PV system flyback converter controlled PI control to charge battery under variable temperature and irradiance

This paper proposes to Flyback converter sourced photovoltaic (PV) Panel is controlled by PI technology, under variable irradiance (800 W/m
²
to 1000 w/m
²
) and temperature (25 °C to 40 °C). The system was used to charge Lithium ion battery for PV panel applications. Voltage and power of PV panels are nonlinear they depend on environment conditions like irradiation and temperature. PV system can be thought as a DC (direct current) source so that one of the DC-DC converters, flyback converter, is used to regulate voltage and current of the PV panel. Flyback converters provide insulation between load and source also by adjustable turn ratio of transformer the load voltage can be regulated. PI control applied to switch (MOSFET) of flyback converter to regulate duty cycle of PWM (Pulse Width Modulation), to charge battery with constant voltage method. The maximum power point of PV module which used in this system, under STC (1000 W/m
²
and 25 °C), is around 50 W and the load power of the flyback converter in that condition is around 40 W. The efficiency of system under STC is around 80 %, but when irradiation level decreases to 800 W/m
²
and the temperature step up to 40 °C the efficiency of system increases (>95 %). The system was analyzed and constructed in Matlab/Simulink.