Møller, Henrik

Pedersen, Steffen

English

This paper discusses noise control systems for implementation in compact HVAC units. The control of low-frequency noise presents different problems than at higher frequencies. This is mainly related to the long wavelength, which means that passive solutions require a significant volume of space, often not available in compact HVAC units. Active control can provide attenuation over a significant frequency range, including low frequencies, while requiring a more limited space. While the concept of active noise control is simple, a number of limitations in the acoustical, electrical and control systems affect the performance of implementations. The source pressure and the impedance of a centrifugal fan were measured, and a number of configurations for noise control were investigated. The performance of a simple analogue feedback control was tested in a physical prototype. An adaptive digital controller (feedback and feedforward using FXLMS with cancellation of feedback to reference) was simulated and implemented on a low-cost TI C55XX DSP platform.This paper discusses noise control systems for implementation in compact HVAC units. The control of low-frequency noise presents different problems than at higher frequencies. This is mainly related to the long wavelength, which means that passive solutions require a significant volume of space, often not available in compact HVAC units. Active control can provide attenuation over a significant frequency range, including low frequencies, while requiring a more limited space. While the concept of active noise control is simple, a number of limitations in the acoustical, electrical and control systems affect the performance of implementations. The source pressure and the impedance of a centrifugal fan were measured, and a number of configurations for noise control were investigated. The performance of a simple analogue feedback control was tested in a physical prototype. An adaptive digital controller (feedback and feedforward using FXLMS with cancellation of feedback to reference) was simulated and implemented on a low-cost TI C55XX DSP platform

Control of noise - systems for compact HVAC units

https://vbn.aau.dk/ws/files/227978157/2012_Pedersen_and_M_ller_LF_Stratford_u_A.pdf

Control of noise - systems for compact HVAC units

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