IGBT模塊電路雜散電感測(cè)量方法

圖1為IGBT半橋拓?fù)潆娐穲D，及當(dāng)開關(guān)IGBT1時(shí)產(chǎn)生的電壓電流波形。該電路雜散電感Ls代表所有的分布電感（電容器，母線和IGBT模塊）。 Due to the changing current a voltage drop of Ls * dioff/dt occurs across the stray inductance Ls. It is overlayed to the DC link voltage VCC and seen as a voltage spike across the turning-off IGBT1. According to the RBSOA diagram, this spike must be limited to the blocking voltage VCES of the IGBT module (measured at the chip, means measured at the CE auxiliary terminals). Also a derated curve is given in the data-sheet for measurements at the power terminals, taking into account the internal module stray inductance between main and auxiliary terminals of the module.文章來源：http://wwwcb863.com/il/150.html
換流回路的雜散電感可以通過IGBT在開通時(shí)的兩端壓降獲得：當(dāng)IGBT依然處于阻斷狀態(tài)，而電流已經(jīng)開始上升時(shí)，可以測(cè)量di/dt及電壓降DV，根據(jù)測(cè)量值計(jì)算電感值，見下式：
Ls = DV / di/dt. Example:
i: 400A / div (green) v: 200V / div. (black)
該電壓降發(fā)生的時(shí)刻，二極管仍然沒有阻斷能力。因此電壓降只能是由雜散電感產(chǎn)生，不需考慮其他的影響。The circuit stray inductance is calculated according to the above shown formula at zero
crossing of current. We get the following values:
DV » 230V
di/dt » 3200A/800ns
Å Ls » 58nH