現今工業快速發展當中，鐵製品已經大量的存在我們生活當中。然而，首當其衝的問題是，鐵製品容易生鏽。因此，此篇論文研究主題，希望透過建立一個小型的脈衝功率系統來達成除鏽的目的。我們利用集膚效應(skin effect)的原理，將一個短脈衝、高功率的電流傳遞到有鏽的金屬表面，藉此將能量釋放到金屬表面，將鏽從固態加熱至汽態蒸發，完成除鏽的功能。我們的小型脈衝功率系統內部包含兩個40 nF的電容串聯，將電容分別充到 ±8 kV儲存2.56 J的能量。為了製作小型的脈衝功率系統，我們建製了一個耐壓達 20 kV 的間隙開關(spark gap switch)，及一個使用汽車點火線圈製作而成的脈衝觸發產生器，提供上升時間(rise time，定義為四分之一週期)為 55.0±0.4 μs、輸出電壓為 -18 kV 觸發脈衝訊號。此小型脈衝功率系統最後可輸出一個上升時間為 5.2 ± 0.2 μs，最高輸出電流為 15.9 ± 0.6 kA的脈衝電流，相對應的系統電感值、電阻值及鐵表面的集膚深度(skin depth)分別為 212 ± 85 nH、1.00 ± 0.04 Ω、0.4μm，電流的角頻率為(4.9 ± 0.1 ) x 106 sec-1。系統的總放電時間為11 μs，估算出系統的總輸出平均功率為230 kW。我們預期每一次的放電(discharge)將可以除去面積約1.8 cm x 1.8 cm 的鏽。我們針對相同的鐵鏽放電了至少 2500 次，然而，效果並不如預期，並沒有觀察到顯著的除鏽效果。推測原因是因為能量不止只有釋放到鐵鏽的表面，還有釋放到了電流流經系統放電迴路中所有的金屬表面上。但是藉由此結果可以知道，未來我們實驗室將要建立的脈衝功率系統，其中的金屬導線不會因為大電流的放電而被侵蝕。

A rust remover was built using a small pulsed-power system. It is very important since there are a lot of iron products that exist in our daily life. A common problem of all iron tools is that they rust. The rust remover we built is to remove rust using the skin effect of a short pulse current propagating through rusted metal surface. To provide a high current, a small pulsed-power system using two 40 nF capacitors connected in series charged to ~ ± 8 kV storing 2.56 J of total energy was built. A controlled spark gap that can hold up to 16kV voltage was built. To trigger the spark gap, a high voltage trigger pulse generator providing a -18 kV trigger pulse with 55.0 ± 0.4 μs rise time was built by using an ignition coil for cars. In this small pulsed-power system, the rise time of the current (quarter period), the calculated skin depth of iron, and the peak current are 5.2 ± 0.2 μs, 0.4 um and 15.9 ± 0.6 kA, respectively, with an fitted inductance of 212 ± 85 nH and fitted resistance of 1.00± 0.04 Ω. The oscillation frequency is (4.9 ± 0.1) x 106 sec-1. The averaged power of our pulsed-power system is about 230 kW before the output current is full damped in ~ 11 μs. Rust on an iron surface, ~1.8 cm long and ~1.8 cm wide, were expected to be removed in each discharge. More than 2500 shots on the same rusted object were conducted. Unfortunately, the result didn’t meet our expectation and no significant amount of rust was removed. The most possible reason is that the energy was released not only on the rusted surface but also on any (metal) surface along the current path. However, it shows that we don’t need to worry about the erosion on the cables in a pulsed-power system which will be built as the long term goal in our lab.

[1]Yifan Wu, “Repetitive and High Voltage Marx Generator Using Solid-state Devices”, IEEE Transactions on Dielectric and Electrical Insulation Vol. 14, No. 4; August 2007
[2] H. Bluhm,”Pulsed Power Systems Principles and Applications”, Springer, Germany, 2006
[3] Michael G. Mazarakis, “High current, 0.5-MA, fast, 100-ns, linear transformer driver experiments”, Phys. Rev. ST Aceel. Beams 12, 050401(2009)
[4] A. A. Kim, “Development and tests of fast 1-MA linear transformer driver stages”, Phys. Rev. ST Aceel. Beams 12, 050402(2009)
[5] J. R. Woodworth, “Low-inductance gas switches for linear transformer drivers”, Phys. Rev. ST Aceel. Beams 12, 060401(2009)
[6] D. V. Rose, “Circuit models and three-dimensional electromagnetic simulations of a 1-MA linear transformer driver stage”, Phys. Rev. ST Aceel. Beams 13, 090401(2010)
[7] E. Husain, “Analysis of Paschen curves for air, N2 and SF6 using the townsend breakdown equation”, IEEE. Transaction on Electrical Insulation, VOL. EI-17, NO. 4(1982)
[8] B. M. Kovalchuk, “Capacitor blocks for linear transformer driver stages”, Phys. Rev. Sci. Instrum. 85, 013501(2014)
[9] M.G.Mazarakis, “A COMPACT, HIGH-VOLTAGE E-BEAM PULSER”, IEEE, 0-7803-5498-2, 6528415, (2002)
[10] https://en.wikipedia.org/wiki/Skin_effect
[11] http://tw.tek.com/high-voltage-probe-manual/p6015a
[12] http://uk.rs-online.com/web/p/fibre-optic-transceivers/8188855/
[13] https://en.wikipedia.org/wiki/Latch-up
[14] http://www.sandia.gov/z-machine/news/image_gallery.html
[15] http://web.tiscali.it/itischivasso/Progetti%20didattici/Area%20di%20Progetto.htm
[16]http://macao.communications.museum/eng/exhibition/secondfloor/MoreInfo/2_10_3_HowTransistorWorks.html
[17]https://zh.wikipedia.org/wiki/%E9%87%91%E5%B1%AC%E6%B0%A7%E5%8C%96%E7%89%A9%E5%8D%8A%E5%B0%8E%E9%AB%94%E5%A0%B4%E6%95%88%E9%9B%BB%E6%99%B6%E9%AB%94
[18] https://www.pcmag.com/encyclopedia/term/59900/igbt
[19] https://thinkelectronics.org/igbt/
[20] http://www.electronics-tutorials.ws/power/insulated-gate-bipolar-transistor.html
[21] http://www.altium.com/