切換式電源具備高效率、高功率密度、物理尺寸較小等優點。隨著其快速發展和應用的同時，內部電磁環境也日益複雜，伴隨產生大量電磁干擾將嚴重影響設備正常運行。EMI濾波器是抑制開關電源中傳導電磁干擾的有效手段，因此本研究具有重要意義。
本研究首先從外部因素和切換式電源內部因素兩方面分析了電磁干擾產生的原理，並分析三相轉換器工作原理以及其EMI雜訊源產生和傳播路徑。其次，本文說明了傳導電磁干擾實驗環境和規範，提出三相轉換器的傳導電磁干擾濾波器設計系統化公式，分析濾波器元件頻率特性，並選擇合理的電容、電感元件使其通過標準規範。
本研究的主要貢獻如下：第一提出新型傳導電磁干擾濾波器設計公式，有別於傳統轉折頻率法設計方式，彌補其無法說明共模電感值對應工作頻率和濾波器因高頻效應無法發揮正常濾波功能等缺點。第二是介紹了常用EMI濾波器材料的特點和差異，分析濾波器組成元件的頻率特性，並合理選擇適當磁芯材料和繞線方式使濾波效果達到最佳。同時，對阻尼消除EMI高頻諧振進行分析，計算諧振迴路等效參數並模擬驗證。最後，本研究基於三相三線轉換器的電磁干擾進行濾波器設計和實驗，頻譜分析儀上呈現的共模、差模雜訊頻譜和時域電壓電流量測波形均驗證了EMI濾波器設計的正確性，能夠很好的通過電磁干擾標準規範。

Switching power supplies have the advantages of high efficiency, high power density, and small physical size. Along with their rapid development and application, the internal electromagnetic environment is also becoming increasingly complex, and accompanied by a large number of electromagnetic interference (EMI), it will seriously affect the normal operation of the equipment. EMI filter is an effective mean to suppress conductive electromagnetic interference in switching power supplies, thus, this study is of significant importance.
This research first analyzes the mechanism of EMI from the external factors and the internal factors of switching power supplies, and focuses on the principle of a three-phase inverter and its EMI noise source generation and propagation path. Secondly, this paper describes the experimental environment and specifications of conducted EMI, proposes systematic formula for the design of conductive EMI filters for three-phase inverters, analyzes the frequency characteristics of the filter components, and selects proper capacitor and inductor components to comply with the EMI standard (EN55011).
The main contributions of this research are as follows: The first is to propose new conductive EMI filter design formula, which are different from the traditional corner frequency design method, making up for its inability to explain the common mode inductance corresponding to the operating frequency. Additionally the conventional filter design can not play the normal filter function due to high frequency effects and other shortcomings. The second is to introduce the characteristics and differences of commonly used EMI filter materials, analyze the frequency characteristics of the filter components and select appropriate core material and winding method to achieve the best filtering effect. At the same time, the high-frequency resonance of damping EMI is analyzed, and the equivalent parameters of the resonance loop are calculated, simulated and verified. Finally, the filter design and experiment are based on the EMI of a three-phase three-wire inverter. The common-mode and differential-mode noise spectrum presented on the spectrum analyzer and the experimental waveforms of the time-domain voltage and current verify the design of the EMI filter, which can well comply with the EMI standard.
Keywords—Electromagnetic Interference, EMI Filter, EMI Magnetic Component Analysis, Conducted EMI Experiments, Damping Simulation.

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