Noise Estimation Of An Electric Machine For A Parallel Hybrid Helicopter Propulsion System

Abstract

With the growing interest in electrifying the propulsion systems of current and future aircraft, research on the noise emissions of these new concepts is increasingly important. This is particularly true for future rotorcraft concepts, where the propulsion system and major noise sources are in close proximity to passengers. In this paper, the radiated noise of an electric machine that provides power to a parallel hybrid helicopter propulsion system during specific flight phases using various simulation software is estimated. To achieve this, a mission profile for an EC145 intended for Helicopter Emergency Medical Services is provided to calculate the power requirements of the machine. Using a simplified approach, the equivalent radiated power is calculated and then compared to the radiated sound obtained with a higher-fidelity model. The results indicate that the noise generated by electric machines in an aviation context is a significant noise source that should be taken into consideration during machine design.