A simplified maximal power controller for terrestrial photovoltaic panel arrays

Perusal of the V-I characteristics of commercial solar panels with insolation, ambient temperature and production spreads as parameter, indicate that the maximum power is obtained from such a panel when it is loaded to a working voltage that is a fixed percentage of its open circuit voltage within (+2)%. This contribution describes a system that uses this characteristic to achieve maximum power control by determining the open circuit voltage and automatically loading the panel to the maximum power point as applied to a battery charging installation. The description includes the application of a novel modified darlington circuit to boost the efficiency of a pulse width controlled switch mode type regulator by reducing the darlington saturation voltage by a compensating voltage. Advanced switching technology is applied to reduce switching losses, and maximise efficiency.