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wallscheid committed Nov 24, 2024
2 parents c0b338f + 1cfab43 commit 1dd1449
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30 changes: 30 additions & 0 deletions exercise/fig/ex04/Fig_currentI1PeriodTask1.tex
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\begin{solutionfigure}[htb]
\centering
\begin{tikzpicture}
\begin{axis}[
width=7cm, height=4.5cm,
grid=both,
major grid style={line width=.2pt,draw=gray!50},
minor grid style={line width=.1pt,draw=gray!20},
xlabel={$t$ / µs},
ylabel={$i_\mathrm{1}(t)$ / A},
% title={$i_\mathrm{L}$ for minimum output power},
xmin=0, xmax=40,
ymin=-0, ymax=2,
xtick={0, 20, 40},
ytick={0, 1,2},
]
% Einschaltverhalten graph
\addplot[
thick,
mark=none,
color=black,
] coordinates {
(0,0) (2.5, 1.257) (2.5, 0) (20, 0)(22.5, 1.257) (22.5, 0) (40, 0)
};
\end{axis}
\end{tikzpicture}
\hspace{1cm} % Abstand zwischen den beiden Diagrammen
\caption{Display of the current $i_\mathrm{1}(t)$.}
\label{fig:currentSecondarySideTask1}
\end{solutionfigure}
30 changes: 30 additions & 0 deletions exercise/fig/ex04/Fig_currentI2PeriodTask1.tex
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\begin{solutionfigure}[htb]
\centering
\begin{tikzpicture}
\begin{axis}[
width=7cm, height=4.5cm,
grid=both,
major grid style={line width=.2pt,draw=gray!50},
minor grid style={line width=.1pt,draw=gray!20},
xlabel={$t$ / µs},
ylabel={$i_\mathrm{2}(t)$ / A},
% title={$i_\mathrm{L}$ for minimum output power},
xmin=0, xmax=40,
ymin=-0, ymax=8,
xtick={0, 20, 40},
ytick={0, 2,4,6,8},
]
% Einschaltverhalten graph
\addplot[
thick,
mark=none,
color=black,
] coordinates {
(0,0) (2.5, 0) (2.5, 6.28) (12.7, 0) (22.5, 0)(22.5, 6.28) (32.7, 0) (40, 0)
};
\end{axis}
\end{tikzpicture}
\hspace{1cm} % Abstand zwischen den beiden Diagrammen
\caption{Display of the current $i_\mathrm{2}(t)$.}
\label{fig:currentSecondarySideTask1}
\end{solutionfigure}
2 changes: 1 addition & 1 deletion exercise/fig/ex04/Fig_voltageTransistorPeriodTask1.tex
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Expand Up @@ -8,7 +8,7 @@
minor grid style={line width=.1pt,draw=gray!20},
xlabel={$t$ / µs},
ylabel={$u_\mathrm{T}(t)$ / V},
title={$i_\mathrm{L}$ for minimum output power},
% title={$i_\mathrm{L}$ for minimum output power},
xmin=0, xmax=40,
ymin=-100, ymax=600,
xtick={0, 20, 40},
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30 changes: 30 additions & 0 deletions exercise/fig/ex04/Fig_voltageUsPeriodTask1.tex
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@@ -0,0 +1,30 @@
\begin{solutionfigure}[htb]
\centering
\begin{tikzpicture}
\begin{axis}[
width=7cm, height=4.5cm,
grid=both,
major grid style={line width=.2pt,draw=gray!50},
minor grid style={line width=.1pt,draw=gray!20},
xlabel={$t$ / µs},
ylabel={$u_\mathrm{S}(t)$ / V},
% title={$i_\mathrm{L}$ for minimum output power},
xmin=0, xmax=40,
ymin=-100, ymax=60,
xtick={0, 20, 40},
ytick={-100, -50, 0, 50},
]
% Einschaltverhalten graph
\addplot[
thick,
mark=none,
color=black,
] coordinates {
(0,0) (0,-76.4) (2.5,-76.4) (2.5, 15) (12.7, 15) (12.7, 0) (20, 0) (20, 0) (20, -76.4) (22.5, -76.4)(22.5, 15) (32.7, 15) (32.7, 0) (40, 0)
};
\end{axis}
\end{tikzpicture}
\hspace{1cm} % Abstand zwischen den beiden Diagrammen
\caption{Display of the voltage $u_\mathrm{S}(t)$.}
\label{fig:voltageSecondarySideTask1}
\end{solutionfigure}
2 changes: 1 addition & 1 deletion exercise/main.tex
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@@ -1,7 +1,7 @@
\documentclass[solution]{../course_template/exerciseClass}
\title{Power Electronics}

