TITLE:
Boost Chopper Behaviors in Solar Photovoltaic System
AUTHORS:
Sameer Khader, Abdel-Karim Daud
KEYWORDS:
DC-DC Converters, Photovoltaic Source, PWM, Buck-Boost, Boost Converters
JOURNAL NAME:
Smart Grid and Renewable Energy,
Vol.12 No.3,
March
31,
2021
ABSTRACT: This
paper investigates the behaviors of Boost DC Chopper used in Photovoltaic
energy systems where the solar irradiation changes during the day time causing
current and voltage changes. Varying the solar irradiation causes output
chopper voltage changes in order to keep working at maximum extracted solar
power. The chopper voltage changes leading to variable duty cycle operation of
chopper switch and causes a significant change in switch losses in terms of the dissipated power. In
addition to that the chopper behaviors are studied when the chopper voltage is
boosting up to a predetermined reference value leading to a significant
change in chopper current, voltage, duty cycle and occurred losses. A
mathematical model for chopper performances and switch losses is derived,
and a simulation model using Matlab/ Simulink platforms is conducted to follow
the chopper behaviors. Simulation results for concreteSUNPOWER panel type
SPR-315E-WHT-D with 315 Watts peak indicates that during the daylight time
transistors are exposed to complicated changes in their
current, voltage and dissipated power. Furthermore changing the output voltage
according to load requirements causes heavy stress on the transistor in terms
of current, oscillations and losses as well. Simulation results show that there
are optimized values of irradiation, chopper voltage and duty cycle where the
transistor losses are minimized. In addition to that, projecting the transistor
losses over the daylight time at a given irradiation
rate shows how these losses vary among the year, and the amount of energy
dissipated across the main chopper switch which is around 2970 Whr/yr for the present case. Furthermore, the conducted simulation also shows the
occurred in the transistor behaviors when solar irradiation changes, and can be
serving for further studies.