Flyttat lite saker från metod till resultat och discussion

rapport/discussion.tex

@@ -15,6 +15,10 @@ The fact that these two ways of expressing attenuation could be mixed up was not
 
 There are infinitely many constellations to approximate the nominal value, in this project it was tried to use as few resistors as possible. This process was performed manually, since no suitable software for solving the problem was found. Thus the chosen constellations might not be optimal.
 
+
+\subsection{Desired vs implemented (simulation)}
+Parasitic effects. (real life, back to simulation)
+
 \section{The work in a wider context}
 Ethical aspects
 

rapport/methods.tex

@@ -32,7 +32,7 @@ In either case, the following tasks should be considered if there is time:
     \item Evaluate these methods.
 \end{enumerate}
 
-\section{Initial measurement of the performance of the old equipment}
+\section{Initial measurement of the old equipment}
 To decide the forthcoming of the project, the equipment first had to be checked for it's performance and if it is within the limits for use with the newer standard. Because there is no dummy loads available at this point of the project, only open load measurements could be done.
 
 With exception for Pulse 3a and Pulse 3b, all of these pulses were measured with the use of the high voltage differential probe described in \autoref{sec:hv-diff-probe}. The pulses are measured both directly on each generator connected according to \autoref{fig:manual-measurement-hv-diff} and also through the coupling network CNA~200, as depicted in \autoref{fig:manual-measurement-hv-diff-cna}. 
@@ -54,6 +54,8 @@ Additionally there needs to be some sort of measurement fixture for evaluating t
 \subsection{Alternative 1 -- Human assisted}
 The test can be performed semi-automatically by means of the existing equipment complemented by some dummy loads and, in the same manner the manual performance tests were executed. A computer could control the equipment and compare the results, by the assist of a human that can make the necessary reconnections between the tests.
 
+\todo[försök hitta källor på följande påståenden]
+
 The main advantage of this is that it would probably require the least amount of time for development of the automation software. It also doesn't need any extra hardware except from the dummy loads needed to do the verification.
 
 The biggest disadvantage is that it would be very cumbersome to perform and also very prone to human error. If the verification list is studied carefully one can minimise is to five reconnections after the initial connections are made, for example in the following order: No load, \SI{2}{\ohm}, \SI{10}{\ohm}, \SI{50}{\ohm} low frequency, \SI{50}{\ohm} high frequency, \SI{1}{\kilo\ohm} high frequency.
@@ -63,6 +65,8 @@ To accurately measure Pulse 3a and Pulse 3b, the probes should be attached as cl
 
 The dummy loads for all pulses, but Pulse 3a and Pulse 3b, will need to be put in a separate enclosure because of the power dissipation needed. The proposed architecture is depicted in \autoref{fig:automatic-rig-1}.
 
+\todo[Fint schema här]
+
 The advantage of this method is that the verification can be performed fully automatically, except for the initial connection of the test rig. This also uses the commercially created attenuators that are already available.
 
 The disadvantage to this setup is that the fixture needs to be designed, making the development costs greater. The fixture that attaches to the generator will expose high voltage on its measurement connectors, making it a safety hazard.
@@ -70,6 +74,8 @@ The disadvantage to this setup is that the fixture needs to be designed, making
 \subsection{Alternative 3 -- Fully automatic rig with embedded attenuators}
 To cope with the high voltage exposure, of alternative 1, the high frequency attenuators can be embedded inside the switching fixture, removing the need for high-voltage connectors. \autoref{fig:automatic-rig-2}.
 
+\todo[Fint schema här]
+
 The advantage of this, on top of the advantages of alternative 2, is that there is no longer need for external attenuators and that the connectors will no longer expose high voltage.
 
 The disadvantage of this would be that the embedded attenuators might prove difficult to design. They need to be accurate up to high frequencies, be tolerable to high voltage, dissipate the power necessary and also be electrically safe.
@@ -112,11 +118,11 @@ The voltages used in the calculations are specified in \autoref{tab:dummy_load_w
 \subsection{PCB}
 Since the dummy loads consists of many discrete resistors, it was decided to design a PCB to connect them. This also gives good mechanical control of the resistors and the possibility to design for good heat dissipation.
 
-Because of the high voltages present on the board it was decided to keep a minimum of 3mm functional isolation creepage distance between all traces on the board, in line with the EN 60664-1 standard \cite{en_60664_1}. The board was perforated to allow for better air flow past the resistors. The mounting holes for the card was placed in a \SI[product-units=single]{105 x 105}{\milli\meter} square, allowing for a \SI{120}{\milli\meter} fan to be mounted on top of the card using mounting hardware.
+Because of the high voltages present on the board it was decided to keep a minimum of 3mm functional isolation creepage distance between all traces on the board, in line with the EN 60664-1 standard \cite{en_60664_1}. The board was perforated to allow for better air flow past the resistors, improoving the heat dissipation. The mounting holes for the card was placed in a \SI[product-units=single]{105 x 105}{\milli\meter} square, allowing for a \SI{120}{\milli\meter} fan to be mounted on top of the card using mounting hardware.
 
