# In IEEEtran, why does fontspec package automatically change the font type once loaded?

By default, the body text font for IEEEtran document class is like this:

When I load fontspec package, the font type changes:

What is the name of the new font? How can I retain the original IEEEtran main body font when loading fontspec? And how can I change it on demand to any type I desire (such as Bookman)?

\documentclass[]{IEEEtran}

\usepackage[T1]{fontenc}
\usepackage{fontspec}
\usepackage[]{mathtools}
\usepackage{bigfoot}

\begin{document}

\title{Development of a Generalized PV Model in MATLAB/Simulink Using Datasheet Values}

% Authors names and emails
\author{Al-Motasem I. Aldaoudeyeh
% Information about the authors (in the margins)
\thanks{Al-Motasem I. Aldaoudeyeh is with the Department of Electrical and Computer Engineering, North Dakota State University, Fargo, ND, 58102 USA. email: almotasem.aldaoudeye@ndsu.edu}
}

% Make titles available (this command goes here for IEEE style)
\maketitle
% This command is important for both title and author names and information. Without it, none of the previously mentioned appears on the text.

\begin{abstract}

This paper proposes an improved single-diode modeling approach for PV modules suitable for a broad range of the PV technologies available today, including modules on tandem cell structures. After establishing the model (which has an overall of seven parameters), the paper devises a methodology to estimate its parameters using Standard Test Conditions (STC) data, Nominal Operating Cell Temperature (NOCT) data, and temperature coefficients values as provided in most manufacturers' datasheets. Simulation results and their comparison with a previous work show a very accurate prediction of critical points in the current-voltage characteristics curve. The precise prediction happens for both STC and NOCT conditions and the error in predicting maximum power point lies within $1\%$ limit, and the error in its corresponding voltage and current is almost always within $2\%$ limit. Further, for both maximum power point and open-circuit voltage, the statistical variance around manufacturer measurements due to temperature changes is demonstrated to be low for five various module technologies.

\end{abstract}

\begin{IEEEkeywords}

temperature coefficients, thin film cells, tandem cells, photovoltaic arrays, I-V curves, evolutionary algorithms, parameterization

\end{IEEEkeywords}

% ===== End of IEEE Format =====
% =========================================================
% =========================================================
%\end{comment}

\section{Introduction}
\label{section:introduction}

\textit{Solar photovoltaics (PV)} is one of the fastest growing power industries in the world thanks to its appealing merits,like the widespread accessibility to natural solar resources, high reliability, easy integration into buildings and structures, fast installation, modularity, and predictable annual output. Between 2000 and 2013, total PV production has been experiencing annual growth rates between $40\%$ and $90\%$ reaching an overall increase of two orders of magnitude. By 2010, thin film PV technologies accounted for around $13\%$ of the PV market share. The values were distributed as follows: $5\%$ for a-Si, for $2\%$ Copper indium di-selenide/Copper indium gallium selenide (CIS/CIGS), and $6\%$ for Cadmium Telluride / Cadmium sulfide (CdTe/CdS). However, most of the efforts in modeling PV modules focus on modules on crystalline silicon (c-Si) cells technology which exhibits characteristics closer to ideal cells. Thus, it is necessary to develop generalized models suitable for different types of technologies \footnote{this is a footnote test}.

\end{document}

• Are you using xelatex or lualatex to typeset the file? If not don’t load fontspec. If so don’t load fontenc. Apr 20, 2018 at 17:21
• do not use \usepackage[T1]{fontenc} with fontspec (or more generally do not use that with xelatex or lualatex) Apr 20, 2018 at 20:05

The IEEEtran class has

% The IEEE uses Times Roman font, so we'll default to Times.
% These three commands make up the entire times.sty package.
\renewcommand{\sfdefault}{phv}
\renewcommand{\rmdefault}{ptm}
\renewcommand{\ttdefault}{pcr}


Doing \renewcommand{\rmdefault}{ptm} for typesetting in Times has been deprecated for about 20 years, but apparently this is not a sufficient timeframe for realizing it. For instance, math formulas will be typeset in Computer Modern with a very bad final effect, because the two fonts are visually incompatible.

You can get Times with fontspec, though: add

\setmainfont{TeX Gyre Termes}


to your document preamble. Math will still be in Computer Modern, but apparently the people at IEEE is satisfied with bad typesetting.

If you want better typesetting, add

\usepackage{newtxmath}


Example:

\documentclass[]{IEEEtran}

\usepackage{mathtools}
\usepackage{newtxmath}
\usepackage[no-math]{fontspec}

\setmainfont{TeX Gyre Termes}

\begin{document}

\title{Development of a Generalized PV Model

% Authors names and emails
\author{Al-Motasem I. Aldaoudeyeh%
% Information about the authors (in the margins)
\thanks{Al-Motasem I. Aldaoudeyeh is with the Department
of Electrical and Computer Engineering, North Dakota State
University, Fargo, ND, 58102 USA. email: almotasem.aldaoudeye@ndsu.edu%
}%
}

% Make titles available (this command goes here for IEEE style)
\maketitle

\begin{abstract}
This paper proposes an improved single-diode modeling
approach for PV modules suitable for a broad range of
the PV technologies available today, including modules
on tandem cell structures. After establishing the model
(which has an overall of seven parameters), the paper
devises a methodology to estimate its parameters using
Standard Test Conditions (STC) data, Nominal Operating
Cell Temperature (NOCT) data, and temperature coefficients
values as provided in most manufacturers' datasheets.
Simulation results and their comparison with a previous
work show a very accurate prediction of critical points
in the current-voltage characteristics curve. The precise
prediction happens for both STC and NOCT conditions and
the error in predicting maximum power point lies within
$1\%$~limit, and the error in its corresponding voltage
and current is almost always within $2\%$ limit. Further,
for both maximum power point and open-circuit voltage,
the statistical variance around manufacturer measurements
due to temperature changes is demonstrated to be low for
five various module technologies.
\end{abstract}

\begin{IEEEkeywords}
temperature coefficients, thin film cells, tandem cells,
photovoltaic arrays, I-V curves, evolutionary algorithms,
parameterization
\end{IEEEkeywords}

\section{Introduction}
\label{section:introduction}

Some math just to see what happens: $a+2b=3c$.

\textit{Solar photovoltaics (PV)} is one of the fastest
growing power industries in the world thanks to its
to natural solar resources, high reliability, easy
integration into buildings and structures, fast installation,
modularity, and predictable annual output. Between 2000~and~2013,
total PV production has been experiencing annual growth rates
between $40\%$ and $90\%$ reaching an overall increase of two
orders of magnitude. By 2010, thin film PV technologies accounted
for around $13\%$ of the PV market share. The values were
distributed as follows: $5\%$ for a-Si, for $2\%$ Copper
indium di-selenide/Copper indium gallium selenide (CIS/CIGS),
and $6\%$ for Cadmium Telluride / Cadmium sulfide (CdTe/CdS).
However, most of the efforts in modeling PV modules focus on
modules on crystalline silicon (c-Si) cells technology which
exhibits characteristics closer to ideal cells. Thus, it is
necessary to develop generalized models suitable for different
types of technologies\footnote{this is a footnote test}.

\end{document}


• Thanks! A small follow up question: How to match the default IEEE math font in case I use \usepackage{fontspec,mathtools,unicode-math}\setmainfont{TeX Gyre Termes} ? Or is the default math font provided by unicode-math aready the right one in this case? Apr 13, 2019 at 8:44
• @bonanza The default math font would be Latin Modern Math. It is right to the eyes of IEEE people, not to mine. Apr 13, 2019 at 8:45