Simulation Model of a SiC Power MOSFET
Variables Estimation and Control of a Power Source
E. Baghaz, N. K. M’Sirdi, K. Frifita, A. Naamane and M. Boussak
Aix Marseille Universit´e, CNRS, ENSAM, Universit´e de Toulon, LSIS UMR 7296, 13397, Marseille, France
LSIS UMR 7296 and HyRES Lab, RMEI, France
Keywords:
Electro-thermal Model, Boost DC/DC Converter, Power Source, SiC MOSFET Behavior, Estimation and
Control.
Abstract:
An electro-thermal model of a power SiC MOSFET is proposed. The thermal model, is coupled with the
physical model through the interaction between the transistor power loss and the junction temperature. For
validation of this model, the simulation curves are compared to the manufacturer’s experimental curves. As
first application, a boost DC/DC converter is considered. An observer is proposed to estimate the MOSFET
voltage V
DS
, the power and the junction temperature. These estimates are used to control the converter. The
proposed model and estimator give sufficiently good temperature and power estimation. The Power source
obtained using DC/DC converter is efficient, allowing the power loss reduction and robust.
1 INTRODUCTION
SiC MOSFET devices have a wide operation ranges
in voltage, current and temperatures, then the knowl-
edge of their characteristics and disposal of a good
model become necessary . As wide as is the model
validity domain, more and more high can be the con-
trol precision to achieve a high efficiency (Maxim and
Maxim, 1999; Pushpakaran et al., 2015). A simple
analytical PSpice model for SiCMOSFET have been
proposed for high power modules in (Johannesson
and Nawaz, 2016). In this paper we are interested
by the SiC MOSFET C2M0025120D CREE (1200V,
90A), when operating at very high frequencies.
The MOSFET device characteristics can be ex-
tracted from manufacturer’s experimental curves
(data sheets). Simulations are very important in elec-
tric systems design as well as for mechatronics case
study. Prototyping is necessary for the optimization
of power electronic circuits. To get realistic simula-
tions and accurate results, we need good and precise
models for an operating domain as wide as possible
(Leonardi et al., 1997).
The models proposed in the well known simu-
lation softwares like Psim, Pspice, LMS AMESIM,
Saber and other are often limited in their precision,
field of application or complexity. The most of them
are piece-wise linear. They are very, often valid
only in a restricted area and must be completed us-
ing the components Data Sheet. To get reliable re-
sults based on simulations, we need accurate models,
with acceptable precision.The precision of these mod-
els are very often limited to some operational points
or region. The devices may be, in some applica-
tions, used in very wide operation ranges (Bejoy et
al., 2015a)(Bejoy et al., 2015b).
In this paper, we propose an electro-thermal be-
havior model of a Silicon Carbide MOSFET (SiC).
The electrical behavior sub-model is based on the
well known EKV MOSFET Model (see (Enz et al.,
1987)). Then a thermal dissipation model, expressed
like Resistance-Capacitance (RC) Foster network, is
coupled to the electrical model. The lost power con-
tributes to the heating of the MOSFET internal junc-
tion. The heat transfer is described by a Foster elec-
trical equivalent network.
For validation of this model, the simulation curves
are compared to the manufacturer’s experimental data
(curves of data sheets).
The efficiency of the PhotoVoltaic (PV) system,
obtained using this DC/DC converter and the pro-
posed control, is robust against temperature varia-
tion. When Temperature varies from 25
◦
C to 150
◦
C,
the PV system efficiency is reduced globally by only
4%.The SiC MOSFET power loss is analyzed to re-
duce its effect on the PV source efficiency.
M’Sirdi, N., Baghaz, E., Frifita, K., Naamane, A. and Boussak, M.