-A two layer board was chosen, and all of the traces were mirrored on both layers to get as much conductive cross sectional area as possible, and thus lowering the resistance and voltage drop in the traces. The PCB was ordered with \SI{60}{\micro\meter} thick copper layer to further extend the cross sectional areas. The width of the traces for the \SI{2}{\ohm} load was chosen as wide as possible, since the pulse currents are the highest for this one. \todo[kolla så detta är sant]
+A two layer board was chosen, and all of the traces were mirrored on both layers to get as much conductive cross sectional area as possible, and thus lowering the resistance and power dissipation in the traces. The PCB was ordered with \SI{60}{\micro\meter} thick copper layer to further extend the cross sectional areas. The width of the traces for the \SI{2}{\ohm} load was chosen as wide as possible without violating the functional isolation distance.
 
-Both the circuit schematic and layout editing of the board were performed in the free EDA tool KiCad. Before ordering the PCB, it was printed in 1:1 scale and attached to a piece of card board. The card board was then populated with the components already at hand to ensure that the footprints are correct and that the placement of the components makes sense and does not collide.
+Both the circuit schematic and layout editing of the board were performed in the free EDA, Electronic Design Automation, tool KiCad. Before ordering the PCB, it was printed in 1:1 scale and attached to a piece of card board. The card board was then populated with the components already at hand to ensure that the footprints are correct and that the placement of the components makes sense and does not collide.
 
 \todo[Fin bild på designprocess av PCB, säkerhetsavstånd etc]
 
@@ -125,11 +131,11 @@ When the dummy loads had been assembled, their resistances were determined using
 
 
 \section{Design of the switching fixture and embedded attenuators}
-The chosen implementation requires a fixture that switches and attenuators, which purpose is to switch the pulse to the desired attenuator or to the dummy load. It must be able to handle the momentary pulse energies and voltages.
+The chosen implementation requires a fixture that switches and attenuators, which purpose is to switch the pulse to the desired attenuator or to the dummy load. It must be able to handle the momentary pulse energies and voltages and should not distort the pulse.
 
 \subsection{Attenuators}
 
-The target attenuation was decided to mimic the commercial attenuators, described in \autoref{theory_pat_attenuators}, where the \SI{50}{\ohm} has an attenuation of \SI{54.7}{\deci\bel} and the \SI{1000}{\ohm} has an attenuation of \SI{60.1}{\deci\bel}.
+The target attenuation was decided to mimic the commercial attenuators, described in \autoref{theory_pat_attenuators}, where the \SI{50}{\ohm} attenuator has an attenuation of \SI{54.7}{\deci\bel} and the \SI{1000}{\ohm} attenuator has an attenuation of \SI{60.1}{\deci\bel}.
 
 Only Pulse 3a and Pulse 3b were considered when designing these attenuators, since all other test pulses will be coupled to the separate dummy load.
 
@@ -137,21 +143,13 @@ The two attenuators were implemented as $\Pi$-attenuators. The values for the at
 
 By dividing the attenuators into two $\Pi$-networks, the series resistance required will get a bit lower compared to realising them in a single $\Pi$-link. This is desirable because the parasitic capacitance, which is dependant of the resistor package and not the resistance, will influence a high value resistor at lower frequencies that it would on a low value resistor, as explained in \autoref{theory_parasitic_properties}.
 
-A resistor with high pulse power and high voltage properties had to be chosen. Vishay's CRCW-HP series fitted this description and were easily available.
+A resistor with high pulse power and high voltage properties had to be chosen.
 
-When the ideal resistor values had been derived, the maximum power dissipation and maximum voltage for each resistor was retrieved by simulation. Based on this, the minimum number of discrete resistors needed to withstand the pulse power was calculated. In the same way the minimum number of series resistors to withstand the maximum pulse voltage was calculated. These numbers are presented in \autoref{tab:methods_attenuator_constellations}.
+When the ideal resistor values had been derived, the energy over time and maximum voltage for each resistor was retrieved by simulation, as seen in \autoref{fig:ideal_attenuator_maximum_power}. Based on this, the minimum number of discrete resistors needed to withstand the pulse energy was calculated. In the same way the minimum number of series resistors to withstand the maximum pulse voltage was calculated. These numbers are presented in \autoref{tab:methods_attenuator_constellations}.
 
