A PWM multiplier for maximum power point estimation of a solar panel

Abstract

A simple analog multiplier for the estimation of the power yield of a solar panel may be realized with a pulse width modulator working as analog multiplier circuit of the current yield and the duty cycle of the converter used to condition the panel. Though the output of the pulse width modulator multiplication is not exactly proportional to the output power of the solar panel, its maximum follows the maximum of the power curve of the panel. This multiplier allows a complete analog implementation of the maximum power point tracker of the panel keeping, at the same time, the simplicity needed in robust electronic systems. This paper presents the working principle of the maximum power point estimator for three different power conditioners of the solar panel: a step-down, a step-up and a SEPIC.