變頻式冷氣壓縮機之噪音抑制探討

Study on Compressor Noise Suppression of a Converter-Type Air-Conditioner

黃俊儒(Jim-Ru Huang)

指導教授 ： 蕭俊祥

國立臺北科技大學/機電學院/機電整合研究所/碩士(2005年)

摘要

本論文主要目標是針對窗型冷氣機壓縮機運轉時所產生的噪音，來進行壓縮機噪音之抑制，進而降低冷氣機的整體運轉聲音。為了方便實驗進行，因此使用壓縮機變頻控制板，來獨立供應壓縮機電源並進行壓縮機的轉速控制，以穩定壓縮機的運轉頻率，使其不受外在環境溫度變化影響而改變運轉轉速。
實驗方法首先是量測壓縮機運轉時的音頻，並釐清壓縮機轉速與其所產生噪音主頻的相關性。接著利用黏貼在壓縮機上的加速度計來量測壓縮機運轉時的振動訊號，當作參考的輸入訊號。再利用放置在壓縮機上端之噪音計，來量測壓縮機在不同轉速運轉下的殘留噪音訊號來做回授，並以FIR數位濾波器搭配Filtered-X LMS演算法的適應性數位濾波器作為控制器，使用前饋式、回授式以及混合式控制架構進行減噪，來驗證主動式噪音控制對於壓縮機的運轉噪音抑制可有良好的效果。
實驗結果顯示壓縮機轉速在26rps∼62rps時，其主噪音基頻落在310Hz∼745Hz之間，且每當壓縮機轉速提升3rps，主噪音基頻就會提升35Hz∼40Hz。而控制後平均減噪量前饋式為2.12dB，混合式為3.02dB，回授式控制則有3.48dB。此外，這三種控制架構均能有效地將壓縮機運轉所產生的噪音主頻給抑制下來，且至少都有10dB的抑制效果，甚至轉速在35rps∼44rps的效果能有20dB以上。

關鍵字

冷氣壓縮機 ； 主動式噪音控制 ； 適應性數位濾波器 ； 回授式控制 ； 前饋式控制 ； 混合式控制

並列摘要

This proposal aims to develop techniques for suppressing the unwanted noise emitted by the compressor of a converter-type air-conditioner. In order to proceed our experiment successfully, we use a converter control board to supply the compressor power and set its rotational speed. Then we can fix the compressor operating frequency, which will not be affected even when inside temperature changes.
We use four steps to solve this noise problem. First, try to know the correlation between the compressor rotational speed and the fundamental noise frequency. Second, attach an accelerometer on top of the compressor to measure the vibration which will be treated as the reference input signal. Third, use an error microphone to measure the residual noise and feedback the signal. Last, use Filtered-X LMS algorithm, and employ feed-forward、feed-back and hybrid ANC structures for suppressing the noises.
From experimental data, we observe the fundamental noise frequencies locate at 315Hz∼745Hz when the compressor rotational speed at 26rps∼62rps. Furthermore we find the fundamental noise frequency increase 35Hz∼40Hz when we raise the compressor operating speed every 3rps. Experimental investigation also reveals that feed-forward ANC can attain averaged 2.12dB noise attenuation, hybrid ANC 3.48dB noise attenuation and feed-back ANC 3.02dB. In addition, these three ANC control structures can effectively reduce the fundamental frequency noise at least 10dB, even more than 20dB attenuation obtained when the compressor rotational speed is within the range of 35rps∼44rps.

並列關鍵字

Compressor ； Active noise control ； Adaptive digital filter ； Feedback control ； Feedforward control ； Hybrid control

參考文獻

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