\documentclass[]{jsbook}
\usepackage{psfrag,graphicx,color,defvar2,eclepsf,othermac}
\pagestyle{empty}
\begin{document}
\begin{center}
 \begin{minipage}[c]{0.3\columnwidth}
   \begin{center}
    \psfrag{Vt1}[][]{$V_{vm1}$(p.u.)}
    \psfrag{Vt2}[][]{$V_{vm2}$(p.u.)}
    \includegraphics[width=1\textwidth,clip]{eps1/bset6209-ra=0.7-M2=9.eps}
    \par
    \medskip
    \par
     (a) $M_2$ = 9 s
 \end{center} 
 \end{minipage}
%
%
 \begin{minipage}[c]{0.3\columnwidth}
   \begin{center}
    \psfrag{Vt1}[][]{$V_{vm1}$(p.u.)}
    \psfrag{Vt2}[][]{$V_{vm2}$(p.u.)}
    \includegraphics[width=1\textwidth,clip]{eps1/bset6209-ra=0.7-M2=10.eps}
    \par
    \medskip
    \par
     (b) $M_2$ = 10 s
 \end{center} 
 \end{minipage}
%
 \begin{minipage}[c]{0.3\columnwidth}
   \begin{center}
    \psfrag{Vt1}[][]{$V_{vm1}$(p.u.)}
    \psfrag{Vt2}[][]{$V_{vm2}$(p.u.)}
    \includegraphics[width=1\textwidth,clip]{eps1/bset6209-ra=0.7-M2=11.eps}
    \par
    \medskip
    \par
     (c) $M_2$ = 11 s
 \end{center} 
 \end{minipage}

\medskip
\end{center}

\end{document}
