A Hybrid Pv-wind Generator System Using a Maximum Power Point Tracking Technique

A hybrid renewable energy system is described which consists of twelve photovoltaic (PV) panels and a wind generator and can supply continuous electric power of 1.5 kW. An Energy Management System (EMS) was developed for this purpose in order to maximize the electric power produced using a maximum power point tracking (MPPT) method and consists of Buck-type DC/DC converters controlled by a microcontroller. The main difference between the method used in this system and other techniques used in the past is that the generated power controls directly the DC/DC converters, thus reducing the complexity of the system. The resulting system has high efficiency, lower cost and can be easily modified to handle more energy sources. Experimental results show that the use of the MPPT control method may increase the output power of the PV panels by as much as 15%. The energy produced by the renewable energy sources can be stored in lead-acid batteries for a stable supply of electric power. The system can be also connected to a diesel generator, in which case, it becomes 100% autonomous and can be used to supply power to a TV repeater or other applications in islands and remote places. 1. SYSTEM DESCRIPTION Renewable energy sources and among them photovoltaic (PV) panels and wind generators are widely used today in many applications. They are especially useful in islands and remote areas. They are maintenance and pollution free, but their initial cost is high and, in most applications, they require power DC/DC and/or DC/AC converters for load interface. Using high efficiency power converters which, in addition are designed to extract the maximum possible produced power, can reduce the overall system cost. This paper describes a renewable energy system that can supply 1.5 kW of power to a TV repeater and which was financed by the Region of Crete under the PEP programs for Crete (1994-1999). The system was developed and constructed at the Technical University of Crete (Electronics Laboratory) with the cooperation of the Technological Educational Institute of Crete, Chania branch (Dept. of Electronics). The system, whose block diagram is shown in Fig.1, consists of 12 photovoltaic (PV) panels, which can provide a total power of 900 W, and a wind generator that can produce a maximum power of 2200 W. Lamp Load State of Charge Control