Implementation of a MPT for a photovoltaic array using a digital signal processor

Photovoltaic power systems normally use a maximum power point tracker (MPT) to continuously deliver the highest possible power to the load when there are changes in insolation and temperature. Due to the MPT´s characteristics there is no longer a constant voltage available at the bus. If this load is a DC motor with a separately-excited field winding, the motor´s efficiency drops considerably unless operated at its rated values. To alter the motor´s efficiency, the only variable which can be altered is the field voltage by a buck-boost converter. An optimum field voltage is sought. This paper describes a drive system controlled by a 96002 digital signal processor to obtain the optimum efficiency for any input power level under complex conditions of changing terminal voltage which is itself a function of the field setting