\includeonly{tex/exercise03}
\includeonly{tex/exercise04}

\begin{document}
\include{tex/exercise01}
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61 changes: 48 additions & 13 deletions exercise/tex/exercise04.tex
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Expand Up @@ -29,28 +29,29 @@
\subtask{The input voltage is $U_\mathrm{1}=\SI{760}{\volt}$ at rated power at the output. What is the peak value $\hat I_\mathrm{1}$ of the primary current $i_\mathrm{1}$? What is the peak value $\hat I_\mathrm{2}$ of the secundary current $i_\mathrm{2}$? Calculate the duty cycle of the transistor for this operating case.}

\begin{solutionblock}
To determine the current $\hat I_\mathrm{1}$, the equation for determining the output power \eqref{eq:output power ex04} is primarily used. The unknown energy of the inductance of the primary winding side \eqref{eq:energy primary inductance ex04} is inserted into this equation.
\begin{equation}
P_\mathrm{2} = W_\mathrm{L} f_\mathrm{p}
P_\mathrm{2} = W_\mathrm{L} f_\mathrm{p}, \label{eq:output power ex04}
\end{equation}

\begin{equation}
W_\mathrm{L} = \frac{1}{2}L_\mathrm{1}\hat I_\mathrm{1}^2
W_\mathrm{L} = \frac{1}{2}L_\mathrm{1}\hat I_\mathrm{1}^2. \label{eq:energy primary inductance ex04}
\end{equation}

After substituting, you get this equation:
\begin{equation}
\hat I_\mathrm{1} = \sqrt{\frac{2P_\mathrm{2}}{L_\mathrm{1}f_\mathrm{p}}}= \sqrt{\frac{2\cdot\SI{30}{\watt}}{\SI{760}{\micro\henry}\cdot\SI{50}{\kilo\hertz}}}=\SI{1.257}{\ampere}
P_\mathrm{2} = \frac{1}{2}L_\mathrm{1}\hat I_\mathrm{1}^2 f_\mathrm{p}.\label{eq:output power with IDach ex04}
\end{equation}

\eqref{eq:output power with IDach ex04} must be converted to $\hat I_\mathrm{1}$:
\begin{equation}
\hat I_\mathrm{1} = \hat I_\mathrm{2}
\hat I_\mathrm{1} = \sqrt{\frac{2P_\mathrm{2}}{L_\mathrm{1}f_\mathrm{p}}}= \sqrt{\frac{2\cdot\SI{30}{\watt}}{\SI{760}{\micro\henry}\cdot\SI{50}{\kilo\hertz}}}=\SI{1.257}{\ampere}.
\end{equation}

In an ideal transformer, the energy is maintained between the primary and secondary sides (neglecting losses). To determine the peak value $\hat I_\mathrm{2}$, the known current $\hat I_\mathrm{1}$ and the number of turns of the primary and secondary side can be used. Because of this background, the following equation can be used:
\begin{equation}
\hat I_\mathrm{2} = \hat I_\mathrm{1} \frac{N_\mathrm{1}}{N_\mathrm{2}} = \SI{1.257}{\ampere} \cdot \frac{60}{12} = \SI{6.28}{\ampere}
\hat I_\mathrm{2} = \hat I_\mathrm{1} \frac{N_\mathrm{1}}{N_\mathrm{2}} = \SI{1.257}{\ampere} \cdot \frac{60}{12} = \SI{6.28}{\ampere}.
\end{equation}
Because of CCM the duty cycle $D$ is expressed .....
Because of CCM the duty cycle $D$ is expressed as
\begin{equation}
\frac{U_2}{U_1} = \frac{D^2}{2} \frac{\Delta i_\mathrm{m,max}}{\overline{i}_2} \label{eq:Duty cycle ex04}
\frac{U_2}{U_1} = \frac{D^2}{2} \frac{\Delta i_\mathrm{m,max}}{\overline{i}_2}. \label{eq:Duty cycle ex04}
\end{equation}
Because of the unknown $\Delta i_\mathrm{m,max}$ this value has to be calculate first as
\begin{equation}
Expand All @@ -67,12 +68,46 @@
\subtask{The input voltage is $U_\mathrm{1}=\SI{382}{\volt}$ at nominal load. Calculate and sketch the following voltage and current curves for this operating case over one cycle period: $u_\mathrm{T}(t), u_\mathrm{s}(t), i_\mathrm{2}(t), i_\mathrm{1}(t)$ (Note: corresponds to the switch-on time of the transistor).}

\input{./fig/ex04/Fig_voltageTransistorPeriodTask1.tex}

\input{./fig/ex04/Fig_voltageUsPeriodTask1.tex}
\input{./fig/ex04/Fig_currentI2PeriodTask1.tex}
\input{./fig/ex04/Fig_currentI1PeriodTask1.tex}

