Recent Technological Advances in Spatial Active Noise Control Systems

Abstract

This article provides a broad overview of the recent advances in the field of active noise control techniques to reduce unwanted noise over a certain spatial region of interest. By both commercial and technological advances in local active noise control systems extending the size of the quiet zone seems to be a crucial step to develop the next generation of active control systems for a more personalized and quieter audio products. In this review article, the advances over the past decade in design and development of spatial active noise control techniques to enlarge the controlled sound zone is reviewed. The focus is specifically on the adaptive control techniques and the methods proposed in the frequency domain to control the sound field. The study has paid a specific attention into the most important performance measures in designing a spatial active noise control system such as convergence rate, stability and robustness of the algorithm, and the size of quite zone and how it can be enlarged by configuring the loudspeaker and microphone array geometries. Finally, the authors will discuss the current and future challenges that should be overcome to improve the effectiveness of the recently proposed methods to expand the silence zone.

A novel auxetic stator winding to improve the performance of permanent magnet synchronous electric motors

“…Previous studies on NVH for e-motors confirm that they are mostly affected by tonal noise (harmonics of the rotor speed), commonly referred to as whistling noise, that is generated from the flux density forces [3]. In general, there are two main complementary techniques to improve sound quality and design in automobiles, namely passive and active methods [4,5]. Active control techniques are most effective in shaping low-frequency noises [6][7][8][9], while passive methods are proven to be efficient in dealing with high-frequency e-motor noises [10].…”