Analysis of Hybrid PV-Fuel Cell System for Load Power Flow Control

Hybrid PV system has many advantages and thus find many applications due to increase in demand of renewable energy. Single renewable energy technology is less reliable and efficient due to intermittent nature of renewable energy source. Purpose of hybrid system is to reduce fluctuation in power supply, increase reliability and enhance the system performance and flexibility. In this paper a small-scale hybrid PV-fuel cell system is proposed for supplying constant power to a load. Variation in PV insolation level is simulated, which causes power generation to vary and this gets reflected as variation in DC bus bar voltage. This bus bar voltage is sensed by Fuel cell controller and power is drawn from fuel cell to compensate reduction in available power. This reduces power fluctuation at load. It can be seen that by maintaining constant bus bar voltage, not only power profile but voltage fluctuation across load is also improved. Power flow to load can be controlled by adjusting reference voltage. Efficiency of Fuel cell varies depending upon requirement of power drawn. Fuel cell operates in ohmic region and exhibit excellent operating performance. Overall fuel consumption of fuel cell is minimized as it is used to supply only deficit power as demanded by load when PV is not supplying rated power and thus it finds application in many small-scale critical applications.