摘要
電子科技推陳出新日新月異，商品演進為輕小精緻，容量大速度快。因為體積小限制了設計空間，導致電磁干擾(EMI-Electromagnetic interference)問題益發嚴重，越來越令工程師頭痛。電磁干擾主要分為輻射性(Radiation)電磁干擾與傳導性(Conductivity)電磁干擾兩種。傳導性電磁干擾是經由電源線來傳遞雜訊的，所以在 同一個電力系統迴路，所產生的電磁干擾會透過電源線互相干擾。一般傳導型電磁干擾解決方法是在電源端入口加入一個電感與電容組成的LC 濾波器，阻隔干擾的流出。 以往EMI 工程師為了要量測EMI 干擾，需租用昂貴儀器與認證場地及預訂量測時段。好不容易安排好時間去實驗室進行測試，身上卻只帶了幾種規格化的電感與電容。這些元件值是憑工程師以往的經驗判斷試用，當下若沒有適用的元件可以符合抗干擾要求，則下次再帶不同元件值來測試。本文針對EMI 干擾，提供可調式的傳導型EMI 濾波器。主要是以可連續性變動的共模電感，可現場即時調整電感值，找到所對應的理想濾波頻率。如此可以減少工程師來回於外面測試實驗室及修改電路等所浪費的時間。這樣的設計能幫助所有的工程師，大幅縮短傳導型電磁干擾驗證測試時間，並且更有效的解決電磁干擾問題。
並列摘要
The rapid evolution of electronic science and technology innovation yields small and light goods with large capacity and high speed. The small size limits the design space, leading to increasingly serious EMI (electromagnetic interference) problems. EMI is mainly divided into radiation type and conductivity type. Conducted EMI noise passes through the power lines. Hence, EMI in the same power system circuit will interfere with each other through the power lines. Generally, the solution of conducted EMI is to add an LC filter at the supply side entrance. Then, the EMI can be prevented to outflow. In order to solve EMI problem, engineers need to rent expensive equipment, certificated venue and booking measurement time slots. They often take only several normalized inductances and capacitors to go to a lab for testing. If engineers can not figure out the solution of the EMI noise after the testing, they need to prepare other inductances and capacitors next time. This thesis proposes an adjustable conducted EMI filter. The common-mode inductance can be on-line and continuously adjusted. Hence we can find the corresponding ideal filter frequency very soon. With this design, engineers do not to need to spend so much time to go back and forth to the laboratory to do circuit modification. By doing this, EMI issues can be fixed more efficiently.