\subtask{The input voltage is $U_\mathrm{1}=\SI{382}{\volt}$ at nominal load. Determine the mean value $\overline i_\mathrm{T}$ and the effective value of the current $i_\mathrm{T, rms}$ through the transistor. Determine the mean value $\overline i_\mathrm{D}$ and the effective value of the current $i_\mathrm{D, rms}$ through the diode. What is the maximum reverse voltage load $u_\mathrm{T, max}$ of the transistor? What is the maximum reverse voltage load $u_\mathrm{D, max}$ of the diode?}
\begin{solutionblock}
\begin{equation}
\overline{i}_\mathrm{T} = \frac{1}{T_\mathrm{S}}\frac{1}{2}\hat I_\mathrm{1}T_\mathrm{on}=\frac{1}{\SI{20}{\micro\s}}\cdot\frac{1}{2}\SI{1.257}{\ampere}\cdot\SI{2.5}{\micro\s}=\SI{78.53}{\milli\ampere}
\end{equation}
\begin{equation}
i_\mathrm{T,rms}^2=\frac{1}{T_\mathrm{S}} \int_{0}^{T_\mathrm{S}} i_\mathrm{1}^2(t) \,dt \ = \frac{1}{T_\mathrm{S}}\int_{0}^{T_\mathrm{on}} \frac{\hat I_\mathrm{1}^2t^2}{T_\mathrm{on}^2} \,dt \ = \frac{\hat I_\mathrm{1}^2T_\mathrm{on}}{3T_\mathrm{on}}
\end{equation}
\begin{equation}
i_\mathrm{T,rms} = \hat I_\mathrm{1} \sqrt{\frac{T_\mathrm{on}}{3T_\mathrm{S}}}= \SI{1.257}{\ampere}\cdot\sqrt{\frac{\SI{2.5}{\micro\s}}{3\cdot\SI{20}{\micro\s}}}= \SI{256.58}{\milli\ampere}
\end{equation}

\begin{equation}
\overline{i}_\mathrm{D} = \frac{1}{T_\mathrm{S}}\frac{1}{2}\hat I_\mathrm{2}T_\mathrm{off}=\frac{1}{\SI{20}{\micro\s}}\cdot\frac{1}{2}\SI{6.28}{\ampere}\cdot\SI{12.7}{\micro\s}=\SI{2}{\ampere}
\end{equation}

\begin{equation}
i_\mathrm{D,rms} = \hat I_\mathrm{2} \sqrt{\frac{T_\mathrm{off}}{3T_\mathrm{S}}}= \SI{6.28}{\ampere}\cdot\sqrt{\frac{\SI{12.7}{\micro\s}}{3\cdot\SI{20}{\micro\s}}}= \SI{2.89}{\milli\ampere}
\end{equation}

\begin{equation}
u_\mathrm{T,max} = U_\mathrm{1} + \frac{N_\mathrm{1}}{N_\mathrm{2}}U_\mathrm{2}= \SI{382}{\volt}+\frac{60}{12}\cdot\SI{15}{\volt}= \SI{457}{\volt}
\end{equation}

\begin{equation}
u_\mathrm{D,max} = U_\mathrm{2} + \frac{N_\mathrm{2}}{N_\mathrm{1}}U_\mathrm{1}= \SI{15}{\volt}+\frac{12}{60}\cdot\SI{382}{\volt}= \SI{91.4}{\volt}
\end{equation}

\subtask{The input voltage is $U_\mathrm{1}=\SI{382}{\volt}$ at nominal load. Determine the mean value $\overline i_\mathrm{T}$ and the effective value of the current $i_\mathrm{T, rms}$ through the transistor. Determine the mean value $\overline i_\mathrm{D}$ and the effective value of the current $i_\mathrm{D, rms}$ through the diode. What is the maximum reverse voltage load $u_\mathrm{T, max}$ of the transistor? What is the maximum reverse voltage load $u_\mathrm{D, max}$ of the diode? Calculate the fluctuation range $\Delta i_\mathrm{C, pp}$ of the current $i_\mathrm{C}$ in the output capacitor.}
\end{solutionblock}

\subtask{The input voltage is $U_\mathrm{1}=\SI{382}{\volt}$ at nominal load.How much energy is transferred from the input to the output per switching period $\Delta E$ and what is the resulting average power? What happens if there is no ideal voltage source on the output side but an unloaded capacitor and the circuit is operated with $D>0$?}
\subtask{The input voltage is $U_\mathrm{1}=\SI{382}{\volt}$ at nominal load. How much energy is transferred from the input to the output per switching period $\Delta E$ and what is the resulting average power? What happens if there is no ideal voltage source on the output side but an unloaded capacitor and the circuit is operated with $D>0$?}

\begin{solutionblock}

At each switching interval, energy is pushed into the capacitor, the voltage of which continues to rise until a component fails due to a lack of dielectric strength.
\end{solutionblock}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Task 2: Forward converter with asymmetric half-bridge
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