Mission profile-based assessment of photovoltaic system reliability for Indian climatic zones

ABSTRACT

Solar energy is expected to overtake wind energy as the leading renewable energy source by 2050, and therefore, accurate lifetime and reliability predictions for solar photovoltaic (PV) installations are necessary. The microinverter is a pivotal component of stand-alone PV power systems. The reliability of the microinverter depends on the mission profile of the geographical location, such as solar irradiance, ambient temperature, and wind velocity. This study developed a comprehensive reliability map for a 200Wp monocrystalline panel and a 250W microinverter based on mission profile data collected from 198 locations across India. A novel mathematical model is developed and validated using Ansys Icepak to evaluate the junction temperatures of microinverter components. The results show that the junction temperature significantly affects the reliability of PV system. In the hot and dry climatic zone of Jaisalmer, Rajasthan, the maximum MOSFET junction temperature and Mean Time Between Failure (MTBF) obtained were 63.14°C, and 27.34 years, respectively. Furthermore, in the cold and dry climatic zone of Leh, Ladakh, the junction temperature dropped to 29.74°C, increasing MOSFET’s MTBF to 49.8 years. These results prove that the reliability depends on the mission profile, and it should not be ignored in evaluating the reliability of solar PV systems.

KEYWORDS:

• Junction temperature
• microinverters
• mean time between failures
• PV system
• reliability
• solar energy

Acknowledgements

AK acknowledges the Center of Excellence for Electronic Cooling and CFD Sim Lab, SRM Institute of Science and Technology for the ANSYS Icepak simulation.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Nomenclature

f	=	frequency
t	=	time (ns)
AC	=	Alternating Current
C	=	Capacitor
D	=	Diode
DC	=	Direct Current
GW	=	Giga Watt
I	=	Current (A)
MOSFET	=	Metal-Oxide-Semiconductor Field-Effect Transistor
MPPT	=	Maximum Power Point Tracking
P	=	Power (W)
PCM	=	Part Count Method
PV	=	Photovoltaics
R	=	Resistance (Ω)
S	=	Switch
T	=	Temperature (oC)
TMY	=	Typical Meteorological Year
V	=	Voltage (V)
W	=	Watt
Greek Letters	=
$\pi$	=	Factor
$\lambda$	=	Failure rate
Subscripts	=
a	=	Ambient
c	=	Cell
ca	=	Capacitor
c-s	=	case to sink
f	=	Fall
in	=	Input
j	=	Junction
j-c	=	junction to case
o	=	Output
p	=	Peak
r	=	Rise
s	=	electrical stress
sw	=	Switching
s-a	=	sink to ambient
th	=	Thermal
A	=	Application
CL	=	conduction loss
DS	=	drain-source
E	=	Environment
GL	=	gate charge loss
Q	=	Quality
SL	=	switching loss
SR	=	Series resistance
V	=	voltage stress

Additional information

Notes on contributors

Anusuya K

Anusuya K earned a B.E. in Electrical and Electronics Engineering and an M.E. in Energy Engineering. Currently, she is a research scholar in the Department of Electrical and Electronics Engineering at the SRM Institute of Science and Technology, specializing in Photovoltaics (PV). Her work focuses on enhancing solar energy efficiency. She is a member of the International Solar Energy Society (ISES).

Vijayakumar K

Vijayakumar K received his B. E. and M. E. degrees from Annamalai University, Annamalai Nagar, India; and his Ph.D. degree from SRMIST (Formerly SRM University), Kattankulathur, India. He is presently working as a Professor and the Head of the Department of Electrical and Electronics Engineering of SRMIST (Formerly SRM University). His current research interests include power system modeling, power electronics converters for grid connected PV systems, computational intelligence applications in power systems, FACTS devices and power quality. He has been awarded a Best Teacher Award in his department for the academic years 2004 and 2006. He is a Member of various professional societies such as the IEEE, IET,FIE, ISTE and ISCA.