diff --git a/Article_Scientifique/lowtech.tex b/Article_Scientifique/lowtech.tex index 9e27576..d094c55 100644 --- a/Article_Scientifique/lowtech.tex +++ b/Article_Scientifique/lowtech.tex @@ -17,7 +17,7 @@ The most challenging part of this section is the replacement of semiconductor pa ST Microelectronics at Labège designs and manufactures gallium nitride transistors under the commercial designation STPOWER PowerGaN, this confirmed by a colleague who visited the plant and engineering teams in late 2022, Etienne Gadefait. Gallium nitride transistors are great for high speed power electronics \cite{noauthor_PowerGaN_nodate} but this is a very recent technology, and none of the big material players in GaN are European, let alone French or Occitanian (US, China, Japan and India are predominant)\cite{noauthor_GaN-manufacturer_nodate}. Because of this and very high costs, we chose to consider this a supply chain-constrained technology, which could not be relied on in a non-global future, and we moved on to other options. -The LAAS semiconductor lab was deemed less reachable and more technologically advanced than the AIME semiconductor lab, as we were told they mostly did research on carbon nanotubes and other fancy semiconductor materials. We therefore chose not to contact the LAAS, and +The LAAS semiconductor lab was deemed less reachable and more technologically advanced than the AIME semiconductor lab, as we were told they mostly did research on carbon nanotubes and other fancy semiconductor materials. We therefore chose not to contact the LAAS, and rather prioritise contacting the AIME lab. The AIME is a small research lab located on our campus. Their capabilities and projects were not publicly available, so we decided to contact them. We met two researchers Mr. Tan and Mr. Lincelles to enquire about the manufacturability of certain components, and eventual costs. The AIME specialises in logic circuits, and has not developed any power components at least a decade. Therefore, the research teams have not maintained any know-how in power semiconductors. However, they were very interested in developing this field in their lab, and came with a proposal to start, based on their existing knowledge. Here are some of AIME's capabilities and prices: @@ -65,23 +65,22 @@ Transistor count & $\sim$400 000 & \\ Die size & 1-2 cm$^2$ & \\ Wafer & 2'' ($\sim$50mm) epitaxial & 100-200 € \\ Dies per wafer & 1 & 100-200 € per die \\ -Lab rental & subsidised & reason: academia \\ +Lab rental & subsidised & \\ Masks needed & 4 & 1200 € \\ Dies per set of masks & $>$ 1000 dies & \\ \bottomrule \end{tabular} \end{table} -These costs are much larger than what we have for this project, but are not insurmountable for a department like the GEI. This project also needs a lot of time or more people to be made, more than what we have at our disposal. The researchers were very interested in collaborating on such a project in the future, and considered it very strongly as a replacement for the current AIME project for the 5th year PTP Energie students at INSA Toulouse (currently a CO2 sensor), with GEI's backing and funding. +These costs are much larger than what we have for this project, but are not insurmountable for a department like the GEI. If we run the calculations of static costs (no lab time), this project would cost 1300-1400 € for 1 transistor, 300-400 € per transistor for 6 transistors and 101-201 € per transistor for 1000 of them (the mask costs being absorbed by the sheer number of produced transistors). This project also needs a lot of time or more people to be completed, more than what we have at our disposal. The researchers were very interested in collaborating on such a project in the future, and considered it very strongly as a replacement for the current AIME project for the 5th year PTP Energie students at INSA Toulouse (currently a CO2 sensor), with GEI's backing and funding. -The complexity of manufacturing power transistors made us go for the strategy of choosing readily available and cheap components. +The complexity and price of manufacturing power transistors made us go for the strategy of choosing readily available and cheap components. \subsection{Replacing an IC} +Replacing the IC of a motor controller requires using traditional logic gates. This approach can be done in several methods. The AIME would easily be able to produce such a circuit at a relatively low cost, but this is neither easily accessible nor repairable. We therefore needed to use another form of logic gates. The simplest form of gates are diode gates, which use two diodes to make either an AND or OR-gate. They cannot make NOT-gates, which need a CMOS-cell (two transistors). We continued by simulating this in LTSpice XVII, based on Mr. Rocacher's circuits. This circuit ended up needing 4 AND-gates, 2 OR-gates and 1 NOT-gate ("CMOS cell" using two N-Channel MOSFETs and possibly a MOSFET driver) per phase, with additional transistors to compensate for voltage lost at the diodes, as well as one additional OR-gate. The total would be like this: -Replacing the IC of a motor controller requires using traditional logic gates. This approach can be done in several methods. The AIME would easily be able to produce such a circuit at a relatively low cost, but this is neither easily accessible nor repairable. We therefore needed to use another form of logic gates. The simplest form of gates are diode gates, which use two diodes to make either an AND or OR-gate. They cannot make NOT-gates, which need a CMOS-cell (two transistors). We continued by simulating this in LTSpice XVII, based on Mr. Rocacher's circuits. This circuit ended up needing 4 AND-gates, 2 OR-gates and 1 NOT-gate (CMOS cell) per phase, with additional transistors to compensate for voltage lost at the diodes, as well as one additional OR-gate. The total would be like this : - -\begin{table}[htbp] +\begin{table}[H][htbp] \caption{Minimum number of diodes and transistors needed} \label{tab:decompte} \centering diff --git a/Article_Scientifique/main.pdf b/Article_Scientifique/main.pdf index c4dc1b1..d4c5efa 100644 Binary files a/Article_Scientifique/main.pdf and b/Article_Scientifique/main.pdf differ diff --git a/Article_Scientifique/main.tex b/Article_Scientifique/main.tex index 4f6863a..0b35362 100644 --- a/Article_Scientifique/main.tex +++ b/Article_Scientifique/main.tex @@ -2,6 +2,7 @@ \IEEEoverridecommandlockouts % The preceding line is only needed to identify funding in the first footnote. If that is unneeded, please comment it out. \usepackage[UKenglish]{babel} +\usepackage{float} \usepackage{cite} \usepackage{amsmath,amssymb,amsfonts} \usepackage{algorithmic}