In a text, how to align text pieces together and equations together?

Question

I am preparing a LaTeX document. I am stuck in a problem where I wanted to make my document somehow look like the attached image. The text all together aligned to the left of the page, and equations aligned together at the center. I have made too many trials but failed. Any help?

Answer 1

It's not really clear what the question is asking. I'd simply type in the text with equation environments for the three equations.

If you really want to align the equations, you can use \intertext and align, but the result is not pretty.

\documentclass{article}
\usepackage{amsmath}

\usepackage{newtxtext,newtxmath} % image uses Times

\numberwithin{equation}{section}

\newcommand{\der}[2]{\frac{d#1}{d#2}}


\begin{document}

\section{No alignment}
\setcounter{equation}{57} % to emulate the picture

For the PMSM with multiple pairs of poles, the electrical speed relates
to the mechanical speed by
\begin{equation}\label{elec-mech}
\omega_e = Z_p \omega_m
\end{equation}
where $Z_p$ denotes the pair of poles of the PMSM. The rotation of motor
could be described by the following dynamic equation:
\begin{equation}\label{dynamic-m}
J_m\der{\omega_m}{t} = T_e - B_v\omega_m - T_L
\end{equation}
with $J_m$ denoting the total inertia, $B_v$ viscous friction and $T_L$
load torque. Replacing the mechanical speed $\omega_m$ with electrical
speed $\omega_e$ in~\eqref{dynamic-m} gives
\begin{equation}\label{dynamic-e}
\der{\omega_e}{t} = \frac{Z_p}{J_m}\biggl(T_e - \frac{B_v}{Z_p}\omega_e - T_L\biggr)
\end{equation}

\section{With alignment}
\setcounter{equation}{57} % to emulate the picture

For the PMSM with multiple pairs of poles, the electrical speed relates
to the mechanical speed by
\begin{align}
\omega_e &= Z_p \omega_m \label{elec-mech-A} \\
\intertext{where $Z_p$ denotes the pair of poles of the PMSM. The rotation of motor
could be described by the following dynamic equation:}
J_m\der{\omega_m}{t} &= T_e - B_v\omega_m - T_L \label{dynamic-m-A} \\
\intertext{with $J_m$ denoting the total inertia, $B_v$ viscous friction and $T_L$
load torque. Replacing the mechanical speed $\omega_m$ with electrical
speed $\omega_e$ in~\eqref{dynamic-m-A} gives}
\der{\omega_e}{t} &= \frac{Z_p}{J_m}\biggl(T_e - \frac{B_v}{Z_p}\omega_e - T_L\biggr)
  \label{dynamic-e-A}
\end{align}

\end{document}