Optimal Solar Array Configuration and DC Motor Field Parameters for Maximum Annual Output Mechanical Energy

This paper presents a method for the design of systems comprising photovoltaic generators directly supplying DC motors. It is based on maximizing the total annual gross mechanical energy delivered to a mechanical load with a given torque speed characteristic. Seasonal variations of the insolation level and the ambient temperature are taken into account. Using an optimization technique, it is possible to determine the array configuration, and accordingly the optimal motor voltage and current ratings, as well as the motor field parameter that yields the maximum output energy for a given annual radiation and ambient temperature variation curves. The proposed technique is applied to two practical case studies, and the resulting optimal design parameters are compared with those available in the literature. A comparison is also made between the optimal separately-excited and series motor design alternatives regarding the annual gross mechanical output energy.