Design and Control of A Low Power DC-DC Converter fed by a Photovoltaic array

In this paper, we present a DC-DC converter fed by a PV array for stand alone applications up to 50 W. It is dedicated to rural areas in countries having abundant sunshine and where there is no grid connection to the utility network or the power supply is weak as in many underdeveloped countries. Using a single PV array of 50 W as typical power, the aim is to have a simple system, robust, free- maintenance and highly efficient. The design of the structure has led to a double boost for the DC-DC module (325 V as output voltage) where a high gain is needed ( the input rated voltage is approximately 17 V). Using simulation packages, we have extracted the required characteristics of the power components (switches and diodes) and set the switching frequency. The natural switching behavior of the boost converter is particularly adapted to the use of a sliding mode controller which has been studied. A linear controller based on a linearized model of the DC-DC converter has also been designed and tested. Both controllers have been implemented and the results in terms of dynamic and static performances, robustness and efficiency are promising.