Electromagnetic torque ripple and copper losses reduction in permanent magnet synchronous machines

Abstract

SUMMARY This paper presents a method for electromagnetic torque ripple and copper losses reduction in (non‐sinusoidal or trapezoidal) surface‐mount permanent magnet synchronous machines (SM‐PMSM). The method is based on an extension of classical dq transformation that makes it possible to write a vectorial model for this kind of machine (with a non‐sinusoidal back‐EMF waveform). This model is obtained by the application of that transformation in the classical machine per‐phase model. That transformation can be applied to machines that have any type of back‐EMF waveform, and not only trapezoidal or square‐wave back‐EMF waveforms. Implementation results are shown for an electrical converter, using the proposed vectorial model, feeding a non‐sinusoidal synchronous machine (brushless DC motor). They show that the use of this vectorial mode is a way to achieve improvements in the performance of this kind of machine, considering the electromagnetic torque ripple and copper losses, if compared to a drive system that employs a classical six‐step mode as a converter. Copyright © 2011 John Wiley & Sons, Ltd.

Modeling and Control of Local Electromagnetic Actuation for Robotic-Assisted Surgical Devices

“…Damping terms from the interaction with biological tissue is considered relatively insignificant and is neglected in this paper. The electromagnetic torque, T e , which is produced by the interaction between the magnetic field of the PM rotor and the resultant magnetic field flux density of the stators, can be represented based on the stator currents and back-emf voltages induced in the stators due to the rotation of PM as [19]:…”

“…In PMSMs, the stator current vectors which are equal to the number of stator pairs are projected to two stationary orthogonal axes and then the resultant vectors from this projection are projected to two orthogonal components in the parallel and the perpendicular directions to the axis of the rotor (d-q coordinate) which is attached to the PM rotor and rotates with the same speed [19]. This projection not only decouples the stator current, it also removes the dependency on rotor angular displacement.…”

Bond graphs representation of a Brushless DC motor and inverter driver

“…the sinusoidal type of motors has a sinusoidal distribution, and the trapezoidal type has more concentrated windings. The waveform also depends of the constructive form and magnetization of the permanent magnets [9] [10].…”

Influência da saturação no torque da máquina síncrona de ímã permanente no rotor

“…No início do intervalo é possível notar valores maiores de indutância, enquanto os menores valores se encontram no fim do intervalo de 60º elétricos, demonstrando relação inversamente proporcional a componente direta da corrente apresentada em (Monteiro et al, 2012). Como explicado na Seção 6.2.3, a queda no valor da indutância de fase é justificada pelo alinhamento dos fluxos dos ímãs e bobinas à medida que o rotor gira.…”