使用複合頻率分析之印刷電路板佈局寄生參數驗證

PCB Layout Parasitic Parameter Verification Using Multi-Frequency Analysis

鄭翔任(Shiang-Ren Jeng)

指導教授 ： 陳耀銘

國立臺灣大學/電機資訊學院/電機工程學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201904401

摘要

氮化鎵功率電晶體因為其超凡的電氣特性，成為最具前景的新世代功率元件候選人之一。然而氮化鎵功率電晶體有個令人無法忽視的缺點，那就是它的閘極非常脆弱，以至於幾乎無法忍受任何電壓雜訊，否則會馬上損毀。因此，許多研究者與企業投入大量精力在探討如何正確評估與計算印刷電路板上的寄生元件，以避免寄生效應造成氮化鎵功率元件的損壞。這些針對寄生元件的嚴密估算與精密設計以往大多出現於積體電路類的超高速(兆赫等級以上)電路應用。當要使用軟體進行寄生參數萃取以進行電路模擬時，設計者將面臨挑戰。極致準確的參數萃取讓軟體設定變得冗長且許多環節容易出錯。縱使寄生參數被成功萃取，電路模擬與實際測試結果仍有差距。最終極且準確的辦法是將整個電路之物理模型進行軟體模擬，但這種全域模擬曠日費時且需強大電腦運算能力方可達成；此外，設計者須具備多領域的專業知識才可正確完成並解讀全域模擬。

這篇論文將會引入一個新的模擬流程，讓開發者更快速且準確的驗證所設計電路的寄生元件效應。這包含兩部分:第一部分為寄生參數的簡化萃取過程，以期透過軟體更迅速、可靠地計算參數量值，同時避開全域模擬繁瑣且易出錯的設定流程，終能維持準確性。第二部分為複合頻率分析方式，此方式依照不同權重，疊加多個頻率的電路模擬結果，降低單一頻率電路模擬時高頻響應易被犧牲的缺點；此外，在實際電路中許多寄生參數因難用集成元件等效其量值，其造成的訊號上升時間差也會對高頻響應造成影響，亦可透過此分析法提升準確性。本論文介紹了複合頻率選取的原理以及實務上的操作；同時透過所提出的精簡化參數萃取方式與複合頻率分析，再彙整眾多積體電路設計之電路佈局準則，完成了一款用於車用電子輔助動力方向盤的400瓦馬達逆變器和一款用於電動摩托車動力系統的2.2千瓦馬達逆變器。最終由實測驗證複合頻率寄生參驗證法之整套模擬流程的可適用性與設計成效。

關鍵字

氮化鎵功率電晶體 ； 電路寄生參數萃取法 ； 多頻率分析 ； 電磁干擾 ； 印刷電路板線路布局 ； 三相逆變器 ； 車用馬達驅動

並列摘要

Gallium Nitride High Electron Mobility Transistor (GaN HEMT) is one of the most promising candidates for next generation power devices due to its electrical characteristics. However, the Achilles’ heel of GaN HEMT is its fragile gate which does not tolerate voltage noise well. Researchers and companies have made great efforts on evaluating the parasitic effect of PCB layout that was often taken into consideration on IC-related high frequency (MHz or above) application in the past. Complicated simulation environment set-up often causes software conflicts and erroneous results. Even if the parameter is accurately extracted, circuit simulation result is often not decent enough. Most accurate methodology is to conduct an all-system simulation, which requires all-around background knowledge and is computation-intensive.

In this thesis, a new procedure for evaluating parasitic parameter on PCB design is introduced. It consists of two parts, the first part is a condensed process that use software to calculate parasitic and save great effort on environment establishment at the same time. The second part is a multi-frequency analysis that superimpose several circuit simulation results to form final waveform. This method could retain higher harmonics response of a certain signal compared to conventional single-frequency simulation. Response problem caused by parasitic that is hard to implement in software lumped components could also be addressed. The theoretical selection basics of multi-frequency analysis will be elaborated in this thesis. With new evaluation method and critical design principles consolidated in this thesis, a 400 W EPS motor drive inverter along with a 2.2 kW e-Scooter power train inverter is implemented to verify the applicability of proposed analysis methodology.

並列關鍵字

GaN HEMT ； parasitic parameter extraction ； multi-frequency analysis ； EMI ； PCB layout design ； three phase inverter ； automotive motor drive

參考文獻

[1] Alex Lidow, J.S., Michael de Rooij, David Reusch, “GaN Transistors for Efficient Power Conversion.” 2014: WILEY.

[2] Systems, G., “Design with GaN Enhancement Mode HEMT.” 2018.

[3] Reusch, D. and M.d. Rooij. “Evaluation of gate drive overvoltage management methods for enhancement mode gallium nitride transistors.” in 2017 IEEE Applied Power Electronics Conference and Exposition (APEC).

[4] Alex Lidow, M.d.R., “Paralleling eGaN FETs.” 2012, Efficient Power Conversion, Inc.

[5] David Reusch, P.d., “Optimizing PCB Layout.” 2014, Efficient Power Conversion, Inc.