Direct torque control of AC drive

The direct torque control (DTC) method and the voltage vectors. Adapted from the figure in the handout by Jorma Luomi (2009).

Edit and compile if you like:

% The direct torque control (DTC) method and the voltage vectors.
% Adapted from the figure in the handout by Jorma Luomi (2009).
% Author: Erno Pentzin (2013)
\documentclass{article}
\usepackage{tikz}
\usepackage[active,tightpage]{preview}
\PreviewEnvironment{tikzpicture}
\setlength\PreviewBorder{10pt}%
\usetikzlibrary{decorations.markings}
\begin{document}

\begin{tikzpicture}[
	path/.style={
		->,
		>=stealth,
	},
	decoration={
		markings,
		mark=at position 0.59cm*1 with {\arrow[black]{stealth}},
		mark=at position 0.59cm*2 with {\arrow[black]{stealth}},
		mark=at position 0.59cm*3 with {\arrow[black]{stealth}},
		mark=at position 0.59cm*4 with {\draw (0,0) circle;},
		mark=at position 0.6cm*5-0.01cm with {\arrow[black]{stealth}},
		mark=at position 6mm*6-0.1 with {\arrow[black]{stealth}},
		mark=at position 7*6mm-0.1 with {\arrow[black]{stealth}},
		mark=at position 8*6mm-0.1 with {\draw (0,0) circle;},
		mark=at position 9*6mm-0.1 with {\draw (0,0) circle;},
		mark=at position 10*6mm-0.1 with {\draw (0,0) circle;},
		mark=at position 11*6mm-0.1 with {\arrow[black]{stealth}},
		mark=at position 12*6mm-0.1 with {\arrow[black]{stealth}},
		mark=at position 13*6mm-0.1 with {\arrow[black]{stealth}},
		mark=at position 14*6mm-0.1 with {\draw (0,0) circle;},
		mark=at position 15*6mm-0.1 with {\arrow[black]{stealth}},
		mark=at position 16*6mm-0.1 with {\arrow[black]{stealth}},
		mark=at position 17*6mm-0.1 with {\arrow[black]{stealth}},
		mark=at position 18*6mm-0.1 with {\arrow[black]{stealth}},
		mark=at position 19*6mm-0.1 with {\draw (0,0) circle;},
		mark=at position 20*6mm-0.1 with {\arrow[black]{stealth}},
		mark=at position 21*6mm-0.1 with {\arrow[black]{stealth}},
		mark=at position 22*6mm-0.1 with {\arrow[black]{stealth}},
		mark=at position 23*6mm-0.1 with {\draw (0,0) circle;},
	},
	radius=1pt,
]

% outer circle
\draw[dashed] (4,0) arc (0:180:4);
\draw[dashed] (4,0) arc (0:-30:4);
\draw[dashed] (-4,0) arc (180:210:4);

% inner circle
\draw[dashed] (3.5,0) arc (0:180:3.5);
\draw[dashed] (3.5,0) arc (0:-30:3.5);
\draw[dashed] (-3.5,0) arc (180:210:4);

% voltage vectors
\foreach \x in {0,60,120,180,240,300}
	\draw[->,thick] (0,0) to (\x:1);

% labels
\foreach \x/\xtext in {0/1,60/2,120/3,180/4,240/5,300/6}
	\draw (\x:1.3) node {$\underline{u}_\xtext$};

% sector dividers
\foreach \x in {30,90,150,210,270,330}
	\draw[dotted] (0,0) -- (\x:2);

% path of the stator flux
\draw[path] (0,0) -- (20:3.5); % initial flux
\draw[path,postaction=decorate] (20:3.5) -- ++(60:0.6) --
	++(120:0.6) -- ++(180:0.6) -- ++(120:0.6*2) --
	++(180:0.6) -- ++(120:0.6) -- ++(180:0.6*4) --
	++(240:0.6) -- ++(180:0.6) -- ++(240:0.6*2) --
	++(180:0.6) -- ++(240:0.6) -- ++(300:0.6) --
	++(240:0.6*2) -- ++(300:0.6) -- ++(240:0.6) --
	++(300:0.6*2);
\end{tikzpicture}

\end{document}