This is due to the reluctance torque component being dependent on the phase current before the extended speed range. A real-time maximum torque per current and voltage strategy is employed to find the trajectory and optimum commutation angles, γ , where the level of accuracy depends on the application and available computational speed. A magnet volume reduction is proposed in this paper to minimize the permanent magnet mass to motor torque density, whilst maintaining the phase current below its maximum rated value. A mapping of γ allows the determination of the optimum angles as shown in this paper. The 3rd generation Toyota Prius IPMSM is considered the reference motor, where only the rotor configuration is altered to allow for an individual assessment. The electric vehicle's performance during acceleration and deceleration using various IPMSM rotor configurations is evaluated for a given four-wheel-drive vehicle. The powertrain uses two single-gear onboard, under standard drive cycles.Peer reviewe

Three-Dimensional Magnetic Field Modeling of a Cylindrical Halbach Array

A semi-analytical description of the 3-D magnetic field distribution of a cylindrical quasi-Halbach permanent magnet array is derived. This model avoids the necessity of time-consuming finite element analyses and allows for fast parameterization to investigate the influence of the number of segments on the magnetic flux density distribution. The segmented magnet is used to approximate an ideal radial magnetized ring in a cylindrical quasi-Halbach array. The model is obtained by solving the Maxwell equations using the magnetic scalar potential and describes the magnetic fields by a Fourier series

Eddy-current losses in laminated and solid steel stator back iron in a small rotary brushless permanent-magnet actuator Citation for published version (APA): Eddy-Current Losses in Laminated and Solid Steel Stator Back Iron in a Small Rotary Brushless Per

The ever-increasing necessity to miniaturize smooth torque rotary actuators has placed severe constraints on the current slotless permanent-magnet technology. These constraints are mainly the consequence of the relatively large effective magnetic airgap which limits the achievable magnetic loading and, therefore, the torque density of slotless permanent-magnet rotary actuators. Further, the miniaturization has to be achieved at ever-decreasing costs and, therefore, it would be advantageous to implement solid back irons. However this, even at reduced magnetic loading, still results in considerable eddy-current losses. Therefore, a careful selection of the various actuator dimensions and most appropriate soft magnetic laminated or solid material is a prerequisite for applications that require smooth speed and torque characteristic. This paper will identify the influence of various parameters of the slotless permanent-magnet actuator on the eddy-current loss in the back iron using both 2-D and 3-D finite-element analysis

An Evaluation of Alternative Stator Lamination Materials for a High-Speed, 1.5 MW, Permanent Magnet Generator

Abstract—The influence of the choice of stator lamination mate-rial on the iron loss in a high speed, high power permanent magnet generator, which is interfaced to a DC link via a simple bridge recti-fier, is investigated. The rating of the generator is representative of machines which would be employed in ‘more-electric ’ ships and for embedded power generation. It is shown that the iron loss can be reduced considerably by employing 6.5 % SiFe laminations rather than 3 % SiFe. It is also shown that, due to the high harmonic con-tent in the phase current waveforms, the iron loss density can vary widely over the stator laminations. Index Terms—Generator, iron loss, permanent magnet, 6.5% SiFe. I