1. INTRODUCTION The need to expand applications of hybrid electric vehicles (HEV) into new configurations has increased rapidly. New applications of hybrid electric vehicles range from compact to large cars and from sedans to sport utility vehicles. A beneficial feature of HEV systems is that they can drive using their electric motor alone ( 1), (2), (3), (4), and due to the lack of engine noise and vibration there is considerable need for motor quietness. Consequently, responses for HEV and electric vehicles (EV) that focus on the relatedness of vehicle sensitivity, vibration transfer path (1),(2),(5) and gear noise reduction have been proposed ( 6). One approach that is frequently taken to reduce motor vibration and noise is to adopt distributed windings for the stator in the drive motor as an effective way of reducing torque fluctuation ( 7). However, distributed windings make the coil-end larger, thus limiting the available locations in which it can be mounted. Also using distributed windings make the coil-end more compact and introduce complications in structure and manufacturing methods ( 7). Meanwhile, concentrated windings are one way of making the coil-end more compact ( 8). If concentrated windings can achieve the same reduction in torque fluctuation as distributed windings, then that approach would be effective for the drive motor. Attention was focused on the shape of the magnetic circuits as a method for reducing motor vibration. Methods for reducing torque fluctuation connected with the electric angle 6th order are known ( 9). Methods of design that limit radial excitation force by the shape of the magnetic circuits have also been proposed ( 10), (11), (12), (13), (14), (15). Additionally, methods of reduction using control have also been reported ( 16),(17).Vibration Reduction in Motors for the SPORT HYBRID SH-AWD Manabu Yazaki Honda R&D Co., Ltd. ABSTRACT A new motor has been developed that combines the goals of greater compactness, increased power and a quiet drive. This motor is an interior permanent magnet synchronous motor (IPM motor) that combines an interior permanent magnet rotor and a stator with concentrated windings. In addition, development of the motor focused on the slot combination, the shape of the magnetic circuits and the control method all designed to reduce motor noise and vibration. An 8-pole rotor, 12-slot stator combination was employed, and a gradually enlarged air gap configuration was used in the magnetic circuits. The gradually enlarged air gap brings the centers of the rotor and the stator out of alignment, changing the curvature, and continually changing the amount of air gap as the rotor rotates. The use of the gradually enlar ged air gap brings torque degradation to a minimum, and significantly reduces torque fluctuation and iron loss of rotor and stator . A superposed harmonic current is used as the control method for the motor. This control method reduces torque fluctuation by adding a harmonic current component on the motor drive control in order to cancel the peaks of the torque waveform. The application of the newly developed three motors in the SPORT HYBRID SH-AWD reduced cogging torque by 50% and torque fluctuation by 50% at an average torque of 5 Nm. The noise and vibration were reduced by at least 12 dB. This technology made it possible to realize quiet motor operation. CITATION: Yazaki, M., "Vibration Reduction in Motors for the SPORT HYBRID SH-AWD," SAE Int. J. Alt. Power. 4(1):2015, doi:10.4271/2015-01-1206.2015-01-1206 Published 04/14/2015 Copyright © 2015 SAE International doi:10.4271/2015-01-1206 saealtpow.saejournals.org 153This paper will report on how a stator with concentrated windings and interior permanent magnet (IPM) rotor were combined in an AC synchronous motor (IPM motor) that achieves greater compactness and higher torque. Reduced vibration and noise were achieved by optimizing the magnetic circuit design and control