An Improved Feed Forward PWM Control for MPPT of Solar PV Systems Under Varying Atmospheric Conditions

Abstract

The objective of this paper is to harvest maximum power from the solar panel using voltage based MPPT circuit for low power application under varying atmospheric conditions.  A voltage based tracking system consisting of a voltage sensor, DC-DC boost converter, maximum power point tracker and a LED lighting load is designed and developed. The analog MPPT controller using direct feed forward PWM control signal for DC-DC converter operated in the continuous conduction mode is the principle block performing the tracking operation. Since the output of solar panel is nonlinear, the optimal power point will vary due to change in irradiance and temperature. Irrespective of the change in atmospheric conditions, the voltage sensor developed here has the ability to generate accurate reference voltage in accordance with the panel output and thereby maintains maximum power at the load. The experimental results have proved a power conversion efficiency of 95.46 % in clear sky condition, and (90.49 to 93.78) % in partial shading conditions resulting from the feed forward control technique employed in the MPPT circuit. The proposed tracking system is less complex and low cost one that has high tracking efficiency with less fluctuation in real time dynamic conditions. 

Keywords

• Boost converter; Feed forward; MPPT; Pulse width modulation (PWM); Power conversion efficiency

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