絕緣閘極雙極性電晶體之二階段主動式閘極驅動電路設計

Design of an Active Gate Driver for IGBTs with Two-Level Turn-On and Turn-Off

陳佑達(You-Da Chen)

指導教授 ： 黃智方

國立清華大學/電機資訊學院/電機工程學系/碩士(2013年)

摘要

IGBT驅動在傳統上的做法，會使用如緩衝、減震電路一樣的被動元件，來取得切換時的功率損耗與電壓電流突波之間的平衡。雖然此類型的作法在技術執行上容易達成，但是額外的被動元件、以及其造成的額外功率損耗卻為人詬病。歷來有許多關於IGBT驅動的研究，絕大多數是利用不同開迴路、閉迴路控制架構來調變切換過程中的驅動強弱，藉此來減低di/dt與dv/dt，進而達成抑制暫態電壓電流突波的效果。然而，許多研究僅止於學術層面，對於在實際應用的技術執行上有不小的難度。
本論文研究的目標即為設計一個主動式IGBT閘極驅動電路，採用二階段式閘極控制架構來達成抑制反向回復電流峰值與過電壓的效果，而電源低電壓保護機制則用以提升操作可靠度。關於如何利用二階段式閘極控制來優化IGBT的硬性切換特性，在文中將有詳細分析探討。
該驅動電路利用高壓0.25μm BCD製程來實現。晶片面積為2mm × 2mm。在模擬與實驗量測中，由於IGBT元件切換過程中電流變化速率過高所導致的電壓、電流過衝現象皆有大幅度改善，且與切換能量損耗可達到平衡。

關鍵字

絕緣閘極雙極性電晶體 ； 主動式閘極驅動 ； 二階段式驅動 ； 反向回復電流 ； 切換功率耗損

並列摘要

Traditionally, gate control of IGBTs could be a way to reduce switching losses and voltage overshoots by means of adding passive components such as snubbers in the circuits. While they are easy to implement and effective, additional part count and power losses make them less attractive. Previous studies focus on methods of changeable driving speed during switching process, with open-loop or close-loop controls, in order to lower di/dt and dv/dt. However, in some cases, the complexity of the control methodology makes them hard to implement for practical uses.
The objective of this study is to design a gate driver circuit for insulated gate bipolar transistors (IGBTs) with functions such as two-level turn-on to reduce peak reverse recovery current when turning on the device, two-level turn-off to limit over-voltage when the device is turned off, and under-voltage lock out protection. Based on several requirements to achieve optimal switching performance for IGBTs under hard-switching conditions, principles and operations of the two-level gate control are explained. The improvements of current overshoot at turn-on, voltage overshoot at turn-off, and switching energy losses are measured and discussed.
The proposed IC is realized using a foundry’s HV 0.25μm BCD technology. The die area of the IGBT gate driver IC is 2mm × 2mm. Both the simulation and experimental results show good agreement with the theoretical analysis.

並列關鍵字

Insulated gate bipolar transistor (IGBT) ； active gate drive ； two-level driver ； reverse recovery current ； switching loss

參考文獻

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