 With the minimum number of discrete resistors needed for each ideal resistor known, a constellation of available resistor values was constructed to approximate the nominal value with as few resistors as possible.
 
-The \SI{54.7}{\deci\bel} attenuator was divided into two \SI{27.35}{\deci\bel} $\Pi$ attenuator links. When the closest values for the resistors had been chosen, using \SI{56}{\ohm} as shunt resistors and \SI{56}{\ohm} in series, the final attenuation was \SI{53.66}{\deci\bel} for the two links according to the simulation, seen in \autoref{fig:ltspice-att-ideal-54}. The input and output resistance was 
-
-Nice graphs.
-
-The \SI{60.1}{\deci\bel} attenuator was divided into one \SI{27.35}{\deci\bel} $\Pi$ attenuator links \SI{32.75}{\deci\bel}. When the closest values for the resistors had been chosen, using \SI{56}{\ohm} as shunt resistors and \SI{56}{\ohm} in series, the final attenuation was \SI{53.66}{\deci\bel} for the two links according to the simulation, seen in \autoref{fig:ltspice-att-ideal-54}. The input and output resistance was 
-\autoref{discussion_attenuators}
-
-\subsection{Desired vs implemented (simulation)}
-Parasitic effects. (real life, back to simulation) \todo[kanske borde ligga under results?]
+When the number of resistors and its constellations was decided, all of the discrete ideal resistors were replaced with non-ideal models in the simulation software. Then the attenuators were checked in frequency domain, as well as how the pulses were affected in time domain.
 
 \subsection{PCB}
 \todo[Fin bild på designprocess av PVB, säkerhetsavstånd etc]

rapport/notation.tex

@@ -14,3 +14,11 @@
     \abbrDUT\index{DUT@\abbrDUT!abbreviation} & Device Under Test \\
   \end{notationtabular}
 \end{notation}
+
+\todo[Lägg till följande]
+
+EDA
+
+
+
+

rapport/results.tex

@@ -90,6 +90,15 @@ The values measured are, presented in \autoref{tab:four-wire-result}, are well w
 \section{Design of the switching fixture}
 
 
+ Vishay's CRCW-HP series fitted this description and were easily available.
+ 
+ The \SI{54.7}{\deci\bel} attenuator was divided into two \SI{27.35}{\deci\bel} $\Pi$ attenuator links. When the closest values for the resistors had been chosen, using \SI{56}{\ohm} as shunt resistors and \SI{56}{\ohm} in series, the final attenuation was \SI{53.66}{\deci\bel} for the two links according to the simulation, seen in \autoref{fig:ltspice-att-ideal-54}. The input and output resistance was 
+
+Nice graphs.
+
+The \SI{60.1}{\deci\bel} attenuator was divided into one \SI{27.35}{\deci\bel} $\Pi$ attenuator links \SI{32.75}{\deci\bel}. When the closest values for the resistors had been chosen, using \SI{56}{\ohm} as shunt resistors and \SI{56}{\ohm} in series, the final attenuation was \SI{53.66}{\deci\bel} for the two links according to the simulation, seen in \autoref{fig:ltspice-att-ideal-54}. The input and output resistance was 
+\autoref{discussion_attenuators}
+
 \section{Measurement}
 
 \section{Analysis}

rapport/theory.tex

@@ -70,7 +70,7 @@ The Load dump Test A simulates the event of disconnecting a battery that is char
 
 This pulse has the longest duration, $t_d$, of all the test pulses. It also has the lowest internal resistance. These properties makes it capable of transferring high energies into a low impedance DUT or dummy load.
 
-Prior to 2011, the Load dump Test A was part of the ISO~7637-2 standard under the name \emph{Test pulse 5a}. The surge voltage $U_s$ was in the older standard, ISO~7637-2:2004, defined as the voltage between DC offset voltage $U_A$ and the maximum voltage. In the newer standard ,ISO~16750-2:2012, $U_s$ is defined as the absolute peak voltage. Only the former definition is used in this paper, $U_s = \hat{U} - U_A$.
+Prior to 2011, the Load dump Test A was part of the ISO~7637-2 standard under the name \emph{Test pulse 5a}. The surge voltage $U_s$ was in the older standard, \mbox{ISO~7637-2:2004}, defined as the voltage between the DC offset voltage $U_A$ and the maximum voltage. In the newer standard, \mbox{ISO~16750-2:2012}, $U_s$ is defined as the absolute peak voltage. Only the former definition is used in this paper, $U_s = \hat{U} - U_A$.
 
 \todo[Två bilder, en på kurvan och en på kretsen som orsakar den. En tabell med parametervärden.]